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Your Good Health: People on vegan diet should take vitamin B12 supplements

Those who consume no animal products at all will not get any vitamin B12 and will develop B12 deficiency unless they take a supplement.
Dr. Keith Roach

Dear Dr. Roach: I’m a vegan, and my multivitamin is my only source of B12. It states I’m getting 200% of my daily requirement. Is that sufficient?


People who are strict vegans — that is, those who consume no animal products at all — will not get any vitamin B12 and will develop B12 deficiency unless they take a supplement. It takes years to become B12 deficient after starting a strict vegan diet.

A hundred percent of the recommended daily allowance (2.4 mcg daily) is enough to meet the nutritional requirements for 97.5% of the population, so 200% is very likely to be sufficient. That being said, I recommend higher doses, at least 10 mcg, since a few people don’t absorb B12 correctly. Some medicines, such as omeprazole and other proton pump inhibitors (acid-suppressing stomach medicines) reduce absorption. Most B12 supplements sold at the pharmacy or health food stores have much greater amounts, often at or above 1,000 mcg. They are safe to take. Your body simply excretes the excess B12.

Dear Dr. Roach: I am a 78-year-old man in fairly good health. I read an excerpt from a study on the link between cataracts and dementia. According to the study, people with cataracts who underwent lens replacement surgery were also found to have significantly improved their chances of staving off dementia. The report suggested this was a result of “higher quality sensory input” to the brain.

My problem is that even though I had my cataract evaluation with my ophthalmologist in December, the soonest I will be able to have surgery on my right eye is the middle of May. First of all, I was wondering what your thoughts are concerning the validity of the study. Second, assuming the study is valid, should I be concerned with how the five-month delay might adversely affect my mental health?


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

As far as timing goes, the study looked at time periods up to 25 years. I don’t think a five-month delay will significantly affect you. While you are waiting, you certainly want to keep your mind active, and it’s best to use several types of activities. Word puzzles (such as crosswords) seem to have different benefits from number games (such as Sudoku) or visual puzzles.

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

Others recommended pickle juice or mustard. These have been found to be beneficial in some types of cramps. Interestingly, it isn’t the salts or other minerals that is effective; it seems to be a neurological reflex that stops the muscle cramping. These might be helpful for some, but most people do well with the stretching and muscle exercises I recommended. A vitamin B complex supplement was found to help some people with muscle cramps who did not respond to initial therapy in a small trial.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to