In November of 2010, the Institute of Medicine released a report, Dietary Reference Intakes for Calcium and Vitamin D. This was a long-awaited report given that in the time since their previous report from 1997, many researchers have been arguing that:

• In addition to causing rickets and osteomalacia, vitamin D deficiency can lead to many other diseases including cancer and autoimmune diseases.
• Optimal amounts of vitamin D in the blood are between 80 to 100 nmol/l (32 to 40 ng/ml), which was much higher than previously thought.
• Many more people than ever before are deficient in vitamin D, especially given the higher levels thought to be optimal.

I also promoted the higher levels for vitamin D, especially given that studies published in the late 2000s on vitamin D listed categories of “insufficiency” and “deficiency” that were in line with the more recent, higher recommendations by some researchers.

But when the Institute of Medicine released their report last November, they did not agree, for the most part, with the three points above. Their Report Brief summarizes their findings (on both calcium and vitamin D):

The committee assessed more than one thousand studies and reports and listened to testimony from scientists and stakeholders before making its conclusions. It reviewed a range of health outcomes, including but not limited to cancer, cardiovascular disease and hypertension, diabetes and metabolic syndrome, falls, immune response, neuropsychological functioning, physical performance, preeclampsia, and reproductive outcomes. This thorough review found that information about the health benefits beyond bone health—benefits often reported in the media— were from studies that provided often mixed and inconclusive results and could not be considered reliable. However, a strong body of evidence from rigorous testing substantiates the importance of vitamin D and calcium in promoting bone growth and maintenance.

The IOM did increase the RDA for vitamin D from 400 IU to 600 IU for adults. But they continue to recommend ideal levels of vitamin D to be between 40 – 50 nmol/l (16 – 20 ng/ml).

I recently finished going back through many of the study summaries on the Bones, Vitamin D, and Calcium page of VeganHealth.org and adjusted them to reflect the IOM’s findings. I also added some information from other vitamin D studies, such as one on tanning beds, another on vitamin D2 vs. D3, and a 2011 report from EPIC-Oxford on vitamin D levels in vegetarians.

The good news is that many vegans who were struggling to raise their vitamin D levels to 80 nmol/l no longer need to worry about that, as 40 – 50 nmol/l is apparently fine and is the recommendation I will be promoting unless the IOM changes its recommendations in the future or there is other overwhelming evidence to do so.

This does not negate the importance of vegans making sure they get a reliable source of vitamin D. As I’ve pointed out many times, I have been contacted by many vegans whose vitamin D levels dropped well below 40 nmol/l and developed symptoms of deficiency. And even without overt symptoms (such as fatigue, or muscle or bone pain), you should not allow your bones to be harmed because you are neglecting vitamin D. My recommendations have stayed pretty much the same – if you are not getting enough sun to produce plenty of vitamin D, you should take about 1,000 IU of vitamin D per day.

Fat Soluble Vitamins: Do They Stand Between Vegans and Health?

If you’ve ever thought that nutrition research has no rhyme or reason to it, this article should help clear up the different types of studies and what they are useful for:

Basics of Nutrition Research

Afterwards, I will be signing copies of Vegan For Life which comes out July 12. You can pre-order a copy by clicking on the box:

Facebook Event Page

Erik Marcus of Vegan.com has published his book, The Ultimate Vegan Guide, as a 99 cents download for the Kindle. The Ultimate Vegan Guide is packed full of helpful tips about being vegan and will quickly bring any newbie up to speed.

Click here to order:
The Ultimate Vegan Guide

JackNorrisRD.com will get a percentage of your order. Thank you!

Dr. Andreea Soare from Washington University is looking for vegans to be part of their study on diet and gut bacteria. Dr. Soare writes:

If you are interested in participating in this study we will send you at home:
– A revised informed consent for you to read and sign.
– A box with all the materials (small container, etc) and directions needed to obtain and ship a stool sample to us, twice at one month intervals, we may ask you for a third stool sample.

