Some odds and ends:

1. If you haven’t checked out PeaCounter.com in awhile, I have made it a lot more user-friendly over the course of the last few months. The latest improvements are to allow you to choose either US or metric units when calculating BMI, Ideal Body Weight, or Energy Requirements, and to allow for commas in place of decimal points on those pages (as some people requested).

2. Don’t forget that you can support JackNorrisRD.com by using the Amazon and Pangea (the Vegan Store) links in the sidebar of the website.

3. You can click here for a video of my Vegan Nutrition: What Does the Science Say? talk that I gave to the San Francisco Vegetarian Society in March of 2012. I have placed a permanent to link to this talk on the About page of JackNorrisRD.com.

Thank you!

Nina Planck is up to her old shenanigans of spreading joy to the world. Ginny’s response:

The New York Times, Nina Planck, and Safety of Vegan Diets

And Ginny and VeganHealth.org are mentioned in a seemingly related LA Times piece:

In vegan debate, one thing parents must agree on

Two bits of vitamin D2 news:

1. Vesanto Melina, author of Becoming Vegan, kindly passed on a study about vitamin D2 in UV-irradiated mushrooms. 28,000 IU of vitamin D2 was fed to subjects either in the form of a supplement or from mushrooms, one time per week for four weeks. Vitamin D levels increased from 34 to 57 nmol/l in the mushroom group, and from 29 to 58 nmol/l in the supplement group (recommended levels are 40 – 50 nmol/l). The placebo group’s vitamin D2 levels decreased over the course of the study (1).

2. Dole is now making a Portobello Mushroom Powder with the RDA of 600 IU per teaspoon. (Link)

Reference

1. Urbain P, Singler F, Ihorst G, Biesalski HK, Bertz H. Bioavailability of vitamin D₂ from UV-B-irradiated button mushrooms in healthy adults deficient in serum 25-hydroxyvitamin D: a randomized controlled trial. Eur J Clin Nutr. 2011 Aug;65(8):965-71. doi: 10.1038/ejcn.2011.53. Epub 2011 May 4. | link

From March 20, 2012:

I was wondering if you saw this study [showing that increased vitamin D intake, but not increased dairy and calcium, protected adolescent girls against stress fractures] that went around yesterday, and saw PCRM’s release on it. I only read the abstract, but didn’t see that higher intakes of calcium was correlated with higher risk of bone fracture. I was wondering what you thought about this, because I remember you referencing some studies showing that vegans have higher rates of bone fracture, and that the difference went away when the vegans had high enough intakes of calcium. Was that because they were getting the calcium from plant sources, you reckon?

Answer:

It is only one study (EPIC-Oxford, 2007) showing vegans to have a higher fracture rate, the only study measuring fracture rates in Western vegans. It showed that the category of vegans getting less than 525 mg/day of calcium had a higher fracture rate than other diet groups, but that vegans getting more calcium had the same rate.

I did see PCRM’s press release on this study and have since obtained a copy of the paper. Although not mentioned in the abstract, the study found a trend towards increased risk of stress fracture with increased calcium intakes, among girls in the high impact activity category, though the finding was not statistically significant.

These results have little bearing, one way or the other, on my recommendations that vegans get more than 525 mg/day of calcium (and preferably 700 – 1,000 mg/day). The lowest category of calcium intake was 541 mg/day. The second lowest was 825 mg/day and that category didn’t have a practically different risk compared to the lowest category. It wasn’t until the middle category of calcium intake, an average of 1,111 mg per day, that there was a strong trend towards higher risk of stress fracture (though, again, it wasn’t statistically significant).

Here are some excerpts from the paper’s discussion:

“Our findings are not consistent with those reported in a prospective study of 125 young adult female competitive distance runners, which found that higher intakes of calcium and dairy products predicted lower rates of stress fracture and that higher intakes of vitamin D, calcium, and dairy foods were all associated with significant gains in hip bone mineral density during the 2 years of follow-up.

“Our findings are supported by several studies that have found no association between dairy intake and bone health in children and adolescents. While 2 randomized trials reported a positive relationship between dairy product consumption and measures of bone health, most cross-sectional, retrospective, and prospective studies did not. A review of calcium intake, dairy product intake, and bone health found that the vast majority of controlled studies of dairy supplementation or total dietary calcium intake show that, although very low calcium intake may be harmful to bone development, increases in dairy or total dietary calcium intakes higher than 400 to 500 mg/d are not correlated with nor represent a predictor of bone mineral density or fracture rate in children or adolescents.”

