Archive for the ‘Bones’ Category

Vitamin K

Friday, May 21st, 2010

I just updated with a page on vitamin K. Some people have claimed that you must eat animal products in order to obtain one of the two main types of vitamin K. After reviewing the research, that does not appear to be the case. Click here to read more about it.

Vitamin D Home Test Kit Available and Other Updates

Tuesday, April 20th, 2010

I just updated with the following tidbits:

Dr. Jacqueline Chan sums up the studies on vitamin D2 vs. D3, “Treatment for most of the studies finding D2 to be less effective than D3 were extremely large boluses given only once, whereas in studies finding them equally effective, the treatment was daily amounts between 400 and 2,000 IU.” (38)

Test Kit

The Vitamin D Council has partnered with ZRT Labs to make a discounted take-home vitamin D test kit available (for $65 as of April 2010).

Sun Tips

According to Dr. Jacqueline Chan, in order to make vitamin D, “The sun must shine directly on skin without being blocked by sunscreen, glass and most plastics. Glass and most plastics block UVB, the part of the spectrum that converts pro-vitamin D3 but allow passage of UVA which contributes to skin cancer.” (38)

Also according to Dr. Chan, increasing the surface of the skin exposed to the sun proportionately decreases the amount of time needed in the sun to produce the same amount of vitamin D. The duration of the sun exposure should be no more than about half the amount of time it takes for the skin to turn pink. (38)

I have also been getting the impression, based on hearing from people who have been supplementing and getting tested regularly, that it could take large amounts of vitamin D2 (1,000 – 2,000 IU per day) over the course of months to see a significant increase in 25(OH)D levels.


38. Vitamin D Update for Nutrition Professionals. Chan J. Vegetarian Nutrition. Volume XVIII, Number 1 and 2, 2009:1.

Tanning Beds, Vitamin D, and Skin Cancer

Monday, April 19th, 2010

Here are some studies addressing the question of whether tanning beds are a safe and reliable source of vitamin D.

A 2004 study found that tanners had much higher levels of vitamin D (and lower rates of vitamin D deficiency) than non-tanning bed users. They noted that to produce vitamin D, the tanning bed must emit ultraviolet B rays of 290–315 nm. This study did not indicate that they screened subjects based on the UV ray type of the tanning bed they used. A link to entire study is below (1). This study was confounded by the fact that the tanners stayed out in the sun significantly longer than non-tanners (2).

In their 2010 paper, Woo and Eide state that most tanning “devices” emit ultraviolet A rays, which do not produce much vitamin D (2). They say:

“Given the relative inefficiency of UVA-emitting tanning devices in increasing serum vitamin D levels, especially in those most at risk of vitamin D deficiency, indoor tanning is not recommendable as a way to achieve optimal vitamin D levels in the general public.”

The authors also argue that for tanning to occur, DNA damage must also occur. In fact, the American Academy of Dermatology (AAD) says, “There is no scientifically validated, safe threshold level of UV exposure from the sun or indoor tanning devices that allows for maximal vitamin D synthesis without increasing skin cancer risk (3).” The AAD recommends against using even sunlight to raise vitamin D levels.

In summary, it appears that you can get vitamin D from tanning beds if you make sure the bed uses UV B rays of 290–315 nm, but doing so can raise the risk of skin cancer.


1. Tangpricha V, Turner A, Spina C, Decastro S, Chen TC, Holick MF. Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density. Am J Clin Nutr. 2004 Dec;80(6):1645-9.

2. Woo DK, Eide MJ. Tanning beds, skin cancer, and vitamin D: An examination of the scientific evidence and public health implications. Dermatol Ther. 2010 Jan;23(1):61-71.

3. The American Academy of Dermatology. Position Statement on Vitamin D. Amended by the Board of Directors December 22, 2010. Link

Also Reviewed:

Schulman JM, Fisher DE. Indoor ultraviolet tanning and skin cancer: health risks and opportunities. Curr Opin Oncol. 2009 Mar;21(2):144-9.

Many Vegans are Not Getting Enough Vitamin D!

Saturday, March 20th, 2010

It is the end of the winter and the time of year when people’s vitamin D levels will naturally be the lowest. I am hearing from a disconcerting number of vegans (4 to be exact) who have had their vitamin D levels tested in the last month or so and have been well below normal, and close to zero in some cases. Three of these people have lived in San Diego, Santa Monica, and San Jose, which means living in a sunny climate does not guarantee you are getting enough vitamin D, unfortunately.

