Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43% Plus: How Ammonia, Glutamine, Arginine & Low Carb Could be Involved

Tired, exhausted, had to cut your workout short today? Is it the flu, or just too much BCAAs?

When some is good and more is better, even more is not necessarily going to be 'betterer' - and that's not simply due to the fact that there is no comparative to an adjective that's already in the comparative. Therefore it is actually not surprising that a team of researchers from the Department of Food and Experimental Nutrition at the Faculty of Pharmaceutical Sciences, the Department of Nutrition at the School of Public Health and the Department of Physiology and Biophysics at the Institute of Biomedical Sciences of the University of Sã o Paulo in Brazil has just published the results of a study (Falavigna. 2012) which demonstrates that there is an upper limit to the benefits of BCAA supplementation. What I guess will be surprising at least for some not so regular SuppVersity visitors, is that there is more than just a saturation effect: Too much BCAAs can actually have ergolytic (= anti-ergogenic) effects - at least under certain circumstances.

Another chapter in the book of good things that turn against you, when taken in excess

In their latest paper that has just been published in nutrients, Gina Falavigna and her colleagues analyzed effects of chronic BCAA supplementation on exercise performance in male Wistar rats. Based on previous animal and human data and the still widely supported, though actually experimentally non-validated (cf. Meeusen. 2007) theory that BCAAs would work their non-hypertrophy specific, endurance enhancing magic via the blockade of exercise induced 5-HT (serotonin) accumulation in the brain, the researchers speculated that ...

"[...] chronic BCAA supplementation (through the diet, using different BCAA  concentrations) would increase performance in rats subjected to a swimming exhaustion  test." (Falavigna. 2012)

To verify this hypothesis, Flavigna et al. randomized their rats to three different groups receiving either the standard AIN-93M diet for the maintenance of adult rodents (control group) or the same diet with additional additional 3.57% (group S1) and 4.76% (group S2) BCAAs at a ~2:1:1 ratio of lecine : valine : isoleucine (the BCAAs were manufactured by the Brazilian branch of Ajinomoto). The rodents in the S1 and S2 groups did thus receive 50% and 100% more branched-chain amino acids than the rodents in the control group which had to contend themselves with the BCAAs in the casein fraction of their diets (see figure 1, right). In order to assure that the diets would be isocaloric, an amount of starch equivalent to the amoung of BCCAs that had been added to the chow was removed from the supplemented diets.

Overall, the study lasted for six weeks. During this time the rodents were subjected to a 1h/day weight bearing swimming protocol five times a week. In the first two weeks, the rats were ...

"[...] adapted to the water medium and exercised with increasing overloads attached to the tail until an overload corresponding to 5% of total body weight was reached. This final overload was used until the end of the training protocol [...] The overloads were corrected weekly according to the variations in animal weight.  The efficiency of the training protocol was assessed on the basis of maximum activity of the enzyme citrate synthase in the soleus muscle, with a group of sedentary animals being used as the control for this parameter." (Falavigna. 2012)

Neither the overall amount of food nor the body weight gain of the rodents in the control, and the two exercise groups showed any statistically significant difference. The latter cannot be said about the exercise performance, as well as the accumulation of ammonia, though (see figure 1):

Figure 1: Exercise duration and plasma ammonia levels during / after swmming test (left) and macronutrient composition of the experimental diets (right; based on Falavigna.. 2012)

While the rodents in the +50% BCAA group (S1) do show the expected increase in endurance (+37%) their peers in the high dose (+100%) BCAA group (S2) experienced an even more pronounced drop in endurance performance (-43% vs. control), which went hand in hand with a profound increase in blood ammonia (+34%).

"Ammonia is a ubiquitous metabolic product producing multiple effects on physiological and biochemical systems. Its concentration in several body compartments is elevated during exercise, predominantly by the increased activity of the purine nucleotide cycle in skeletal muscle. Depending on the intensity and duration of exercise, muscle ammonia may be elevated to the extent that it leaks (diffuses) from muscle to blood, and thereby can be carried to other organs. The direction of movement of ammonia or the ammonium ion is dependent on concentration and pH gradients between tissues. As such, ammonia can also cross the blood-brain barrier, although the rate of diffusion of ammonia from blood to brain during exercise is unknown. It seems reasonable to assume that exhaustive exercise may induce a state of acute ammonia toxicity which, although transient and reversible relative to disease states, may be severe enough in critical regions of the central nervous system (CNS) to affect continuing coordinated activity. Regional differences in brain ammonia content, detoxification capacity, and specific sensitivity may account for the variability of precipitating factors and latency of response in CNS-mediated dysfunction arising from an exercise" stimulus, e.g., motor incoordination, ataxia and stupor. There have been numerous suggestions that elevated ammonia is associated with, or perhaps is responsible for, exercise fatigue, although evidence for this relies extensively on temporal relationships." (Falvigna. 2012; my emphasis)

Mark the last words of the previously cited paragraph: "[E]vidence for [the role of ammonia] in exercise fatigue relies extensively on temporal relationships". It is thus - as for now - a solely corollary, not yet a causative association, of which I do however feel that it would be very likely to turn into a causal one if someone actually measured the influx of ammonia into the brain during a workout.

Wait, ammonia? But ain't it more likely that the BCAAs block the uptake of tryptophan?

What's for sure is that another hypothesis, which relates to the blockade of tryptophan uptake can be ruled out as an underlying reason of the differences. After all the scientists who argue that ...

"[t]he increased synthesis of serotonin during exercise may be related to the development of central fatigue, because this neurotransmitter has several physiological functions, since it operates by  mood, lethargy, individual behavior, regulation of sleep, body temperature and blood  pressure, appetite suppression and changes in perceived exertion." (Falavigna. 2012)

...actually measured the 5-HT levels and observed no differences between the dietary groups. Overall, the study results to thus clearly indicate that both, medium nor high dose "chronic BCAA supplementation was not effective in improving the main parameters indicative of central fatigue" (Falavigna. 2012) - well, at least as long as we still stick to the hypothesis that the latter is induced by the accumulation of 5-HT in the brain.

Forget about tryptophan and serotonin, focus on ammonia

The fact that neither the high, nor medium dose of BCAAs did exert any effects on the serotonin levels in the brain does yet not explain why the medium dose supplementation regimen produced ergogenic, while the high dose regimen induced ergolytic effects.

The occurrence of direct toxic effects due to (too) high amounts of branched-chain amino acids can be ruled out based on previous studies in which the administration of more than 10g/kg body weight of BCAAs (the human equivalent would be 130g+ per day), as well as dosages of 2.5g/kg body weight chronically did not entail any toxic side effects (Shimomura.  2004). The same is true for other confounding variables, such as the citrate synthase activity, a measure of the general efficiency of the training protocol, bood glucose, insulin,free fatty acids, and lactate levels, as well as liver and muscle glycogen content, which were virtually identical in both groups. This leaves us with the increase in plasma ammonia as our 'last resort' to explain the -58% shorter swimming time in the high (S2) vs. medium (S1) dose BCAA group (-43% lower vs. non-supplemented control).

Figure 2: The reduced performance of the high BCAA group could well be related to peripheral and/or central ammonia build-up as a results of increased BCAA oxidation, camparably low glutamine intakes and the rate-limited enzymantic conversion and recycling of gluatmine (illustration originally from Earrante. 2003). Studies by Snow (2000) and Carvalho-Peixoto (2007) suggest: Both carbohydrate & glutamine supplements could help.

