DEAR DR. GOTT: Testing six months ago found I had a vitamin D test result of 34. Since then I have been taking 3,000 IUs of D and have been getting more sunshine by spending more time playing tennis. I was tested last week and had a vitamin D test result of 5. My doctor has now prescribed 50,000 IUs twice a week for four weeks. What causes the deficiency and how will the four weeks of treatment be a cure?
I am a vegetarian so my sources of D supplements are not animal based. I also had kidney stones years ago so I’m not sure that the vitamin D will not adversely affect my calcium levels. I also have bone spurs and that is a concern with the vitamin D treatment.
Thank you very much for any insight.
DEAR READER: It appears that because you are a vegetarian who hasn’t spent much time in the sun, you have been at risk for a deficiency that has not been recognized until recently. You are obviously well-versed when it comes to your dietary choices and supplements, since most of the natural sources of this vitamin are animal-based. Vitamin D is necessary for the growth and development of teeth and strong bones, as well as for the absorption of calcium and phosphorous from the intestines. D can be used alone or in combination with supplemental calcium to decrease the probability of fractures and increase bone mineral density.
There is an abundance of dietary sources, to include fortified milk, cheese, egg yolks, fish (primarily salmon), butter, and cod liver oil. And, as you have discovered, sunlight makes a significant contribution to the production of D. In fact, it is believed that as little as 10 minutes of sunlight each day can be sufficient to prevent a deficiency but skin color, geographical location, season and sunblock use can alter production.
There are a number of reasons other than being a vegetarian and obtaining minimal exposure to sunlight why an individual such as yourself might be deficient. You don’t mention whether you are dark or light skinned but those with naturally darker skin are at a higher risk for deficiency because the pigment melanin reduces the skin’s ability to produce D when exposed to the sun. Certain digestive diseases to include Crohn’s or celiac disease and cystic fibrosis have been linked with the malabsorption of vitamin D from food in the intestines. You may also be at risk if you have been diagnosed with kidney or liver disease. You don’t indicate your age. As part of the aging process, the kidneys can no longer convert D and the digestive tract can no longer absorb D as easily into its active form as it did when we were younger. Because D is extracted from the blood by fat cells, people who are obese often test low for levels of vitamin D.
Blood testing is the appropriate method of determining whether levels are normal or not. I am not sure what type of testing you had but it appears the most accurate measure is the 25-hydroxy vitamin D test. 25-Hydroxy D changes into an active form of the vitamin. Levels less than 12, the category you now fall in to, indicate deficiency. The answer? Speak with your physician regarding the possibility of the disorders I mention being contributing factors as well as the possibility of a lab error (a repeat test before increasing treatment would be best) as your drop was drastic. Obtain more D through two means – exposure to sunlight (unless you are dark skinned) and supplements. The upper limit considered safe is now 4,000 IUs daily, so your physician is appropriately prescribing what appears to be a jump start to bring you within safer limits.
Readers who would like related information can order my Health Report “Vitamins and Minerals” by sending a self-addressed, stamped number 10 envelope and $2 in the form of a check or US money order to my attention at PO Box 433, Lakeville, CT 06039. Be sure to mention the title when writing or print out an order form from my website www.AskDrGottMD.com.
