Science Round-Up Seconds - GABA & Exercise: Both Can Improve and Mess With Your Sleep. Plus: Natural GABA Alternatives and Sleep As An Overtraining-Gauge

Don't forget that and prioritize proper sleep hygiene over pills and powders.

Let me make get this straight, yesterday's episode (please note that at the minute I post this article, the download is not yet working, should go up within the next hour, though) of the Science Round-Up on Super Human Radio was not only ultra-long (120min+), it was also largely speculative. If you already listened to the show, you will know that Carl and I took up on a discussion Dan Rollins triggered on his, Carl's and my Facebook page(s). Contrary to what you would expects Dan felt that gamma-Aminobutyric acid aka GABA would not help him calm down and let him sleep. For him GABA turned out to have stimulative rather than sedative effects.

I am not going to repeat all the potential explanations I went through in the first ~40min of the show here. Instead, I'd suggest you simply download the podcast and listen to the various hypothesis which range from (a) the general issue of whether or not GABA even crosses the blood-brain-barrier, over (b) the possibility that the GH spike, the sedative (low blood glucose) and the agitating effect (catecholamine + cortisol release with very low blood glucose) could all be brought about by a GABA induced increase in insulin production and a corresponding reduction in blood glucose levels to (c) potential confounding factors such as caffeine consumption (Roca. 1988; Desaulles. 1991; Mukhopadhyay. 1995), interactions with beta alanine, taurine or glycine (Tiedje. 2010; El Idrissi. 2013; Kletke. 2013), (d) genetic differences as with the tingling for beta alanine (Macphee. 2013) or (e) the influence of exercise on the density of GABA receptors in the brain (Dishman. 1990).

Enough of the speculations: What are proven alternatives

Against the background that we still don't really know why Dan and others don't seem to benefit from GABA supplementation the way Carl and Alisa do, we do know that there are other natural alternatives:

• Valerian [dosage: 400-900mg] - inhibits breakdown of GABA in the brain; assuming that GABA makes it across the blood-brain-barrier, valerian would thus work synergistically with oral GABA 

• 

  Due to its anti-PPAR-gamma effect ginseng also made it into the list of "agents that may help you to stay lean" I posted earlier this year. Want to know about the other "20 Anti-Obesity Agents Have the Potential to Inhibit Fat Gain Right at the Cellular Level"? Here you go!

  Ginseng [1-2g crude root extract or 200-600mg of extract] - ginsenoids compete with GABA on both the GABA-A & GABA-B receptor and are thus thought to exert their calming (only in low! doses) effects on the CNS via direct GABA-ergic effects; sedative effects have been observed for Panax ginseng (Korean or Asian ginseng), Panax quinquefolius (American ginseng), and Panax vietnamensis (Vietnamese ginseng); if you feel agitated, reduce the dosage
• Kava kava [180-210mg of kava lactones] - the active agents in Kava kava belong to a group of resinous compounds known as kava lactones or kava pyrones, they bind to the benzodiazepine binding site of the GABA receptor, which could reduce the risk of unwanted excitatory effects
• Passion flower (Passiflora incarnata) [4-8g as a tea] - has been used as a sleeping aid for centuries; chrysin, a mild anti-estrogen appears to be the active ingredient (GABA-A binding; cf. Zhai. 2008); warning: must not be consumed by pregnant women (!) PI can initiate uterine contractions

• 

  I know you don't want to hear that, but(!) don't forget that it could also be your BCAA product that keeps you you from falling asleep and makes you wake up several times during the night by blocking the uptake of tryptophan and thus depleting your brain of the raw material for serotonin (read more).

