New Study Answers Questions about the Vegan Diet, Calcium, and Bone Health

March 1, 2007

Here's an article I wrote about a study that just came out. I think it's important that vegans be aware of it.

Jack Norris, Registered DietitianVegan Outreachwww.veganoutreach.org

If you’ve been a vegan for long, you’ve probably heard that:

Too much protein, especially animal protein, is the major cause of osteoporosis.

Not only does dairy not protect against osteoporosis, it actually contributes to it.

Calcium intake isn’t very important for protecting against osteoporosis.

Finally, you might have come to the conclusion that the lower levels of protein in a vegan diet protect against osteoporosis.

For almost ten years now, Vegan Outreach has cautioned vegans that the jury was still out on these issues and that vegans should try to meet the U.S. recommended intakes for calcium. In recent years, the evidence has been mounting against the above statements. In February of 2007, a study was released, the first study of its kind, that gives us pretty good answers to these questions (1).

The EPIC-Oxford study recruited 57,000 participants, including over 1,000 vegans and almost 10,000 lacto-ovo vegetarians (LOV), from 1993 to 2000. They were asked to fill out a questionnaire to measure what they ate. About 5 years after entering the study, they were sent a follow-up questionnaire asking if they had suffered any bone fractures.

After adjusting for age alone, the vegans had a 37% higher fracture rate than meat-eaters. After adjusting for age, smoking, alcohol consumption, body mass, physical activity, marital status, and births and hormone replacement therapy for women, the vegans still had a 30% higher fracture rate.

That’s not good news; in fact, it’s something I’ve feared for some time now given the vegan propaganda about animal protein, calcium, and bones which has fostered complacency among vegans about calcium and vitamin D.

Yet, there is some good news in this study. When calcium intake was adjusted for, the vegans no longer had a higher rate of fractures. And among the subjects who got 525 mg of calcium a day (only 55% of the vegans compared to about 95% of the other diet groups), vegans had the same fracture rates as the other diet groups. (And if you’re wondering about how the other diet groups (meat-eaters, fish-eaters, and LOV) fared over all, none of them differed from each other in any of the analyses performed.)

Does this mean lower calcium intakes are the cause of the fractures? It could be that people who eat more calcium also eat more or less protein or get more vitamin D. The authors noted that fracture rates did not correlate with protein or vitamin D intake among the people in this study. For now, we should assume that calcium is what the vegans with higher fracture rates were lacking.

The study did not measure calcium intake from supplements. I’m not sure if this affected the results, but for now I would assume it did not.

The US recommended intake for calcium is 1,000 mg for most adults. The UK’s recommended intake is 700 mg. You can get this much calcium by having 3 servings of high calcium foods (fortified drinks, large portion of high calcium greens, and calcium tablets) each day. I drink soymilk fortified with calcium on most days and take a 500 mg calcium pill each night before bed.

More information on calcium, vitamin D, and bones can be found at VeganHealth.org on this page: http://www.veganhealth.org/articles/bones

Footnote

1. Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr. 2007 Feb 7; [Epub ahead of print]

http://tinyurl.com/2ms6kq