Based on what we know about the mammalian body, the increased build-up of ammonia in the high BCAA group could be a result of the unfortunate combination of temporary energy shortage and learned wastefulness' in a situation, where the otherwise sparse BCAAs are available in abundance. Furthermore, with a glutamine content of only 9-13% in the casein fraction of their diets (Swails. 1992), the rodents in the high BCAA group did ingest more than 2.6-3.8 times more BCAAs than glutamine; a fact which may have contributed to a temporary glutamine deficiency as a result of its increased use in the detoxification of the ammonia that's generated when the BCAAs are oxidized. The resulting peripheral and possibly central ammonia build-up (see figure 2) could then have begun to intoxicate liver and brains of the rodents and thus hampered gluconeogensis (normal levels stimulate, high levels of ammonia hamper gluconeogensis; cf. Fritz. 1988) and induced central fatigue (Wagenmakers. 1990; Nybo. 2004) -- and that not despite, but rather due to the chronic "high dose" BCAA supplementation (HED ~50g/day).

So do I have to drop my BCAAs now or what? Whether these results are relevant for you will probably depend on a whole host of parameters, which include

• the type, intensity and duration of exercise you do, 
• the ratio of BCAAs to glutamine in your diet,
• the amount of arginine, which acts as a substrate for the urea cycle and is therefore necessary to for the excretion of ammonia by the kindeys (Schaefer. 2002),
• the amount of carbohydrates in your diet (with more = less amino acid oxidation = lower ammonia and very low carb = you are in trouble; e.g. Czarnowski. 1995; Snow. 2000; Carvalho-Peixoto. 2007), 

... and those factors I will probably have forgotten to mention now. Unless you don't forget that you can neither lifve from BCCAs and protein alone, but accept the neflglected truth that too much protein is about as bad a too little protein, you can file this post under "show your stupid friends" and get back out, when they complain about feeling sick, bloated and fat "despite" eating a BCAA supplemented high protein, low carb (and often even low fat) diets.

References:

• Carvalho-Peixoto J, Alves RC, Cameron LC. Glutamine and carbohydrate supplements reduce ammonemia increase during endurance field exercise. Appl Physiol Nutr Metab. 2007 Dec;32(6):1186-90.
• Errante LD, Petroff OA. Acute effects of gabapentin and pregabalin on rat forebrain cellular GABA, glutamate, and glutamine concentrations. Seizure. 2003 Jul;12(5):300-6.
• Falavigna G, de Araú jo Junior JA, Rogero MM, de Oliveira Pires IS, rio Graç a Pedrosa R, Martins Junior E, Alves de Castro I, Tirapegui J. Effects of Diets Supplemented with Branched-Chain Amino Acids on the Performance and Fatigue Mechanisms of Rats Submitted to Prolonged Physical Exercise. Nutrients 2012. 4; 1767-1780.
• Fritz S, Bohnensack R. Stimulation of alanine metabolism in rat liver by ammonia. Biomed Biochim Acta. 1988;47(12):923-32.
• Meeusen R, Watson P. Amino acids and the brain: do they play a role in "central fatigue"? Int J Sport Nutr Exerc Metab. 2007 Aug;17 Suppl:S37-46.
• Nybo L, Dalsgaard MK, Steensberg A, Møller K, Secher NH. Cerebral ammonia uptake and accumulation during prolonged exercise in humans. J Physiol. 2005 Feb 15;563(Pt 1):285-90. Epub 2004 Dec 20. 
• Schaefer A, Piquard F, Geny B, Doutreleau S, Lampert E, Mettauer B, Lonsdorfer J. L-arginine reduces exercise-induced increase in plasma lactate and ammonia. Int J Sports Med. 2002 Aug;23(6):403-7.
• Shimomura, Y.; Murakami, T.; Nakai, N.; Nagasaki, M.; Harris, R.A. Exercise promotes BCAA catabolism:  Effects  of BCAA supplementation on skeletal muscle during exercise.  J. Nutr.  2004, 134, 1583S–1587S.
• Snow RJ, Carey MF, Stathis CG, Febbraio MA, Hargreaves M. Effect of carbohydrate ingestion on ammonia metabolism during exercise in humans. J Appl Physiol. 2000 May;88(5):1576-80.
• Swails WS, Bell SJ, Borlase BC, Forse RA, Blackburn GL. Glutamine content of whole proteins: implications for enteral formulas. Nutr Clin Pract. 1992 Apr;7(2):77-80.
• Wagenmakers AJ, Coakley JH, Edwards RH. Metabolism of branched-chain amino acids and ammonia during exercise: clues from McArdle's disease. Int J Sports Med. 1990 May;11 Suppl 2:S101-13.

The Neurotransmitter Depleting Effects of Branched Chain Amino Acids (BCAAs) and Their Potential Ergolytic, Anxiogenic & Depressive Downstream Effects

Oh yes, this will happen despite if not because you've taken large amounts of BCAA before the workout.

Usually you don't put the cart before the horse, but I guess you won't mind if I do so and postpone a summary of the information on magnesium from yesterday's installment of the Science Round-Up to tomorrow, when this means that we are going to take care of the "BCAA crisis" today.

Ok, maybe "crisis" is not the best word to describe the reverberations the recent publication of a study by SuJean Choi et al. should be having (=nobody buys BCAAs anymore), but I was looking for something better than the usual "the truth about..." Science, and I am not going to tire repeating that, is after all not about truth (that's what the confessional box is about), but about experimentally verifiable/verified and non-verifiable/non-verified hypothesis (Popper. 1994).

BCAAs can have ergolytic effects - A verifiable hypotheses?

Based on the observations Choi et al. made in by then decapitated lab animals (so much about the "why don't they prove this works in humans"-argument), the administration of a solution that contained either a BCAA + Arginine + Glutamine mix, or one out of two different EAA mixtures, it is safe to say that the hypothesis formulated in the subheading of this paragraph could belong to the former, i.e. the verifiable, hypothesis; and that despite the fact that the addition of glutamine and arginine to the human equivalent of 19:12:12 mg/kg body weight of leucine:isoleucine:valine (less than most BCAA products offer) would at least buffer the previously discussed performance decrements due to the accumulation of ammonia (learn more)

Table 1: Amino acid composition (mg/kg body weight) of the AA supplements tested (Choi. 2013)

In the end, the results Choi et al. present contradict both, the promises on the labels of the countless BCAA products and Newsholme's and Blomstrand's hypothesis that the inhibitory effect the BCAAs exert on the uptake of tryptophan from the blood into the brain and the way this forestalls the subsequent conversion of tryptophan to serotonin would lead to a reduction of central fatigue during exercise (Newsholme. 1996).

Figure 1: Effects of BCAA and BCAA + 100mg/kg l-tyrosine supplementation on serum and brain amino acid and neurotransmitter levels in sedentary rats; data expressed relative to vehicle (Choi. 2013)

Now, the data in figure 1 does confirm the first part of the Newsholme + Blomstrand hypothesis: The adminstration of BCAAs in an amount similar to many low dose BCAA supplements that are currently being marketed as ergogenic agents does blunt the increase in serotonin by competitively inhibiting the uptake of l-tryptophan from the bloodstream. The latter is a necessary consequence of the fact that both the BCAAs and the said 5-HTP (=serotonin) precursor are being transported by the same large amino acid transporter (think of it like a taxi that is allowed to pass the blood brain barrier) as l-tryptophan.

A note on the pro-obesity effects mentioned during the show: While some scientists invoke the increased BCAA levels in obese individuals and the subsequent blockade of serotonin (and dopamine) production in the brain to the constant insatiable cravings, anxiety and depression in these individuals (Breum. 2003; She. 2007; Coppola. 2013) a more fundemental contribution to the obesity pandemic has been proposed by Newgard et al. (2009). Their hypothesis is that a continuous presence of BCAAs in the blood will lead to a continuous overexpression of mTOR that increases the susceptibility to diet induced obesity and insulin resistance.

Now, it is also true that this will blunt the increase in 5-HTP synthesis in the brain (-48%; in the absence of exercise; see figure 1), but with the concomitant -25% decline in hypothalamic DOPA (=dopamine, the "get going neurotransmitter") in the brain after ~30min, the net ergogenic effect will, just as it was the case in the majority of pertinent rodent and human studies, be negligible, at best!

