This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
No, it's not about potatoes, but about potato products:
Eating more potato chips and French fries is likely to lead to a bigger weight gain over the years than the weight change associated with eating more of other foods, new research indicates.
Apparently these are worst than cakes and sugary foods
Marion Nestle, New York University professor of nutrition and public health, expressed surprise that potato products were linked with more weight gain than desserts like cake, cookies and doughnuts, which contribute the most calories to the American diet, other research shows. She says she suspects people who eat potato chips and fries also tend to eat too much in general, making these foods markers for a diet leading to weight gain.
Personally, I'm not surprised. The difference is in the industrial vegetable oil. While many baked goods do contain some vegetable oil, I suspect fried potato products contain much more.
More science on the study at Gene Expression. As with all self-reported population studies, serious problems loom. I suspect "whole grain" eaters are just health-conscious individuals. Most people who think they are eating whole grains are eating processed foods masquerading as them. Same goes from yogurt, the food of weight-conscious women, which is often spiked with tons of sugar.
What boggles my mind is that schools still serve fries and baked goods. Pretty much anyone who knows anything about nutrition, from low-fat vegan gurus like Joel Fuhrman to moderates like Marion Nestle to low-carb gurus like Jeff Volek, could agree that fried foods and sugary foods are bad for you. Yet they are on the menu EVERY DAY in most public schools. We should stop arguing about meatless Mondays and local vegetables and still focusing on this sort of trash we are shoveling into our children's mouths. If we can't eliminate these foods being served to our most vulnerable populations, that's just sad.
Probably the best academic treatment of why modern foods play a role in diseases of civilization.
Another hypothesis is that lack of SCFAs is behind such diseases of civilization. A SCFA called butyrate provides some insight into this. Butyrate is the preferred fuel of the colonic epithelial cells and also plays a major role in the regulation of cell proliferation and differentiation (Wong, de Souza, Kendall, Emam, & D. J. a Jenkins, 2006). Lower than normal levels have been found in patients with several diseases, notably types of colitis and inflammatory bowel disorder. Studies show such diseases can be treated through application of butyrate in the colon. That and the fact that some studies show complete remission through bacteriotherapy transplants point to these diseases being caused by disturbed populations of gut bacteria. Interestingly, these diseases are common in captive populations of apes and unheard of in wild apes (McKenna et al., 2008).
Bacteria affect butyrate production, but so do dietary inputs. Certain fibers produce more butyrate than others in humans, whether or not this differs between primates would be an interesting avenue of research (Smith, Yokoyama, & German, 1998).
Figure 1: Butyrate production in response to fiber
Interestingly, one of the top producers is something known as “resistant starch.” Resistant starch represents the growing nuance in understanding of fiber, since it is a starch that acts like a fiber in terms of acting as a bacterial substrate. It first showed up on the scientific radar when scientists found that low rates of colon cancer were not just found in populations with high-fiber diets, but those with high-starch diets (O'Keefe, Kidd, Espitalier-Noel, & Owira, 1999)1. Researchers found that a particular starch resisted digestion and ended up being fermented by colonic flora. They called this resistant starch and it is found mostly in cooked starches, some raw starches like green bananas, and some rough unprocessed grains and seeds. The former is termed type III and is a major part of the diets of many foraging populations who consume pounded and cooked starches like cassava, taro, true yam, and sago palm.
Whether or not humans are better adapted to certain types of resistant starch remains unexplored, but could account from some inconsistent results in studies that used type I resistant starch, mostly found in grains and seeds that would have probably been relatively uncommon in our ancestral diet. These studies have shown poor results and others with promising results are marred by high drop out rates due to unpleasant gastrointestinal side effects (Rinne et al., 2005; de Vrese & Marteau, 2007; Vuksan et al., 2007). Whether some populations would do better on this type of starch versus others would be an interesting investigation, but very few cultures consume large amounts of unmilled seeds and grains.
What type of starch we are best adapted to is interesting because the role of starch in human evolution is so controversial. Richard Wrangham has suggested that utilization of cooked starches was one of the dietary quality innovations that fed our rapidly expanding expensive brain tissue as it evolved towards hominid size (Wrangham, 2003). Recent analysis throws a wrench in that theory because it suggests habitual use of fire came after encephalization, about 300,000 years ago (Roebroeks & Villa, 2011). However, this does not mean that such cooked starches did not change humans, even if it reduces their significance in human evolution.
