I’ve had an email in my inbox for a long time asking me about lectins. Lectins are one of those topics that are pretty hard to research because there are so many people saying so many different things with mostly animal and in vitro research to back them up. There are few studies on humans to really make any definitive claims. So, an article on lectins is almost tantamount to just taking a poll and seeing what most people who are talking about them think – not the best way to do a review. In any case I have spent a number of hours over the last week reading up on lectins and here is what I’ve found, about which I am relatively confident:

Lectins are proteins found in many plants that can attach themselves to carbohydrates on other proteins. The biggest concern is their ability to attach to the proteins on the lining of our digestive tracts causing acute digestive problems. Uncooked legumes contain the largest amount of and most potent lectins.

Personal example: I once ate a bowl of blended, uncooked black beans, while experimenting with raw foodism long before I was a dietitian, and the result was remarkable to say the least – I don’t recommend it.

Another example is ricin, a lectin from castor beans that can be deadly due to its ability to bind proteins involved in the synthesis of other proteins.

Most lectins are not quite as problematic and can be deactivated by cooking. However, cooking will not necessarily deactivate all of the lectins commonly found in plant foods such as legumes, grains, and night shades.

In his book, Eat Right For Your (Blood) Type, Peter D’Adamo takes the idea of lectins a step further and suggests that lectins that happen to get absorbed into the blood attach to blood cells and cause them to clump together leading to clogging of the arteries and resulting in heart disease. There does not seem to be any significant evidence for this and given how much atherosclerosis has been studied, it would seem that by now we’d know lectin-clumping was a problem if it really was part of the etiology of heart disease. Even after 15 years, Dr. Michael Klaper’s article on the blood type diet is still, to my knowledge, the best response to this theory:

Challenges to the Plant-Based Diet in the 90’s: “The Zone” and “Blood-Type” Diet Fads

A 2013 thorough review of the literature found that there have been no clinical trials published that have tested the Eat Right For Your (Blood) Type diet (1).

Aside from heart disease, should you be worried about lectins? Doubtful. But if you have regular digestive problems, particularly something akin to irritable bowel syndrome, it might be worth considering which foods you might be eating that are high in lectins such as legumes (especially if not thoroughly cooked), whole grains, or night shades, to see if limiting such foods can give you some relief. And although I think it’s much less likely than for digestive problems, if you have unexplained arthritis, lectins might be worth considering.

I happen to be a big fan of vegans eating plenty of legume products for the protein, zinc, and, for women, iron. So if you do cut back on legumes, please make sure you replace nutrients you might be missing from them. See VeganHealth.org for more info on protein, iron, and zinc.

Here are the best articles I found on lectins, starting with an article from Mark’s Daily Apple, a paleo blog. While I am not the biggest fan of the paleo movement, I thought his article was pretty decent:

The Lowdown On Lectins

Fellow veg RD, Ryan Andrews, from Precision Nutrition weighs in on lectins:

All About Lectins

Boring, but the most scientifically detailed article (that I trusted):

Plant Lectins – Cornell University College of Agriculture and Life Sciences

The End

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References

1. Cusack L, De Buck E, Compernolle V, Vandekerckhove P. Blood type diets lack supporting evidence: a systematic review. Am J Clin Nutr. 2013 Jul;98(1):99-104. | link

On June 17, I made a post about a study that had found that rice protein was as effective at increasing muscle mass as whey protein (see Leucine, Whey and Rice Protein). The study was described in a press release, I never found an actual published paper on it.

Pete from VeganBodyBuilding.org pointed out a podcast in which one of the researchers who conducted the study, Jacob Wilson, says that the press release is misleading (click here for the podcast, the part I’m referring to is in the first few minutes).

Dr. Wilson says that because the study used so much protein powder, 48 g of protein to be exact, there was enough leucine provided by the rice protein to achieve similar results to the whey protein. He says that at a lower protein amount, such as 25 g, whey protein is superior because of it’s higher leucine content which has been shown in many studies. From what I could gather, Dr. Wilson considers 3 g of leucine to be necessary to begin muscle synthesis in any given serving of protein.

In the past, I have not had a separate vitamin B12 recommendation for adults 65 years and older. In January, I reviewed a study from the UK suggesting that 500 µg per day might be necessary (see Cyanocobalamin in People 65+). Since then, I took some more time to research the subject and have concluded that I should be recommending 500 – 1,000 µg per day for adults 65 and older.

