science

 In the next few months I hope to write a couple of posts on irritable bowel syndrome. It's interesting because so many (including myself) get relief from IBS by following a low-carb low-fiber grain-free fructose-free diet with probiotic supplementation. There are many reasons this works, but in the long term people following it might want to wean away from probiotic dependence, since probiotics in pills cannot become part of the permanant microbiome of most adult guts. In addition, there are real benefits from short chain fatty acids produced in the colon by fermentation. It's unfortunate so much fiber research has been done on grains, but more and more is being done on the type of fiber that horticulturalists and foragers consume. Here we are getting into self-experimentation since the research is so thin right now. My own goal has been to establish a gut bacterial population that is an asset (har har) rather than a nuisance. I've been trying to do this by feeding my bacterial population appropriately in a way that encourages good bacteria, but does not allow overgrowth. 

On Paleohacks someone said something like "the kind of food you eat cannot affect constipation, just the mechanics of the food, IE, how much fiber and fat." That is the OLD view. The reality is that different gut bacteria react differently to different foods. I've been reading a lot of articles by Dr. Kok-Ann Gwee, who studies IBS in Singapore. His article Fiber, FODMAPs, flora, flatulence, and the functional bowel disorders is a really good one and should be essential reading for all doctors. I'd estimate the majority of primary care physicians are still recommending things like bran to treat IBS when there are mountains of scientific evidence against it. 

The issue was in the 70s some papers came out that said, "huh, looks like this African farmers don't have stomach problems. Must be all the fiber in their diet!" Nevermind their methods for measuring fiber were bad and that certainly wasn't the only difference in their diets. Then some poorly-designed studies were done on bran, which the cereals industry picked up in order to promote BRAN FOR EVERYONE1111!!!!! Dr. Kok-Ann says:

In fact, a number of contrarian studies, which had been largely ignored, had suggested that favorite sources of dietary fiber such as bran and other cereals, and vegetables and fruits, might actually aggravate symptoms in IBS. The symptoms that appeared to be aggravated were flatulence, bloating and abdominal pain.

Yikes, that certainly was my experience. The more I ate the high-fiber stuff my doctor told me to eat, the worst I felt. 

I didn't have Celiac, so that meant wheat was AOK right? Nope, gluten is not the only bad thing in wheat, the fiber in wheat can be quite bad for people with IBS as well. 

Based on the use of an exclusion diet, Nanda et al. from Oxford reported that dairy, grains, in particular wheat and rye, and onions were the major foods implicated by IBS patients, and that patients responding to dietary manipulation were likely to have presented with flatulence as an initial symptom.3 They had also observed that intolerance to either wheat or rye was specifically associated with abdominal distension. Whorwell and Prior from Manchester recorded that 55% of their patients felt worse and only 10% felt better on bran.4 John Hunter's group from Cambridge used a whole-body calorimeter to measure the 24-h excretion of hydrogen and methane in both the flatus and the breath.5,6 They compared the gas production of IBS patients and healthy controls on a standard diet with regular fiber intake, an exclusion diet, and a fiber-free diet. They found that IBS patients had a significantly faster rate of gas production on a fiber-rich diet, which reduced significantly on the exclusion and the fiber-free diet, and this appeared to be associated with an improvement in symptoms. Others have also suggested that malabsorption of fructose and sorbitol, of which fruits are rich sources, may give rise to symptoms in IBS patients.7

So fiber not only doesn't help, it makes you gassy and bloated. This paragraph highlights the foods I found triggered my symptoms through trial and error: onions, grains (esp wheat), and a lot of dairy. These are foods I now know are rich in FODMAPS (Fermentable Oligo-, Di- and Mono-saccharides, and Polyols). Interestingly I've found not all FODMAPs trigger my symptoms. 

In [the Cambridge study], total gas, as well as breath hydrogen production, was similarly reduced with metronidazole (an antibiotic with activity against intestinal anaerobic organisms) treatment despite a fiber-rich diet. This observation brings us back to our recent appreciation that the flora of intestinal microbes is a key player in the development of IBS.10 Even Segal and Walker, two of the early proponents for the high-fiber diet, have recently acknowledged that reduced dietary fiber intake has not resulted in increased colonic diseases in Africans.11 In fact they have now recognized the importance of the “quality of the intestinal bacteria”, and the impact that this has on the fermentation of malabsorbed carbohydrates.12 In their recent paper they have assembled measurements for various classes of immunoglobulins, and other markers of immune activation, that support a high level of exposure to gastrointestinal infections in childhood.11 Their new hypothesis is that it is this early priming that gives the African a more robust gut microflora, better able to withstand the insults in adult life. The corollary is also that if we expect fiber and oligosaccharides that are promoted as prebiotics to enhance the proliferation of ‘good bacteria’, we have to start feeding these substrates to our gut in the early years of life. In the meantime, it appears that eating a ‘healthy Western breakfast’ of milk with high-fiber cereals, whole grain bread with honey, washed down with apple juice, is perhaps the worst way to start off the day for an adult IBS patient!