The burgeoning field of archeological starch grain analysis has transformed our view of hominids once thought to be mostly carnivorous. Microfossils on Neanderthal teeth from around 44,000 years ago show evidence of the consumption of many roots and tubers, some of which show evidence of cooking (Henry, Brooks, & Piperno, 2010). The full impact of the adoption of cooked starches on the human body has not been fully elucidated. One promising adaptation is the starch-digesting salivary amalyse gene, AMY 1 (Perry et al., 2007). Chimpanzees and bonobos have only two copies of this gene, humans have as many as 10 copies, though it varies quite heavily by population from 2 to 10 correlated with the importance of starch in the diet. Molecular genetic evidence places the origin of divergence on this gene at about 200,000 years, about the time when habitual fire use became common. Further genetic analysis shows that adaptations to root and tuber starch as a major source of calories may account for variation in human folic acid metabolism, since folic acid is usually low in starchy vegetables (Hancock et al., 2010).
Another relatively unexplored avenue of research would be whether butyrate in the diet itself has led to decreased reliance on butyrate for colonic fermentation in some cultures that consume large amounts of dietary butyrate. The major source of butyrate in food is from the milk fats of grazing animals (Smith et al., 1998).
It is most common in the modern diet in butter at 3%. It is possible that pastoral cultures consume substantial amounts of exogenous butyrate. Currently there have been few studies on oral consumption of butyrate in humans. Animal studies have been inconclusive, with some showing positive effects and some showing negative effects, which is complicated by the fact that if ingested orally it is also present in the small intestine, where it may play different roles (Sengupta, Muir, & Gibson, 2006; Wächtershäuser & Stein, 2000). A small study found orally-administered butyrate had a positive effect on symptoms of Crohn’s disease, but the method of administration was through pills rather than food (Di Sabatino et al., 2005).
Another potential source of butyrate is fermented foods. Some fermented foods like ogi, a pounded fermented starch, contain measurable levels (Hesseltine, 1979). Fermented foods are worth examining evolutionarily because they represent another human dietary innovation in improving food quality. Fermentation increases the bioavailability of nutrients, breaks down starches, and reduces levels of anti-nutritional factors and toxins (Mugula, 2003). It is unknown how long humans have been purposefully fermenting food. Fermentation naturally occurs in the wild and many wild animals are known to indulge in such foods to the point of drunkenness (Dudley, 2002). Spontaneous fermentation and consumption of such foods by wild primates is unfortunately not well studied. However, fermentation is practiced by almost every known culture to some extent, with the largest diversity in fermented foods among African farmers (Dirar, 1993) It is estimated that fermented foods make up 1/3 of the diet of humans worldwide (van Hylckama Vlieg, Veiga, Zhang, Derrien, & Zhao, 2011). Exogenous fermentation may substitute for the reduced fermentative ability of the human gut.
1. The researchers concluded that colon cancer risk was increased with meat consumption. I will remain skeptical until they do studies on other cultures that eat relatively low-fiber and high-meat diets like the Masai and Siberian cultures for example.
Di Sabatino, A., Morera, R., Ciccocioppo, R., Cazzola, P., Gotti, S., Tinozzi, F. P., et al. (2005). Oral butyrate for mildly to moderately active Crohnʼs disease. Alimentary pharmacology & therapeutics, 22(9), 789-94. doi: 10.1111/j.1365-2036.2005.02639.x.
Dirar, H. A. (1993). The indigenous fermented foods of the Sudan: a study in African food and ... (p. 552). CAB International. Retrieved May 9, 2011, from http://books.google.com/books?id=J-ogAQAAIAAJ&pgis=1.
Dudley, R. (2002). Fermenting fruit and the historical ecology of ethanol ingestion: is alcoholism in modern humans an evolutionary hangover? Addiction (Abingdon, England), 97(4), 381-8. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11964055.
Hancock, A. M., Witonsky, D. B., Ehler, E., Alkorta-Aranburu, G., Beall, C., Gebremedhin, A., et al. (2010). In Light of Evolution IV: The Human Conditions Sackler Colloquium: Human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency. Proceedings of the National Academy of Sciences of the United States of America, 107(Supplement_2), 8924-8930. doi: 10.1073/pnas.0914625107.
Henry, A. G., Brooks, A. S., & Piperno, D. R. (2010). Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets (Shanidar III, Iraq; Spy I and II, Belgium). Proceedings of the National Academy of Sciences of the United States of America, 1-6. doi: 10.1073/pnas.1016868108.
Hesseltine, C. W. (1979). Some important fermented foods of Mid-Asia, the Middle East, and Africa. Journal of the American Oil Chemists’ Society, 56(3), 367-374. Springer Berlin / Heidelberg. doi: 10.1007/BF02671501.
Hylckama Vlieg, J. E. van, Veiga, P., Zhang, C., Derrien, M., & Zhao, L. (2011). Impact of microbial transformation of food on health-from fermented foods to fermentation in the gastro-intestinal tract. Current opinion in biotechnology, 22(2), 219-211. doi: 10.1016/j.copbio.2010.12.004.