I updated my B12 recommendation charts and have reproduced below a section I’ve added to VeganHealth.org, Adults Over 65 Years.

Note that I no longer have a twice daily or twice weekly recommendation for adults 65 years and older. I don’t believe there is enough information to determine either recommendation. Also note that these recommendations would hold for omnivores as well as vegans since all these studies were done on omnivores.

Adults Over 65 Years

Summary: Based on the studies below, it appears that 500 – 1,000 µg per day of cyanocobalamin is the ideal amount for people over 65 years of age to take in a daily dose.

There have been at least four relevant studies for how much vitamin B12 people over 65 years need, based on a once daily supplement. To my knowledge all of these supplements were cyanocobalamin.

A 2005 clinical trial from the Netherlands found that among people aged 70-94, who had vitamin B12 deficiency but were otherwise healthy, 16 weeks of 500 µg/day of cyanocobalamin was required to get MMA levels in the healthy range. Other doses tested were 2.5, 100, 250, and 1,000 µg (16).

A 2002 observational study from Canada of 242 people aged 70-94 without vitamin B12 deficiency found that those taking a daily supplement had significantly lower MMA levels (173 vs. 188 µmol/l; p = .042). However, there were many even in the daily supplement group who had elevated MMA levels. The range of supplements was from 2.6-37.5 µg/day with intakes being spread out about evenly over the range (17).

In a 2013 clinical trail from the UK in 100 people aged 65-86 with poor B12 status, 500 µg/day of cyanocobalamin was required to normalize MMA levels in 75-85% of the participants over 8 weeks. 500 µg was significantly better than 10 or 100 µg (18).

In a 2002 study from Seattle on 23 people 65 years and older with B12 deficiency but otherwise healthy, 1,000 µg of B12 was required to get the average MMA level into the normal range, as compared to 10 and 100 µg. This study was continuous in that first they put everyone on 10 µg for 6 weeks (moved average MMA from 581 to 400 nmol/l), then 100 µg for 6 weeks (moved average MMA from 400 to 380 nmol/l), and then 1,000 µg for 6 weeks (moved average MMA from 380 to 200 nmol/l). The final 6 weeks resulted in a big drop after the 2nd six weeks resulted in only a small drop (19).

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References

16. Eussen SJ, de Groot LC, Clarke R, Schneede J, Ueland PM, Hoefnagels WH, van Staveren WA. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial. Arch Intern Med. 2005 May 23;165(10):1167-72. | link

17. Garcia A, Paris-Pombo A, Evans L, Day A, Freedman M. Is low-dose oral cobalamin enough to normalize cobalamin function in older people? J Am Geriatr Soc. 2002 Aug;50(8):1401-4. | link

18. Hill MH, Flatley JE, Barker ME, Garner CM, Manning NJ, Olpin SE, Moat SJ, Russell J, Powers HJ. A vitamin B-12 supplement of 500 μg/d for eight weeks does not normalize urinary methylmalonic acid or other biomarkers of vitamin B-12 status in elderly people with moderately poor vitamin B-12 status. J Nutr. 2013 Feb;143(2):142-7. | link

19. Rajan S, Wallace JI, Brodkin KI, Beresford SA, Allen RH, Stabler SP. Response of elevated methylmalonic acid to three dose levels of oral cobalamin in older adults. J Am Geriatr Soc. 2002 Nov;50(11):1789-95. | link

In her latest blog post, Calcium and Protein and Bone Health in Vegans, Ginny has a good reminder about the need for vegans to make sure they’re getting enough calcium and protein. Excerpt:

“The theory is that animal protein, through its acidifying action, “leaches” calcium from bones, eventually weakening them and causing bone fractures. If that’s true, it means that those of us who eat no animal protein are likely to have better bone health. And maybe even lower calcium needs.

“Unfortunately, it’s not true. Or at the very least, the evidence in support of this relationship has fizzled over the years. I’ve written about this before, but it remains such a pervasive and potentially harmful belief that it deserves an occasional revisit.”

Read more…

I just added a section on Lactobacillus and a section on Japanese fermented black tea to B12 in Vegan Foods. I have reproduced them below.

