Vegetarian and Vegan Diets, Part 2: Fertility Issues

Did you miss Vegetarian and Vegan Diets: Nutritional Disasters Part 1? Read it HERE

Vegetarian Diets and Homocysteine

Vitamin B12 deficiencies caused by vegetarian or vegan diets are just as devastating to adults as they are to infants and pregnant women. Vitamins technically are defined as “organic catalysts” – meaning that without their presence in our diets, our metabolic machinery slows, or is sufficiently damaged to eventually cause illness and disease. One of the most destructive changes in our bodies caused by vitamin B12 deficiency is the appearance of a toxic substance in our bloodstream known as homocysteine. Without sufficient dietary sources of vitamin B12, a chemical reaction within our bodies, known as the Folate Cycle, is impaired and causes blood concentrations of homocysteine to rise. Homocysteine is a toxin for almost every cell in our bodies, and increases the risk for birth defects, infertility, dementia, psychological illness, stroke, heart attacks, blood vessel disease, blood clots, osteoporosis and overall death rates. Worldwide studies of vegetarians and vegans show that the less animal food they eat, the higher their blood concentrations of homocysteine become.^{9, 21, 38, 60, 67, 70, 94, 101}

Let’s take a look at how vegetarian diets raise blood concentrations of homocysteine and increase the risk for numerous diseases.

Homocysteine and Cardiovascular Disease

It is widely assumed that vegetarian diets reduce the risk for cardiovascular disease and heart attacks because they lower both the total fat and saturated fats in our diets. Unfortunately, this simplistic explanation is only part of the story. Total fat and saturated fat have been shown in large meta analyses to have negligible effect upon the atherosclerotic process that clogs the arteries and causes heart and blood vessel disease.^143-146

In contrast, meta analyses published in the past 15 years have confirmed that homocysteine is an independent risk factor for cardiovascular disease and heart attacks.^{61, 130} The higher your blood levels of homocysteine, the greater will be your risk of having a stroke or heart attack. As I mentioned earlier, homocysteine is toxic to almost all cells in our bodies.

It is particularly dangerous when high concentrations build up in our bloodstreams because it damages the cells that line our blood vessels. This initial injury to the blood vessels represents one of the first steps in the artery clogging process. If blood concentrations of homocysteine remain high and the blood vessel damage goes on unabated for decades, it may result in fatal strokes and heart attacks. A recent (2008) meta analysis by Dr. Humphrey and colleagues indicated that for each (5 micromol/L) increase in blood homocysteine levels, the risk for cardiovascular disease events increases by approximately 20%.⁶¹

Because vegetarian diets cause vitamin B12 levels in the bloodstream to plummet, which in turn causes homocysteine levels to dangerously rise, you might expect to find high rates of cardiovascular disease in strict lifelong vegetarians. One of the problems in examining cardiovascular disease in vegetarians from the U.S. and Europe is that many of them aren’t strict vegetarians, and typically haven’t consumed vegetarian diets for their entire lives. All of these variables tend to confound the results of epidemiological studies.

Given these issues, what better place to examine vegetarian diets and cardiovascular disease than in India? With a population of 1.17 billion people, 31% (362,700,000) of whom are vegetarians,⁴² India represents a country which can give us insight into cardiovascular disease and vegetarian/vegan diets. As opposed to vegetarians in the U.S. and Europe, many Indian vegetarians are committed to lifelong vegetarian diets due to their religious convictions and family conventions.

If vegetarian diets provide protection from cardiovascular disease as the ADA suggests, then you might expect to find a low prevalence of heart disease and stroke in India because almost one third of its population are vegetarians. Unfortunately, this is not the case.¹³⁷ In reality, the incidence of cardiovascular disease is much higher in India than in most other places in the world. Moreover, Indians develop cardiovascular disease at a much earlier age than people from other countries. In the largest study ever of 368 lifelong Indian vegetarians with cardiovascular disease, Dr. Kumar and co-workers showed that heart disease was higher in vegetarians and that they had lower blood levels of vitamin B12.⁷⁹ I quote Dr. Kumar, “We believe that the beneficial effect of a vegetarian diet in this population is circumvented by deficiency of vitamin B12.“

Homocysteine and Neurological Diseases

Not only is homocysteine toxic to our blood vessels, but numerous studies also have found that it adversely affects brain function, behavior, and mood.^{23, 129} People with higher blood concentrations of homocysteine have a greater risk for Alzheimer’s disease, dementia, depression, Parkinson’s disease, and stroke.

In a comprehensive 2010 review of 1,627 articles on high blood levels of homocysteine and vitamin B12 Dr. Werder¹³³ concluded that: “Hyperhomocysteinemia (high blood levels of homocysteine) with or without hypovitaminosis B12 (low blood levels of vitamin B12) is a risk factor for dementia.“

In addition to vitamin B12 deficiencies another B vitamin, folate, can cause blood concentrations of homocysteine to rise. However in a study involving 2,403 older people, Dr. Clarke and colleagues²⁴ found that, “the relative importance of vitamin B12 deficiency as a determinant of homocysteine concentrations and cognitive impairment is probably greater than that of folate deficiency in older adults.” Additionally, a recent study by Dr. Selhub’s research group showed that high dietary intakes of folate seems to make B12 deficiencies worse by further increasing blood concentrations of homocysteine.¹¹⁴

This is precisely the dietary pattern found in the blood of most vegetarians – low B12 and adequate or elevated folate. Is it any wonder why so many vegetarians and vegans have dangerously high blood levels of homocysteine?

Homocysteine and Bone Disease

The list of chronic diseases associated with high blood concentrations of homocysteine seems almost endless and has recently been extended to bone disease. By raising blood homocysteine levels, vegetarian diets may not only increase the risk for neurological disorders and cardiovascular disease, but they also increase bone fracture risk.

