New Results From the "Test Tubers": Paleolithic Men Could Have Been Healthier Had They Microwaved Their Potatoes.

Image 1: Potato roasting caveman-style - probably not the best way to "cook" your potatoes

As a non-native-speaker, I must admit that the first time I heard someone talk about "tubers" was on Robb Wolf's famous podcast, back in the day, when I was "listener #6" (or seven ;-). Contrary to common (foreign) belief, not all Germans subsist on potatoes and sauerkraut and, what's more, even those who do, don't really care that a potato is a "tuber", i.e. a "Knolle" in German - I suppose the idea that it grows in the dirt is not too appealing to some, while the large majority probably just doesn't care as long as those "tubers" make a good addition to their Schweinebraten... yet, whatever the reasons may be, my first encounter with "tubers" has ingrained the link of these "underground structure[s] consisting of a solid thickened portion or outgrowth of a stem or rhizome, of a more or less rounded form, and bearing ‘eyes’ or buds from which new plants may arise" (OED.com), as the venerable Oxford English Dictionary would have it, to the paleo style of eating so deeply into my brain that I have been seeing cavemen with roasted sweet potatoes on their sticks in front of a fireplace in my mind's eye, ever since. Now, if that really was the way life went, back in the paleolithic days, our ancestors did probably miss about 32% of the antioxidant magic of the tuberous roots - at least this is what the results of a recent study on the effects of different cooking methods on polyphenols, pigments, and antioxidant activity in potato tubers from the San Luis Research Center at the Colorado State University  would suggest (Perla. 2011).

In their experiment, Venu Perla, David G. Holm, and Sastry S. Jayanty

• boiled - 1h in a sieved double-boiler,
• microwaved + cooked - 10min in a commercial microwave oven at max. highest level +10min boiling, and
• baked  - 1h at 204°C in a commercial pre-heated oven

six months old stored potato tubers of 5 cultivars and 9 advanced selections of Colorado state (skin-color: 4x russet; 6x red; 1x white; 3x purple) and analyzed the samples for total phenolics, total flavonoids, total flavonols, and DPPH (2,2-Diphenyl-1-pikryl-hydrazyl) radical scavenging activity.

Figure 1: Loss in total polyphenol content of 5 cultivars and 9 advanced selections of Colorado state potato tubers due to cooking, microwaving, and baking (data calculated based on Perla. 2011).

As the data in figure 1 shows, all three preparation methods led to profound reductions of the potatos' total polyphenol counts. With Purple Majesty being most and Russet Nugget being least perceptible to the heat induced reduction in total polyphenol count. The cultivars CO97222-IR/R and CO97226-2R/R exhibited the highest total polyphenol counts (+77% and +137% above average in the raw state), with the former being particularly resistant to cooking (+119% above average) and the latter being particularly resistant to microwaving and baking (+154% and +169% above average, respectively).

Figure 1: Loss in polyphenol, flavenoid and flavenol content of 5 cultivars and 9 advanced selections of Colorado state potato tubers due to cooking, microwaving, and baking (data calculated based on Perla. 2011).

The superior resistance of these red-fleshed potato cultivars to cooking treatments is yet relative polyphenol-specific, due to their extraordinary high flavenoid and flavenol content in the raw state, CO97222-IR/R and CO97226-2R/R do yet retain a 241%, 155%, 199% and 243%, 331%, 395% higher flavenoid and 78%, 34%, 17% and 80%, 98%, 181% higher flavenol content  than the average potato (in the study) even after cooking, microwaving and baking, respectively.

The scientists also observed that, contrary to the white and yellow fleshed tubers, where the major pigment was lutein, the "dominant pigments in the red and purple fleshed tubers were anthocyanins", the antioxidant activity of which has been implicated in the prevention (by some even the treatment) of obesity, cardiovascular disease, diabetes, hyperlipidemia and even cancer. Unfortunately, these pigments are just as susceptible to cooking, microwaving and baking as the polyphenols, flavenoids and flavenols, so that the total anti-oxidant activity (as measured by DPPH free radical scavenging assays) of the tubers that were tested in this study was reduced by -26%, -32% and -38% by boiling, microwaving and baking, respectively.