The evidence appears to be mixed as to whether calcium intakes higher than 400 to 500 mg in children and adolescents is protective, harmful, or neutral. EPIC-Oxford remains the most important finding for vegans.

Reference

Sonneville KR, Gordon CM, Kocher MS, Pierce LM, Ramappa A, Field AE. Vitamin D, Calcium, and Dairy Intakes and Stress Fractures Among Female Adolescents. Arch Pediatr Adolesc Med. 2012 Mar 5. [Epub ahead of print] | link

A reader told me that she has been seeing aloe vera talked about as a source of vitamin B12 recently. HerbWisdom.com says, “Aloe vera is one of the only known natural vegetarian sources of Vitamin B12,…”

Sigh. It turns out that there have been a couple studies which show that aloe vera enhances the absorption of vitamin B12 for older people:

Yun JM, Singh S, Jialal R, Rockwood J, Jialal I, Devaraj S. A Randomized Placebo-Controlled Crossover trial of Aloe Vera on Bioavailability of Vitamins C and B(12), Blood Glucose, and Lipid Profile in Healthy Human Subjects. J Diet Suppl. 2010 Jun;7(2):145-53. | link

Devaraj, S., Patel, S., Jialal, R., Jialal, I. Aloe supplements enhance bioavailability of vitamin C and B12 in older adults. The FASEB Journal: Experimental Biology 2007 Abstracts 8.1-701.35. Washington, DC; April 28-May 2, 2007. | cited here

Of course, increasing absorption of B12 is not the same as actually containing it. (Please note that I don’t know anything about how to increase B12 absorption through the use of aloe vera.)

And, unsurprisingly, I couldn’t find anything on PubMed that would indicate aloe vera actually contains vitamin B12.

Next!

A study from Poland was just released and I have added a summary to the Vegan Adults page of Vitamin B12: Are You Getting It?

Summary:

“A group of 20 omnivores agreed to follow a vegan diet for 5 years. Half the group ate B12 fortified foods and the other half did not. Neither group took B12 supplements. The amount of B12 received via fortified foods was not measured. After 5 years, B12 levels in the group using fortified foods went from about 340 to 310 pg/ml. B12 levels went from about 290 to 220 pg/ml in the group not using fortified foods. Only two participants had B12 levels fall below 200 pg/ml, traditionally considered the cutoff for B12 deficiency, and they were both from the unfortified foods group.”

The most interesting finding of this study may be that they convinced 20 omnivores to go vegan for five years! They claimed that all 20 participants adhered to the diet.

I was also surprised that they conducted a study that was likely to induce a nutrient deficiency. They might have told the participants that if they started feeling the symptoms of B12 deficiency they should do something about it, but there appeared to be no monitoring between months 24 and 60.

The researchers did not measure homocysteine or methylmalonic acid levels at any point, so it is not clear what level of B12 deficiency these subjects actually had. There is reason to think that B12 levels as high as 400 pg/ml are required to minimize homocysteine, although this likely depends on how much folate someone gets as folate also reduces homocysteine.

Reference

Mądry E, Lisowska A, Grebowiec P, Walkowiak J. The impact of vegan diet on B-12 status in healthy omnivores: five-year prospective study. Acta Sci Pol Technol Aliment. 2012 Apr 2;11(2):209-12. | link

Question (edited for clarity):

It is always explicitly recommended that Vitamin B12 tablets should be dissolved under the tongue (aka “sublingual”). I wonder if that is also true for other minerals and vitamins of special concern to vegetarians, such as iron and vitamin D2? If not, why is this the case with vitamin B12?

Answer:

I have always told people who asked about sublingual B12 that there was no evidence, of which I was aware, that sublingual was any better than just chewing. Despite this, until today, I had been recommending sublingual in my Step 1 Recommendations, which are geared towards people who have not recently had a reliable source of B12. I have recommended sublingual as a precaution just in case it was more effective. In recent years, I have been more diligent about trying not to recommend anything just to be prudent unless specifically stating that is why I am recommending it. This suggestion for sublingual (versus just oral) was a remnant left over from previous times.