  Hops (Humulus lupus) [0.5g of dried herb] - has binding affinities to both the melatonin and serotonine receptor (Abourashed. 2004) and can increase GABA in the brain (Franco. 2012); warning: must not be consumed by women with a (family) history of breast cancer (!) hobs has mild, but distinct pro-estrogenic activity (Hajirahimkhan. 2013)
• L-tryptophan [1g] / 5-HTP [100mg] - both will increase serotonin and could thus be stacked with agents that act on GABA; incidentally, there is paucity of research on the efficacy of either of the two as sleep aid
• Melatonin [1-10mg] - as both Carl and I pointed out on the show, melatonin is not an acute sedative, but a signal that it's time to "shut down", don't expect it to actively "send you into sleep", like a sleeping pill

Aside from these agents, Carl and I talked about accupuncture and low energy emission therapy (LEET), as well. While the mechanisms of the former are still not fully understood (e.g. Kwok. 2013), the amplitude modulated high frequency fields the LEET mouthpiece emits right into your brain have been shown to modify the release of GABA and the concentration of benzodiazepine receptors in the rat brain. In addition, low level electromagnetic fields can directly induce the release of melatonin in mammals (Reiter. 1993).

If you are sprinting because of the increase in EPOC, you are a fool.

Read more about exercise and energy expenditure tomorrow! With the info on energy expenditure also crammed into this article it would have been too packed. Therefore you will have to live with a 24h deleay until you learn about the energetic costs of bench pressing, the laughable EPOC effects of HIIT and the evidence that exercise does not just make you hungry. If you feel that's not tolerable, you can already learn about the pathetic EPOC effects of HIIT and exercise & hunger in previous articles.

I already hinted at the physiological (side?) effects of chronic endurance training on the expression of the GABA receptors in rodent brains early in the show (and this article). It should thus not surprise you that exercise can have major impacts on the onset, quality and duration of your sleep - both positive and negative ones, obviously [based on data from Youngstedt (1997; published online 2003)]:

• 

  "90 Min Sleep Restriction Changes in Insulin Resistance Last For One Week"

  Timing of your workouts: While working out 4-8h before bed will have you fall asleep easily, you may experience problems if you have to ignore the onset of tiredness, because you have been exercising more than 8h before you go to bed or to close to hitting the hay. Incidentally, working out 4-8h before bed another advantage: It will help you to sleep through.
• Working out outdoors: The light exposure, the fresh air all that makes working out outdoors so healthy for you (as long as you are not living in Beijing ;-) will energize you and could keep you from falling asleep.
• Duration of your workout: There is a U-shaped dose-response curve for the negative effects of working out on your REM sleep. As Carl rightly pointed out during the show the negative effects of short exercise durations (<1h) is probably in as much a question of intensity / exhaustion (you train intense, when you train short) as the cumulative effects of "exercising" for more than 2h straight (which is by the way more than twice as detrimental for your sleep quality than the <1h exercise)
  
  Aside from its effect on the workout duration will also affect your overall sleep needs with both exercises in the 1-2h and exercises in the >2h range having a major impact on the amount of time you got to spend in bed to recover.
• Exercise intensity*: With a high propensity of low intensity exercise to help you sleep through, a walk on a treadmill in the evening is not going to compromise a good nights sleep, the HIIT workout that would improve your postprandial triglyceride response on the next day (I used this SuppVersity Facebook News as a discussion starter in the live-show), on the other hand may have you wake up several times during the night (*note: I used the studies on the post-exercise heat load in Youngstedt et al. as a proxy for intensity).

If you wanted to distill some practical advice on how you can / should exercise to avoid that your workouts will interfere with your sleep, you should (a) leave at least 4h between any intense workout and hitting the hay (HIIT, weight lifting, etc.) and (b) make use of the beneficial effects of moderate duration (20-40min) light intensity workouts (walking on an incline treadmill, cycling etc.) on sleep onset and quality.

Did you know that...

there are other agents that can "spike" GH temporarily?

• intravenous (iv) insulin 0.2 IU/kg - 50x increase
• intramuscular (im) glucagon 1 mg - 21x incr.
• iv. arginine 20 g/m² as an infusion over 30 minutes - 11x incr.

All observed in a human study involving 18 perfectly healthy young men(Rahim. 1996).