McKenna, P., Hoffmann, C., Minkah, N., Aye, P. P., Lackner, A., Liu, Z., et al. (2008). The macaque gut microbiome in health, lentiviral infection, and chronic enterocolitis. PLoS pathogens, 4(2), e20. doi: 10.1371/journal.ppat.0040020.
Mugula, J. (2003). Microbiological and fermentation characteristics of togwa, a Tanzanian fermented food. International Journal of Food Microbiology, 80(3), 187-199. doi: 10.1016/S0168-1605(02)00141-1.
OʼKeefe, S. J., Kidd, M., Espitalier-Noel, G., & Owira, P. (1999). Rarity of colon cancer in Africans is associated with low animal product consumption, not fiber. The American journal of gastroenterology, 94(5), 1373-80. doi: 10.1111/j.1572-0241.1999.01089.x.
Perry, G. H., Dominy, N. J., Claw, K. G., Lee, A. S., Fiegler, H., Redon, R., et al. (2007). Diet and the evolution of human amylase gene copy number variation. Nature genetics, 39(10), 1256-60. doi: 10.1038/ng2123.
Rinne, M. M., Gueimonde, M., Kalliomäki, M., Hoppu, U., Salminen, S. J., & Isolauri, E. (2005). Similar bifidogenic effects of prebiotic-supplemented partially hydrolyzed infant formula and breastfeeding on infant gut microbiota. FEMS immunology and medical microbiology, 43(1), 59-65. doi: 10.1016/j.femsim.2004.07.005.
Roebroeks, W., & Villa, P. (2011). On the earliest evidence for habitual use of fire in Europe. Proceedings of the National Academy of Sciences of the United States of America, 1018116108-. doi: 10.1073/pnas.1018116108.
Sengupta, S., Muir, J. G., & Gibson, P. R. (2006). Does butyrate protect from colorectal cancer? Journal of gastroenterology and hepatology, 21(1 Pt 2), 209-18. doi: 10.1111/j.1440-1746.2006.04213.x.
Smith, J., Yokoyama, W., & German, J. B. (1998). Butyric Acid from the Diet: Actions at the Level of Gene Expression. Critical Reviews in Food Science and Nutrition, 38(4), 259-297. doi: 10.1080/10408699891274200.
Vrese, M. de, & Marteau, P. R. (2007). Probiotics and Prebiotics: Effects on Diarrhea. J. Nutr., 137(3), 803S-811. Retrieved May 9, 2011, from http://jn.nutrition.org/cgi/content/abstract/137/3/803S.
Vuksan, V., Whitham, D., Sievenpiper, J. L., Jenkins, A. L., Rogovik, A. L., Bazinet, R. P., et al. (2007). Supplementation of conventional therapy with the novel grain Salba (Salvia hispanica L.) improves major and emerging cardiovascular risk factors in type 2 diabetes: results of a randomized controlled trial. Diabetes care, 30(11), 2804-10. doi: 10.2337/dc07-1144.
Wong, J. M. W., Souza, R. de, Kendall, C. W. C., Emam, A., & Jenkins, D. J. a. (2006). Colonic health: fermentation and short chain fatty acids. Journal of clinical gastroenterology, 40(3), 235-43. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/16633129.
Wrangham, R. (2003). “Cooking as a biological trait.” Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, 136(1), 35-46. doi: 10.1016/S1095-6433(03)00020-5.
Wächtershäuser, a, & Stein, J. (2000). Rationale for the luminal provision of butyrate in intestinal diseases. European journal of nutrition, 39(4), 164-71. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11079736.
It's funny because when I started reading Fanatic Cook I was vegan and she was a low-carber. I thought she was wrong, but just liked reading her stuff (I read a bunch of vegan blogs still). Now she is a nutritarian and I'm the carnivore. Most of the time I think she is missing the bigger picture, but she picks up interesting articles.
Either way, her latest post on eggs caught my eye. It's about a news item that's bound to annoy both paleos and vegans: "Eggs Are Now Naturally Lower in Cholesterol," which talks about the newest analysis of the average nutrient content of eggs. Paleos who think the lipid hypothesis is bunk are bound to be unimpressed. And vegans are annoyed that USDA is saying that this now makes eggs a health food.
Either way, seems like we both lose. As Bix points out, the Brave New Egg is just soy repackaged. Instead of 574 mg of omega-6, it has 792mg! Yes, omega-3 has increased a bit, but I don't think this is good news since total PUFA (polyunsaturated fatty acid) content has increased. It also has less of the best fat ever, monosaturated fat, which is seriously sad. But wait, now you get more glucose for free! Instead of a measley 105mg, you get 180mg per egg.
"Hens are fed a high-quality, nutritionally balanced diet of feed made up mostly of corn, soybean meal, vitamins and minerals." Hmmm, no thanks.