The study is very easy and noninvasive (and you do not have to travel to St.Louis):
– We will ask you to do a 7-day food diary record previously of every stool collection.
– We will send you a box with instructions on how to collect the stool sample. Once the collection has been done, you can send it back to us via FedEx (we will pay for FedEx service).

Inclusion and Exclusion criteria for the study are:
– You have to be free of any chronic disease and to have followed the vegan diet for at least 3 years.
– No exclusively raw diets.
– If you took an antibiotic in the previous 3 months, we need to postpone the stool collection.

If you are interested in taking part of the study “Long-term effects of calorie restriction in humans: comparison to usual USA diet, exercise training, or a vegan diet”, in order to get started, we need your current address where we can mail the box, your birth date, age, gender, race, dietary history (how long are you on vegan diet), gastro-intestinal disease history and if you took any antibiotics in the last 3 months.

Andreea Soare, MD
Washington University
660 S. Euclid Eve. – Campus Box 8113
St Louis, MO, 63110-1093

Tel. +1-314-362-2394
Fax. +1-314-747-1050

E-mail: asoare@dom.wustl.edu

I was reading the latest issue of the Vegetarian Nutrition Dietetic Practice Group’s newsletter and saw that there had been a review article published in 2009 that listed data from the Adventist Health Study-2 that has not been reported elsewhere to my knowledge. It is cross-sectional data that showed vegans to have a 75% reduced risk of high blood pressure compared to non-vegetarians.

More details can be seen in Table 11 of Disease Markers of Vegetarians.

Because this is cross-sectional data, it does not mean a vegan diet reduces the risk of high blood pressure by 75%. It could be that people with high blood pressure are less likely to become vegan. And the results were not adjusted for smoking.

Prospective data from AHS-2 should help clarify how much is from the vegan diet in the coming years.

I have finally finished my article on choline! It is posted at VeganHealth.org.

After all was said and done, it was much ado about not much. Still, it is important that the issue of choline in vegan diets has now been researched.

Here is the summary from the article:

Choline is found in a wide range of plant foods in small amounts. Eating a well-balanced vegan diet with plenty of whole foods should ensure you are getting enough choline. Soymilk, tofu, quinoa, and broccoli are particularly rich sources.

The Dietary Reference Intake (DRI) for choline is 550 mg/day for men and 425 mg/day for women. It is based on only one study comparing those amounts to 50 mg/day, with no intermediary amounts examined. Eating less than 50 mg/day can result in liver damage, but it is very unlikely that a vegan would have such a low intake.

Some people have genetic mutations that increase the need for choline; it is not clear how much choline such people need but the DRI is probably adequate for almost everyone. If you suspect any sort of liver dysfunction, it might be worth talking to your physician about boosting your choline intake or supplementing with it in moderate amounts.

The data on choline and chronic disease (cardiovascular disease, dementia, and cancer) is somewhat mixed. Ideal amounts appear to be about 300 mg per day. Most vegans probably get about that much from the foods they eat.

Vegan women who are considering getting pregnant should make sure they are meeting the DRI for choline to reduce the risk of neural tube defects, and might need a modest supplement.

End summary.

As part of writing this article, I recorded everything I ate from one day and then calculated the amount of choline. When I recorded the food I ate, I didn’t know how much choline was in any of it as I had never done more than casually browse the USDA’s list of the choline content of foods. I actually expected it to be quite low, so it came as a nice surprise to find I met the recommendations I had already formulated before conducting the diet analysis. You can see my diet record in Table 2 of the article.

My choline intake came to 343 mg. However, there was no amount listed for hummus (or garbanzo beans) in the USDA database. Based on other legumes, I would assume at least 20 mg for 1/2 cup of hummus which would boost my intake to 363 mg. I was pretty surprised that after I plugged everything into the database, the only foods without values were hummus, canola oil, and grapeseed oil.

I list eating .5 cup of tofu. That was actually my estimate for the amount of tofu in Tofurky (4 slices for lunch and a 1/2 sausage for dinner). Tofurky is made from pressed tofu.