The notion that vegetarians have weaker bones than their meat eating counterparts was verified in the largest study ever undertaken in a vegetarian population (9,420 vegetarians and 1,126 vegans). The authors of the EPIC-Oxford study concluded that, “The higher fracture risk in the vegans appeared to be a consequence of their considerably lower mean calcium intake.”²

Low calcium and vitamin D intakes are well known risk factors for bone fractures and osteoporosis, and these nutritional deficiencies are common in vegan and vegetarian populations. But to add insult to injury, you can now add another strike against vegan and vegetarian diets in promoting bone disease. Since 2003, numerous studies have identified low B12, low folate, or high homocysteine blood levels as risk factors for poor bone density, increased fractures, or osteoporosis.^{2, 4, 17, 34, 51, 53, 54, 58, 78, 82, 112, 125}

Although we don’t completely understand how high blood levels of homocysteine adversely affect bone, tissue studies have identified a number of mechanisms. First homocysteine seems to impair the normal bone mineralization process.¹⁷ It also causes an accelerated breakdown of bone and inhibits the formation of new bone cells.⁵¹ Some of the best evidence implicating homocysteine in bone disease comes from human dietary interventions. In a two year study of 559 elderly women in Japan, Dr. Sato and fellow researchers showed that supplementation of vitamin B12 and folate reduced blood concentrations of homocysteine by 38%.¹¹² But more importantly women in the vitamin supplemented group suffered 33 fewer hip fractures than women in the un-supplemented control group.

One of the best ways you can prevent hip fractures is to follow The Paleo Diet®. Because you will be eating meat and fish at virtually every meal, you won’t have to worry about vitamin B12 deficiencies, as these two foods are our best sources of this essential vitamin. The other mainstay of The Paleo Diet is fresh fruit and veggies which are rich sources of the B vitamin, folate. The combination of lots of meat and fish along with plenty of fruits and vegetables at every meal will ensure that you do not develop vitamin B12 or folate deficiencies and that your blood homocysteine levels will remain low throughout your life – just as nature intended.

Homocysteine and Infertility

Before we move on from homocysteine, there’s one more aspect to cover that, for some of you, may be the most important revelation of all about this noxious molecule.

By now, you know that elevated blood concentrations of homocysteine result primarily from too little vitamin B12 and folate in our diets. When adequate stores of these two B vitamins are present from nutritious foods in our diet (e.g. meats, fresh fruits and veggies), then our cells can defuse the poisonous effects of homocysteine and convert it into less toxic compounds. However, when B12 is lacking or deficient, as it almost always is in vegetarian and vegan diets, then homocysteine builds up in our bloodstream and literally infiltrates nearly every cell in our bodies.

Healthy egg cells in women and healthy sperm cells in men are absolutely essential requirements for getting pregnant, staying pregnant, producing normal embryos, and having both vigorous infants and healthy children. Elevated blood levels of homocysteine can cause numerous adverse health problems in pregnant women, their unborn fetuses, and nursing infants.

In addition to these unfavorable effects, a diet deficient or marginal in vitamins B12 and folate can severely reduce your chances for a successful conception. Infertility is a huge problem in both the U.S. and elsewhere^{11, 122} and affects at least 6 million people in the U.S. or more importantly about 7.4% of the reproductive age population.¹¹⁹ Many environmental and genetic factors may be involved. However, one thing is certain, as a couple, if you or your partner’s blood levels of vitamin B12 and/or folate are low and your homocysteine is elevated, your chances for a normal conception and pregnancy will be significantly reduced.^{8, 12-14, 30, 36, 93, 98, 116, 128}

The injurious effects of homocysteine in our bones and in our cardiovascular and nervous systems, have been much better studied than in our reproductive systems. Nevertheless, it is becoming increasingly evident that the low vitamin B12 and folate status responsible for elevated homocysteine is toxic to both sperm and egg cells and may represent a major, previously unrecognized risk factor for infertility. More than 30 years ago, at least one group of researchers pointed out that Indian vegetarian men maintained lower vitamin B12 concentrations in their sperm than non-vegetarians and attributed these values to their vegetarian diet.⁶⁵ Additionally, a number of these earlier studies hinted that vitamin B12 supplementation could improve sperm function and vigor and even boost male fertility.^{57, 65}

In the early 21st century, similar nutritional patterns have been discovered in western populations. In a 2009 study of 172 men and 223 women who were unable to conceive, 36% of men and 23% of women had vitamin B12 deficiencies. Almost 40% of the infertile men had abnormal semen that was directly related to their vitamin B12 deficiencies. Other recent studies in men show that low dietary folate and vitamin B12 are associated with high blood concentrations of homocysteine that likely underlie abnormal sperm function.

On the flip side of the equation, women with compromised dietary B12 and folate intakes frequently have elevated blood levels of homocysteine⁶⁸ which prevent them from becoming pregnant. We are not completely sure how these blood chemistry changes impede successful pregnancies in women, but tissue studies suggest that egg cells infiltrated by homocysteine and deficient in vitamin B12 and folate make them fragile and unable to continue with a normal pregnancy once fertilized.^{13, 126}

Vegetarian Diets: Additional Fertility Problems

Menstrual Problems caused by Vegetarian Diets

In addition to B vitamin deficiencies and elevated blood concentrations of homocysteine, vegetarian diets are frequently associated with menstrual problems known to affect fertility.

A total of five studies have compared the incidence of menstrual irregularities between vegetarians and meat eaters. Four out of these five studies demonstrated significantly higher rates of menstrual complications in vegetarians. Not all types of scientific experiments have equal clout in establishing cause and effect. Of the five studies, four were epidemiological (population) studies and one was an actual experimental intervention. Because dietary interventions represent the most powerful experimental procedure for determining if dietary changes improve health or cause illness, they carry more weight than epidemiological studies. Let’s take a look at the only dietary intervention investigating vegetarian diets on menstrual health.

Dr. Pirke and researchers at the University of Trier in Germany randomly divided 18 young women with normal menstrual periods into either vegetarian or non-vegetarian diet groups. After six weeks, 7 of the 9 women assigned to the vegetarian diet stopped ovulating, whereas only a single woman in the meat eating group experienced this problem.¹⁴⁷ The results of this experiment were shocking. Within only six weeks of consuming a vegetarian diet, 78% of healthy, normally cycling women ceased ovulating. The takeaway is that if you are trying to get pregnant, one of your best strategies is to avoid vegetarian diets. While you’re at it, make sure your husband or partner does the same.

Zinc Deficiencies Impair Sperm Function

One of the most frequent nutritional shortcomings of vegetarian and vegan diets is that they fall short of recommended intakes for zinc.