Please note: While it is unlikely that you will die from eating a single raw potato. The solanine that can be found in all parts of the plant, including the leaves, fruit, and tubers, is a natural fungicide and pesticide the plant produces to protect itself from insects, the ingestion of which can potentially be fatal!

Now, despite the fact that microwaving is only slightly less damaging that baking, I assume that putting the potatos directly into the fire, like the paloelithic men and women in my daydreams use to do it, probably is the worst way to prepare your tubers. Yet while even microwaving would have been a healthier option, the best and, from an evolutionary perspective, more natural solution would be to boil your potatoes.

Turning Bad Into Good Fats, AHA Style: How the American Heart Association (Ab-)Uses Scientific Research According to Their (Hidden?) Agenda

As a diligent student of the SuppVersity, you are well aware that the absolute and relative overabundance of n-6 fatty acids (also known as omega-6 or linolic acid) in Western diets literally lies at the heart of heart disease. It is thus dear to my heart to turn your attention to the recent advances of the American Heart Association Nutrition Subcommittee of the Council on Nutrition to reestablish the myth of the heart-healthy omega-6 polyunsaturated fatty acids.

Image 1: You better watch out, other
than the American Heart Association
wants you to believe, one of the
"better fat sisters" (Poly, the one in the
middle) turns out to have a very dark
six-times unsaturated side ;-)

Back in 2009, already, the American Heart Association had published an article (AHA. 2009 Omega-6 Fatty Acids and Risk for Cardiovascular Disease), the putative intention of which was "to summarize the current evidence on the consumption of omega-6 PUFAs, particularly LA, and CHD risk". Cleverly, selecting only those studies that fit their (hidden?) agenda, William S. Harris from the Sanford School of Medicine , who is a speaker for GlaxoSmithKline and a consultant to several other companies, including Monsanto, Acasti Pharma, Unilever and Omthera (Ramsden. 2011), and the other members of the committee put together seemingly conclusive evidence (if you solely rely on the studies the commitee selected, their argumentation is in fact very conclusive) supporting their objectively questionable, if not dangerous advice to the American public to obtain "at least 5%-10% of [their daily energy intakes] from omega-6 PUFAs [in order to] reduces the risk of CHD [chronic heart disease] relative to lower intakes." The board even went so far to conclude that...

[t]he data also suggest that higher intakes appear to be safe and may be even more beneficial (as part of a low–saturated-fat, low-cholesterol diet). [...] To reduce omega-6 PUFA intakes from their current levels would be more likely to increase than to decrease risk for CHD.

As it seems, neither Harris, nor his colleagues Ingeborg A. Brouwer or Dariush Mozaffarian stuck to their own advice, because, now, two years later, they are obviously still healthy enough to defend their sponsors messages against the results of a paper by Ramsden et al. (Ramsden. 2010), who had addressed the very same topic somewhat more objetcive-, or, I should say "scientifically" in December 2010. In a sneaky letter to the editors of the British Journal of Nutrition with the tell-tale title "n-6 Fatty acids and risk for CHD: consider all the evidence" Harris, Brouwer and Mozaffarian indirectly accuse Ramsden, who happens to work for the National Institute of Health in Bethesda, and his colleagues of unscientific practice due to "not considering all the evidence".