Modulatory Effects of Different Macronutrient & Stress Compositions on Serotonin (read more)

"Following oral intubation with the ‘‘BCAA’’ mixture to sedentary rats (see Table1; n=3/group), serum TRP and TYR concentrations showed non-significant reductions; the serum TRP and TYR ratios, and cortical TRP and TYR concentrations dropped markedly at 30 min. Cortical TRP and TYR concentrations remained low for the duration of the study (120 min), while the ratios began to recover at 90–120 min. DOPA and 5HTP synthesis dropped to nadir values at 60 min; DOPA synthesis remained low, while 5HTP synthesis had rebounded by 120 min (bottom panels, Fig.2).

Inasmuch as the maximal effects on DOPA and 5HTP synthesis occurred 60 min following intubation, all subsequent studies used 60 min as the experimental endpoint." (Choi. 2013)

In fact, the overall and as you've just read persistent drop in neurotransmitter levels can not only make you tired, previous research even suggests that it may be invoked in the etiology of depression / central fatigue (see previous SuppVersity post "Study Investigates Modulatory Effects of Different Macronutrient Compositions on Serotonin in the Presence and Absence of Stress" | read more).

Balancing leucine with tyrosine at a ~1:1 ratio helps

The data in figure 1 does however also tell you that you can mitigate the problem by the addition of 100mg/kg body weight of l-tyrosine to the supplement. With that being roughly equivalent to the amount of leucine in the BCAA formula (cf. table 1), this is yet far more of the dopamine precursor than your average BCAA product is going to have... after all it's a maximal leucine concentration that sells and is propagated as being "modern" and "maximal anabolic".

Figure 2: Hypthalamic DOPA and 5HTP levels after BCAA or BCAA + 100mg/kg tyrosine ingestion with / without exercise, left (Choi. 2013); effects of BCAA or l-tyrosine supplementation on time to exhaustion (Strüder. 1998)

With the addition of 100mg/kg l-tyrosine, you may yet in fact expect to see some benefits. Unfortunately, the currently available literature will put you right in a study that was conducted by Strüder et al. for example neither 21g of BCAAs nor the whopping dose of 20g of pure l-tyrosine resulted in the expected increase in the time-to-exhaustion during time trials in trained cyclists (see figure 2, right; Strüder. 1998) and Blomstrand concludes in his review for the British Journal of Sports Medicine's A-Z Supplement Review Series:

"Under certain conditions, BCAA supplementation can also improve physical performance, although the majority of studies have found no effect of BCAA on performance when supplied together with carbohydrates." (Blomstrand in Burke. 2009)

This, on the other hand, tells you that the performance enhancing effects are a mere result of the oxidation of BCAAs of which both Blomstrand, who is by the way defending his own hypothesis here, and the recently discussed by Falavigna et al. (see SuppVersity News) indicate that the ensuing increased release in ammonia production "may be detrimental to performance" (Blomstrand in Burke. 2009). If you also take into consideration that a study by van Hall et al. from 1995, i.e. before Newsholme & Blomstrand came up with the hypothesis the whole BCAA myth was built on, basically falsified the tryptophan hypothesis of fatigue, In the pertinent study the scientists were after all able to show that the provision of BCAAs as workout fuel is not superior to that of tryptophan and that despite a 8-12% reduction in brain tryptophan uptake at exhaustion with BCAAs and a 7- to 20-fold increase in response to the ingestion of a tryptophan supplement (van Hall. 1995).

Milk protein EAAs: An option, but a logical one?

If you finally take a look at the data in figure 3  you will notice that the head-to-head comparison would place an amino acid pattern as the one you can find in milk proteins, would probably be the best amino acid supplement source to resort to (don't ask me what exactly it is that makes the difference, I can't tell, but suspect it could be related to lysine which is also going to block the same small AA channel into the brain + the inclusion of non-essential amino acids in milk protein vs. pure EAAs).

Figure 3: Comparison of the the effects of BCAA, regular EAAs and an EAA amino acid mix from milk protein; composition of the mixtures see table 1 (Choi. 2013)

But let's be honest, does it really make sense to buy an additional supplement, when you already have a pouch of cheap and tasty whey and/or another fast digesting high BCAA protein such as pea protein lying around at home?

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So what's the verdict then? As you've heard on the Science Round-Up, yesterday, I personally think that this does not make sense, because ...

1. .

   

   Suggested Read: "Spiking Whey W/ EAA Will Provide Inferior Results" (read more)

   .. neither the total amount of amino acids that are obsorbed within 1h from free form EAAs, nor the the utilization speak in favor of EEAs - both have been shown to be +7% and +92% higher with slightly hydrolized whey vs. EAAs (Monchi. 1993),
2. ... nor is there any anabolic benefit to the addition of EAAs or leucine to whey, in fact "25 g of whey is better suited to increase resistance exercise-induced muscle anabolism" compared to lower amount of whey that has been pimped with additional EAAs and leucine to offer the same amount of the purpoted "anabolics" as the 25g dose of plain whey protein (click on the picture to the right to learn more; Churchward-Venne. 2012)

Contrary to Carl's jovial suggestion to simply throw away your BCAA supplements, I would suggest you keep them (unless you already have problems with anxiety, etc.), cut back on the dosage and monitor your response closely. The latter is especially true, when you take them on an empty stomach. After you've run out, train a month with nothing but cheap protein and decide afterwards whether or not your past "great training experience", "superior intensity" and whatever else the ads tell you the respective products will do was more than just another instance of the brocebo effect (learn more about brocebos).

References:

• Breum L, Rasmussen MH, Hilsted J, Fernstrom JD. Twenty-four-hour plasma tryptophan concentrations and ratios are below normal in obese subjects and are not normalized by substantial weight reduction. Am J Clin Nutr. 2003 May;77(5):1112-8. 
• Burke LM, Castell LM, Stear SJ, Rogers PJ, Blomstrand E, Gurr S, Mitchell N, Stephens FB, Greenhaff PL. BJSM reviews: A-Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance Part 4. Br J Sports Med. 2009 Dec;43(14):1088-90.
• Choi S, Disilvio B, Fernstrom MH, Fernstrom JD. Oral branched-chain amino acid supplements that reduce brain serotonin during exercise in rats also lower brain catecholamines. Amino Acids. 2013 Aug 1. [Epub ahead of print] 
• Coppola A, Wenner BR, Ilkayeva O, Stevens RD, Maggioni M, Slotkin TA, Levin ED, Newgard CB. Branched-chain amino acids alter neurobehavioral function in rats. Am J Physiol Endocrinol Metab. 2013 Feb 15;304(4):E405-13.
  
• Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012 Jun 1;590(Pt 11):2751-65.
• Monchi M, Rérat AA. Comparison of net protein utilization of milk protein mild enzymatic hydrolysates and free amino acid mixtures with a close pattern in the rat. JPEN J Parenter Enteral Nutr. 1993 Jul-Aug;17(4):355-63. 
• Newgard CB, An J, Bain JR, Muehlbauer MJ, Stevens RD, Lien LF, Haqq AM, Shah SH, Arlotto M, Slentz CA, Rochon J, Gallup D, Ilkayeva O, Wenner BR, Yancy WS Jr, Eisenson H, Musante G, Surwit RS, Millington DS, Butler MD, Svetkey LP. A branched-chain amino acid-related metabolic signature that differentiates obese and lean humans and contributes to insulin resistance. Cell Metab. 2009 Apr;9(4):311-26.
• Newsholme EA, Blomstrand E. The plasma level of some amino acids and physical and mental fatigue. Experientia. 1996 May 15;52(5):413-5. Review.
• Popper, KR. Zwei Bedeutungen von Falsifizierbarkeit [Two meanings of falsifiability]. In Seiffert, H.; Radnitzky, G. Handlexikon der Wissenschaftstheorie. München: Deutscher Taschenbuch Verlag. 1994.  
• She P, Van Horn C, Reid T, Hutson SM, Cooney RN, Lynch CJ. Obesity-related elevations in plasma leucine are associated with alterations in enzymes involved in branched-chain amino acid metabolism. Am J Physiol Endocrinol Metab. 2007 Dec;293(6):E1552-63. Epub 2007 Oct 9.
• Strüder HK, Hollmann W, Platen P, Donike M, Gotzmann A, Weber K. Influence of paroxetine, branched-chain amino acids and tyrosine on neuroendocrine system responses and fatigue in humans. Horm Metab Res. 1998 Apr;30(4):188-94.  
• van Hall G, Raaymakers JS, Saris WH, Wagenmakers AJ. Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance. J Physiol. 1995 Aug 1;486 ( Pt 3):789-94.