Try to take your lunch break outside in the sun!

(Of course, don’t overdo it and get burned.)

Vitamin D Recommendations for Blacks

Thursday, March 18th, 2010

I have lowered my vitamin D recommendations for black people black people with type 2 diabetes based on some recent, albeit preliminary, research.

Here is the paragraph I added to the article Bones, Vitamin D, and Calcium:

A 2010 study on obese African-Americans with type 2 diabetes showed that those with higher blood levels of vitamin D had more calcification of some arteries (but not others) (35). In a related article, Vitamin D levels have different effects on atherosclerosis in blacks and whites, the lead researcher, Barry I. Freedman, MD, stated, “We should use caution when supplementing vitamin D in black patients while we investigate if we are actually worsening calcium deposition in the arteries with treatment.” That said, there has also been concern about black people not getting enough vitamin D (36). It seems prudent, then, for black people to get moderate amounts of sun and if they cannot, to supplement with smaller amounts of vitamin D, such as 250 IU per day. It seems prudent, then, for black people who have type 2 diabetes not to overdo vitamin D supplementation and take closer to the DRI until more research is conducted.


35. Freedman BI, Wagenknecht LE, Hairston KG, Bowden DW, Carr JJ, Hightower RC, Gordon EJ, Xu J, Langefeld CD, Divers J. Vitamin d, adiposity, and calcified atherosclerotic plaque in african-americans. J Clin Endocrinol Metab. 2010 Mar;95(3):1076-83. Epub 2010 Jan 8. (Abstract)

36. Harris SS. Vitamin D and African Americans. J Nutr. 2006 Apr;136(4):1126-9. PubMed Abstract..

Vitamin D in UV-Treated Mushrooms

Saturday, March 6th, 2010

A couple days ago, someone posted to the SFBAVeg email list that they saw some white mushrooms in Safeway advertised as having 100% RDA for vitamin D. I was aware that some mushrooms had small amounts of vitamin D2 in them, but 100% of the RDA (5 mcg / 200 IU) was a surprise.

A follow up post linked to the article Light-zapped mushrooms filled with vitamin D, from 2006, which reported a study being conducted measuring the levels of vitamin D2 in mushrooms exposed to ultraviolet (UV) rays. I then went to PubMed and found a few abstracts (listed below) of completed studies indicating that exposing mushrooms to uv rays does increase their vitamin D content.

I’m not sure what the exact content of vitamin D in such mushrooms tends to be, but if it is about the RDA per serving, then one serving is still far short of the 25 mcg (1,000 IU) that recent research indicates might be needed for optimal health (for people not getting much sunlight). That said, eating UV treated mushrooms could be a big boost.

More info on vitamin D.

Ko JA, Lee BH, Lee JS, Park HJ. Effect of UV-B exposure on the concentration of vitamin D2 in sliced shiitake mushroom (Lentinus edodes) and white button mushroom (Agaricus bisporus). J Agric Food Chem. 2008 May 28;56(10):3671-4. Epub 2008 Apr 29.

Koyyalamudi SR, Jeong SC, Song CH, Cho KY, Pang G. Vitamin D2 formation and bioavailability from Agaricus bisporus button mushrooms treated with ultraviolet irradiation. J Agric Food Chem. 2009 Apr 22;57(8):3351-5.

Vitamin B12 & Bones

Wednesday, January 13th, 2010

I just updated’s articles on bones and homocysteine with the following:

Vitamin B12 and Bone Mineral Density

Taking vitamin B12 might also be important for bone mineral density.

A 2009 cross-sectional study of lacto-ovo vegetarian women in Slovakia found that their higher homocysteine (16.5 vs. 12.5 µmol/l; 78% vs. 45% were elevated) and lower vitamin B12 levels (246 vs. 302 pmol/l; 47% vs. 28% were deficient) were associated with significantly lower bone mineral density in the femur (1). Participants were not allowed to have been taking vitamin or mineral supplements. The researchers did not measure calcium intake or vitamin D status.

You can read more about vitamin B12 and homocysteine here.

1. Krivosikova Z, Krajcovicova-Kudlackova M, Spustova V, Stefikova K, Valachovicova M, Blazicek P, Nemcova T. The association between high plasma
homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet.
Eur J Nutr. 2009 Oct 7.