In fact, Ramsden et al. had, as Harris and his collaborators point out "stratified studies by whether the vegetable oil intervention included any n-3 PUFA", or not, but other than the guys from the agro-lobby... ahh, pardon me, the American Heart Association would have it, this is the way a meta-analysis of the CHD outcomes of randomised controlled trials (RCT), in which oils were used that contained a natural mix of both n-6 and n-3 PUFAs, must be designed, in order elucidate the individual effects of n-6 and n-3 polyunsaturated fatty acids on heart health. Any other approach, such as the one cited by the authors themselves (Mozaffarian. 2010),  apparently overlooks the "significant different effects on risk of non-fatal myocardial infarction (MI) and CHD death", Ramsden et al.  found in their heterogeneity analysis (Ramsden. 2010) of all the available data. In their aptly titled response "Don't disregard the essential distinction between PUFA species" (Ramsden. 2011) Ramsden, Hibbeln, Majchrzak-Hong and Davis, state:

Harris et al. have not fully appreciated the essential distinction between n-3 and n-6 PUFA species in attributing benefits from our pooled analysis of mixed n-3/n-6 PUFA RCT datasets to ‘vegetable oils rich in n-6 PUFA’ or simply ‘soybean oil’, despite substantial increases in n-3 EPA+DHA in two of the four datasets.

They also point out that the influence of n-3 fatty acids has been (I would say purposefully) underestimated by Harris and elsewhere, and provide the famous Oslo Diet Heart Study as an example:

The experimental dieters in the Oslo Diet Heart Study (ODHS) were actually provided with ‘substantial quantities of Norwegian sardines canned in cod liver oil’ and not simply ‘encouraged’ as Harris et al. state here and elsewhere. Oslo dieters consumed about 5 g EPA+DHA per d (thirty times the average US intake); therefore it is not valid to attribute CHD benefits to LA or soybean oil.

They go on to mention that interventions "specific to n-6 LA", on the other "provide no indication of benefit and a relatively consistent signal toward harm" and draw the yet to be validated conclusion that "lowering dietary n-6 LA [Ramsden et al. suggest to 2% of energy, which would be consistent with evolutionary and historical US diets] is likely to potentiate the benefits of n-3 PUFA and/or have independent CHD benefits".

Guess where I found this advertisement,
right within the official Fats 101 of the
American Heart Association.

The advertisement banner on the left, taken directly from the official Fats 101 of the American Heart Association shall remind you of this blogpost, the next time you read about what the American Heart Association has to tell you about "healthy eating" practices. It may be remotely possible that those are healthy first and foremost for the corn- and soy-driven American economy.

Carbohydrate Shortage in Paleo Land: New Data for A Scientific Outlook at the Low-to-No Carb Paleo Confusion. Will More Than 125g of Carbs Make You Fat?

Image 1: Salmon, one of the few foods,
even the extremists allow themselves
(photo by Dezidor)

"Do you [eat] Paleo?" Over the last years, the "Paleo lifestyle", once some sort of esoteric "back to the roots" movement, has attracted more and more followers and has long become a multi-million dollar business. Somewhere in the course of this process, however, the original idea, which was to look at the nutritional history of humanity to identify those nutritional strategies that have been working for humanoids for ten-thousands of years, got lost. Mainstream paleo has turned into an obscure cult the members of which add food item after food item to their lists of "bad foods", the consumption or rather non-consumption of which distinguishes the "real" from the 99% paleo-eaters. Yet, while eating gluten-containing (the paleos would probably say "contaminated") foods has, probably not without reason, been considered a deadly sin, all along, carbohydrates in general have only recently moved up in the ranks of the worst offenders of a neolithic paleo-lifestyle. Being infiltrated by renegades from the low-fat and low-carb camps the Paleo diet is misinterpreted by more and more of its followers (mostly children of the fat-phobic 1980s) as a high protein, low-fat, no-carb diet. Looking at this unfortunate trend one could certainly go nuts, if, yes if nuts had not been added to the paleo-food-ban-list, lately, as well...

Oh, before I forget. This is not another pro- or anti-paleo carb or paleo blog, but the SuppVersity - so let's try to tackle the low-to-no carb conundrum from a somewhat more scientific perspective. Only very recently Alexander Ströhle and Andreas Hahn (Ströhle. 2011) have published a paper in Nutrition Research, in which the authors take another, closer look at the purportedly low carbohydrate content of THE paleolithic diet. In that their most relevant finding unquestionably is that the "diets of hunter-gatherers showed substantial variation in their carbohydrate content". So, even if the ludicrous assumption that the way our ancestors ate would be the "optimal" way to eat for us held true, we still would not know whether this "optimal" diet would contain <3% or >50% of our daily caloric intake in the form of carbohydrates, for these are the variations Ströhle and Hahn found for different ecoenvironments.