Capsaicin - 2.56mg to Keep Your Metabolism Running on a Diet. Cold Thermogenesis - 5°C for 6kcal/h. Mobile Phones - 0.853 W/kg Pulsed EMR to Mess Up Neurotransmitters

You don't have to worry, the "guidelines" do not require you to perform either your 150 minutes of moderate cardio, or your 75 minutes of vigorous-intensity aerobic activity, and not even your two weekly full-body workouts in these shorts.

24% that's the SuppVersity Figure of the Week and it is actually not so low as I would have expected it to be, after all those 24% describe the ratio of US adults who meet the Physical Activity Guidelines for muscle-strengthening physical activity. Which guideline? Ah, you are the US guys and gals, so you should know that you are advised to

"perform muscle-strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week, because these activities provide additional health benefit" (2008 Physical Activity Guidelines for Americans)

Additional benefit? Well, it goes without saying that the 150 minutes of moderate aerobic training and the reduction of salt, as well as the use of healthy vegetable oils are the primary object for every 'true American'.

Not That Hot: Cold Thermogenesis

Figure 1: An avg. effect size of 6kcal/h, non-responders + "negative-responders"; it doesn't work for those past the 30y mark - how on earth is cold thermogenesis going to help us solve the obesity pandemic?

(Chen. 2013) In a single-blind, randomized crossover intervention 24 volunteers (14 men, 10 women) were exposed to a 5°C temperature reduction (from 24°C to 19°C). During that treatment they wre sitting in a whole-room indirect calorimeter to measure their energy expenditure and lay in a positron emission tomography (PET) scanner afterwards (results, see image to the right).

Now, based on previous SuppVersity articles on the matter, you'll know that it is not exactly easy to find people who actually harbor a "significant" (and in this case this means "any at all") amount of metabolically active brown adipose tissue to get the thermogenesis going.

And with 23cm³ and 35cm³ for the men and women participating in the study at hand, the amount of the "good fat" they were carrying around is still pretty stingy. No wonder ...

• there was no thermogenic response in the male participants, but a
• 10% increase in energy expenditure in the female participants

I already see your eyes glow in the cold, ladies, but you crow too soon - those 10% were 6kcal/h, I repeat in full words "six additional calories per hour". Or roughly as much energy as a single set of body weight squats would be burning .

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If you are looking to shed 18% fat in 21 days, increase your health and your physical appearance, turn up the heat during your workouts, clean up your diet and don't move into the fridge (learn more)!

Bottom line: Against the background that there were neither significant changes in the hormonal profile (thyroid, adrenal, etc.) and considering the fact that the effect declined with age and was hardly measurable for 5 and negative (=lower energy expenditure in the cold) for 4 subjects, I stick to previous assessment: cold thermogenesis as a means of "expending more energy to get rid", is about as stupid as the whole concept of expending more energy to lose fat and it certainly does not, as the scientists state "represent a novel environmental strategy in obesity treatment".

If you want a "environmental strategy in obesity treatment", ban all the junkfood, switch off the elevators, hand out bikes and increase the health insurance cost for everyone who refuses to get his or her ass off the couch on a regular bases. Zealous? Unrealistic? Yeah, it is - but not more unrealistic than the hilarious notion that cooling the overweight majority of the inhabitants of the Western Obesity Belt down by 5°C would solve the obesity problem.

Mobile phones mess with neurotransmitter levels

Andreassen et al. have already developed a "Facebook Addiction Scale" and found that Facebook junkies tend to be

neurotic and extraverted, but lack a reasonable amount of conscientiousness (Andreassen. 2012)

(Aboul Ezz. 2013) I am well aware that many of you don't want to hear this and will discard the results researchers from the Cairo University present in their latest paper in the European Review forMedical and Pharmacological Sciences as "just another worthless rodent study" and I freely admit, you may be right.

It is well possible that rodents are more susceptible to the pulsed electromagnetic radiation from mobile phones than humans are, but I gather you will have to agree that the chance that there are still residual effects in human beings is by no means zero... and based on my personal observations, I would even argue that you see certain abnormalities in mobile phone junkies, already. Ok, those could have psychological and behavioral roots, but ...

Before I digress even further into the abyss of the "I cannot live without my mobile" virus that has already befallen many of my real world students, let's rather take a look at the outcome of Aboul Ezz et al.'s latest experiment.

Table 1: While the first six are actually the TOP (=low SAR) phones that are currently on the market, the others are random picks of mine from the data on SARdatabase.com

In the course of the latter, the scientists exposed a group of adult rats to the pulsed electromagnetic radiation of a mobile phone having a power density of 0.02W/cm² and an average specific absorption rate (the notorious SAR-value) of 0.843W/kg for 1h/day (that happens to be a little less of what your neat iPhone5 is pumping into your brain day in and day out) and measured the monoamine levels after one, two and four months, as well as on a follow-up one month after the last exposure and found:

The exposure to EMR resulted in significant changes in DA [dopamine], NE [norepenephrine] and 5-HT [serotinine levels] in the four selected areas of adult rat brain" (Aboul Ezz. 2013)

And the Egyptian researchers add, these chance could well explain the adverse effects that have been reported in conjunction with chronic "low level" exposure to pulsed electromagnetic radiation, which are usually related to memory problems and chronic stress.

What they don't mention in the abstract though is that the changes were not really consistent. It appeared as if there was some cyclicity involved with an initial increase in 5HT, a concomittant decrease in dopamine a newly established "balance" between the two leading to an increase in norepinephrine (=chronic stress) in months four.

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Bottom line: That being said, I can only repeat that even in the absence of direct physiological effects of the EMR exposure, the constant state of "being available" to whoever wants to reach you, as well as the addictive potential of being in contact with all your (often fake) facebook friends alone should be reason enough to re-evaluate your own mobile phone use.

Capsaicin keeps fatty acid oxidation & total energy expenditure up, when you're dieting

No this is not Liza Oz after taking Mehmet's beloved RK supplements - and it is not one of the subjects from the "Kitchen Sink Approach to Fat Loss study"... although, who knows? (learn more about that study)

(Janssens. 2013) Right from the Department of Human Biology, School for Nutrition, Toxicology and Metabolism (NUTRIM) at the Maastricht University in The Netherlands comes a new study that confirms that capsaicin a long-touted "fat burner" and anti-obesity agent  that's also turning up your heat, when you consume hot peppers, will maintain your energy balance and fatty oxidation rates in the normal zone, when you are dieting.

The 15 healthy Caucasian subjects underwent four 36 h sessions in a respiration chamber, which allowed the scientists to accurately measure their energy expenditure, the ratio of glucose / fat oxidation and blood pressure after receiving a dose of 2.56mg (1.03g of red chili pepper worth 39,050 Scoville heat units (SHU)) with every meal.

