Dear Dr. Roach: My 90-year-old mother lost her sense of smell several years ago. We think it was related to a new medication. I read that vitamin A deficiency can be responsible for this, and I have reason to believe she has a real deficiency. She also has poor night vision, dry eyes and skin problems.
Her doctor nixed the idea of taking any quantity of vitamin A or beta carotene. I am perplexed. Can you think of any reason why she shouldn’t try 5,000-10,000 IU daily for a month or two? Would moderate kidney damage preclude vitamin A in these doses? Is there a test for deficiency?
— M.M.
Answer: Vitamin A is important for eye, bone and skin health, and it is also necessary for a properly running immune system. But vitamin A is a fat-soluble vitamin, which means it is possible to get vitamin A toxicity. It’s also teratogenic at high doses — meaning, it can cause birth defects if taken by pregnant women. Doses greater than 6,000 IU should not be taken by women who might be pregnant.
I found an article from 1962 showing that healthy people who lose their sense of smell can improve the sense by treatment with vitamin A.
More recently, there have been studies looking at using vitamin A preparations directly to the nose. So, there is some reason to believe that it might help.
There is a test for vitamin A deficiency. The blood level can be measured directly. Vitamin A deficiency is seen most frequently in people who have medical issues with absorption, such as celiac, but especially after gastric bypass surgery.
I don’t know why her doctor is flat refusing to consider the diagnosis. Either a therapeutic trial or measuring the level seems reasonable.