Not too long before I started writing this article, I purchased a bottle of choline supplements and started taking 300 mg twice a day (600 mg total). As I got further along in the choline research, I decided it might not be such a good idea to take so much. And since doing my diet analysis, I haven’t seen much need to to take any at all. It had been an experiment to see if taking choline would make me feel any different and I didn’t notice any change after a few weeks.

In conclusion, most vegans are probably getting enough choline in their diets.

I’d like to give special thanks to Jean Bettanny for doing another fantastic job in proofing the choline article!

On April 27, Dr. Neal Barnard of PCRM wrote about a study, the Prostate Cancer Prevention Trial (1), which found that men with a higher percentage of DHA in their blood had a higher risk of high grade prostate cancer (Omega-3 Fatty Acids Linked to Prostate Cancer Risk). Dr. Barnard’s article also suggested that eating fish (the primary source of DHA for most people) five times or more a week could cause type 2 diabetes. People have written me asking if this means they should stop taking DHA supplements.

Based on the results from the Prostate Cancer Prevention Trial (PCPT) and some other studies, it is probably safe to conclude that large amounts of DHA do not prevent prostate cancer, but I think it is too soon to say that large amounts causes it. There are many variables when comparing percentages of fatty acids and disease, and the results tend to be all over the map. For example, the report from PCPT also found that the dreaded trans fats were inversely linked to high grade prostate cancer.

The levels of DHA in the blood of the men who had a higher rate of prostate cancer in the PCPT were >3.3% (compared to the lowest category of ≤2.6%), whereas vegans tend to have much lower levels of DHA, typically about 1% (see Omega-3 Fatty Acid Recommendations for Vegetarians).

DHA (and EPA) are normally promoted for reducing heart disease, but that is only a minor reason why I promote it for vegans. Vegans have much lower levels than omnivores and my concern is getting enough DHA for nerve tissue to function optimally. The amounts I recommend are much lower than what are typically suggested for fish oil supplements (usually 500 mg per day or more). I would not recommend taking that much DHA, EPA, or a combination.

It is still a good idea for vegans to take DHA at the rate of 200 to 300 mg every 2 to 3 days. The recent research does give me some pause in continuing to recommend 200 to 300 mg per day for those over 60 years old, cutting that down to every other day might be prudent. Unfortunately, there is no research showing how much these amounts of DHA will raise blood levels of DHA in vegans, but based on related research, I do not think it is enough to raise it much above 2%, which would still put someone in the lowest category of DHA percentage from the PCPT trial.

Reference

1. Brasky TM, Till C, White E, Neuhouser ML, Song X, Goodman P, Thompson IM, King IB, Albanes D, Kristal AR. Serum Phospholipid Fatty Acids and Prostate Cancer Risk: Results From the Prostate Cancer Prevention Trial. Am J Epidemiol. 2011 Apr 24. [Epub ahead of print] (Link)

Metabolic syndrome is a cluster of disorders that are associated with an increased risk of diabetes and cardiovascular disease. The disorders generally include high blood pressure, triglycerides, waist circumference, blood sugar, and low HDL cholesterol.

Cross-sectional data of 773 subjects from the Adventist Health Study-2 (AHS2) showed that, when compared to regular meat-eaters, vegetarians (those eating meat or fish less than 1 time per month) had a 56% lower rate of metabolic syndrome (0.44, 0.30-0.64). Adjustments were made for age, sex, ethnicity, smoking, alcohol intake, physical activity, and caloric intake.

Semi-vegetarians (defined as consuming fish at any frequency but consuming other meats ≥ 1 time per month but < 1 time/week), had an intermediate rate (specific data not reported).

It was somewhat disturbing (though not completely surprising given a previous report from the AHS2) to see that although the vegetarians had the lowest average body mass index of the three groups, even theirs would be considered overweight at 25.7 kg/m² (healthy is considered to be 20.0 to 25.0).

Thanks, Matt and Dima.

Reference

Rizzo NS, Sabaté J, Jaceldo-Siegl K, Fraser GE. Vegetarian Dietary Patterns Are Associated With a Lower Risk of Metabolic Syndrome: The Adventist Health Study 2. Diabetes Care. 2011 Mar 16. (Link)