Dr. Keith Roach
Dear Dr. Roach: When my doctor told me that as a vegetarian I needed a B12 supplement, I didn’t take it seriously, and went with nutritional yeast to supply it. I had always read that supplements are unreliable and it’s better to get your vitamins and minerals from a food source. Well, I became extremely anemic with a very low B12 level, probably related to having depleted my B12 storage over 25 years. When we hear the pleas to go vegetarian, why can’t it also be impressed upon people that B12 supplementation may be required?
Dear M.R.: People who eat a mostly plant-based diet but who also eat eggs, cheese or fish are not at risk for dietary vitamin B12 deficiency. People who are strictly vegan are at risk, and do need to supplement vitamin B12. I seldom see dietary B12 deficiency in my practice, because most people who are vegetarian aren’t strict enough to get B12 deficiency — very small amounts are needed for prevention — and those who are strict mostly know that they need to supplement. The body contains nearly three years’ worth of B12, so deficiency can take a long time to show up after starting a strict vegan diet.
Nutritional yeast is a source of B12, but only when it contains supplemental B12. Vitamin B12 is found only in animal products. I wonder if you were using a nonfortified nutritional yeast. Of course, it is possible to have a low B12 level due to poor absorption. The most common cause is pernicious anemia, an autoimmune condition where the body cannot make a cofactor to help absorb vitamin B12. Monthly injections of B12 or high doses of oral B12 are both effective treatments for this condition. It can be diagnosed by antibody tests.
A vegan diet can be a very healthy option, but you are absolutely right to emphasize the importance of supplemental B12.
Dear Dr. Roach: I’m a reasonably fit 83-year-old said to be younger biologically than chronologically. Medical and pharmaceutical research reported in the press rarely involves subjects over the age of 70. There is much in the popular press about advanced age, but little from the medical side. Investigations seem to be missing this (increasing) market. Where is the evidence about medications I am being prescribed (statins, e.g.) in the elderly?
Dear S.F.F: I agree with your implication that this is a problem. For someone like me, who tries to make medical decisions based on data, not having good studies limits the ability to make good decisions.
I do think things are changing. My own institution, for example, is involved in a large study to see whether statins are beneficial in an older population than has previously been studied.
In absence of data, doctors are forced to extrapolate based on what we know about the biology, and our inferences may not be correct. Further, many older people are on a great deal of medications, and it would be ideal to have data to be sure these medicines are safe and effective specifically in the older population to avoid excess medication, with potential for dangerous interactions.
It has been my experience that many medications are prescribed to older adults even when there is good evidence these medicines have increased risk. The American Geriatrics Society frequently publishes a list (called the Beers Criteria) of medicines that may not be appropriate in older adults. Statins are not on the Beers Criteria list.
Readers may email questions to ToYourGoodHealth@med.cornell.edu.