Now, this wouldn’t be something we have not seen in previous studies, already. With the study at hand, however, the capsaicin intake, was not the only controlled variable. In addition to simply checking what happens, when you consume one serving of capsaicin with each meal, the scientists also assessed the influence of the baseline energy intake of the subjects, with them being randomly assigned to receive adequate amounts of energy (= 100% of the daily energy requirements), or a calorically reduced diet (=75% of the daily energy requirements) during the tests.
 
The first noteworthy observation the scientists made is the adaptiation induced amelioration of the energy deficit. Contrary to what the simply calories in vs. calories out equation would suggest, the participants who received 25% less energy than they would need ended up having an effective energy deficit of only 20.5% - in other words, the missing 4.5% were simply conserved by the dreaded metabolic downregulation that’s one of the most important reasons for weight loss plateaus.

Figure 2: Changes in energy expenditure at rest, during sleep in response to food intake and activity, as well as substrate oxidation in 15 healthy Caucasian subjects (seven women, eight men) during the supplemented (CAP) and non-supplemented (PLA) energy sufficient (100) and restricted (75) conditions (Janssens. 2013).

Now this is where the capsaicin comes into play, as the results of the study at hand clearly demonstrate, the additional provision of 2.56 mg of the hot spice with every meal can negate the reduction in diet-induced thermogenesis and restore the lowered sleeping metabolic rate the 25% caloric reduction has brought about.

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Suggested read for those looking to stacking different ingredients to propel their weight loss efforts: "Forgotten Dieting Aids: Choline, Carnitine, Caffeine and the Anti-Weight-Loss Plateau Effects of Sugar and Phosphates" (read more)

Bottom line: In view of the fact that the capsaicin supplement also increased the fat oxidation during both the calorically reduced and the normal dieting conditions, it may in fact be that we've hot a pretty "hot" fat burner here... unfortunately, just with any other "fat burner", you still got to give your body the chance to actually burn the fat. Without sweat and a slightly reduced energy intake (25% does by the way make a good rule of thumb) this is yet not going to work.

Moreover, it is also questionable, whether the effects will be that noticeable after 1-2 weeks of chronic usage. I'd bet money they will either disappear completely or be drastically reduced, but that would be the topic for another study ;-)

All that's left are... *drumrolls* the Facebook news and an awesome weekend!

You know what's coming now, right? Correct, first I will enumerate a couple of Facebook News you may or may not have seen on the SuppVersity Timline (ha! I did not write "wall", am I now going to be rewarded, Mark Zuckerberg?)

• SuppVersity Highly Suggested Read - Part II of Sean Casey's summary of the ISSN conference | read more...
• Science for Science Sake - In the current scientific environment many scientists turn to biased reporting, intrinsically flawed study design & the like to produce "break through" results that are at best irrelevant, in the worst case threaten the live of participants in follow up studies | learn more... 
• Moderate Drinking Probably Lacks Life-Extending Effects - Sociologists argue: The lifestyle and not the booze of moderate drinkers is what prolongs their lives | learn more...
• Barefoot Running is Good for Your Knees: Take your shoes off to reduce patellofemoral joint stress during running | read more ...
• Can Supplements Precipitate Headaches? At least in a recent study from China the researchers observed correlations between isoflavone-supps in men and B-complex, vitamin C and green algae supplements in women | read more...

And afterwards I am telling you to have a nice weekend and reminding you of the fact that Sunday is no "off day" here at the SuppVersity ... although, for many of you it appears to be, which is why I am actually thinking about dropping the Sunday posts completely. Whatever... enjoy your weekend!

References:

• Aboul Ezz HS, Khadrawy YA, Ahmed NA, Radwan NM, El Bakry MM. The effect of pulsed electromagnetic radiation from mobile phone on the levels of monoamine neurotransmitters in four different areas of rat brain. Eur Rev Med Pharmacol Sci. 2013 Jul;17(13):1782-8.
• Andreassen CS, Torsheim T, Brunborg GS, Pallesen S. Development of a Facebook
  Addiction Scale. Psychol Rep. 2012 Apr;110(2):501-17.
• Chen KY, Brychta RJ, Linderman JD, Smith S, Courville A, Dieckmann W, Herscovitch P, Millo CM, Remaley A, Lee P, Celi FS. Brown fat activation mediates cold-induced thermogenesis in adult humans in response to a mild decrease in ambient temperature. J Clin Endocrinol Metab. 2013 Jul;98(7):E1218-23. 
• Janssens PL, Hursel R, Martens EA, Westerterp-Plantenga MS. Acute effects of capsaicin on energy expenditure and fat oxidation in negative energy balance. PLoS One. 2013 Jul 2;8(7):e67786.
   

Sunlight, L-Tryptophan & Vitamin B6 With Breakfast Increase Serotonin and Wakefulness During the Day and Melatonin and Restful Sleep at Night

Image 1: For these kids the high tryptophan + B6 breakfast would be useless unless they already got their 10min+ of direct sun exposure this morning

A recently published study that was conducted by a team of international researchers led by Miyo Nakade from the Gakuen University in Nagoya, Japan (Nakade. 2012), concludes that sunlight exposure and vitamin B6 and l-tryptophan intake with breakfast could be profound modulators of circadian rhytmicity in young children (N=816, age = 2-6 years). The results the researchers published in the latest issue of the Journal of Physiological Anthropology clearly suggest that the increased production of serotonin from l-tryptophan and the vitamin B6 metabolite pyridoxal 5’-phosphate (also known as PLP or p5p) exerts beneficial effects on the morningness-eveningness (M-E) score - a measure for the natural and highly desirable difference in wakefulness in the morning and sleepiness in the evening, the disturbance of which is among the emerging correlates of metabolic diseases, such as diabetes, obesity and abnormal lipid metabolism.

[C]hildren showed a tendency to be more morning-typed if they ate breakfast with
a high estimated Trp content. This study also confirmed a similar trend with estimated Vi-B6
content. Among essential amino acids, the Trp content in food is quite small, and thus it is
necessary to make a special effort to consume a sufficient amount in one’s diet.

That those foods with specifically high tryptophan content are, as so often, eggs, meats, and fish is something I probably don't have to tell you - just as I don't have to tell you that soybeans, and other soy products, which also contain significant amounts of tryptophan should not constitute a major part of your diet; regardless of whether you are a man or a woman.

Sunlight must not be hidden behind curtains or seen just through the windows your car

Interestingly, all the vitamin B6 and tryptophan in the world appears to be of little use, if you get too little sun-exposure (Rosenthal. 1997). And, now listen up!, they can become disturbed when you sleep with black out curtains and use an alarm clock to wake you up (Harada. 2003) - in how far these effects are mitigated, or even reversed (i.e. using black-out curtains = beneficial) in people who would otherwise be constantly exposed to unnatural light-exposure (e.g. a street lantern right before your window) would require further investigation, though.

Figure 1: Distribution of early birds (low M-E score on the x-axes) and late risers (high M-E score) among the study population (data calculated based on Nakade. 2012).

Anyways, as you can see in figure 1 the effect of the curtains was statistically significant, but not as pronounced as the scientists' emphasis in their report would have it. There are tendencies for more morning types (lower M-E scores) in the children sleeping without blackout curtains, yes. And there are no real evening types in the children sleeping without blackout curtains, but the broad majority falls into the same 18-23 M-E score range on the 7-28 early bird to long sleeper scale Nakade et al. employed.

Vitamin B6 and inflammation: Although this is only indirectly related to the topic of circadian rythmicity and wake-sleep patterns, it is quite intriguing that vitamin B6 is still touted as an anti-inflammatory agent. And though even very recent population based studies confirm that there is in fact an inverse relation of low plasma vitamin B6 and its active metabolite pyridoxal-5-phosphate (PLP) are inversely associated with the "overall inflammation" score in the US population (Sakakeeny. 2012), another recent study by Ulvik et al. clearly suggests that these associations are corollary, at best (Ulvik. 2012). In their trial, the results of which have been published in the May issue of the American Journal of Clinical Nutrition, Ulvik et al. administered 40 mg pyridoxine hydrochloride per day to patients with stable angina pectoris. Contrary to their expectations, this practice did neither replete the low vitamin B6 levels, nor sooth the inflammation. On the contrary, the rapidly metabolized vitamin B6 appeared to preserve or even increased the expression of inflammatory markers.

