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 D-3 (also 40) and vitamin D-2 (less than 4, and presumably 0 based on the overall score). What is vitamin D-2, and should I be taking supplements or eating certain foods to boost its levels?
P.S.
Both vitamin D-2 and vitamin D-3 are found in diet and in supplements. D-2 is found at low amounts in vegetables; D-3 is found in some fish. Both D-2 and D-3 are used to fortify milk and other dairy products. The body normally makes vitamin D-3 when your skin is exposed to sunlight. Without adequate sunlight, it鈥檚 very difficult to get adequate vitamin D without supplementation. The fact that your D-3 is much higher than your D-2 suggests that you are taking supplemental D-3 or you are getting adequate sunlight (or a combination).
Both D-2 and D-3 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鈥檚 the overall vitamin D number that you need to be concerned about, not the individual components, so there is no need for a D-2 supplement.
I generally prefer D-3 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, maybe five or six times. Is this normal? Why does he do this?
E.C.
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 鈥済ustatory rhinitis鈥�), and this may trigger the sneeze reflex.
There are other nerve reflexes that can have the same effect, including 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鈥檛 sneeze once, but several times in a row (some people attach significance to the number, but these suppositions aren鈥檛 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.
Dr. Roach is unable to answer individual letters, but will incorporate them in the column when possible. Readers can email questions to [email protected].