In the largest epidemiological study ever of vegetarians (The EPIC-Oxford Study) Dr. Davey and colleagues noted that vegans had “…the lowest intakes of retinol [vitamin A], vitamin B12, vitamin D, calcium and zinc…” when compared to meat and fish eaters.³¹ More importantly, with zinc it’s not just how much is present in your food, but how much is actually absorbed in your body. Although dietary zinc intakes in vegetarian diets sometimes appear to be adequate on paper – in the body these diets actually result in deficiencies^{32, 44, 45, 62} because most plant-based zinc is bound to phytate and can’t be absorbed by our bodies.

Phytate is an antinutrient found in whole grains, beans, soy and other legumes that prevents normal assimilation of many minerals. Laboratory experiments show that vegetarians only absorb about half as much zinc as meat eaters because zinc from animal food is much better assimilated than from plant foods.

You might expect blood concentrations of zinc to be lower in vegetarians than meat eaters and sometimes scientists have found this to be the case, but not always. The problem has to do with where zinc ends up in our bodies after we ingest it. Most zinc finds its way into the interior of cells and does not accumulate in the liquid portion (plasma) of blood. Consequently, unless scientists examine zinc concentrations within cells, readings obtained in blood plasma frequently do not accurately reflect body stores of this essential mineral.

In virtually every study of vegetarians which measured zinc levels inside various cells (red blood cells, hair cells, and skin cells in saliva), plant based diets caused zinc deficiencies. In one study, 12 meat eating women were put on a lacto-ovo vegetarian diet, and after only 22 days Dr. Freeland-Graves and co-workers reported that zinc concentrations in the women’s salivary cells plunged by 27%.⁴⁴ Similar results were described by Dr. Srikumar and colleagues from a longer term experiment in which 20 meat eating men and women adopted a lactovegetarian diet for an entire year.¹¹⁷ In this study, both hair cells and blood levels of zinc sharply declined and remained low throughout the 12 month experiment.

Because of their low zinc content and bioavailability, long term vegetarian diets almost always cause zinc deficiencies.^{20, 32, 44, 45, 62} Numerous studies have shown that infertile/subfertile men had poor seminal quality that was associated with vegetarian diets^{6, 65} or reduced zinc levels in their semen. Virtually every well controlled experimental study ever conducted shows that men put on zinc deficient diets ended up with reduced sperm counts, impaired sperm health, and often depressed blood testosterone levels.

The good news is that these deleterious changes in male reproductive function can be reversed if zinc rich diets (e.g. The Paleo Diet) are consumed, or if zinc pills are supplemented.¹³⁶ Dr. Steegers-Theunissen’s research group in the Netherlands showed dramatic improvements in the reproductive health of 103 sub-fertile men when zinc and folic acid were supplemented.³⁷ Following the six month supplementation program, sperm counts increased significantly in the sub-fertile men while sperm abnormalities declined by 4%. A similar study of 14 infertile men from India also indicated that zinc supplementation increased sperm health, sperm counts and shortly thereafter resulted in three successful conceptions by these men’s wives.¹²³

Whether you are a man or woman, if you want to sidestep infertility problems, the best advice I can give you is to abandon vegetarian diets and adopt the nutritional patterns that have sustained our hunter-gatherer ancestors for the past 2.6 million years. There are no known risks to adopting The Paleo Diet. In fact, regular consumption of meat, seafood and fresh fruit and vegetables at the expense of cereals, dairy and processed foods will prevent vitamin B12 and folate deficiencies. In turn these essential vitamins will ensure that your blood levels of homocysteine will return to normal – effectively reducing your risk for cardiovascular, neurological, bone and reproductive diseases.

In Vegetarian and Vegan Diets, Part 3, we’ll discuss additional shortcomings of vegetarian diets and why The Paleo Diet is optimal for health and wellbeing.

References

1. Alexander D, Ball MJ, Mann J. Nutrient intake and haematological status of vegetarians and age-sex matched omnivores. Eur J Clin Nutr. 1994 Aug;48(8):538-46.

2. Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr. 2007 Dec;61(12):1400-6.

3. Appleton KM, Rogers PJ, Ness AR. Updated systematic review and meta-analysis of the effects of n-3 long-chain polyunsaturated fatty acids on depressed mood. Am J Clin Nutr. 2010 Mar;91(3):757-70

4. Baines M, Kredan MB, Davison A, Higgins G, West C, Fraser WD, Ranganath LR. The association between cysteine, bone turnover, and low bone mass. Calcif Tissue Int. 2007 Dec;81(6):450-4

5. Baines S, Powers J, Brown WJ. How does the health and well-being of young Australian vegetarian and semi-vegetarian women compare with non-vegetarians? Public Health Nutr. 2007 May;10(5):436-42.

6. Bhushan S, Pandey RC, Singh SP, Pandey DN, Seth P. Some observations on human semen analysis. Indian J Physiol Pharmacol. 1978 Oct-Dec;22(4):393-6.

7. Bennett M. Vitamin B12 deficiency, infertility and recurrent fetal loss. J Reprod Med. 2001 Mar;46(3):209-12.

8. Berker B, Kaya C, Aytac R, Satiroglu H. Homocysteine concentrations in follicular fluid are associated with poor oocyte and embryo qualities in polycystic ovary syndrome patients undergoing assisted reproduction. Hum Reprod. 2009 Sep;24(9):2293-302

9. Bissoli L, Di Francesco V, Ballarin A, Mandragona R, Trespidi R, Brocco G, Caruso B, Bosello O, Zamboni M. Effect of vegetarian diet on homocysteine levels. Ann Nutr Metab. 2002;46(2):73-9.

10. Bocherens H, Drucker DG, Billiou D, Patou-Mathis M, Vandermeersch B. Isotopic evidence for diet and subsistence pattern of the Saint-Cesaire I Neanderthal: review and use of a multi-source mixing model. J Hum Evol. 2005 Jul;49(1):71-87

11. Boivin J, Bunting L, Collins JA, Nygren KG. International estimates of infertility prevalence and treatment-seeking: potential need and demand for infertility medical care. Hum Reprod. 2007 Jun;22(6):1506-12.

12. Boxmeer JC, Smit M, Weber RF, Lindemans J, Romijn JC, Eijkemans MJ, Macklon NS, Steegers-Theunissen RP. Seminal plasma cobalamin significantly correlates with sperm concentration in men undergoing IVF or ICSI procedures. J Androl. 2007 Jul-Aug;28(4):521-7

13. Boxmeer JC, Brouns RM, Lindemans J, Steegers EA, Martini E, Macklon NS, Steegers-Theunissen RP. Preconception folic acid treatment affects the microenvironment of the maturing oocyte in humans. Fertil Steril. 2008 Jun;89(6):1766-70.

