Position of the Academy of Nutrition and Dietetics: Vegetarian Diets has been released!

It states:

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage.

The paper contains a review of all the nutrients of concern for vegetarians and a summary of the research on the health and environmental benefits.

As of this writing, a free PDF was downloadable at the links to the paper above and below.

Reference

1. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016 Dec;116(12):1970-1980. • link

A paper came out in December reporting mortality rates of different diet groups from the large EPIC-Oxford study containing 60,310 people from the UK  (1).

The mortality rate before age 90 was no different between vegetarians (including vegans) and regular meat-eaters (1.02, 0.94-1.10). Vegetarians had lower rates of mortality from pancreatic cancer (0.48, 0.28-0.82) and lymphatic cancer (0.50, 0.32-0.79). Semi-vegetarians had lower rates of death from pancreatic cancer (0.55, 0.36-.86). Pesco-vegetarians had lower death rates from all cancers (0.82, 0.70-0.97) but higher rates of cardiovascular disease (1.22, 1.02-1.46).

In the main analysis (in the paragraph above), some participants were recategorized based on a change in their diet over the course of the study which included over one million person-years of follow-up. The researchers did a second analysis in which participants who changed their diets were removed, and found an 8% reduced risk of early death in vegetarians that was just statistically significant (0.92, 0.84-0.99). Limiting the results further, to deaths before age 75, strengthened the finding (0.86, 0.77-0.97).

When vegans were separated from other vegetarians, there were no statistically significant differences in mortality rates for the six main categories of death. Eliminating participants who had changed diet categories didn’t significantly change the results for vegans. There were only 166 vegan deaths as distinct from 1,929 deaths in the entire cohort; meaning that reaching statistical significance was going to be unlikely.

Results above were not adjusted for differences in body mass index (BMI); such adjustments were performed but they didn’t change the results substantially.

The fact that vegetarians didn’t have lower rates of death from heart disease in this study is surprising given that a 2013 report from EPIC-Oxford showed a highly statistically significant, 31% reduction in heart disease incidence among vegetarians (0.69, 0.58-0.82). This discrepancy as well as the lower death rates for vegetarians before age 75, but not before age 90, might be explained by cases of nonfatal heart disease leading to effective treatment.

See the link in the reference for a free copy of the paper. For results of other similar studies, please see Disease Rates of Vegetarians and Vegans.

References

1. Appleby PN, Crowe FL, Bradbury KE, Travis RC, Key TJ. Mortality in vegetarians and comparable nonvegetarians in the United Kingdom. Am J Clin Nutr. 2016 Jan;103(1):218-30. | link

A study from Taiwan shows differences between vegans, lacto-ovo vegetarians, and omnivores (1).

I’m only going to report the findings for vegans, but the study abstract lists the findings for lacto-ovo vegetarians if you’re interested.

At baseline, vegans had lower rates of abnormally high waist circumference, body mass index, blood pressure, blood glucose, total cholesterol, and LDL cholesterol. Vegans had a higher rate of abnormally low HDL cholesterol, but a lower rate of abnormally high total to HDL cholesterol ratio (which is more important than absolute HDL levels). Theses finding are all very similar to what’s been found in Western vegans.

Subjects were followed for an average of 2 years. The one statistically significant finding during follow-up for vegans was that each additional year of a vegan diet lowered the risk of obesity by 7%.

Other items of note are that the lower rates of high blood pressure could be explained by lower body mass index and that vegans ate the smallest amount of fried foods of any diet group.

In conclusion, Taiwanese vegans have better metabolic markers than omnivores.

References

1. Chiu YF, Hsu CC, Chiu TH, Lee CY, Liu TT, Tsao CK, Chuang SC, Hsiung CA. Cross-sectional and longitudinal comparisons of metabolic profiles between vegetarian and non-vegetarian subjects: a matched cohort study. Br J Nutr. 2015 Sep 10:1-8. [Epub ahead of print] | link

In December, I blogged about the Humane Research Council’s report on vegetarian recidivism (Vegetarian Recidivism Survey, Dec 15 2014).