Still, I did not know whether sublingual was better than oral until I got this question and decided to check in on the research. As it turned out, there was a study as long ago as 2003. Yikes! I guess I hadn’t checked in quite a long time.

The 2003 study compared 500 µg per day via the sublingual and oral routes. The results were that sublingual was absolutely no better than oral B12 at raising vitamin B12 levels or improving B12 activity (as measured by homocysteine and methylmalonic acid levels). The report did not specifically state whether the tablets were chewed or not (I assume that they were swallowed whole). So now I’m not sure I should even suggest that the tablets be chewed, but because other studies have shown a benefit to chewing, I will leave that in my recommendations.

As for other vitamins and minerals, I have never checked into the research on taking them via the sublingual route, but my sense is that there would not be any benefit. It might even be dangerous to try this with iron given that it is a pro-oxidant and probably should not be held in constant contact with your tissues.

Reference

Sharabi A, Cohen E, Sulkes J, Garty M. Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route. Br J Clin Pharmacol. 2003 Dec;56(6):635-8. | link

Edited Question:

I buy 3 lbs of collards every week (lots of cabbage and broccoli as well). I don’t like them raw, so I steam them for about 15-20 minutes. Is the calcium content of leafy vegetables greatly reduced from cooking/overcooking? Do I overcook my greens? I have no idea about how long I need to steam them. I simply follow the instructions of the steaming machine’s manual. As I don’t wish to lose too much nutrition, can you please tell me if I’m overdoing my greens?

Answer:

If you compare raw collards to boiled and drained collards at PeaCounter.com, you will see that they have, respectively, 4.8 and 5.4 mg of calcium per calorie. In this case, cooking the collards miraculously increased their calcium! I think it’s safe to assume this was from variance among batches of collards.

If you compare raw kale to boiled and drained kale, you will see that they have, respectively, 2.7 and 2.6 mg of calcium per calorie.

So, it appears that cooking greens results in only negligible calcium loss, if any.

15-20 minutes seems rather long to cook collards, but steaming can take longer than steeping (which is what I do), so I’m not sure. You could try steaming for 10 minutes to see if that’s long enough.

I’ve had a study on the acid load of vegan diets in my queue for awhile now and finally read it carefully. I just added this to the Bones, Vitamin D, and Calcium article at VeganHealth.org:

“Sulfur-containing amino acids are more prevalent in animal products, although they are also found in high amounts in many grains. A 2011 study from Germany tracked the diets of 98 vegans and 56 near-vegans for a week and used models to predict the effect of their diets on renal acid load. They found both diets to be neutral, whereas other studies show a typical omnivorous diet to be more acid producing (1).”

One thing that surprised me about this study was that they estimated that the vegans were consuming an average of 854 mg/day of calcium. That’s one of the higher estimates I’ve seen and the study didn’t indicate that they included supplements or calcium from fortified foods.

Since they merely estimated the acid load from models, rather than actually measuring it directly, the conclusion should be taken with some caution. And, as I’ve said many times before, the acid load of a vegan diet might not have all that much to do with the risk of osteoporosis for vegans – calcium and vitamin D appear to be much more important (see the link above on bones for more information).

Reference

1. Ströhle A, Waldmann A, Koschizke J, Leitzmann C, Hahn A. Diet-dependent net endogenous acid load of vegan diets in relation to food groups and bone health-related nutrients: results from the German Vegan Study. Ann Nutr Metab. 2011;59(2-4):117-26. Link

Do you have any thoughts on the possible risk of prostate cancer from higher calcium intakes? In this study it seems unrelated to the animal/vegetable source, particularly for men with low BMI: cancerres.aacrjournals.org/content/70/12/4941.long

Those findings seem fairly weak. Back in 2003, I reviewed all the research on dairy and prostate cancer and it appeared that there might be a correlation, particularly in colder climates. There was a suspicion that it could be due to higher calcium intakes depressing vitamin D levels which in turn cause prostate cancer. I haven’t followed the research carefully since then.

But, in any case, I recommend 700 to 1,000 mg per day for vegans and that upper limit is the RDA so I do not think, and not that you were suggesting this, that I am endangering men with prostate cancer by suggesting such an amount.