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| Healthy whole grains? |
I'll start off with some of the knocks on grains and work my way back to the big picture. One of the main arguments made by those in the paleo crowd about grains is that they decreased the stature of man and increased the incidence of disease. Now in their defense there are scientific studies to validate these claims (1,2,3,4), however, I believe this is a classic example of mistaking an association with causation. Popular paleo "gurus" such as the Robb Wolfs and Art DeVaneys of the world point out the fact that archaelogical records show decreased stature and increased incidence of disease, but they fail to mention that real archaelogists also acknowledge that this occurence may be the result of other concommitant factors, such as a more sedentary lifestyle (2,4) or as anthropologist and Pulitzer Prize winner Jared Diamond points out that hunter gatherer tribes often had longer gaps in between bearing their children, thus allowing the mother more time to replete the nutrient depletion that accompanies carrying, birthing , and nourishing a child in the perinatal period (Guns,Germs and Steel p.89).
In addition, to these historical arguments against, further claims of grains being an evolutionary novelty have also been made. The argument goes as follows, grains were introduced only roughly 10, 000 years ago and that humans simply cannot tolerate them in a manner conducive to promotin g optimal health. In addition to these claims being made by popular diet writers, such as those mentioned above, one can also find these claims in the scientific literature linking agriculture, mostly grains, to prevalent ailments and disease states such as Alzheimers (5,6). Again, I believe we have to think about this more closely before ascertaining that grains are causing many or all of th modern diseases of man.
In the classis book Nutrition and Physical Degeneration, Weston A. Price observed several culture's diets, or as he liked to call them dietaries.Some of the peoples he observed ate very little grain such as the Inuit and until very recently, the Massai , but he also observed several healthy cultures that subsited largely on grain such as the Kikuyu and Gaelics. In a series of very intriguing blog posts last year, Denisse Minger ran regression analyses on the China Study by T. Colin Campbell and colleagues and found that one of the most long lived and healthiest groups of people observed in the study were theTuoli (see here), essentianly contemporary pastoralists subsisting off of dairy and wheat bread. I think with that in mind, we also have to look at another point made by Jared Diamond in his book Guns, Germs, and Steel, the advent of agriculture invited the improvement and proliferation of further agricultuaral development. Basically it can be understood as follows, once a tribe of previous hunter gatherers had decided to take up the agricultaural lifestyle whether partly or in wholeness, they then have the incentive to improve upon their means by domestication of other flora and fauna species.
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| Maybe we didn't evolve eating whole grains, but I bet theyre alot less problematic than items such as high fructose cornsyrup, there refined counterparts (ie pastry), and processed oils. |
The example given by Diamond is of the Fertile cresecent. The first domesticated plant species he lists are wheat, peas, flax and barey (p. 181). This is also supported by primary scinetific findings in the field of archaeology as well (7,8). Following the domestication of these grains, foods such as banana, pomegranates, figs, grapes, olives, etc. followed. So with this line of reasoning (that grains are an evolutionary novelty) then is one to reason that apples, almonds, pecans, and so forth should not be eaten either?
There is some scientific literature suggesting dairy may not be optimal either, but it is largely speculative as with the grain argument (6). One might even play devils advocate and argue that modern breeds of cattle and swine are evolutionary novelties as well (see here or here). After all, the typical corn fed confinement cow of todays agribusiness establshment isnt quite the same beast as a wild game mammal found in the pleistocene era. In fact there nutrient profile isn't even equivalent to their grass fed counterparts (9). That is actually part of the reason (aside from ethical reasons) that many people are now making the transition to grass fed beef over "conventional. Nonetheless popular beef breeds are very new in evolutionary time as well, and thats where this point ties in with the grain argument. The same can be said for many of our vegetable breeds as well. The argument doesn't hold water. It is no longer possible to eat exactly as our ancestors did.