Another report has been released on vegetarian recidivism, this time from the Toronto Vegetarian Association. You can download the 10-page report from their post, TVA Conducts First Study of Lapsed Vegetarians in Canada.

Their study surveyed 1,112 people of which 113 were lapsed vegetarians.

Getting enough nutrients was listed at the most common challenge for lapsed vegetarians with 83% listing it as a challenge (as compared to 44% of current vegetarians). Eating out was listed as the second most common challenge, with 75% of lapsed and 65% of current vegetarians considering it a challenge.

It would be interesting to know in what way they believed getting enough nutrients was a challenge–was this theoretical or did they feel bad and suspect they weren’t obtaining enough nutrients?

The report quotes a couple of the lapsed vegetarians regarding nutrition. One person said:

“I grew tired of spending so much time on meal planning to make sure I was getting the proper amount of essential amino acids, etc.”

That makes me wonder what sort of information vegetarians are getting. While vegetarians should include high-lysine foods each day, there are so many–all legumes as well as quinoa and seitan–that it really takes little planning. Hopefully they weren’t carrying around a 1971 copy of Diet for a Small Planet, adding up all the essential amino acids from every meal.

Another respondent said:

“My iron levels were dangerously low and I needed to reintroduce meat sources of iron into my diet; I began having extreme meat cravings near the end of my vegetarianism and I believe that was my body telling me I needed the iron (which I found out later due to blood tests).”

This is disconcerting, but it also reinforces a view that I’ve been cultivating for some time–that cravings for meat might be due to iron deficiency. I would like to see research done on whether this is the case and, more importantly, how easily iron deficiency anemia can be cured while vegan by using the methods I suggest of adding vitamin C to meals and avoiding coffee and tea at meal times (more info).

I have been discussing the possibilities of this sort of research with a medical doctor at a large university and perhaps something will come of it.

The underlying motivation for my nutrition work is to prevent vegetarian/vegan recidivism. I have focused on nutrition and put myself out there as someone who will help people who are having health issues with becoming vegetarian/vegan. Because of this, I regularly hear from people who are struggling and it can sometimes seem like a lot of people, but I know my view is likely skewed and I have always wanted to know just how many people quit due to health difficulties.

On December 2, the Humane Research Council (HRC) released a report, How Many Former Vegetarians Are There? which sheds some light on this question. I helped out a bit in designing some of the nutrition-related questions and have been anxiously anticipating the results. I would like to thank HRC and all the people who funded this important research.

A quick overview of the report is that it was a cross-sectional survey of 11,000 people in the USA aged 17 and older. They found that 2% are currently vegetarian/vegan, 10% are ex-vegetarian/vegan, and 84% of people who go vegetarian/vegan quit.

The researchers used a high bar for determining who was vegetarian/vegan and ex-vegetarian/vegan – the participants had to answer a food list questionnaire indicating that they were vegetarian/vegan and then also say that they considered themselves “vegetarian” or “vegan”. I have not seen such a high bar used in any previous research.

Their report covers many of the difficulties former vegetarians/vegans had on the diet, but I’m only going to focus on the health aspects in this post. I have more to say about the rest in my post Humane Research Council Survey on Vegetarian Recidivism on Vegan Outreach’s blog.

The HRC blog post linked above does not include much information about health issues, but their complete report (which you can access by signing up for a free account on their site) has more. Below are excerpts followed by my comments.

“Former vegetarians/vegans were asked if they began to experience any of the following when they were eating a vegetarian/vegan diet: depression/anxiety, digestive problems, food allergies, low cholesterol, an eating disorder, thyroid problems, protein deficiency, B12 deficiency, calcium deficiency, iron deficiency, iodine deficiency, vitamin A deficiency, vitamin D deficiency, zinc deficiency. The findings show that 71% of former vegetarians/vegans experienced none of the above. It is quite noteworthy that such a small proportion of individuals experienced ill health.”