Figure 1: Average minimal and maximal carbohydrate content of the diet of paleolithic individuals living at different latitudes; data in %-age of calorie consumption (based on data from Ströhle. 2011)

As the illustration in figure 1 shows, it would largely depend on how far from the equator your ancestors lived, whether you would strive on an Inuit diet with <5% carbohydrate or mimic the mediocre carbohydrate intake of a Mediterranean diet. Yet, wherever your grand-grand-grand-parents may have come from, one thing is almost certain: following one of the official guidelines depicted in figure 2 will certainly provide way more energy from carbohydrates than what the paleolithic part of your genome will be able to tolerate.

Figure 2: Recommended (mean) carbohydrate intake in %-age of total calorie consumption
(data adapted from Ströhle. 2011)

If you have a closer look at who suggests what, you may notice that the WHO and the US Food and Nutrition Board propagate the (ridiculously) highest amounts of carbohydrates. Well, consider this: The WHO is hardly able to feed all their members even when they use the cheapest among the cheap nutrients, which obviously are carbohydrates, and the US have got to get rid, ahh... I mean, sell their annual production of  more than 256,900,000 metric tons of corn to somebody... what? "Scandal"? No, I didn't say that...

But let's put this hot topic aside and get back to the issue at hand and ask our selves: "How low-carb was the paleo diet, then?" Well, 22% of a 2.000kcal diet would still be 440kcal, which is equivalent to 110g of carbs, which is at the upper end of the low-carb continuum (ranging from 50-130g of carbs per day), as it was proposed by Accruso et al. (Accruso. 2008) and that is far from no-carb or recommendations <80g, where it becomes increasingly hard to find nutrient dense foods, the sum of which would not exceed your daily carbohydrate limit. Maybe I should add, that it is by no means accidentally that the limit appears to be somewhere around 500kcal. A 1988 overfeeding and depletion study by Acheson (Acheson. 1988) reports that  "an average male human being canaccommodate a gain of approximately 500 g before net lipid synthesis contributes to increasing body fat mass". So even within the upper ranges (and without exercise!) you are way below the fat storage zone. Under circumstances of continuous glycogen depletion such as exercise training, which go hand in hand with severe muscle and liver glycogen depletion, you may well be able to tolerate much higher amounts of glucose, because overall, your body is able to store roughly 5 g glucose per kg of body weight. So, once carb-depleted (notice: 100% carb depletion is a state you will not achieve; probably not even by running a marathon) an 80kg human being could safely refuel on 400g of carbs or 1.600kcal without running the risk of overloading his glycogen stores.

A note of caution: 400g of pure glucose, especially when taken on a regular basis, could have metabolic side effects unrelated to the overflow of glycogen stores that you better want to avoid; the same (better avoid) is true for fructose, as it is metabolized into triglycerides by the liver and will refuel your glucose stores only indirectly, if it is not previously taken up by adipose tissue.

All these arguments aside, it is also noteworthy that the restriction in carbohydrates, our ancestors practiced, was by no means self-inflicted, it exhibited great seasonal varieties and there is NO proof whatsoever that a higher carbohydrate intake - of course in the form of those whole foods that were available to the paleolithic individuals - would have made them more susceptible to "modern disease" - but this would be whole other blogpost. And let's be honest without your highly processed breads, cakes and pies, your high-fructose corn-syrup laden sugary drinks and all the pasta, pizza and rice the restaurants serve in order to keep you from noticing that they economized all the expensive stuff such as meat, vegetables and fruit, you probably would not even get beyond the 35%-margin Ströhle and Hahn identified at the maximal (seasonal mean) carbohydrate intake in across various hunter-gatherer populations, and latitude and ecological environments. And isn't it ironic, that the very sweet tooth that kept our ancestors alive, is killing us today.