Doc: Supplement with beta carotene not good for smokers
Dear Dr. Roach: In a recent column, you said “current or former smokers should not take the standard supplement, as it contains beta carotene, which may increase lung cancer risk.” By “standard supplement,” do you mean AREDS? Also, I’ve never heard that smokers or former smokers should not take beta carotene. Why? I havn’t smoked in 30 years. Would this affect me?
Dear V.W.: Two large studies showed the benefit of vitamin supplementation in slowing the progression of macular degeneration. The first one, the AREDS, used a combination of vitamins, including beta carotene. The second, AREDS2, did not.
A different study, designed to determine whether vitamin supplements help to prevent smokers from getting lung cancer, found that active smokers taking beta carotene were more likely to get lung cancer. That study had some methodological weaknesses, but most experts recommend against current smokers taking a supplement with beta carotene. That’s why I recommend that people with macular degeneration use the AREDS2 formulation, which is appropriate for both smokers and nonsmokers. I would recommend that former smokers use the AREDS2 formulation, based only on minimizing risk.
Please note that foods high in beta carotene are still thought to be helpful in cutting risk for many conditions, including several cancers, for smokers and for nonsmokers (but quitting is the best way to cut cancer risk).
Dear Dr. Roach: My doctor just tested me for high calcium, and my vitamin D was low. He put me on 12 weeks of 50,000 IU once a week. You said something in a recent article about high vitamin D. Why the difference?
Dear A.K.: Unfortunately, I am confused by your vitamin D treatment: I suspect the vitamin D has nothing to do with the calcium. A high calcium level can be caused by many things, including faulty technique in obtaining blood (if the tourniquet is on too long, the blood can become more acidic, which makes the calcium level appear higher), but I mentioned excess vitamin D (a rare cause) and elevated parathyroid hormone levels in my recent column. A repeated high calcium level should get your doctor to check a PTH hormone level. A high PTH level almost always means a benign tumor of the parathyroid gland, which is often but not always treated surgically.
Email questions to ToYourGoodHealth@med.cornell.edu.