Lactobacillus species

Lactobacillus is a genus of bacteria found in some people’s digestive tracts and in most probiotic supplements. There is evidence that some species produce vitamin B12.

A 2003 study of Lactobacillus reuteri CRL1098 determined that it produces vitamin B12 and that this B12 was equivalent to cyanocobalamin (1).

In a 2006 study from Egypt, school children were fed yogurt fermented only with Lactobaccillus acidophilus, 2 cups daily with 5 X 10⁹ colony-forming units (2). After 42 days, their B12 status was compared to children who were fed a commercially prepared yogurt. Urinary MMA levels went from 3.49 to 2.09 mmol/mol of creatinine in the experimental group (P = .02) versus no change in the commercial yogurt group.

In a 2000 study of vegan raw foodists, 4 vegans were fed a probiotic supplement containing Lactobacillus acidolphilus and other Lactobacillus species (3). After 3 months, the urinary MMA levels of 3 of the 4 subjects had decreased, though not to normal levels. More details of this study are on the page, Raw Foodist Vegans.

While Lactobacillus shows some promise, it is too soon to rely on it for keeping your vitamin B12 status at healthy levels.

Japanese fermented black tea (Batabata-cha)

A 2004 study by the Watanabe group found that fermented black tea (Batabata-cha) contained vitamin B12 analogues that, when fed to rats, improved their vitamin B12 status (4). It would be interesting to see if this tea could consistently improve B12 status in humans.

Apology

I’m afraid I’m going to have to eat some humble pie here, as I had written a company, Tonix, telling them that they should not be claiming their coconut water kefir has vitamin B12 in it based on the fact that they have Lactobacillus and Bifidobacteria in it. And looking more closely at their claims, they don’t claim their product has vitamin B12 in it, they only claim that their product contains Lactobacillus and Bifidobacteria which can produce vitamin B12. So, I really messed up on that one. Sorry, Tonix! Not that they cared – they never wrote me back.

Here is that post: Coconut Water Kefir – Latest Unproven Source of Vitamin B12

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References

1. Taranto MP, Vera JL, Hugenholtz J, De Valdez GF, Sesma F. Lactobacillus reuteri CRL1098 produces cobalamin. J Bacteriol. 2003 Sep;185(18):5643-7. | link

2. Mohammad MA, Molloy A, Scott J, Hussein L. Plasma cobalamin and folate and their metabolic markers methylmalonic acid and total homocysteine among Egyptian children before and after nutritional supplementation with the probiotic bacteria Lactobacillus acidophilus in yoghurt matrix. Int J Food Sci Nutr. 2006 Nov-Dec;57(7-8):470-80. | link

3. Donaldson MS. Metabolic vitamin B12 status on a mostly raw vegan diet with follow-up using tablets, nutritional yeast, or probiotic supplements. Ann Nutr Metab. 2000;44(5-6):229-34. | link

4. Kittaka-Katsura H, Ebara S, Watanabe F, Nakano Y. Characterization of corrinoid compounds from a Japanese black tea (Batabata-cha) fermented by bacteria. J Agric Food Chem. 2004 Feb 25;52(4):909-11. | link

Just a quick pic of me sodium loading via Chipotle’s Sofritas before a weekend of ultimate frisbee in the hot Chico, CA sun. Thanks for the idea, Doug Graham!

Sofritas are now available at all CA, OR, WA, and BC locations.

Mild vitamin B12 deficiency causes homocysteine levels to rise. This has been a concern for vegans who do not supplement regularly with vitamin B12 because their homocysteine tends to be at a level that has been associated with cardiovascular disease and early death.

In the past few years, however, evidence has been mounting that homocysteine-reducing therapy is not effective in reducing cardiovascular disease. Two meta-analyses, from 2010 (1) and 2013 (2) indicate that there may be no benefit from lowering homocysteine levels for cardiovascular disease.

At the same time, evidence continues to mount that elevated homocysteine can cause dementia, with a 2013 study showing that homocysteine-lowering treatment can significantly reduce brain atrophy (3).

Because of these findings, I have drastically changed the VeganHealth.org article, Mild B12 Deficiency – Cardiovascular Disease | Dementia | Birth Defects | Bone Mineral Density. It is too much to reproduce here, but I hope you will check it out!

