Because the comments section to my post, Comments on Bone Health Article in the Vegetarian Voice, has gotten so long, I decided to create a new post that includes Dr. Amy Joy Lanou’s response and my follow-up.

From Dr. Lanou:

“I appreciate that you have taken the time to read our article and critique it. I fear, though, that you may have missed the main point. Our overall point is that the literature is pointing to the benefits to bone of a dietary pattern that high in fruits, vegetables and other plant-matter and low protein from animal sources along with adequate weight bearing physical activity to stimulate new bone cell formation. In our book (Building Bone Vitality) we highlight the importance of consuming the at least 17 other nutrients that are important to bone (including adequate, but not excessive protein and vitamin D among 15 others) as part of a healthy dietary pattern based on whole foods from plant sources.

“The single nutrient, calcium, or single food (cow’s milk) approach to osteoporosis prevention that we have grown up with and are still being sold is not working and may even be counterproductive. Vegan nutritionists arguing over whether the actual amount of recommended calcium should be 400 to 500 mg/day as the World Health Organization recommends for avoiding osteoporosis, >525mg a day as the Appleby and Key study would suggest, or the 700 or 800 mg/day that Jack Norris, RD recommends is part of the problem….not part of the solution. We are still focusing on that same single nutrient.

“I agree that the literature is not clear on what the exact optimum amount of calcium that an individual vegan may need is…in fact, the “right amount” quite likely has to do with the persons overall dietary pattern, activity level and other individual characteristics. It is, however, quite clear to me from a broad review of the literature that vegans, vegetarians, and omnivores alike are not getting a measurable benefit to hip fracture from pushing calcium intakes via dairy products and calcium supplements from 1000 to 1200 to 1500 to 2000 mg a day as some professionals recommend. I purposefully chose not to make a personal (albeit expert) recommendation for the level of calcium for vegans to consume but instead chose to go with the recommendation of an authoritative source (the WHO) as a useful starting point. I have no argument against a person targeting a calcium intake of 800 milligrams in a whole foods vegan diet (though I would be surprised if it did help prevent fractures more than targeting 500 mg/day calcium intake.) I would suggest, however, that people taking 1000 mg of supplemental or dairy calcium a day (or more) to prevent osteoporosis stop doing so and look instead at putting their efforts instead into moving to a dietary and lifestyle pattern that supports bone health.

“Please keep in mind that Building Bone Vitality and the article in question were both written to help vegetarians and omnivores alike to understand that milk drinking is not necessary for healthy bones and to urge people to move to a diet built from health-giving and bone-supporting foods the fruits, vegetables and other plant foods and away from a diet that is built from highly processed foods, meat and cheeses. I understand that our message may not be detailed or specific enough for some clinicians and long time vegans. (I appreciate that clinicians are working to make sense out of the research and make more specific recommendations than we have.) I hope your readers will forgive us for this lack of specificity if we manage to do some good with the message (for human health, for the animals, and for the environment) along the way.

“A couple other points of clarification:

“We do address the Appleby study in the book, but not in the article. Dr. McDougall has written about the Appleby study as well and he notes that none of the fractures experienced by the vegans in this study were fractures of the hip compared to 30 in the meat eaters, 9 in the fish eaters, and 14 in the vegetarians (dairy). Hip and spine fractures are arguably the most important end point for osteoporotic fracture. Dr. McDougall suggests and this is confirmed to some degree by correspondence with Dr. Key that the younger, thinner and more highly active vegans may have had more injuries due to vigorous physical activity.

“The meta-analysis of protein intake on bone health by Darling et al published in AJCN in 2009 fails to find either benefit or a lack of benefit of protein on bone. If one approaches this study from the perspective of trying to understand the relationship between dietary patterns and bone, this result is not surprising. Again these researchers are trying to understand relationship of the single nutrient (this time) protein, in the context of widely varying dietary patterns. It makes sense then that any effect of this single nutrient might be obscured in a meta-analysis since other potentially important dietary factors likely also varied widely (fruit and vegetable intake, potassium, vitamin D, sodium, etc.).”

Dr. Lanou,

Thank you for your response. I appreciate your goal of helping humans, animals, and the environment.
I have a few more comments below.

Jack

“Hip and spine fractures are arguably the most important end point for osteoporotic fracture. Dr. McDougall suggests and this is confirmed to some degree by correspondence with Dr. Key that the younger, thinner and more highly active vegans may have had more injuries due to vigorous physical activity.”

It is interesting that the vegans did not have any hip fractures. However, the study did adjust for physical activity and age, so those differences should not explain much of the results. And to my knowledge, there is no reason to think that the lifestyles of the vegans getting more than 525 mg of calcium were any less active than the vegans getting less than 525 mg, yet those getting more than 525 mg did not have a higher fracture rate.

The cross-sectional studies on vegans’ bone health have, for the most part, not shown them to have better bone health than omnivores. Those studies are cited here.

Thus, to date, there is very little evidence that a vegan diet helps prevent osteoporosis.

I have not seen a study, that tracked calcium intake over time, that showed people with intakes of 500 mg or less have less fractures than those with higher intakes.

I realize that Dr. Lanou’s point is that we need to take a holistic approach to bone health and not focus on one nutrient. But even holistic approaches only affect bone on a molecular level; if there isn’t enough calcium to maintain bones, it doesn’t matter if the approach is holistic or not.

Because of the harm it causes cows, I very much want to see an end to the dairy industry. But it could harm cows and humans just as much if, at the same time, we tell them that it is not important to concern themselves with calcium. In my opinion, the evidence doesn’t justify taking this risk.

This entry was posted on Tuesday, December 29th, 2009 at 10:48 pm and is filed under Bones, Calcium. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.