WHO Calcium Recommendations

Sunday, January 10th, 2010

After the posts I made regarding the article, A Whole Diet Approach to Building Better Bones, in the Vegetarian Voice, two people contacted me to say that the World Health Organization recommends more than the 400 to 500 mg of calcium per day as stated in the article. According to Table 4.2 on p. 71 in their document, Vitamin and Mineral Requirements in Human Nutrition, Second Edition (2004), the WHO recommends:

1,300 mg for ages 10 to 18
1,000 mg for women 19 to menopause
1,300 mg for women past menopause
1,000 mg for men 19 to 65
1,300 mg for men ages 65+

And if you missed them, there have been many comments in response to these two posts (link, link).

Dr. Lanou Responds to Jack’s Post about Calcium

Tuesday, December 29th, 2009

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.


“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.

Comments on Bone Health Article in the Vegetarian Voice

Wednesday, December 23rd, 2009

The Fall 2009 issue of Vegetarian Voice magazine, the newsletter of the North American Vegetarian Society, has an article by Amy Joy Lanou and Michael Castleman, “A Whole Diet Approach to Building Better Bones.”

I will quote from the article to sum up their arguments:

“[W]e have known for at least 20 years that fracture rates are highest in areas where dairy and calcium consumption are also the highest.”

“Research shows that a low-acid diet, one that is high in fruits and vegetables and devoid of (or low in) animal protein (meats, poultry, fish, milk, eggs and cheese) helps keep calcium in bones.”

“[Osteoporosis is] actually a disease of calcium imbalance. Drinking milk and eating dairy foods provides calcium – but these foods are so high in protein that they draw more calcium out of bone then they replace.”

“We do need some calcium. The World Health Organization recommends 400 to 500 mg/day for people in countries at high risk of osteoporosis.”

“The best approach to osteoporosis prevention – the only one that makes scientific sense – is a diet very low in or devoid of animal foods and high in fruits and vegetables, combined with walking or equivalent exercise for 30 to 60 minutes a day, every day.”

If you have been following vegan nutrition advocacy for the past two decades, nothing above should be new to you. And here are the major problems I have with it:

1. Most non-vegans in Western countries get around 800 to 1200 mg of calcium per day. At this level of intake, I agree that there is little evidence that to prevent osteoporosis one needs even more calcium. However, Lanou and Castleman imply that all you need is a vegan diet containing 400 – 500 mg of calcium per day and walking for 30 to 60 minutes for strong bones. And they leave out the most important study published to date on bone health and vegans, a 2007 report from the EPIC-Oxford study which showed that vegans had a 30% higher rate of bone fractures than did meat-eaters and lacto-ovo vegetarians!

In that study, the vegans who got more than 525 mg of calcium had the same rate of bone fractures as the meat-eaters and lacto-ovo vegetarians, showing that vegans need more than 525 mg of calcium. (In the study, 32% of vegans had calcium intakes between 525 and 699 mg per day, and 24% had greater than 699 mg per day.)

This is the only study looking at the bone fracture rates of vegans.

2. Lanou and Castleman base most of their argument on the idea that animal protein leeches calcium from the bones. As I posted a few weeks ago, a meta-analysis looking at bone health and fractures found that “Overall, the weight of the evidence shows that the effect of dietary protein [including animal protein] on the skeleton appears to be favorable to a small extent or, at least, is not detrimental.”

In my opinion, the argument that a primary cause of osteoporosis is animal protein has always been on shaky ground.

3. Lanou and Castleman leave vitamin D out of their final recommendations (they briefly mention you can get it from the sun earlier in the article). Vitamin D can be a significant problem for many vegans and needs to be addressed in discussions of bone health.

4. I do not see why it is necessary to make an argument that people only need 400 to 500 mg of calcium per day, when the evidence is so lacking (and actually points in the other direction). What harm could come from encouraging vegans to get at least the low end of what is a normal amount of calcium (like 700 to 800 mg/day) in Western countries? None. But what harm could come from vegans not getting that much? Only osteoporosis!

In summary, there is no direct evidence that a vegan diet with only 400 to 500 mg of calcium per day prevents osteoporosis. The direct evidence is just the opposite.

More info on vegan diets and bone health.