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References

1. Clarke R, Halsey J, Lewington S, Lonn E, Armitage J, Manson JE, Bønaa KH, Spence JD, Nygård O, Jamison R, Gaziano JM, Guarino P, Bennett D, Mir F, Peto R, Collins R; B-Vitamin Treatment Trialists\’ Collaboration. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals. Arch Intern Med. 2010 Oct 11;170(18):1622-31. | link

2. Martí-Carvajal AJ, Solà I, Lathyris D, Karakitsiou DE, Simancas-Racines D. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev. 2013 Jan 31;1:CD006612. | link

3. Douaud G, Refsum H, de Jager CA, Jacoby R, Nichols TE, Smith SM, Smith AD. Preventing Alzheimer\’s disease-related gray matter atrophy by B-vitamin treatment. Proc Natl Acad Sci U S A. 2013 Jun 4;110(23):9523-8. doi: 10.1073/pnas.1301816110. Epub 2013 May 20. | link

I have been catching up on the B12 in plants and algae research.

When I read these papers and see the not-insignificant amount of preparation and analysis that goes into the laboratory methods for trying to measure and accurately describe the B12 in these foods, it seems a lot easier just to feed the foods to humans and see if it improves their B12 status. Instead, we have a never-ending flow of research trying to quantify how much B12 is in various plants which does us almost no good because:

– Even if you find some molecules that seem to be vitamin B12, you don’t know how it will interact with other inactive B12 molecules inevitably also prevalent in these foods.

– We do not know how the B12 got there: whether the plant made it (unlikely), whether it has come from symbiotic bacteria, or whether it came from fecal or insect contamination. Thus, we do not know how reliable it would be in other batches of that food throughout the world.

– The packaging, storage, transportation, and preparation methods can differ greatly between the careful laboratory methods used in these reports and the versions someone might buy in a grocery store.

Nevertheless, this topic is of great interest to much of the vegan community and I will summarize some of the latest papers I’ve come across, though not all are recent.

The Watanabe group, as I refer to them because Fumio Watanabe is often the lead author, is a group of researchers from Japan who regularly publish on these subjects. They published a review of the research in 2013 (1) which was almost an exact duplicate of their review from 2007 (2).

There wasn’t much to report from their 2013 review, but a reader questioned me about one statement they make about B12 being degraded in the presence of both copper and vitamin C. Since many multivitamins contain both copper and vitamin C, is the B12 in these supplements useless? It’s a good question, but the research they base their observation on is, once again, not measuring whether a multivitamin with B12 and copper can improve vitamin B12 status (3). Rather, they took vitamin B12 and added vitamin C and copper to it and then analyzed the B12 to see if it was damaged – a process that significantly differs from eating a multivitamin.

I have not seen research looking at multivitamins and their effects on B12 status, which is a question that needs to be answered even for multivitamins without copper and vitamin C. As a bit of reassurance, I cannot recall any vegans who regularly take a multivitamin with B12 coming down with overt deficiency. That said, it would probably be best for vegans to avoid copper in their multivitamins. I don’t think it warrants throwing out a bottle of multivtiamins, but if you can get a multivitamin without copper, other things being equal, I’d suggest it. I’ll have more on copper absorption in a future post.

The Watanabe group published another paper in 2013, this time testing to see if hydroponically grown lettuce would absorb vitamin B12 if it was injected into the growing medium (4). Indeed, it does, at a rate of .02% to .03%. Enough B12 was absorbed that two lettuce leaves could meet the RDA of 2.4 µg. But it would seem much more efficient to get the B12 directly from fortified foods or supplements rather than running it through hydroponically grown lettuce and losing over 99%.

An Indian research group published an article in 2010 examining the vitamin B12 content of spirulina (Spirulina platensis) (5). They found 35 – 38 µg of methylcobalamin per 100 g of dry mass. Unfortunately, it doesn’t mean much based on the bulleted points above and the fact that other batches of spirulina have not improved vitamin B12 status (see B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods).