When I saw these photos of an "uncontacted" tribe it became very clear to me that we must contact them as soon as possible. As you can see in the above photo, they are consumers of cassava, which is a starchy tuberous root. Someone has gotta tell them that all that starch will make them obese.
In all seriousness, this morning I got an email from Maria Rainer, one of many content farmers who generously offer to write "guest posts" for my blog. I totally understand her plight, since the modern university scam is to give a massive percentage of undergraduates degrees in English regardless of the fact that only 10% have writing talent and there are almost no openings in writing jobs that require any sort of craft. The rest of the English majors are forced to work in debt collecting, retail, or content farming. I'm not judging. After all, I'm even more of a sucker since I thought I was getting a useful degree, but it has really only served me in blogging. OK, actually I am judging and would appreciate if content farmers would refrain from contacting me.
I shall not grace one of her pieces with hits, but her resume she sent me includes one on how to eat vegan AND paleo. It recommends you avoid coconut since cavemen didn't live in Hawaii (a simple Google would inform her that coconuts aren't even native there!). It mentions how some modern hunter-gatherers get over 50% of their calories from plants, but again enters major fail territory by saying NO to starchy tubers. Guess what plants those hunter-gatherers are getting their calories from? Hint: it's not lettuce.
Starchy tubers are exactly what most hunter-gatherers (or horticulturalists in this case I suspect) rely on for plant foods. The bitter cassava seen above is perfect because it can't be eaten raw by animals, but humans can soak out the cyanide and consume it.
Lately out of curiosity I've been experimenting with tropical starches. This weekend I made some sweet cassava (cyanide free) and it was surprisingly easy. The peel came off quickly and it boiled much faster than potatoes. It soaks up sauce wonderfully.
Another starch Chris and I tried this weekend was plantains. I'm surprised that more paleos aren't into it. Maybe it's the carbophobia. But it has the best of a banana and a potato. If you are eating bananas, might as well switch to green plantains since they are lower in sugar. And they get crispy in leftover bacon grease MUCH faster than potatoes and taste nearly identical. There are also sweet plantains, which make a decent dessert dressed with coconut oil and cinnamon.
Next up: The malanga(cocoyam), taro, and true yam. The true yam intimidated me this weekend. It's lumpy and unfriendly, though not as menaching as the cocoyam. I might have to check out a local Nigerian restaurant to learn how to do it the right way.
If you are venturing into paleo-izing a vegan diet, these starches are worth checking out. Personally, I feel quite good when I have a little starch with my meat.
Any tips would be appreciated!
What about The China Study?
Why did you stop being vegan? Isn't veganism more sustainable?
What do you think about carbs?
My diet is more about real whole foods than macronutrients. A low-carb diet can be therapeutic for certain illnesses like migraines, but I do not think they are optimal for everyone. You can see all my posts on the subject of carbs using the tag system.
While paleo dieters generally agree on many things, we are not immune from infighting. Unforunately I haven't been involved in too many fights, but I can recap some of them here for your general amusement:
Richard Nikoley started posting about how potatoes weren't so bad and proudly displayed some of his favorite potato-licious meals. Don Wiss of paleodiet.com took offense and angrily removed his links to Richard's site. Richard was not swayed and posted more delicious pictures of baked potatoes, as well as a rebuttal.
Outcome: The potato-haters have been surprisingly quiet of late, especially since Stephen Guyenet posted a series on how delicious and awesome they are. Potatoes remain generally considered unpaleo, but people don't need to freak out about them.
My Take: I think this caused people to think about what foods are paleo. Do we classify them based on taxonomy and history? Or on how our bodies react biochemically?
The latest paleo controversy involves Mark Sisson's newest product, a meal-replacement powder made of whey, coconut, and prebiotics. Even though he already sells an assortment of various powders, the annoucement was met with acrimony. Some complained about the price, others about the ingredients. Leigh Peel wrote a bitter post about how terrible and overpriced was, which ironically you have to pay to read. But don't worry, her blog has a nice free cookie recipes featuring Smart Balance and good old fashioned white sugar. Always eager to enter the fray, Richard at Free the Animal defended Mark and told people to take a freaking chill pill. Mark calmly clarified information about his product.
Outcome: Mark kept his composure, making his critics look a bit dramatic to say the least. But will his product be a hit?
My Take: I personally would turn into a raging monster if I ate a meal that was so few calories and I question the value of powdered food in general. I guess this product alienated a few groups of people, mine being the locavore "real food" faction of paleo. I hate the idea of my food dollars going to labs rather than farmers. It reminds me of the Joan Gussow quote: "I trust cows more than chemists."
Are there more paleo controversies I'm missing here? Everyone likes a good fight :)