What about those of us who didn't get that advantage? Is there hope to normalize? In his other article he points to several factors anyone with IBS should think about: 

• The role of gut flora in their end products, immune mediators, and neuroendocrine factors
• Beneficial and pathogenic parasites

Then there are some more factors to think about from Irritable bowel syndrome: towards biomarker identification:

• The gut-brain axis
• Hypothalamic-pituitary-adrenal (HPA) axis dyfunction
• Inflammation
• Stress

More soon!

Isn't it cute when scientifically ignorant people accuse other people of being scientifically ignorant? You know they are scientifically ignorant because they blather on about "peer reviewed research" while obviously never having read any.

I don't know when or why I subscribed to the mindless platitude drivel blog Zen Habits, but their recent post about soy caught my eye.

It’s one of those things that has spread on the Internet and unbelievably, has become accepted truth to many people: that soy is unhealthy, even dangerous. I mention (to otherwise smart and informed people) that I drink soymilk sometimes, and a look of pity comes over their faces. ‘This guy doesn’t know the dangers of soy, and might get cancer, or worse … man boobs,’ they’re thinking. Just about every fitness expert I read — people I respect and trust — says that soy is bad for you, from Tim Ferriss to the primal/paleo folk. I absolutely respect most of these guys and otherwise think their work on fitness-related matters is great. And yet, when I look for their sources on soy, often they don’t exist, and when they do, I can always trace them back to one place. The Weston A. Price Foundation.

Um, suuuure. So the whole thing is basically setting up a straw man - "only teh evil WAPF sayz soy is baad! WAPF is teh stupid, here are some blag posts from some vegan blogs that sayz they are teh wrong!"

Unfortunately it is true that some WAPF article are pretty questionable. There is an element of woo I can't get behind as a scientist. But there are also articles with scientific references and it would be useful to follow those. But nope, instead the idiot just cites some forum posts and vegan websites.

As for only WAPF having a vendetta, I sincerely doubt Dr. Staffan Lindeberg and Dr. Loren Cordain are associated with WAPF. Maybe you don't know about that because then you might have to go to the library and check out Food and Western Disease instead of Googling crap like the quasi-content farmer you are.

This book has multiple sections about soy.

Soya products cannot be recommended, particularly not for women being treated for breast cancer with tamoxifen, since the tumour-inhibiting effect seems to be counteracted by genistein447,846,852. Genistein, the dominant phytoestrogen in soya bean, potentially stimulates the growth of oestrogen-dependent breast cancers by acting as a so-called promoter that accelerates the progress of existing breast cancer42,321,1464,1622,1803. The idea that soya consumption would explain the relatively low risk of breast cancer in women living in Japan is open for debate730. There are all sorts of reasons why breast cancer could have been less common in Japan than in Europe and North America. On these grounds, the former enthusiasm for soya has lately turned into caution447,1445.

See these little numbers? Those are called references. Real references. Let's compare these references to some references you think are just dandy.

3. FALSE: Soy causes (insert scare claim here: Alzheimer’s, birth defects, etc.). There isn’t any evidence for any of the scare claims that originate from WAPF. I’m not going to argue them all, but I urge you to read these articles from John Robbins, Dr. Neil Barnard, Syd Baumel, and Dr. Joel Fuhrman — they contain many more sources than I could list here, and they’re based on actual evidence.

ACTUAL EVIDENCE? OMG. I am so excited to find out about this actual evidence you speak of.

Do primitive peoples really live longer? No. For example, Innuit Greenlanders, who historically have had limited access to fruits and vegetables, have the worst longevity statistics in North America. Research from the past and present shows that they die on average about 10 years younger and have a higher rate of cancer that the overall Canadian population. 1 Similar statistics are available for the high meat-consuming Maasai in Kenya. They eat a diet high in wild hunted meats and have the worst life expectancy in the modern world. Life expectancy is 45 years for women and 42 years for men. African researchers report that historically Maasai rarely lived beyond age 60. Adult mortality figures on the Kenyan Maasai show that they have a 50% chance of dying before the age of 59.2 We now know that greatly increasing the consumption of vegetables, legumes, fruits, and raw nuts and seeds (and greatly decreasing the consumption of animal products) offers profound increased longevity potential, due in large part to the broad symphony of life-extending phytochemical nutrients that a vegetable-based diet contains. By taking advantage of the year-round availability of high-quality plant foods, we have a unique opportunity to live both healthier and longer than ever before in human history. 1. Iburg KM, Brennum-Hansen H, Bjerregaard P. Health expectancy in Greenland. Scan J Public Health 2001;29(1):5-12 2. http://www.kenya.za.net/maasai-cycles-of-life.html, http://www.who.int/countries/ken/en/

So a defunct website and an article about a modern population in Greenland (I imagine the people of Greenland would be seriously unhappy to be called a "primitive people" since they live a modern lifestyle including books, computers, guns, and modern food and drink and it's just racist to cite the entire country of Kenya when debunking health claims about "primitive people" 0_o ). It's also quite hilarious that Zen Habits cites Dr. Andrew Weil, a potent woo meister himself.