HRC sounds pleased that only 29% experienced ill health – but that’s almost one-third of people who tried the diet. I was actually hoping to find out that, say, only 1% of former vegetarians experienced poor health because it would allow me to retire from my nutrition work that, while being a labor of love, is indeed a labor, and takes away from my other efforts. At almost 1 out of 3 people, I’m not so sure it’s time to cross the finish line and declare victory.

“All of the conditions [listed above] were experienced by some participants, though only rarely. In each case, less than 10% of lapsed vegetarians/vegans experienced one of these issues, except iron deficiency (experienced by 11%).”

Fatigue is the most common complaint I hear. I have not found any one explanation for most cases of fatigue though vitamin D deficiency and iron deficiency in female endurance runners are common.

The fact that B12 deficiency was not a big complaint is not surprising given that overt vitamin B12 deficiency symptoms normally take years to develop whereas most of the former vegetarians/vegans were only on the diet for a few months, and any lacto-ovo-vegetarians would be getting B12 from dairy and eggs.

“Respondents who indicated they began to experience at least one of the conditions were asked if it improved after they started eating meat. 82% of these respondents indicated that some or all of the conditions improved when they reintroduced meat. The most typical timeframes for improvement were: within 2–6 days (20%), within 1–3 weeks (33%), and within 1–3 months (22%).”

Interesting. For some people who come to me with severe problems that we cannot seem to solve, I have often wondered if I should suggest they try going back to eating animal products, reset their health (if it does in fact reset), and then try becoming vegetarian/vegan again more slowly.

HRC emphasized the rates at which vegetarians/vegans had gotten their vitamin B12 levels checked. I would find this somewhat irrelevant other than as a marker for knowing that vitamin B12 is important for vegans. I generally discourage vegans from getting their B12 levels checked as a way to prevent B12 deficiency in most cases because of the unreliability for people who regularly eat seaweed (including sushi) and the fact that no matter what your B12 levels turn out to be, all vegans should be getting a regular, reliable source of B12 (see Should I Get My B12 Status Tested?).

In their section on Taste, they found that about one-third of former vegetarians/vegans craved meat compared to about 8% of current. It’s a mistake to consider “cravings” and “taste” to be equivalent. You can’t simply add the taste of meat to a low-fat, low-protein vegetable and expect that to take away someone’s meat cravings. Meat cravings are about the nutrients, most notably fat and protein. Craving the “taste” of meat is a Pavlovian response for craving those nutrients. (Note: I don’t know if this has been scientifically tested in a rigorous way.)

There were two positive findings from the HRC report:

More than one-third of former vegetarians/vegans said they are interested in resuming the diet, and vegans were less likely to abandon the diet (at rate of 70% compared to 86% for vegetarians).

The rest of my comments on this survey are regarding what it means for advocacy. If interested, please see Humane Research Council Survey on Vegetarian Recidivism.

As I hope most of my readers know, I do not quickly dismiss a study just because I don’t like the results.

In 2007, when EPIC-Oxford found a higher risk of fractures among vegans who didn’t get over 525 mg of calcium day, rather than finding some limitation of the study which is always possible to do, I started emphasizing that vegans need to get more than 525 mg of calcium per day. There are many other examples.

So when I say a study whose results I don’t like is pretty much useless, it’s because the study is pretty much useless and not because I don’t like the results.

In December 2013, a cross-sectional study from Austria aiming to compare the health status of vegetarians to other diet groups was released (1), and I wrote about it in the post Austrian Vegetarians: Good News? It was, with all due respect to the researchers, one of the most oddly designed studies I have seen to describe vegetarians.

In the study, the diet categories were:

– Vegetarian (vegans, lacto-ovo-vegetarians, and pesco-vegetarians)
– Carnivorous diet rich in fruits and vegetables
– Carnivorous diet less rich in meat
– Carnivorous diet rich in meat

The researchers didn’t define these categories for the participants when they were asking them which category they belonged to.