Interestingly, the Watanabe group didn’t cite the Indian paper in their 2013 review which included a section on spirulina, so apparently I’m not the only one to hear about these papers years after they’ve been published. 🙂

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References

1. Watanabe F, Yabuta Y, Tanioka Y, Bito T. Biologically Active Vitamin B12 Compounds in Foods for Preventing Deficiency among Vegetarians and Elderly Subjects. J Agric Food Chem. 2013 Jul 17;61(28):6769-75. | link

2. Watanabe F. Vitamin B12 sources and bioavailability. Exp Biol Med (Maywood). 2007 Nov;232(10):1266-74. | link

3. Takenaka, S.; Sugiyama, S.; Watanabe, F.; Abe, K.; Tamura, Y.; Nakano, Y. Effects of carnosine and anserine on the destruction of vitamin B12 with vitamin C in the presence of copper. Biosci., Biotechnol., Biochem. 1997, 61, 2137-2139. | link

4. Bito T, Ohishi N, Hatanaka Y, Takenaka S, Nishihara E, Yabuta Y, Watanabe F. Production and Characterization of Cyanocobalamin-Enriched Lettuce ( Lactuca sativa L.) Grown Using Hydroponics. J Agric Food Chem. 2013 Apr 12. [Epub ahead of print] | link

5. Kumudha A, Kumar SS, Thakur MS, Ravishankar GA, Sarada R. Purification, identification, and characterization of methylcobalamin from Spirulina platensis. J Agric Food Chem. 2010 Sep 22;58(18):9925-30. | link

A case study of B12 deficiency from 2009 has been sitting in my “to read” folder and I finally got to it due to being confined to an airplane for a few hours today. The patient was a 31-year old Taiwanese male. Over the course of a few years he became more and more paranoid and schizophrenic until he was admitted due to alarming paranoid behavior. At first he was placed on an anti-psychotic drug. 7 weeks later, he was back in the hospital and this time it was discovered that he had been vegetarian since his teenage years with his only source of vitamin B12 being “minimal intake of dairy products.” The anti-psychotic drug was replaced with 1,000 µg per day of oral cobalamin. His state improved in 2 weeks and 1 year after discharge he had not had another episode. His B12 levels went from 136 to 227 pg/ml in the first 2 months of therapy.

Another more recent paper (2013) reported that of 19 patients demonstrating psychiatric illness at an Indian clinic, 14 had followed a “strict” vegetarian diet. Not many details were given, though 15 of the 19 patients had low B12 levels, defined as < 225 pg/ml.

I have no more papers on B12-deficient vegetarians in my “to read” folder. I hope it lasts for awhile…

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References

1. Kuo SC, Yeh CB, Yeh YW, Tzeng NS. Schizophrenia-like psychotic episode precipitated by cobalamin deficiency. Gen Hosp Psychiatry. 2009 Nov-Dec;31(6):586-8. | link

2. Jayaram N, Rao MG, Narasimha A, Raveendranathan D, Varambally S, Venkatasubramanian G, Gangadhar BN. Vitamin B₁₂ levels and psychiatric symptomatology: a case series. J Neuropsychiatry Clin Neurosci. 2013 Spring;25(2):150-2. | link

It has been two months since I asked for support. I got some good support in June so I didn’t send out a request, but I received very little in July.

I didn’t make too many posts in July due to being out of town and because two of the posts I made required a lot of research. Still, when I look over the posts from June and July, I am stunned at the amount of info! Here are the highlights:

– Mortality Rates in Adventist Health Study-2

– Iron and Vegetarian Diets

– Do Calcium and Vitamin D Need to be Taken Together?

– Iron Supplements Improve Unexplained Fatigue in Premenopausal Women

– Leucine, Whey and Rice Protein (Still have some follow-up to do on this one.)

– How Much Processed Food is Healthy?

– Cadmium Levels in Vegans, Zinc Supplements and Alzheimer’s Disease

– DHA Supplements and Prostate Cancer

Now I ask you — where else can you get this sort of information?! I write about the good, the bad, and the ugly, all in an effort to cut through the propaganda and keep vegans as healthy as possible.

Please support my writing by giving a donation if you can afford one (click here). And also please like and share my posts and use the links in the box below to purchase items you buy online. Thank you very much – it really does allow me to write more!

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Please share and/or like my posts! Thanks!

I greatly appreciate donations of any amount and it allows me to spend more time on nutrition (click here).

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Vegan for Life: Everything You Need to Know to Be Healthy and Fit on a Plant-Based Diet from Amazon.com