What about the refs in Food and Western Disease?

Duffy, C., Perez, K.&Partridge, A. (2007) Implications of phytoestrogen intake for breast cancer. CA Cancer J Clin 57, 260–77. Power, K.A. & Thompson, L.U. (2007) Can the combination of flaxseed and its lignans with soy and its isoflavones reduce the growth stimulatory effect of soy and its isoflavones on established breast cancer? Mol Nutr Food Res 51, 845–56.

Hmm, these seem different. They almost seem real, as in really relevant and really from real sources or something.

As mentioned earlier, one of the more obvious problems with a vegetarian diet is the development of iron deficiency, which often affects vegetarians, in particular vegans. A high intake of grains and beans contribute to this condition to a considerable degree488,590,669. Soya beans also contain other substances that impede iron absorption besides phytates1099.

Enzymatic digestion of the same proteins in the gut should also be supported through a low intake of protease inhibitors from cereals and beans, including soya products. Finally, the intake of plant lectins from grains and beans should be minimised in an attempt to limit the permeability of the intestines and the blood–brain barrier, and prevent potentially damaging proteins and peptides (food-derived or coming from other sources) from entering the body.

Rats who are fed soya beans after weaning have limited growth, partly due to the effect of lectins.

These apprehensions certainly apply to soya beans. Two experts on health effects of soya beans at the US Food and Drug Administration (FDA), Doergeand Sheehan, the former chief of the Oestrogen Base Program, wrote in 1999 a public letter in protest of the FDA’s approval of health claims for soya products (http://www.dcnutrition.com/news/Detail.CFM?RecordNumber=546). The researchers were concerned about the results of animal experiments where flavonoids in soya (genistein and daidzein) were found to have toxic effects on oestrogen-sensitive tissues and on the pancreas431. Particular caution is needed for children and adolescents children, but this has not prevented the large-scale development and marketing of soya-based infant formulas. Consumption of soya products during pregnancy has been suggested to increase the risk of abnormal development in the nerve system and reproductive organs of the offspring. It has been shown that realistic doses of genistein cause atrophy of the thymus in mice1983. Ishizuki et al. reported goitre and elevated individual thyroid-stimulating hormone levels, although still within the normal range, in 37 healthy iodine-sufficient adults without known thyroid disease, who were fed 30 g of pickled soya beans per day for as little as 1 month431. One study found genistein to disrupt female reproductive function in mice, but the effect in humans has not been examined27.

On the other hand, it has also been suggested that flavonoids in soya beans have beneficial effects, including inhibiting the growth of cancer, but none of these effects have been proven convincingly629. With regard to breast cancer prevention, soya can no longer be recommended, as discussed in Section 4.11.

In old Chinese cuisine, soya products were eaten with caution, and the intake of genistein, e.g., is thought to have been well below the intake of ‘health conscious’ Westerners369.

Whether or not the WAPF is biased, there is a whole lot of bias in the soy industry and a whole lot of funding for people to find uses for soy. When I was an undergrad I participated in soy board research and the food sci department received quite generous stipends for this. I've written about some negative effects of soy and the "soy cartel" in a previous post.

I eat soy sauce and I confess I sometimes indulge in Korean tofu stew (simmered in stock), I just don't use soy as a staple food because I've seen the science and the science says "caution."

And more caution about geting dietary advice from a blog about "zen habits." A hint for future writers from that blog: You can't find studies about why soy might be bad by searching "soy bad." You have to know something about biology and what to look for.

Selected refs, since I'm not spending my entire night copying them. 

447. Duffy, C., Perez, K.&Partridge, A. (2007) Implications of phytoestrogen intake for breast cancer. CA Cancer J Clin 57, 260–77.

1445. Power, K.A. & Thompson, L.U. (2007) Can the combination of flaxseed and its lignans with soy and its isoflavones reduce the growth stimulatory effect of soy and its isoflavones on established breast cancer? Mol Nutr Food Res 51, 845–56.

846 . Jones, J.L., Daley, B.J., Enderson, B.L., Zhou, J.R. & Karlstad, M.D. (2002) Genistein inhibits tamoxifen effects on cell proliferation and cell cycle arrest in T47D breast cancer
cells. Am Surg 68, 575–7; discussion 577–8.