What's good in the morning won't hurt at night

With tryptophan being a serotonine precursor and vitamin B6 a necessary co-factor in its synthesis, it may come as a surprise that both, and the sunlight induced serotonin synthesis boost can boost "morningness" and make you more alert. After all, you will probably have read on the label of various dietary supplements that tryptophan is supposed to make you sleepy, right? What those labels don't tell you is that the exposure to sunlight and not the shear availability of precursors and co-factors, let alone the position of the hands on your clock modulate its destiny. And determine whether the tryptophan will get you going, as it obviously does in the children with the highest breakfast intake of tryptophan and vitamin B6 (cf. figure 2), or helps you fall and stay asleep at night.

Figure 2: M-E index relative to group mean in high / low tryptophan & vitamin B6 breakfast intake groups (data calculated based on Nakade. 2012)

That both is possible and obviously works quite fine, is thus the main message of this study, the results of which Nakade et al. interpret as direct evidence for the potential usefulness of

[...] a higher Trp and Vi-B6 intake [to] promote the synthesis of serotonin via light stimulation in the morning and have a natural sleep-inducing effect when converted to melatonin at night [and thus] help prevent a phase delay in young children’s circadian clocks and promote their morningness against the effects of the 24-h commercialization of society.

Against the background, that similar improvements have been observed in 35 middle-aged/elderly (aged 55-75 year) volunteers who consumed a tryptophan enriched  (+30mg per serving) cereal at breakfast and dinner for three weeks by Bravo et al. (Bravo. 2012). And since there is no effect without "side effects", I guess I better mention that the Spanish researchers also observed significant increases in

Table 1: Tryptophan content of various foods (in g per 100g, 2nd column), ordered by tryptophan per protein content (3rd column; data based on Wikipedia)

• sleeping time,
• sleep efficiency, and
• immobile time

as well as concomitant decreases in

• sleep latency (almost 25%!),
• wake bouts,
• total activity, and
• sleep fragmentation index

If you take into consideration that their subjects' total antioxidant capacity levels and mood improved, as well and that the treatment elicited a -50% decrease in state anxiety and a significant drop on Beck's Depression Inventory Index, both of which returned to their initial value, when the treatment was seized, it should be obvious that you better make get out in the sun, immediately after you made the right food choices (and no, I am not talking about tryptophan-enriched breakfast cerals, here) at breakfast and watch the sunset after dinner ;-)

References:

1. Bravo R, Matito S, Cubero J, Paredes SD, Franco L, Rivero M, Rodríguez AB, Barriga C. Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans. Age (Dordr). 2012 May 24.
2. Harada T, Matsumura A, Takeuchi H: Effects of the usage of a blacked-out curtain on the sleep-wake rhythm of Japanese University students. Sleep Biol Rhythms 2003, 1:179–181
3. Nakade M, Takeuchi H, Taniwaki N, Noji T, Harada T. An integrated effect of protein intake at breakfast and morning exposure to sunlight on the circadian typology in Japanese infants aged 2-6 years. J Physiol Anthropol. 2009 Sep;28(5):239-45. 
4. Nakade M, et al. Can breakfast Tryptophan and Vitamin B6 intake and morning exposure to
   sunlight promote morning-typology in young children aged 2-6 years? Journal of Physiological Anthropology 2012, 31:11
5. Sakakeeny L, Roubenoff R, Obin M, Fontes JD, Benjamin EJ, Bujanover Y, Jacques  PF, Selhub J. Plasma Pyridoxal-5-Phosphate Is Inversely Associated with Systemic Markers of Inflammation in a Population of U.S. Adults. J Nutr. 2012 May 23.
6. Rosenthal N, Schwartz P, Tumer E, Nalm S, Matthews J, Hardin T, Barnett R, Wehr T:
   The psychobiology of SAD and the mechanism of action of light therapy. Biol Psychiatry
   1997, 42:57S.
7. Ulvik A, Midttun O, Ringdal Pedersen E, Nygård O, Ueland PM. Association of plasma B-6 vitamers with systemic markers of inflammation before and after pyridoxine treatment in patients with stable angina pectoris. Am J Clin Nutr. 2012 May;95(5):1072-8. 
8. Wikipedia contributors. Tryptophan. Wikipedia, The Free Encyclopedia; 2012 May 26, 00:42 UTC [cited 2012 May 27]

L-Tryptophan is Reduced While Dieting - Does This Make the Essential Amino Acid a Key to Succesfull Weight Loss?

Trp and it's metabolite 5-HTP may be particularly useful for female sugar cravings and binges.

Can l-tryptophan help you lose body fat? If you look at the results of the latest study from the University for Health Sciences, Medical Informatics and Technology it would seem that the answer to this question may be "Possibly, yes, but..." Before we come to the implications I would yet like to take a closer look at said study which shows that a lack of tryptophan (Trp) during diets does not just affect the biosynthesis of serotonin, but may also be associated with increased susceptibility for mood disturbances and carbohydrate craving. Accordingly, "strategies to supplement Trp while dieting could be highly useful in treating uncontrolled weight gain or in preventing neuropsychiatric symptoms" (Strasser. 2014).

Honestly, fasting and eating / skipping breakfast may be more promising weight loss tools

Breakfast and Circadian Rhythm

Does Meal Timing Matter?

Breakfast & Glucose Metab.

Breaking the Fast, Cardio & the Brain

Does the Break- Fast-Myth Break?

Fasting = Muscle- Loss - Always?

As Strasser et al. point out, both overweight and obesity go hand in hand with significant increases in low-grade inflammation. The latter is not just the reason that obesity increases the risk of cardiovascular disease, though. Recent evidence suggests that it is also associated with errors in the kynurenine (Kyn) pathway, in which tryptophan is broken down to kynurenine which in turn has been associated with increased risk of depressive symptoms, cognitive deficits in schizophrenia, Alzheimer's and, as mentioned before, cardiovascular disease. Weight loss, on the other hand,

"[...] has been shown to improve or prevent many of the aforementioned conditions. Bariatric surgical intervention in patients with adiposity was found not to improve tryptophan breakdown rates and other signs of immune activation and inflammation [4], whereas caloric restriction is known to be a strong activator of protective metabolic pathways, thereby leading to lower blood pressure, improved blood lipids, and reduced inflammatory markers, including CRP [9]. Still, little is known about the effects of an extreme short-term hypocaloric diet on Trp metabolism and changes in inflammatory biomarkers" (Strasser. 2014).

The study Barbara Strasser, Ken Berger and Dietmar Fuchs conducted was thus designed to assess the effect of a 2-week caloric restriction weight loss diet on Trp breakdown, leptin, and inflammatory biomarkers in over weight adults.

Taking tons of BCAAs can deplete your brain Trp and serotonin and leave you tired and depressed.

Beware of your beloved BCAAs,  Trp competes with the other large neutral amino acids (LNAA), namely valine, leucine, isoleucine, Tyr, and Phe for transport across the blood–brain barrier. In fact, scientists use large boluses of BCAAs to practically deplete tryptophan and thus reduce serotonin (Fernstrom. 2005). If you want to learn more about this unwanted side effects of BCAA, I'd suggest you take another look at my article "The Neurotransmitter Depleting Effects of Branched Chain Amino Acids (BCAAs) and Their Potential Ergolytic, Anxiogenic & Depressive Downstream Effects" | read more.