14. Boxmeer JC, Smit M, Utomo E, Romijn JC, Eijkemans MJ, Lindemans J, Laven JS, Macklon NS, Steegers EA, Steegers-Theunissen RP. Low folate in seminal plasma is associated with increased sperm DNA damage. Fertil Steril. 2009 Aug;92(2):548-56.

15. Brenna JT, Salem N Jr, Sinclair AJ, Cunnane SC. alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Prostaglandins Leukot Essent Fatty Acids. 2009 Feb-Mar;80(2-3):85-91.

16. Brown KH, Peerson JM, Baker SK, Hess SY. Preventive zinc supplementation among infants, preschoolers, and older prepubertal children. Food Nutr Bull. 2009 Mar;30(1 Suppl):S12-40.

17. Bucciarelli P, Martini G, Martinelli I, Ceccarelli E, Gennari L, Bader R, Valenti R, Franci B, Nuti R, Mannucci PM. The relationship between plasma homocysteine levels and bone mineral density in post-menopausal women. Eur J Intern Med. 2010 Aug;21(4):301-5

18. Bunn, HT, Kroll EM. Systematic butchery by Plio-Pleistocene hominids at Olduvai Gorge, Tanzania. Curr Anthropol 1986;20:365–398.

19. Calder PC, Yaqoob P. Omega-3 (n-3) fatty acids, cardiovascular disease and stability of atherosclerotic plaques. Cell Mol Biol (Noisy-le-grand). 2010 Feb 25;56(1):28-37.

20. Campbell-Brown M, Ward RJ, Haines AP, North WR, Abraham R, McFadyen IR, Turnlund JR, King JC. Zinc and copper in Asian pregnancies–is there evidence for a nutritional deficiency? Br J Obstet Gynaecol. 1985 Sep;92(9):875-85

21. Cappuccio FP, Bell R, Perry IJ, Gilg J, Ueland PM, Refsum H, Sagnella GA, Jeffery S, Cook DG. Homocysteine levels in men and women of different ethnic and cultural background living in England. Atherosclerosis. 2002 Sep;164(1):95-102.

22. Clarke R, Sherliker P, Hin H, Nexo E, Hvas AM, Schneede J, Birks J, Ueland PM, Emmens K, Scott JM, Molloy AM, Evans JG. Detection of vitamin B12 deficiency in older people by measuring vitamin B12 or the active fraction of vitamin B12, holotranscobalamin. Clin Chem. 2007 May;53(5):963-70

23. Clarke R. B-vitamins and prevention of dementia. Proc Nutr Soc. 2008 Feb;67(1):75-81.

24. Clarke R, Birks J, Nexo E, Ueland PM, Schneede J, Scott J, Molloy A, Evans JG. Low vitamin B-12 status and risk of cognitive decline in older adults. Am J Clin Nutr. 2007 Nov;86(5):1384-91.

25. Cogswell ME, Looker AC, Pfeiffer CM, Cook JD, Lacher DA, Beard JL, Lynch SR, Grummer-Strawn LM. Assessment of iron deficiency in US preschool children and nonpregnant females of childbearing age: National Health and Nutrition Examination Survey 2003-2006. Am J Clin Nutr. 2009 May;89(5):1334-42

26. Cordain L, Miller JB, Eaton SB, Mann N, Holt SH, Speth JD. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.Am J Clin Nutr. 2000 Mar;71(3):682-92.

27. Cordain L, Campbell TC. The protein debate. Catalyst Athletics, March 19, 2008. //www.cathletics.com/articles/article.php?articleID=50

28. Craig WJ, Mangels AR; American Dietetic Association. Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc. 2009 Jul;109(7):1266-82.

29. Crowe FL, Steur M, Allen NE, Appleby PN, Travis RC, Key TJ. Plasma concentrations of 25-hydroxyvitamin D in meat eaters, fish eaters, vegetarians and vegans: results from the EPIC-Oxford study. Public Health Nutr. 2011 Feb;14(2):340-6.

30. Dasarathy J, Gruca LL, Bennett C, Parimi PS, Duenas C, Marczewski S, Fierro JL, Kalhan SC. Methionine metabolism in human pregnancy. Am J Clin Nutr. 2010 Feb;91(2):357-65.

31. Davey GK, Spencer EA, Appleby PN, Allen NE, Knox KH, Key TJ. EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non meat-eaters in the UK. Public Health Nutr. 2003 May;6(3):259-69.

32. de Bortoli MC, Cozzolino SM. Zinc and selenium nutritional status in vegetarians. Biol Trace Elem Res. 2009 Mar;127(3):228-33.

33. de Heinzelin J, Clark JD, White T, Hart W, Renne P, WoldeGabriel G, Beyene Y, Vrba E. Environment and behavior of 2.5-million-year-old Bouri hominids. Science. 1999 Apr 23;284(5414):625-9

34. Dhonukshe-Rutten RA, van Dusseldorp M, Schneede J, de Groot LC, van Staveren WA. Low bone mineral density and bone mineral content are associated with low cobalamin status in adolescents. Eur J Nutr. 2005 Sep;44(6):341-7.

35. Dror DK, Allen LH. Effect of vitamin B12 deficiency on neurodevelopment in infants: current knowledge and possible mechanisms. Nutr Rev. 2008 May;66(5):250-5.

36. Ebisch IM, Peters WH, Thomas CM, Wetzels AM, Peer PG, Steegers-Theunissen RP. Homocysteine, glutathione and related thiols affect fertility parameters in the (sub)fertile couple. Hum Reprod. 2006 Jul;21(7):1725-33.

37. Ebisch IM, Pierik FH, DE Jong FH, Thomas CM, Steegers-Theunissen RP. Does folic acid and zinc sulphate intervention affect endocrine parameters and sperm characteristics in men? Int J Androl. 2006 Apr;29(2):339-45.

38. Elmadfa I, Singer I.Vitamin B-12 and homocysteine status among vegetarians: a global perspective. Am J Clin Nutr. 2009 May;89(5):1693S-1698S.

