STU

Dr. Roach

DEAR DR. ROACH: I recently received my blood test results. My overall vitamin D was 40 (within the target range of 30 to 60 listed), but I noticed that it was broken up into vitamin D3 (also 40) and vitamin D2 (less than 4, and presumably 0 based on the overall score). What is vitamin D2, and should I be taking supplements or eating certain foods to boost its levels? — P.S.

ANSWER: Both vitamin D2 and vitamin D3 are found in our diets and in supplements. D2 is found at low amounts in vegetables; D3 is found in some fish. Both D2 and D3 are used to fortify milk and other dairy products. The body normally makes vitamin D3 when your skin is exposed to sunlight. Without adequate sunlight (such as in the winter north of the line from Los Angeles to Atlanta), it’s very difficult to get adequate vitamin D without supplementation. The fact that your D3 is much higher than your D2 suggests that you are taking supplemental D3 or you are getting adequate sunlight (or a combination).

Both D2 and D3 are converted in the kidney to the active form of vitamin D, called 1,25-dihydroxyvitamin D. (Only people with kidney disease require this form of vitamin D supplementation.) This is the form that is necessary for bone health and has a role in maintaining many other processes in the body. It is not yet clear whether supplemental vitamin D will reduce the risk of heart disease and cancer, but an ongoing study hopes to answer that question.

It’s the overall vitamin D number that you need to be concerned about, not the individual components, so there is no need for a D2 supplement. I generally prefer D3 for supplementing; it seems to provide better levels and lasts longer. The target overall blood level remains controversial, with some experts saying that over 20 is adequate, while others recommend levels of 40 (or even higher). However, virtually everyone would agree that your level of 40 does not need treatment. I would not recommend further supplementation or changing your diet for the sake of vitamin D.

DEAR DR. ROACH: Every time my husband finishes a meal, he starts to sneeze. Not only once, but maybe five or six times. Is this normal? Why does he do this? — E.C.

ANSWER: Sneezing is a neurological reflex, normally triggered by inflammation in the nasal passages, such as in people with upper respiratory tract infections or people with allergic rhinitis. However, some people can develop nasal discharge while eating (this is called “gustatory rhinitis”), and this may trigger the sneeze reflex. There are other nerve reflexes that can have the same effect. This includes the photic sneeze reflex, when people sneeze uncontrollably when looking at the sun or another bright light source, which interestingly is a dominant genetic trait.

I often have been asked why people don’t sneeze once, but several times in a row (some people attach significance to the number, but these suppositions aren’t based in science).

The answer is that while sneezing propels the fluid in the nasal passages a surprising distance and at considerable velocity, it does not immediately stop the inflammation, which is the trigger for the sneeze.

Treatment for sneezing is mostly to reduce inflammation in the airways, which can be done with oral or nasal antihistamines, nasal steroids and other anti-inflammatories.

READERS: The booklet on colon cancer provides useful information on the causes and cures of this common malady. Readers can obtain a copy by writing:

Dr. Roach

Book No. 505

628 Virginia Drive

Orlando, FL 32803 Enclose a check or money order (no cash) for $4.75 U.S. with the recipient’s printed name and address. Please allow four weeks for delivery.

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 ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Drive, Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.