The scientists randomized 27 overweight and 11 obese participants (22 men and 16 women, mean age 52.8 ± 9.1 years) from the health center Lanserhof, Innsbruck–Lans, into two diet groups:

• a very low kcal diet group (VLCD; Ø 600 kcal/ day) and 
• a low kcal diet group (LCD; Ø 1,200 kcal/day). 

Only healthy subjects with BMI [25 kg/m²] between the ages of 35 and 70 years were accepted for the study. A physician performed physical examinations on all subjects before the study. Subjects were excluded if they consume any anti-inflammatory drugs (e.g., ibuprofen or aspirin) or supplements (such as antioxidants or fish-oil capsules). None from either group was involved in regular training programs.

Figure 1: Changes in body composition pre- vs. post (Strasser. 2015).

As the measurements of body composition, which were just like the energy intake and biologic markers conducted in all subjects before and after the 2-week energy restriction intervention period, indicate, both diets lead to significant reductions in body mass - and that almost exclusively in form of body fat.

Table 1: Biologic markers before and after a 2-week very low kcal diet (VLCD) or low kcal die (LCD) in 38 overweight subjects (mean ± SD)

"Data for biologic markers are shown in Table [1]. Fasting blood glucose declined significantly (P < 0.05) in the LCD group with no significant changes in insulin sensitivity in both groups after 2 weeks of caloric restriction. Weight loss diet lowered leptin levels in both groups, although not reaching the level of significance. Inflammatory biomarkers were not significantly altered during the trial, although there was a tendency toward an increase in IL-6 and TNF-a in the LCD group" (Strasser. 2015).

In contrast to what the researchers expected, both the Trp and Kyn concentrations decreased significantly by 21 and 16 % for VLCD and by 15 and 17 % for the LCD group, respectively, with no significant difference between groups. Practically speaking, this means that the ratio of Kyn/Trp concentrations did not change significantly in both groups.

Adding 900mg 5-HTP to the diet of obese women helps them to reduce their energy intake significantly (Cangiano. 1992).

5-HTP the better choice? While it makes sense to keep an eye on the Trp:LNAA ratio in your diet, it is questionable, whether supplementing with Trp on top of a Trp-sufficient diet will have significant beneficial effects. In this respect, 5-hydroxytryptophan aka 5-HTP a direct serotonin precursor appears to be the more promising supplement. Taken in dosages of 400-1,000mg/day it has been shown to (a) reduce food intake (up to 18% more than placebo in a 1989 study w/ obese women | Ceci. 1989), (b) increase weight loss in 12-week study with obese women (Cangiano. 1992) and (c) reduced the food and specifically carbohydrate intake in both male and female type II diabetics (Cangiano. 1998).

A significant reduction in Phe concentrations was only seen after VLCD. Neopterin and Tyr levels remained unchanged during the trial. Which leaves us with only one significant finding:

"Trp concentrations decreased significantly with a caloric restriction weight loss diet, and lowest Trp concentrations were observed in the group of individuals with the lowest calorie intake." (Strasser. 2015)

This reduction in Trp levels may well induce a disturbance in the biosynthesis of neurotransmitter 5-hydroxytryptamine (5-HT | Anderson. 1990), and appears to be associated with an increased susceptibility for depression (Widnet. 2002; Raison. 2009). Strasser et al. highlight:

Figure 2: The consumption of tryptophan-free amino acid supplements leads to highly significant increases in hunger ratings in healthy female subjects (Rieber. 2010).

"Because Trp is precursor in various biochemical pathways, e.g., it is hydroxylated by tryptophan-5-hydroxylase (T5H) into the intermediate product 5-hydroxy-tryptophan, which by decarboxylation is further converted to neurotransmitter 5-HT (serotonin), and because substrate saturation of T5H is only about 50 % (Dantzer. 2011), changes in plasma Trp levels may have an immediate impact on brain serotonin levels" (Strasser. 2014).

Experiments in which Trp was acutely depleted (in many studies by administering BCAAs | see red boy) support this assumption. Young et al. (2013), for example, confirmed that the acute depletion of tryptophan will lead to low serotonin and subsequently lower mood and increased aggression, although results vary somewhat between studies with similar participants.

Figure 3: Correlations between changes in tryp:LNAA ratio and appetite ratings (Gendall. 2000).

For the link to obesity, though, the correlation (r-values in Figure 3) between high Trp:LNAA (BCAAs, tyrosine, phenlylanine) and a reduction carbohydrate cravings, general hunger and binge eating is yet way more important - and that specifically for women, who appear more vulnerable than men both to the diet-induced reductions in Trp and to its consequences for brain serotonin function (Anderson. 1990).

Ah, and in case you are asking yourself why carbohydrate / sugar binges are a common consequence of low tryptophane:LNAA ratios, it's important to know that increases in glucose and insulin in response to high carbohydrate meals will trigger an increase in brain tryptophan and serotonin synthesis (Benton. 2002). This is why the effects of low tryptophan or high LNAA (BCAA, tyrosine, phenylalanine) levels are more pronounced if you avoid dietary carbohydrates.

There is evidence of direct effects of serotonine on metabolic rate, but there is no evidence that the administration of Trp will induce similar increases in fatty acid oxidation and thermogenesis as serotonin (Le Feuvre. 1991; Cui. 1993). It does therefore remain speculative whether the use of tryptophan supplements will have beneficial effects on the success of your next diet that go beyond an increased ability to stick to your predetermined caloric deficit due to reduced hunger and (CHO) cravings. Furthermore it's not 100% clear whether taking 5-HTP which is significantly closer to serotonin would have different and/or more pronounced beneficial effects compared to its precursor Trp.

This raises the question: Does supplementation help? It's one thing to observe correlations, it's another thing to have scientific evidence from controlled trials which support a causative link between higher tryptophan intakes and/or supplementation and increased adherence to calorically restricted diets and/or reduced cravings and binges.

Let's take the study by Rieber et al. (2010 | Figure 2), for example, in their study a tryptophan-free amino acid supplement like the ones people sell as muscle builders lead to significant increases in hunger scores in healthy young women. Only recently, scientists from the University of Barcelona were able to show that chronic treatment with a tryptophan-rich protein hydrolysate improves emotional processing, mental energy levels and reaction time in middle-aged women. A result that suggests that chronic vs. acute treatments may have different effects, as well.

Direct evidence that tryptophan will also affect the reduction in energy expenditure, when dieting is yet not available from human trials. As of now, it's thus the reduction in appetite and cravings that is furthermore particularly pronounced in women that may considered among the scientifically warranted benefits of tryptophan supplementation and the avoidance of tryptophan depleting Trp-free amino acid supplements containing BCAAs, phenylalanine and tyrosine | Comment on Facebook!

References:

• Anderson, I. M., et al. "Dieting reduces plasma tryptophan and alters brain 5-HT function in women." Psychological medicine 20.04 (1990): 785-791. 
• Benton, David. "Carbohydrate ingestion, blood glucose and mood." Neuroscience & Biobehavioral Reviews 26.3 (2002): 293-308.
• Cangiano, Carlo, et al. "Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophan." The American journal of clinical nutrition 56.5 (1992): 863-867.
• Cangiano, Carlos, et al. "Effects of oral 5-hydroxy-tryptophan on energy intake and macronutrient selection in non-insulin dependent diabetic patients." International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity 22.7 (1998): 648-654.
• Ceci, F., et al. "The effects of oral 5-hydroxytryptophan administration on feeding behavior in obese adult female subjects." Journal of neural transmission 76.2 (1989): 109-117.
• Cui, Y., T. F. Lee, and L. C. H. Wang. "Thermoregulatory responses following injection of 5-hydroxytryptamine into the septohippocampal complex in rats." Pharmacology Biochemistry and Behavior 45.4 (1993): 935-939.
• Dantzer, Robert, et al. "Inflammation-associated depression: from serotonin to kynurenine." Psychoneuroendocrinology 36.3 (2011): 426-436. 
• Fernstrom, John D. "Branched-chain amino acids and brain function." The Journal of nutrition 135.6 (2005): 1539S-1546S.
• Gendall, Kelly A., and Peter R. Joyce. "Meal-induced changes in tryptophan: LNAA ratio: effects on craving and binge eating." Eating behaviors 1.1 (2000): 53-62. 
• Le Feuvre, R. A., L. Aisenthal, and N. J. Rothwell. "Involvement of corticotrophin releasing factor (CRF) in the thermogenic and anorexic actions of serotonin (5-HT) and related compounds." Brain research 555.2 (1991): 245-250.
• Nieuwenhuizen, Arie G., et al. "Acute effects of breakfasts containing α-lactalbumin, or gelatin with or without added tryptophan, on hunger,‘satiety’hormones and amino acid profiles." British journal of nutrition 101.12 (2009): 1859-1866.
• Raison, Charles L., et al. "CSF concentrations of brain tryptophan and kynurenines during immune stimulation with IFN-α: relationship to CNS immune responses and depression." Molecular psychiatry 15.4 (2009): 393-403.
• Rieber, N., et al. "Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects." Neurogastroenterology & Motility 22.7 (2010): 752-e220.
• Strasser, Barbara, Ken Berger, and Dietmar Fuchs. "Effects of a caloric restriction weight loss diet on tryptophan metabolism and inflammatory biomarkers in overweight adults." European journal of nutrition (2014): 1-7.
• Widner, Bernhard, et al. "Neopterin production, tryptophan degradation, and mental depression—What is the link?." Brain, behavior, and immunity 16.5 (2002): 590-595.
• Young, Simon N. "The effect of raising and lowering tryptophan levels on human mood and social behaviour." Philosophical Transactions of the Royal Society B: Biological Sciences 368.1615 (2013): 20110375.

Sugar Addicted or Just Stressed Out? Study Investigates Modulatory Effects of Different Macronutrient Compositions on Serotonin in the Presence and Absence of Stress

Image 1: She has the reason she is so relaxed right in her hand... but does she know that sugar is no sustainable way of coping with stress unless you don't care that you thusly pave the way from from initial episodes of hypoglycemia over binges, to obesity and diabetes.

"Sugar addiction" is a recurring theme in the blogosphere and whether it exists or not and what potential causes and treatments might be is still a matter of a partly very emotional debate. If we go by the definition of "addiction", of which the venerable Oxford English Dictionary says that it was "a condition characterized by regular or poorly controlled use of a psychoactive substance despite adverse physical, psychological, or social consequences, often with the development of physiological tolerance and withdrawal symptoms", it would be, if we had prove that sugar is a "psychoactive" substance. After all, the "adverse physical, psychological, or social consequences", i.e. diabetes, obesity, eating disorders, isolation, depression etc., are too obvious to be argued away - and I don't have to tell you about the "withdrawal symptoms", do I? Or, could it be that this is all just in our brains? Well, according to a recently published study from the Neurochemistry and Biochemical Neuropharmacology Research Unit at the Department of Biochemistry of the University of Karachi in Pakistan (Moin. 2011), it actually is ;-)

A amino acidic tale of sugary binge eating and fat anorexia

In their study, which was unfortunately conducted on rodents, not humans (apparently decapitation of human subjects for research purposes is prohibited in Pakistan ;-), Samia Moin and his (or her?) colleagues tried to assess how different dietary macronutrient compositions effect the ability to cope with and the brain response to stress. To this ends the scientists fed 48 rodents with diets that contained either 1/3 sugar (sugar diet), 1/3 beef protein (protein diet) or 1/3 fat (fat diet) in addition to the standard rodent chow (normal diet). Unfortunately, they did not provide the specific macronutrient composition of the diets, so that I had to calculate the latter on my own. The results are depicted in figure 1 and are based on the assumption that the Pakistani "standard rodent chow" is identical to the one animals in US labs are fed ;-)

Figure 1: My calculation of the macronutrient composition of the experimental diets; the calculation is based on the "standard rodent diet" that is used in US labs, whether that was identical to the one the Pakistanis used, I cannot tell.

If you take a look at the macronutrient composition of the different diets, the inter-diet difference between the "normal" and the "sugar diet" ended up to be not so significant. I mean 58% vs. 72% of the calories from carbs? For me both would be high carb and thusly it should not really surprise you that of those 24 rats who had to endure 2h of immobilization stress the rats in the "normal" and "sugar" group showed a similar, yet for the "normal" diet 1-day postponed, stress response: They ate more!

Figure 2: Effect of repeated stress (2h immobilization) on food intake in the different groups (data calculated based on Moin. 2011)

If you look at the data in figure 2, it does yet become obvious that - at least within the study period - "more" has to be understood relative to an initial stress-induced decrease in food intake, which, and this is another interesting finding, was sustained at -44% (average over the 5-day period) in both the high fat and the high protein group.

The Pakistani perspective: "Carbohydrate help you cope with stress!"

From the perspective of the Pakistani scientists, this "restorative effect" of a high carbohydrate diet on stress-induced appetite may be a good thing, from the perspective of someone living in a society with an overabundance of both food and stress, it must however be consider a potential risk factor for obesity.

Figure 3: Changes in serotonin (5-HT), its metabolite 5-HIAA and its precursors in response to dietary intervention; the "normal" diet serves as a reference (data calculated based on Moin. 2011)

If we take a closer look at the diet induced changes in brain 5-HT (=serotonin), 5-HIAA (=main serotonin metabolite) and brain and serum tryptophan (=serotonin precursor) levels in figure 3, it becomes quite obvious that the changes in the macronutrient composition alone already "mess" with the serotonin metabolism. What stands out, here is that, contrary to the "sugar" and the "protein diet", the "fat diet" increases the amount of serotonin in the brains of the unstressed rats compared to the "normal" control by +20%.

Figure 4: Changes in serotonin (5-HT), its metabolite 5-HIAA and its precursors in response to stress in the different diet groups; data expressed relative to unstressed controls; only changes marked with an asterisk (*) are statistically significant, p < 0.05 (data calculated based on Moin. 2011)

A different picture emerges, though, when we take a look at the effects of combined macronutrient modulation and stress (cf. figure 4). Contrary to the changes in the "normal" and "sugar group" which (plasma tryptophan levels aside) lack statistical significance, we see a reduction serotonin metabolism (as indicated by reduced 5-HIAA levels) in both the "protein" and the "fat" diet and the serotonin level in the "protein" group was profoundly elevated in response to the 2h immobilization stress.

What implications do these 5HTs, 5-HIAAs and ABCDEFGs have?

From previous studies, we know for quite some time that high protein diets are associated with higher rates in stress-induced depression (Markus. 1998). Moreover a reduced 5-HIAA / 5-HT ratio in the brain has been identified as a characteristic feature of depression (Zangen. 1997). If we keep that in mind and take a final look at the data in figure 4 and figure 5, we would have to draw the following conclusions:

• a high sugar diet modulates the 5-HIAA / 5-HT in an "anti-depressive" way
   
• a high protein diet does not change the 5-HIAA / 5-HT ratio as long as there are no external stressors, when stress comes into play it is associated with a profound "pro-depressive" decrease in the 5-HIAA / 5-HT ratio
   
• a high fat diet induces a pro-depressive reduction in the 5-HIAA / 5-HT ratio in the absence of stress, but is associated with a less pronounced reduction in the 5-HIAA / 5-HT ratio in response to stress, when compared to a high protein diet

Now its up to you to tell me whether these neurotransmitter changes in a rodent study and the associated pro- and anti-depressive effects reflect the way you feel on different diets in the presence and absence of stress... and I suggest, whenever you feel good with the way you eat, discard all the information I have just given you and keep doing what works for you. Not just because you are no rat, but simply because we are all wired differently and this wiring may change overtime :-)