39. Falkingham M, Abdelhamid A, Curtis P, Fairweather-Tait S, Dye L, Hooper L.The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis. Nutr J. 2010 Jan 25;9:4.

40. Lightowler HJ, Davies GJ. Iodine intake and iodine deficiency in vegans as assessed by the duplicate-portion technique and urinary iodine excretion. Br J Nutr. 1998 Dec;80(6):529-35.

41. Fischer Walker CL, Ezzati M, Black RE. Global and regional child mortality and burden of disease attributable to zinc deficiency. Eur J Clin Nutr. 2009 May;63(5):591-7.

42. Food habits of a nation. In: The Hindu, August 14, 2006.
//www.hinduonnet.com/2006/08/14/stories/2006081403771200.htm

43. Fort P, Moses N, Fasano M, Goldberg T, Lifshitz F. Breast and soy-formula feedings in early infancy and the prevalence of autoimmune thyroid disease in children. J Am Coll Nutr. 1990 Apr;9(2):164-7.

44. Freeland-Graves JH, Ebangit ML, Hendrikson PJ. Alterations in zinc absorption and salivary sediment zinc after a lacto-ovo-vegetarian diet. Am J Clin Nutr. 1980 Aug;33(8):1757-66.

45. Freeland-Graves JH, Bodzy PW, Eppright MA. Zinc status of vegetarians. J Am Diet Assoc. 1980 Dec;77(6):655-61

46. Gilsing AM, Crowe FL, Lloyd-Wright Z, Sanders TA, Appleby PN, Allen NE, Key TJ. Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. Eur J Clin Nutr. 2010 Sep;64(9):933-9

47. Hansen CM, Leklem JE, Miller LT. Vitamin B-6 status indicators decrease in women consuming a diet high in pyridoxine glucoside. J Nutr. 1996 Oct;126(10):2512-8

48. Harris WS, Kris-Etherton PM, Harris KA. Intakes of long-chain omega-3 fatty acid associated with reduced risk for death from coronary heart disease in healthy adults. Curr Atheroscler Rep. 2008 Dec;10(6):503-9.

49. Herbert V. Staging vitamin B-12 (cobalamin) status in vegetarians. Am J Clin Nutr. 1994 May;59(5 Suppl):1213S-1222S

50. Herrmann W, Obeid R, Schorr H, Geisel J. Functional vitamin B12 deficiency and determination of holotranscobalamin in populations at risk. Clin Chem Lab Med. 2003 Nov;41(11):1478-88.

51. Herrmann M, Widmann T, Colaianni G, Colucci S, Zallone A, Herrmann W. Increased osteoclast activity in the presence of increased homocysteine concentrations. Clin Chem. 2005 Dec;51(12):2348-53

52. Herrmann W, Schorr H, Obeid R, Geisel J. Vitamin B-12 status, particularly holotranscobalamin II and methylmalonic acid concentrations, and hyperhomocysteinemia in vegetarians. Am J Clin Nutr. 2003 Jul;78(1):131-6.

53. Herrmann M, Peter Schmidt J, Umanskaya N, Wagner A, Taban-Shomal O, Widmann T, Colaianni G, Wildemann B, Herrmann W. The role of hyperhomocysteinemia as well as folate, vitamin B(6) and B(12) deficiencies in osteoporosis: a systematic review. Clin Chem Lab Med. 2007;45(12):1621-32

54. Herrmann W, Obeid R, Schorr H, Hübner U, Geisel J, Sand-Hill M, Ali N, Herrmann M. Enhanced bone metabolism in vegetarians–the role of vitamin B12 deficiency. Clin Chem Lab Med. 2009;47(11):1381-7.

55. Heyland DK, Jones N, Cvijanovich NZ, Wong H. Zinc supplementation in critically ill patients: a key pharmaconutrient? JPEN J Parenter Enteral Nutr. 2008 Sep-Oct;32(5):509-19.

56. Hinton PS, Sinclair LM. Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes. Eur J Clin Nutr. 2007 Jan;61(1):30-9.

57. Hirwe R, Jathar VS, Desai S, Satoskar RS. Vitamin B12 and potential fertility in male lactovegetarians. J Biosoc Sci. 1976 Jul;8(3):221-7

58. Ho-Pham LT, Nguyen ND, Nguyen TV. Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis. Am J Clin Nutr. 2009 Oct;90(4):943-50.

59. Hotz C. Dietary indicators for assessing the adequacy of population zinc intakes. Food Nutr Bull. 2007 Sep;28(3 Suppl):S430-53.

60. Huang YC, Chang SJ, Chiu YT, Chang HH, Cheng CH. The status of plasma homocysteine and related B-vitamins in healthy young vegetarians and nonvegetarians. Eur J Nutr. 2003 Apr;42(2):84-90.

61. Humphrey LL, Fu R, Rogers K, Freeman M, Helfand M. Homocysteine level and coronary heart disease incidence: a systematic review and meta-analysis. Mayo Clin Proc. 2008 Nov;83(11):1203-12.

62. Hunt JR, Matthys LA, Johnson LK. Zinc absorption, mineral balance, and blood lipids in women consuming controlled lactoovovegetarian and omnivorous diets for 8 wk. Am J Clin Nutr. 1998 Mar;67(3):421-30.

63. Hunt JR, Roughead ZK. Nonheme-iron absorption, fecal ferritin excretion, and blood indexes of iron status in women consuming controlled lactoovovegetarian diets for 8 wk. Am J Clin Nutr. 1999 May;69(5):944-52

64. Hvas AM, Morkbak AL, Nexo E. Plasma holotranscobalamin compared with plasma cobalamins for assessment of vitamin B12 absorption; optimisation of a non-radioactive vitamin B12 absorption test (CobaSorb). Clin Chim Acta. 2007 Feb;376(1-2):150-4

65. Jathar VS, Hirwe R, Desai S, Satoskar RS. Dietetic habits and quality of semen in Indian subjects. Andrologia. 1976;8(4):355-8.

66. Jenkins DJ, Kendall CW, Connelly PW, Jackson CJ, Parker T, Faulkner D, Vidgen E. Effects of high- and low-isoflavone (phytoestrogen) soy foods on inflammatory biomarkers and proinflammatory cytokines in middle-aged men and women. Metabolism. 2002 Jul;51(7):919-24

67. Karabudak E, Kiziltan G, Cigerim N. A comparison of some of the cardiovascular risk factors in vegetarian and omnivorous Turkish females. J Hum Nutr Diet. 2008 Feb;21(1):13-22.