The researchers also created a number of health indicators that I didn’t feel confident in even though they concluded that vegetarians had the best self-rated health and the lowest incidence of chronic conditions.

Then on February 7 2014, another paper from this same study was published (2). I read the abstract and saw that their conclusions were somewhat different in the more recent paper, and less favorable to vegetarians, but given the boondoggle that I considered the study to be, I put it aside with no intention of doing another write-up.

Fast forward to April 1, when an article about the February paper was published on CBSlocal.com (Atlanta), Study: Vegetarians Less Healthy, Lower Quality Of Life Than Meat-Eaters. This CBSlocal article made the rounds quickly and so I decided it was time to comment on the study.

My criticisms of the February paper are pretty much the same as for the one from December. However, the February paper had more information.

With the diet categories so poorly designed, it’s surprising that they found a number of statistically significant differences in disease incidence between the groups. In comparing the vegetarian group to the carnivorous diet rich in meat group, the vegetarians had a higher rate of allergies, cancer, and mental illness, while the rich meat group had a higher rate of urinary incontinence. Asthma, diabetes, cataracts, hypertension, heart attack, stroke, osteoporosis, among other diseases, were not significantly different across diet groups.

As for the self-reported quality of life scores, some of the information didn’t match between the two papers; for example, the December paper lists the chronic conditions score for vegetarians as 1.45 while the February version lists it as 1.29 (lower is worse), a meaningful difference in their scheme.

Enough said about the specifics of this study, other than that the February paper is available for free at the link from the citation below, so if you want to check it out on your own you can. But quibbling over the details of either of these papers is fairly pointless. As the authors state in their relatively long section on the limitations of their study (2):

“Potential limitations of our results are due to the fact that the survey was based on cross-sectional data. Therefore, no statements can be made whether the poorer health in vegetarians in our study is caused by their dietary habit or if they consume this form of diet due to their poorer health status.”

They also bring up my earlier criticism:

“Further limitations include the measurement of dietary habits as a self-reported variable and the fact that subjects were asked how they would describe their eating behavior, without giving them a clear definition of the various dietary habit groups.”

The study from Austria, with all it’s limitations, is one thing. But the article from CBS Atlanta (link), adds insult to injury.

The CBS Atlanta article suggests that the Austrian study indicates causation (“But the vegetarian diet…carries elevated risks of cancer, allergies and mental health disorders”) and ignores a huge body of much better evidence regarding vegetarian diets, making it seem like this Austrian study is all we have to go on.

In fact, as most of my readers probably already know, much better studies following vegetarians over time have shown them to have equal or better health than regular meat-eaters in a number of diseases. You can read all about those studies in the VeganHealth.org section, Research on Vegetarians and Vegans.

For those not familiar with this research, I will point you to the fact that vegans have been found to have only a fraction of the risk of developing type 2 diabetes compared to regular meat-eaters (Type 2 Diabetes and the Vegan Diet).

References

1. Burkert NT, Freidl W, Großschädel F, Muckenhuber J, Stronegger WJ, Rásky E. Nutrition and health: different forms of diet and their relationship with various health parameters among Austrian adults. Wien Klin Wochenschr. 2014 Feb;126(3-4):113-118. Epub 2013 Dec 17. | link

2. Burkert NT, Muckenhuber J, Großschädl F, Rásky E, Freidl W. Nutrition and Health – The Association between Eating Behavior and Various Health Parameters: A Matched Sample Study. PLoS One. 2014 Feb 7;9(2):e88278. | link

A study was released a couple weeks ago from Austria – a cross-sectional survey of eating habits and various health outcomes. But it has so many issues that I don’t think it’s worth commenting on except in the interest of being thorough in documenting the research on vegetarians.

Trying to infer dietary effects on health by using cross-sectional studies is always fraught with problems, but this study had even more than usual.