852. Ju, Y.H., Doerge, D.R., Allred, K.F., Allred, C.D.&Helferich, W.G. (2002) Dietary genistein negates the inhibitory effect of tamoxifen on growth of estrogen-dependent human breast cancer (MCF-7) cells implanted in athymic mice. Cancer Res 62, 2474–7.

42. Allred, C.D., Allred, K.F., Ju, Y.H., Virant, S.M. & Helferich, W.G. (2001) Soy diets containing varying amounts of genistein stimulate growth of estrogen-dependent (MCF-7) tumors in a dose-dependent manner. Cancer Res 61, 5045–50.

1464. Qin, L.Q., Xu, J.Y., Tezuka, H., Wang, P.Y. & Hoshi, K. (2007) Commercial soy milk enhances the development of 7,12-dimethylbenz(a)anthracene-induced mammary tumors in rats. In Vivo 21, 667–71.

1622. Seo, H.S., DeNardo, D.G., Jacquot, Y., et al. (2006) Stimulatory effect of genistein and apigenin on the growth of breast cancer cells correlates with their ability to activate ER
alpha. Breast Cancer Res Treat 99, 121–34.

1803. Tonetti, D.A., Zhang, Y., Zhao, H., Lim, S.B. & Constantinou, A.I. (2007) The effect of the phytoestrogens genistein, daidzein, and equol on the growth of tamoxifen-resistant T47D/PKC alpha. Nutr Cancer 58, 222–9.

730. Hirose, K., Takezaki, T., Hamajima, N., Miura, S. & Tajima, K. (2003) Dietary factors protective against breast cancer in Japanese premenopausal and postmenopausal women. Int J Cancer 107, 276–82.

488. Ellis, R., Kelsay, J.L., Reynolds, R.D., et al. (1987) Phytate:zinc and phytate X calcium:zinc millimolar ratios in self-selected diets of Americans, Asian Indians, and Nepalese. J Am Diet Assoc 87, 1043–7.

590. Gibson, R.S. (1994) Content and bioavailability of trace elements in vegetarian diets. Am J Clin Nutr 59 (5 Suppl), 1223S–32S.

669. Harland, B.F., Smith, S.A., Howard, M.P., Ellis, R. & Smith, J.J. (1988) Nutritional status and phytate:zinc and phytate × calcium:zinc dietary molar ratios of lacto-ovo vegetarian Trappist monks: 10 years later. J Am Diet Assoc 88, 1562–6.

1099. Lynch, S.R., Dassenko, S.A., Cook, J.D., Juillerat, M.A. & Hurrell, R.F. (1994) Inhibitory effect of a soybean-protein-related moiety on iron absorption in humans. Am J Clin Nutr
60, 567–72.

431. Doerge, D.R. & Sheehan, D.M. (2002) Goitrogenic and estrogenic activity of soy isoflavones. Environ Health Perspect 110 (Suppl 3), 349–53.

1983. Yellayi, S., Naaz, A., Szewczykowski, M.A., et al. (2002) The phytoestrogen genistein induces thymic and immune changes: a human health concern? Proc Natl Acad Sci USA 99, 7616–21.

27. Akbas, G.E., Fei, X. & Taylor, H.S. (2007) Regulation of HOXA10 expression by phytoestrogens. Am J Physiol Endocrinol Metab 292, E435–42.

Scientists at the University of Guelph have determined that a fake coffee drink they invented in their lab is really bad for you. "Yeah, we wanted to see if coffee with cream was bad for you, but we wanted to have fun with things so instead of using cream we invented our own more interesting drink!" said researcher Marie-Soleil Beaudoin. She told her graduate students to just "have fun with things" and see what they could come up with using ingredients in their expensive lab. "It was a good opportunity for them to practice things like interesterification. I told them it was a little like Iron Chef!" The final drink her students came up with was a blend of palm stearine and soybean oil chemically interesterified to achieve a random distribution of fatty acids and a ratio of PUFA:SFA of 0.2. The grad students got to show off their culinary skills by making the final drink really tasty using Aspartame and commercially available toffee flavoring. The mixture was homogenized with an electric latte whip and served warm. "It looked really fancy" said graduate student Sarah Wells. The test subjects felt really crappy upon drinking this, but especially crappy when they mixed it with coffee from the hallway vending machine. Their blood sugar levels were 32% higher and they felt awful for several days. "I've had better cofffee from McDonalds" said test subject Robert Smith, a graduate student in philosophy who was paid $5 to drink the dreck. 

No, while I took some artistic license here, this is not a joke, this is a real drink that they fed to people and then used to blame saturated fat in meats... if you didn't read the sugar you might not realize that it wasn't exactly coffee with half & half.