68. Katre P, Bhat D, Lubree H, Otiv S, Joshi S, Joglekar C, Rush E, Yajnik C. Vitamin B12 and folic acid supplementation and plasma total homocysteine concentrations in pregnant Indian women with low B12 and high folate status. Asia Pac J Clin Nutr. 2010;19(3):335-43.

69. Key TJ, Fraser GE, Thorogood M, Appleby PN, Beral V, Reeves G, Burr ML, Chang-Claude J, Frentzel-Beyme R, Kuzma JW, Mann J, McPherson K. Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr. 1999 Sep;70(3 Suppl):516S-524S.

70. Key TJ, Appleby PN, Rosell MS. Health effects of vegetarian and vegan diets. Proc Nutr Soc. 2006 Feb;65(1):35-41.

71. Key TJ, Appleby PN, Spencer EA, Travis RC, Roddam AW, Allen NE. Mortality in British vegetarians: results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). Am J Clin Nutr. 2009 May;89(5):1613S-1619S

72. Key TJ, Appleby PN, Spencer EA, Travis RC, Roddam AW, Allen NE. Cancer incidence in vegetarians: results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). Am J Clin Nutr. 2009 May;89(5):1620S-1626S

73. Khedr E, Hamed SA, Elbeih E, El-Shereef H, Ahmad Y, Ahmed S. Iron states and cognitive abilities in young adults: neuropsychological and neurophysiological assessment. Eur Arch Psychiatry Clin Neurosci. 2008 Dec;258(8):489-96. Epub 2008 Jun 20.

74. Koebnick C, Hoffmann I, Dagnelie PC, Heins UA, Wickramasinghe SN, Ratnayaka ID, Gruendel S, Lindemans J, Leitzmann C. Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women. J Nutr. 2004 Dec;134(12):3319-26.

75. Knovich MA, Storey JA, Coffman LG, Torti SV, Torti FM. Ferritin for the clinician. Blood Rev. 2009 May;23(3):95-104

76. Kornsteiner M, Singer I, Elmadfa I. Very low n-3 long-chain polyunsaturated fatty acid status in Austrian vegetarians and vegans. Ann Nutr Metab. 2008;52(1):37-47

77. Krajcovicová-Kudlácková M, Bucková K, Klimes I, Seboková E. Iodine deficiency in vegetarians and vegans. Ann Nutr Metab. 2003;47(5):183-5.

78. Krivosíková Z, Krajcovicová-Kudlácková M, Spustová V, Stefíková K, Valachovicová M, Blazícek P, Nĕmcová T. The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet. Eur J Nutr. 2010 Apr;49(3):147-53

79. Kumar J, Garg G, Sundaramoorthy E, Prasad PV, Karthikeyan G, Ramakrishnan L, Ghosh S, Sengupta S. Vitamin B12 deficiency is associated with coronary artery disease in an Indian population. Clin Chem Lab Med. 2009;47(3):334-8.

80. Laidlaw SA, Grosvenor M, Kopple JD. The taurine content of common foodstuffs. JPEN J Parenter Enteral Nutr. 1990 Mar-Apr;14(2):183-8.

81. Laidlaw SA, Shultz TD, Cecchino JT, Kopple JD. Plasma and urine taurine levels in vegans. Am J Clin Nutr. 1988 Apr;47(4):660-3

82. Leboff MS, Narweker R, LaCroix A, Wu L, Jackson R, Lee J, Bauer DC, Cauley J, Kooperberg C, Lewis C, Thomas AM, Cummings S. Homocysteine levels and risk of hip fracture in postmenopausal women. J Clin Endocrinol Metab. 2009 Apr;94(4):1207-13

83. Lee-Thorp J, Thackeray JF, van der Merwe N. The hunters and the hunted revisited. J Hum Evol 2000; 39: 565–576.

84. Lin PY, Huang SY, Su KP. A meta-analytic review of polyunsaturated fatty acid compositions in patients with depression. Biol Psychiatry. 2010 Jul 15;68(2):140-7.

85. Mezzano D, Kosiel K, Martínez C, Cuevas A, Panes O, Aranda E, Strobel P, Pérez DD, Pereira J, Rozowski J, Leighton F. Cardiovascular risk factors in vegetarians. Normalization of hyperhomocysteinemia with vitamin B(12) and reduction of platelet aggregation with n-3 fatty acids. Thromb Res. 2000 Nov 1;100(3):153-60.

86. Molloy AM, Kirke PN, Brody LC, Scott JM, Mills JL. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. Food Nutr Bull. 2008 Jun;29(2 Suppl):S101-11

87. Molloy AM, Kirke PN, Troendle JF, Burke H, Sutton M, Brody LC, Scott JM, Mills JL. Maternal vitamin B12 status and risk of neural tube defects in a population with high neural tube defect prevalence and no folic Acid fortification. Pediatrics. 2009 Mar;123(3):917-23.

88. Mann N, Pirotta Y, O’Connell S, Li D, Kelly F, Sinclair A. Fatty acid composition of habitual omnivore and vegetarian diets. Lipids. 2006 Jul;41(7):637-46

89. Mariani A, Chalies S, Jeziorski E, Ludwig C, Lalande M, Rodière M. [Consequences of exclusive breast-feeding in vegan mother newborn–case report]. Arch Pediatr. 2009 Nov;16(11):1461-3.

90. McCann JC, Ames BN. An overview of evidence for a causal relation between iron deficiency during development and deficits in cognitive or behavioral function. Am J Clin Nutr. 2007 Apr;85(4):931-45.

91. McCarty MF. Sub-optimal taurine status may promote platelet hyperaggregability in vegetarians.Med Hypotheses. 2004;63(3):426-33.

92. McClung JP, Karl JP, Cable SJ, Williams KW, Nindl BC, Young AJ, Lieberman HR. Randomized, double-blind, placebo-controlled trial of iron supplementation in female soldiers during military training: effects on iron status, physical performance, and mood. Am J Clin Nutr. 2009 Jul;90(1):124-31.