The diet categories included vegan, lacto-ovo-vegetarian, and pesco-vegetarian which was fine; in the final analysis all of these were grouped as “vegetarians.” The remaining diet groups were:

– carnivorous diet rich in fruits and vegetables
– carnivorous diet less rich in meat
– carnivorous diet rich in meat

This is unusual, and they didn’t define them even for the participants when they were asking them which category they belonged to.

For the health outcomes, instead of a list of diseases and incidence rates, they created a number of indicators that I would not have much confidence in. Finally, their p-values made little sense to me.

To sum up their findings, they say, “Both a vegetarian diet and a carnivorous diet rich in fruits and vegetables were related to the best self-rated health and the lowest incidence of chronic conditions. However, the quality of life was better in subjects who consume a carnivorous diet rich in meat. Nevertheless, as diets rich in fruits and vegetables were associated with better health as well as better health-related behavior, these diets should be recommended, and public health programs will be needed to reduce the health risk due to nutritional factors.”

So for what it’s worth, I suppose this is good news.

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References

1. Burkert NT, Freidl W, Großschädel F, Muckenhuber J, Stronegger WJ, Rásky E. Nutrition and health: different forms of diet and their relationship with various health parameters among Austrian adults. Wien Klin Wochenschr. 2013 Dec 17. [Epub ahead of print] | link

I have updated the VeganHealth.org page, Nutrient Intakes of Vegetarians and Vegans, with data recently released from Adventist Health Study-2 (AHS-2) (1).

Some interesting notes:

– The nutrient intakes included supplements. However, they also used median amounts (rather than averages) which means someone using a very large dose of a supplement would not skew the “average” intake.

– 45% of the AHS-2 subjects were vegetarian and approximately 8% were strict vegetarians or what I’m calling “vegan.” They eat any category of animal products (meat, fish, eggs, dairy) less than once per month.

– There were two tables of nutrient intakes given in the paper and I used the one that was not adjusted for sex, race, and age as I’m not clear what that actually means in the case of nutrient intakes.

– The lacto-ovo vegetarians ate less dairy protein than the regular meat-eaters (median intake of 7.5 vs. 11.8 g per day). I have seen people suggest that lacto-ovo vegetarians tend to eat a lot more dairy than your average meat-eater, but this shows that is, on average, not the case.

– It was great to see that the median intake of vitamin B12 for vegans was 6.3 µg per day, but there were still many vegans not getting nearly enough as the 5th percentile was at a mere .4 µg per day.

– Calcium intake for the vegans was excellent at 933 mg per day. The 5th percentile was 520 mg. This was much better than the calcium intakes in the bone fracture study from EPIC-Oxford where almost half the vegans were getting less than 525 mg per day (more info).

– Sodium wasn’t terrible at 3,066 mg per day, but would ideally not be over 2,300.

– It looks like vegans ate as many calories as the regular meat-eaters. That’s hard for me to believe and could be an error in the methodology. Or, perhaps, the vegans really did eat as many calories, but you don’t see that often.

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References

1. Rizzo NS, Jaceldo-Siegl K, Sabate J, Fraser GE. Nutrient Profiles of Vegetarian and Nonvegetarian Dietary Patterns. J Acad Nutr Diet. 2013 Aug 26. [Epub ahead of print] | link

I have updated the article Disease Rates of Vegetarians and Vegans with the results from a report on vegetarian mortality rates that was released this week from the Adventist Health Study-2. I have reproduced the highlights below.

There was also an article on this study published in the Wall Street Journal, Vegetarians Live Longer Than Meat-Eaters, Study Finds.

In 2013, death rates for the first 5.8 years of Adventist Health Study-2 (AHS2) were released (1). When combining vegans, lacto-ovo-vegetarians, pesco-vegetarians, and semi-vegetarians into one group, vegetarians had a 12% lower risk of mortality. Vegans had a 15% lower risk of death, but it was not quite statistically significant.

