Your good health: people on a vegan diet should take vitamin B12 supplements

Those who do not consume any animal products will not get any vitamin B12 and will develop a B12 deficiency unless they take a supplement.

Dear Dr. Roach: I am vegan and my multivitamin is my only source of B12. It indicates that I am getting 200% of my daily needs. Is it sufficient ?


Strict vegans, that is, those who do not consume any animal products, will not get any vitamin B12 and will develop a vitamin B12 deficiency unless they take a supplement. It takes years to become deficient in B12 after starting a strict vegan diet.

One hundred percent of the recommended daily allowance (2.4 mcg per day) is sufficient to meet the nutritional needs of 97.5% of the population, so 200% is most likely sufficient. That being said, I recommend higher doses, at least 10 mcg, because some people don’t absorb vitamin B12 properly. Some drugs, such as omeprazole and other proton pump inhibitors (stomach antacid drugs) reduce absorption. Most B12 supplements sold in pharmacies or health food stores have much larger amounts, often at or above 1000 mcg. They are safe to take. Your body simply excretes the excess B12.

Dear Dr. Roach: I am a fairly healthy 78 year old male. I read an excerpt from a study on the link between cataracts and dementia. According to the study, people with cataracts who had lens replacement surgery also significantly improved their chances of avoiding dementia. The report suggested this was the result of “higher quality sensory input” to the brain.

My problem is that even though I had my cataract evaluation with my eye doctor in December, the earliest I can have surgery on my right eye is mid-May. First of all, I was wondering what you think about the validity of the study. Second, assuming the study is valid, should I be concerned about how the five-month delay might harm my mental health?


I think the study was well done and supports similar research, including analogous studies looking at hearing aids in people with hearing loss. Our sight and hearing are essential inputs to our brain, and deficiencies in these put aging brains at risk.

With regard to timing, the study covered periods of up to 25 years. I don’t think a five month delay will affect you significantly. While you’re waiting, you definitely want to keep your mind active, and it’s best to use multiple types of activities. Word puzzles (such as crosswords) seem to have different advantages than number games (such as Sudoku) or visual puzzles.

Dr. Roach writes: A recent column on leg cramps generated many letters from the readers. A common question was why I didn’t recommend magnesium, which many readers found helpful. While magnesium supplementation has been shown to be helpful in pregnant women with leg cramps, an analysis of all published trials found no benefit of magnesium supplementation over a placebo pill.

Others recommended pickle juice or mustard. These have been shown to be beneficial in certain types of cramps. Interestingly, it is not the salts or other minerals that are effective; it seems to be a neurological reflex that stops muscle cramps. These may be helpful for some, but most people do well with the stretching and strength training exercises I’ve recommended. A vitamin B complex supplement has been found to help some people with muscle cramps that did not respond to initial treatment in a small trial.

Dr Roach regrets that he cannot respond to individual letters, but will incorporate them into the column whenever possible. Readers can email questions to [email protected]