93. Michie CA, Chambers J, Abramsky L, Kooner JS. Folate deficiency, neural tube defects, and cardiac disease in UK Indians and Pakistanis. Lancet. 1998 Apr 11;351(9109):1105.

94. Misra A, Vikram NK, Pandey RM, Dwivedi M, Ahmad FU, Luthra K, Jain K, Khanna N, Devi JR, Sharma R, Guleria R. Hyperhomocysteinemia, and low intakes of folic acid and vitamin B12 in urban North India. Eur J Nutr. 2002 Apr;41(2):68-77.

95. Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature. Thyroid. 2006 Mar;16(3):249-58.

96. Osendarp SJ, Murray-Kolb LE, Black MM. Case study on iron in mental development–in memory of John Beard (1947-2009). Nutr Rev. 2010 Nov;68 Suppl 1:S48-52. doi: 10.1111/j.1753-4887.2010.00331.x.

97. Plourde M, Cunnane SC. Extremely limited synthesis of long chain polyunsaturates in adults: implications for their dietary essentiality and use as supplements. Appl Physiol Nutr Metab. 2007 Aug;32(4):619-34.

98. Pront R, Margalioth EJ, Green R, Eldar-Geva T, Maimoni Z, Zimran A, Elstein D. Prevalence of low serum cobalamin in infertile couples. Andrologia. 2009 Feb;41(1):46-50.

99. Proudman SM, Cleland LG, James MJ. Dietary omega-3 fats for treatment of inflammatory joint disease: efficacy and utility. Rheum Dis Clin North Am. 2008 May;34(2):469-79.

100. Rana SK, Sanders TA. Taurine concentrations in the diet, plasma, urine and breast milk of vegans compared with omnivores. Br J Nutr. 1986 Jul;56(1):17-27.

101. Refsum H, Yajnik CS, Gadkari M, Schneede J, Vollset SE, Orning L, Guttormsen AB, Joglekar A, Sayyad MG, Ulvik A, Ueland PM. Hyperhomocysteinemia and elevated methylmalonic acid indicate a high prevalence of cobalamin deficiency in Asian Indians. Am J Clin Nutr. 2001 Aug;74(2):233-41.

102. Remer T, Neubert A, Manz F. Increased risk of iodine deficiency with vegetarian nutrition. Br J Nutr. 1999 Jan;81(1):45-9.

103. Reynolds RD: Bioavailability of vitamin B-6 from plant foods. Am J Clin Nutr 1988;48:863-67.

104. Richards MP, Pettitt PB, Trinkaus E, Smith FH, Paunovic M, Karavanic, I. Neanderthal diet at Vindija and Neanderthal predation: The evidence from stable isotopes. Proc Natl Acad Sci 2000;97: 7663–7666.

105. Richards MP, Hedges REM, Jacobi R, Current, A, Stringer C. Focus: Gough’s Cave and Sun Hole Cave human stable isotope values indicate a high animal protein diet in the British Upper Palaeolithic. J Archaeol Sci 2000;27: 1–3.

106. Roe DA. History of promotion of vegetable cereal diets. J Nutr 1986;116:1355-1363.

107. Roed C, Skovby F, Lund AM. Severe vitamin B12 deficiency in infants breastfed by vegans]. Ugeskr Laeger. 2009 Oct 19;171(43):3099-101

108. Rosell MS, Lloyd-Wright Z, Appleby PN, Sanders TA, Allen NE, Key TJ. Long-chain n-3 polyunsaturated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. Am J Clin Nutr. 2005 Aug;82(2):327-34.

109. Rush EC, Chhichhia P, Hinckson E, Nabiryo C. Dietary patterns and vitamin B(12) status of migrant Indian preadolescent girls. Eur J Clin Nutr. 2009 Apr;63(4):585-7. Epub 2007 Dec 19.

110. Sanders TA, Roshanai F. Platelet phospholipid fatty acid composition and function in vegans compared with age- and sex-matched omnivore controls. Eur J Clin Nutr. 1992 Nov;46(11):823-31.

111. Sanders TA. DHA status of vegetarians. Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep;81(2-3):137-41.

112. Sato Y, Honda Y, Iwamoto J, Kanoko T, Satoh K. Effect of folate and mecobalamin on hip fractures in patients with stroke: a randomized controlled trial. JAMA. 2005 Mar 2;293(9):1082-8.

113. Schneede J, Ueland PM. Novel and established markers of cobalamin deficiency: complementary or exclusive diagnostic strategies. Semin Vasc Med. 2005 May;5(2):140-55

114. Selhub J, Morris MS, Jacques PF. In vitamin B12 deficiency, higher serum folate is associated with increased total homocysteine and methylmalonic acid concentrations. Proc Natl Acad Sci U S A. 2007 Dec 11;104(50):19995-20000.

115. Shapin S. Vegetable love: the history of vegetarianism. New Yorker. 2007 Jan 22:80-4.

116. Singh K, Singh SK, Sah R, Singh I, Raman R. Mutation C677T in the methylenetetrahydrofolate reductase gene is associated with male infertility in an Indian population. Int J Androl. 2005 Apr;28(2):115-9.

117. Srikumar TS, Johansson GK, Ockerman PA, Gustafsson JA, Akesson B. Trace element status in healthy subjects switching from a mixed to a lactovegetarian diet for 12 mo. Am J Clin Nutr. 1992 Apr;55(4):885-90.

118. Stabler SP, Allen RH. Vitamin B12 deficiency as a worldwide problem. Annu Rev Nutr. 2004;24:299-326

119. Stephen EH, Chandra A. Declining estimates of infertility in the United States: 1982-2002. Fertil Steril. 2006 Sep;86(3):516-23.

120. Szymanski KM, Wheeler DC, Mucci LA. Fish consumption and prostate cancer risk: a review and meta-analysis. Am J Clin Nutr. 2010 Nov;92(5):1223-33.

121. Taneja S, Bhandari N, Strand TA, Sommerfelt H, Refsum H, Ueland PM, Schneede J, Bahl R, Bhan MK. Cobalamin and folate status in infants and young children in a low-to-middle income community in India. Am J Clin Nutr. 2007 Nov;86(5):1302-9.

122. te Velde E, Burdorf A, Nieschlag E, Eijkemans R, Kremer JA, Roeleveld N, Habbema D.
Is human fecundity declining in Western countries? Hum Reprod. 2010 Jun;25(6):1348-53.