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| The paleo crowd seems to forget, we didn't evolve eating this either. |
The work of Price and researchers such as Piperno (7,8) show that grains were part of a historical diet that is not inherently deleterious to health. Apart from the observational work I've discussed so far, there is the work of Staffon Lindeburg's lab, who has found that the paleo diet is preferential to the meditteranean diet in reducing ad libitum caloric intake (10). So basically if one eats paleo, they get full off less food than the mediterranean diet. While I can't and wont argue with the results, I will say other factors do come into play such that with the paleo, the exclusion of milk and soda removes liquid calories. I know I have a large appetite, but in periods in my life where I have drank calories, they could easily account for well over 500 kcals. In additon I do agree that grains are an easy food to "fill up" on so if the subjects were instructed to eat ad libitum, then yes I would suspect they would eat less when excluding grain, but I don't think that means that a health/weight conscious individual has to completely exclude grains from the if they are monitoring their intake. For thos interested the physiological mechanism proposed by Lindeberg is that grains contains lectins (wiki) a class of glycoproteins that protentially interfere with leptin kinetics, (whether it be receptor competion or binding to the leptin itself is not fully understood).
Leptin and Insulin are thought to be two of the key hormones responsible for appetite regulation, so it can be reasoned that if the lectins in grain are interfering with leptin function then yes grains maybe causing appetite disregulation (11). However there's a problem with this argument as well. Lectins are found in all types of foods, including legumes, dairy, and night shade vegetables (tomatoes, egg plants, potatoes, and peppers). RobbWolf acknowledges this in his book The Paleo Solution and subsequently advises the exclusion of all of these foods. I won't disagree that his reccomendation may be a measure of prudence, but arguments can also be made against meats with epidemiological studies and the gotirogen content of the vegetables brassicae (12). What are we to do? rely on photosynthesis. In all seriousness I would say the point is that an argument can be made against all foods. The key is to try to eat time tested foods, and grains have thousands of years supporting them.
I think I have been more than fair in presenting the dark side of grains, and to boot, I will mention that there are also tannins and other anti nutrients found in grains. The problem with these molecules are as follows. Taninins are and other anti nutrients such as trypsin inhibitors deteriorate the absorption of minerals (iron, zinc, etc.) and inhibit enzymes neccessary for food absorption. So while some grains might provide some iron, magnesium, etc., these anti nutrients may be inhibiting full absorption. That is why the cultures I mentioned earlier used fermentation strategies. Fermementation of the grain with bacteria such as denature some of the nutrient inhibiting protein allowing for further absorption of nutrient. This is exactly what I am referring to when I say time tested. Over periods of millenia our antecedents have perfected (well pretty close) techniques to enhance nutrient bioavailability, and the available cuisine has included grains. Soy and rice are complements in the Orient, sorghum and millet with nuts such as the ground nut and mongogo in parts Africa, and corn with several varieties of pulses in the Americas. With that in mind, it's hard for me to argue that grains are the scourge of the west, but a maybe a small peice of the puzzle.
The last line of evidence against grain I will present here is the the anti gluten argument. Gluten like proteins found through out the grain species also alert me in that they may trigger inflammation and auto-immunity disease. There are over 80 type of autoimmune disease that may associated with the gluten protein as well (see here). The full affects of gluten are not fully understood, and seeing as science generally tensts to isolate foods/nutrients, I doubt we will ever fully understand the effects of gluten in the matrix of molecues that is food. I don't know for sure that grains are going to cause an inflammatory cascade, or an autoimmune disease. I haven't read on the topic thoroughly enough, so I just present this information as precautionary.
In conclucsion, my general thought is that grains won't kill most folks, so they can probably eat them, but should prepare them in a traditional manner, rather than in the form of a Pop tart or something like that. And for those trying to lose weight, or really improve or optimize health, you may want to think pretty long and hard before having that bowl or slice of healthy whole grain. To those who counter that those avoiding grains are missing out on the health promoting benefits of grains, which I mentioned in brevity earlier, I present a chart I have recopied from The Paleo Solution. For almost all sources of vital micronutrients, vegetables and meat can be used in place of grains. I will say that I personally very very rarely eat a grain of any sort. Theres just too much evidence presented above that leaves me skeptical . Personally I eat vegetables, and tubers in place of where most would eat grains. While I concede grains may be okay, they may not be so healthful after all.
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| Table conposed of data from Origins and evolution of the western diet: Health implications for the 21st century. Am Journal of Clinal Nutrition 2005: 81: 341-354 |