The difference in mortality rates can mostly be explained by a lower incidence of cardiovascular disease among vegetarian men. Vegetarian women had about the same rates as non-vegetarian women. This is similar to the findings from the first Adventist Health Study. There was also a benefit for all vegetarians for death from renal and endocrine (mostly diabetes) disease.

The researchers said that having only 5.8 years of follow-up would bias the results towards not finding differences.

In comparing their findings to British vegetarians, they said:

“The lack of similar findings in British vegetarians remains interesting, and this difference deserves careful study. In both cohorts, the non-vegetarians are a relatively healthy reference group. In both studies, the nutrient profiles of vegetarians differ in important ways from those of non-vegetarians, with vegetarians (especially vegans) consuming less saturated fat and more fiber. It appears that British vegetarians and US Adventist vegetarians eat somewhat differently. For instance, the vegetarians in our study consume more fiber and vitamin C than those of the EPIC-Oxford cohort: mean dietary fiber in EPIC-Oxford vegans was 27.7 g/d in men and 26.4 g/d in women compared with 45.6 g/d in men and 47.3 g/d in women in AHS-2 vegans; mean vitamin C in EPIC-Oxford vegans was 125 mg/d in men and 143 mg/d in women compared with 224 mg/d in men and 250 mg/d in women in AHS-2 vegans. Individuals electing vegetarian diets for ethical or environmental reasons may eat differently from those who choose vegetarian diets primarily for reasons of perceived superiority for health promotion. We believe that perceived healthfulness of vegetarian diets may be a major motivator of Adventist vegetarians.”

Make sure you eat your fiber!

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1. Orlich MJ, Singh P, Sabaté J, et al. Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2. JAMA Intern Med. 2013;():1-8. doi:10.1001/jamainternmed.2013.6473. | link

Released last week:

Heart disease rates of all vegetarians compared to all non-vegetarians were calculated for EPIC-Oxford from 1993 until 2009 (1). These participants were all thought to be free of heart disease at the beginning of the study. The results showed that vegetarians had a statistically significant, ~30% reduced risk of heart disease (.68, .58-.81). That is a fairly impressive finding for a nutrition study.

All results were adjusted for age, smoking, alcohol, physical activity, education, socioeconomic status, oral contraceptives, and hormone replacement therapy. The findings held after adjusting for body mass index (BMI) and removing the first two years of follow-up. (See the table in EPIC-Oxford: Heart Disease (2013) of VeganHealth.org for the relative risks.)

The researchers believed the difference in heart disease rates to be due mainly to the lower non-HDL cholesterol and systolic blood pressure of the vegetarians. The non-vegetarians had an average total cholesterol level of 222 mg/dl vs. 203 mg/dl for the vegetarians, while HDL was 52 vs. 50 mg/dl respectively. Systolic blood pressure was 134 for non-vegetarians and 131 mm Hg for vegetarians.

Given that vegetarians had cholesterol levels an average of 203 mg/dl – a full 33% higher than the 150 mg/dl, upper-end-of-healthy that many of the very low-fat doctors recommend – it might come as a surprise to learn that, in the authors’ words, “On the basis of the absolute rates of hospitalization or death from IHD [ischemic heart disease], the cumulative probability of IHD between ages 50 and 70 y was 6.8% for nonvegetarians compared with 4.6% for vegetarians.”

In other words, with cholesterol levels that high in both groups, you might think they would have a very high rate of heart disease, but, from what I can tell (see reference #2), their rates are relatively comparable to the general population of the United States (2).

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Reference

1. Crowe FL, Appleby PN, Travis RC, Key TJ. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. Am J Clin Nutr. 2013 Jan 30. [Epub ahead of print] | link

2. Prevalence of Coronary Heart Disease — United States, 2006–2010
Morbidity and Mortality Weekly Report (MMWR) for October 14, 2011. Accessed February 3, 2013. | link (PDF)