123. Tikkiwal M, Ajmera RL, Mathur NK. Effect of zinc administration on seminal zinc and fertility of oligospermic males. Indian J Physiol Pharmacol. 1987 Jan-Mar;31(1):30-4.

124. van der Merwe NJ, Thackeray JF, Lee-Thorp JA, Luyt J. The carbon isotope ecology and diet of Australopithecus africanus at Sterkfontein, South Africa J Hum Evol 2003;44: 581–597.

125. van Meurs JB, Dhonukshe-Rutten RA, Pluijm SM, van der Klift M, de Jonge R, Lindemans J, de Groot LC, Hofman A, Witteman JC, van Leeuwen JP, Breteler MM, Lips P, Pols HA, Uitterlinden AG. Homocysteine levels and the risk of osteoporotic fracture. N Engl J Med. 2004 May 13;350(20):2033-41.

126. van Mil NH, Oosterbaan AM, Steegers-Theunissen RP. Teratogenicity and underlying mechanisms of homocysteine in animal models: a review. Reprod Toxicol. 2010 Dec;30(4):520-31.

127. Vegetarianism in American. Vegetarian Times Magazine, 2008. //www.vegetariantimes.com/features/archive_of_editorial/667

128. Verkleij-Hagoort AC, Verlinde M, Ursem NT, Lindemans J, Helbing WA, Ottenkamp J, Siebel FM, Gittenberger-de Groot AC, de Jonge R, Bartelings MM, Steegers EA, Steegers-Theunissen RP. Maternal hyperhomocysteinaemia is a risk factor for congenital heart disease. BJOG. 2006 Dec;113(12):1412-8.

129. Vogel T, Dali-Youcef N, Kaltenbach G, Andrès E. Homocysteine, vitamin B12, folate and cognitive functions: a systematic and critical review of the literature. Int J Clin Pract. 2009 Jul;63(7):1061-7

130. Wald DS, Law M, Morris JK. Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis. BMJ. 2002 Nov 23;325(7374):1202.

131. Waldmann A, Dörr B, Koschizke JW, Leitzmann C, Hahn A. Dietary intake of vitamin B6 and concentration of vitamin B6 in blood samples of German vegans. Public Health Nutr. 2006 Sep;9(6):779-84.

132. Wang Q, Yu LG, Campbell BJ, Milton JD, Rhodes JM. Identification of intact peanut lectin in peripheral venous blood. Lancet. 1998;352:1831-2

133. Werder SF. Cobalamin deficiency, hyperhomocysteinemia, and dementia. Neuropsychiatr Dis Treat. 2010 May 6;6:159-95

134. Whorton JC. Historical development of vegetarianism. Am J Clin Nutr 1994;59 (suppl) 1103S-9S.

135. Wilson AK, Ball MJ. Nutrient intake and iron status of Australian male vegetarians. Eur J Clin Nutr. 1999 Mar;53(3):189-94.

136. Wong WY, Merkus HM, Thomas CM, Menkveld R, Zielhuis GA, Steegers-Theunissen RP. Effects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial. Fertil Steril. 2002 Mar;77(3):491-8.

137. Xavier D, Pais P, Devereaux PJ, Xie C, Prabhakaran D, Reddy KS, Gupta R, Joshi P, Kerkar P, Thanikachalam S, Haridas KK, Jaison TM, Naik S, Maity AK, Yusuf S; CREATE registry investigators. Treatment and outcomes of acute coronary syndromes in India (CREATE): a prospective analysis of registry data. Lancet. 2008 Apr 26;371(9622):1435-42.

138. Zhao YT, Chen Q, Sun YX, Li XB, Zhang P, Xu Y, Guo JH. Prevention of sudden cardiac death with omega-3 fatty acids in patients with coronary heart disease: a meta-analysis of randomized controlled trials. Ann Med. 2009;41(4):301-10.

139. Zhao JH, Sun SJ, Horiguchi H, Arao Y, Kanamori N, Kikuchi A, Oguma E, Kayama F.
A soy diet accelerates renal damage in autoimmune MRL/Mp-lpr/lpr mice. Int Immunopharmacol. 2005 Oct;5(11):1601-10.

140. Zimmermann MB. Iodine deficiency. Endocr Rev. 2009 Jun;30(4):376-408

141. Zimmermann MB. The adverse effects of mild-to-moderate iodine deficiency during pregnancy and childhood: a review. Thyroid. 2007 Sep;17(9):829-35.

142. United States Department of Agriculture (USDA). Choose My Plate. gov. Tips for Vegetarians, //www.choosemyplate.gov/healthy-eating-tips/tips-for-vegetarian.html

143. Micha R, Mozaffarian D. Saturated fat and cardiometabolic risk factors, coronary heart disease, stroke, and diabetes: a fresh look at the evidence. Lipids. 2010 Oct;45(10):893-905.

144. Siri-Tarino PW1, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. 2010 Mar;91(3):535-46.

145. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Curr Atheroscler Rep. 2010 Nov;12(6):384-90.

146. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr. 2010 Mar;91(3):502-9

147. Pirke KM, Schweiger U, Laessle R, Dickhaut B, Schweiger M, Waechtler M. Dieting influences the menstrual cycle: vegetarian versus nonvegetarian diet. Fertil Steril. 1986 Dec;46(6):1083-8.

148. Cordain L. Cereal grains: humanity’s double-edged sword. World Rev Nutr Diet. 1999;84:19-73.

149. Rall LC, Meydani SN. Vitamin B6 and immune competence. Nutr Rev. 1993 Aug;51(8):217-25.

150. Folstein M, Liu T, Peter I, Buell J, Arsenault L, Scott T, Qiu WW.The homocysteine hypothesis of depression. Am J Psychiatry. 2007 Jun;164(6):861-7.

151. Zhang XH, Ma J, Smith-Warner SA, Lee JE, Giovannucci E. Vitamin B6 and colorectal cancer: current evidence and future directions. World J Gastroenterol. 2013 Feb 21;19(7):1005-10

152. Bougma K1, Aboud FE, Harding KB, Marquis GS. Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis. Nutrients. 2013 Apr 22;5(4):1384-416.

153. Zimmermann MB. The effects of iodine deficiency in pregnancy and infancy. Paediatr Perinat Epidemiol. 2012 Jul;26 Suppl 1:108-17