Daily Dose of D

Enough of the Good Stuff

For people with HIV, who often have bone problems, the role of vitamin D in bone health is reason enough to be aware of their vitamin D status. The anti-HIV drug tenofovir (Truvada, also in Atripla and Complera) has been linked to thinner bones, so people taking that drug have an additional reason to pay attention to vitamin D. All people with HIV should consider talking with their doctors about vitamin D and the possibility of having their blood levels checked. People with certain other health conditions, including osteopenia or osteoporosis, can often have the cost of a vitamin D blood test covered by provincial and territorial healthcare programs.

If vitamin D is important, and it seems that many people don't get enough, where can they get more? There are three sources of vitamin D: sunlight, food and supplements.

Sunlight: Many factors affect skin production of vitamin D, making it difficult to provide general guidelines. For example, skin colour affects the time needed to make adequate quantities of the vitamin. (Dark-skinned people require between three and five times as much sun exposure to make the same amount of vitamin D as light-skinned people.) Also, many people wear sunscreen to help lower the risk of skin cancer. Moreover, exposure to enough sun is unlikely for much of the Canadian winter. HIV and HIV treatment can also slow or reverse vitamin D production. For all of these reasons, people should look to other sources.

Food: Natural food sources of this vitamin are few: dairy foods (especially certain cheeses, and milk, which by law is fortified with vitamin D), fortified soy and rice milks, orange juice, margarine and certain fatty fish, including salmon, tuna and mackerel. A number of other foods, including cereals, are also fortified with vitamin D.

The recommended daily intake for HIV-negative people between the ages of 9 and 70 is 600 IU. To achieve these amounts naturally, Eating Well with Canada's Food Guide recommends that all Canadians over the age of two consume 500 mL (two cups) of fortified milk or soy beverages every day. The American Endocrine Society suggests that people with certain medical conditions, including HIV, should have two to three times that amount (see How much D for people with HIV?). That would mean four to six cups of fortified beverage a day!

Supplements: The most reliable way to get your vitamin D is through a supplement, and vitamin D3 is the form of vitamin to look for on supplement labels. Vitamin D3 is available as a pill and also in a liquid formulation. At the Sherbourne Health Centre's HIV clinic, the usual recommended intake is 2,000 IU per day. "We err on the side of providing more than what might be necessary," Dr. Huff says. "Certainly, supplementation is most important October through April, particularly among persons with dark skin, a higher BMI, and in those who avoid summer sun exposure."

Even with supplements, it might not be easy to get vitamin D blood levels as high as they need to be. It may require high doses, such as 4,000 IU per day, taken for months to raise levels. Researchers are studying the effect of very high doses, such as 50,000 IU twice a week, over short periods. Early results are promising, with blood levels of the vitamin rising in the majority of people in some studies. More importantly, the doses seem safe and do not affect viral load or CD4 counts. Other trials are planned or underway with the goal of finding a safe and effective dose for HIV-positive people.

While taking a vitamin D supplement should be safe for most people, individuals with certain conditions that cause the immune system to become overly active and produce excess active vitamin D should only supplement under a doctor's supervision. These conditions include tuberculosis, chronic fungal infections and lymphoma.

It remains to be seen whether vitamin D will live up to all the hype, but its role in bone health is reason enough for us all to pay attention to our intake. Evidence suggests that taking a daily multivitamin and mineral supplement is probably not enough to ensure that people with HIV are getting enough vitamin D. A specific supplement of vitamin D3 is likely a good thing, and it comes with the added bonus of providing an excuse for not heading out into the cold Canadian winter.

For more information about vitamin D, check out TreatmentUpdate 185 and A Practical Guide to Nutrition, both available online at www.catie.ca or by calling 1.800.263.1638.

R. Paul Kerston's work at the Positive Living Society of BC includes treatment outreach. When he's not spreading the word on treatment, he can be found trotting the globe (40 countries and counting) and indulging in his longtime passion for theatre performance.