In view of the effect GABA has on the release of insulin from the pancreas, it is not unlikely that my previously voiced hypothesis that the "relaxation" and the "agitation" are responses to low and very low glucose levels would also explain the increase in GH as a response to the hypoglycemic effects of insulin.

What can you take away from the first part of this installment of the Science Round-Up Seconds?

• GABA does not work for everyone
• esp. in higher doses GABA can have excitatory, instead of calming effects
• the exact reasons that this happens is not clear; temporary hypogylcemia is albeit not the least likely candidate
• the hypoglycemia would also explain the GH release which is yet very unlikely to have beneficial effects on muscle growth (GH & gains don't correlate) or fat loss
• among the GABA alternatives, those with a specificity for the benzo docking site on the GABA receptor could work for people for whom GABA itself is excitatory
• working out too late / too intense can compromise sleep
• being "tired but wired" indicates sympathetic overtraining (too much intensity)
• constant fatigue + an increased sleep demand, but light and ineffective sleep is more indicative  parasympathetic overtraining (too much volume)

References:

• Abourashed EA, Koetter U, Brattström A. In vitro binding experiments with a Valerian, hops and their fixed combination extract (Ze91019) to selected central nervous system receptors. Phytomedicine. 2004 Nov;11(7-8):633-8.
• Desaulles E, Boux O, Feltz P. Caffeine-induced Ca2+ release inhibits GABAA responsiveness in rat identified native primary afferents. Eur J Pharmacol. 1991 Oct 2;203(1):137-40. 
• Dishman RK, Dunn AL, Youngstedt SD, Davis JM, Burgess ML, Wilson SP, Wilson MA. Increased open field locomotion and decreased striatal GABAA binding after activity wheel running. Physiol Behav. 1996 Sep;60(3):699-705.
• El Idrissi A, Shen CH, L'amoreaux WJ. Neuroprotective role of taurine during aging. Amino Acids. 2013 Oct;45(4):735-50. doi: 10.1007/s00726-013-1544-7. Epub 2013 Aug 21.
• Kletke O, Gisselmann G, May A, Hatt H, A Sergeeva O. Partial agonism of taurine at gamma-containing native and recombinant GABAA receptors. PLoS One. 2013 Apr 30;8(4):e61733.
• Kwok T, Leung PC, Wing YK, Ip I, Wong B, Ho DW, Wong WM, Ho F. The effectiveness of acupuncture on the sleep quality of elderly with dementia: a within-subjects trial. Clin Interv Aging. 2013;8:923-9.
• Macphee S, Weaver IN, Weaver DF. An Evaluation of Interindividual Responses to the Orally Administered Neurotransmitter β -Alanine. J Amino Acids. 2013;2013:429847.
• Mukhopadhyay S, Poddar MK. Caffeine-induced locomotor activity: possible involvement of GABAergic-dopaminergic-adenosinergic interaction. Neurochem Res. 1995 Jan;20(1):39-44.
• Rahim A, Toogood AA, Shalet SM. The assessment of growth hormone status in normal young adult males using a variety of provocative agents. Clin Endocrinol (Oxf). 1996 Nov;45(5):557-62.
• Reiter RJ. Electromagnetic fields and melatonin production. Biomed Pharmacother. 1993;47(10):439-44.
• Roca DJ, Schiller GD, Farb DH. Chronic caffeine or theophylline exposure reduces gamma-aminobutyric acid/benzodiazepine receptor site interactions. Mol Pharmacol. 1988 May;33(5):481-5.
• Tiedje KE, Stevens K, Barnes S, Weaver DF. Beta-alanine as a small molecule neurotransmitter. Neurochem Int. 2010 Oct;57(3):177-88.
• Youngstedt SD, O'Connor PJ, Dishman RK. The effects of acute exercise on sleep: a quantitative synthesis. Sleep. 1997 Mar;20(3):203-14.
• Zhai K, Hu L, Chen J, Fu CY, Chen Q. Chrysin induces hyperalgesia via the GABAA receptor in mice. Planta Med. 2008 Aug;74(10):1229-34.

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.