POSITIVELY AWARE NOVEMBER/DECEMBER 2010

HIV Wellness Series Tony M. Mills, MD

cowHIV Wellness series
by Tony M. Mills, MD

Nutrition and HIV: The importance of vitamin D

During the nearly three decades that we have been battling HIV, nutrition has always played an important role in keeping us healthy. In the early days, before the discovery of highly effective treatments for HIV, nutrition was one of the few effective means of keeping the virus in check. HIV-associated weight loss, or wasting, was a common presenting symptom of HIV disease. In Africa, HIV was known early on as “slim disease” because of its profound effects on body weight and composition. Encouraging patients to eat, use appetite stimulants, and take anabolic agents were some of the only effective ways of keeping patients healthy and strong. The idea was to keep people healthy enough that when the inevitable opportunistic infection presented itself, patients had enough weight and strength to survive the illness.

We’ve come a long way from those dark days, but nutrition continues to be a very important aspect of HIV care and treatment. While wasting is far less common today, its presence has been replaced with other illnesses that HIV patients have to fight against, such as heart disease, high cholesterol, and bone disease. Nutrition is a fundamental weapon that we can use to tackle these new challenges and nutrition is what will keep us healthy and well and living the normal lifespan that is now projected for us.

Back to basics

Nutrition is the organic process of nourishing the body and supplying it with the things it needs for survival and good health. Nutrition is fundamental not only for growth and development of an organism, but also for the maintenance and ongoing fitness of that organism.

Nutrition can take several forms. Certainly the mainstay is the food that we eat, but nutrition can also be supplied by nutritional supplements, including vitamins, minerals, proteins, and other compounds that provide benefit to us. The term “nutriceutical” refers to a food or naturally occurring food supplement thought to have a beneficial effect on human health. The nutriceutical market in the U.S. is huge and continues to explode in growth every year. As both the HIV and non-HIV populations realize that their life expectancy is increasing, many look to nutrition and nutritional supplements to keep them healthy and well as they move towards the future.

Vitamin D is a potent force in regulating cell growth, energy metabolism,
and immunity. For people living with HIV, bone health is certainly important,
as bone loss may be linked to many HIV meds in use today.

The nutriceutical market has, to a great extent, been unregulated in the past years and companies could introduce a product and make great claims to its benefit without having any clinical research to prove it. As a physician, it’s important to me that there is proven benefit to the therapies that I recommend to my patients. We practice what we call “evidence-based medicine,” which means that we recommend those things that have such proof. Of all the nutritional supplements that have been studied in patients living with HIV, vitamin D has the most evidence-based data behind it and the evaluation and treatment of patients who have inadequate levels of vitamin D is at the forefront of HIV nutrition.

The importance of vitamin D to all individuals, but particularly to those living with HIV, has come increasingly to light in recent years. Vitamins are defined as an essential food constituent that the body requires in small concentrations but that it cannot make on its own and thus must be supplied through foods or supplements. By this definition, vitamin D is actually a misnomer because, unlike other vitamins, the body can produce its own vitamin D.

Vitamin D is produced from a cholesterol-like precursor in the skin which is then changed into the active form of vitamin D by exposure to the UV rays of sunlight.

Vitamin D deficiency was first recognized in children who had abnormally weak and poorly formed bones in a condition known as rickets. Adults can develop a condition called osteomalacia which is distinguished by weakening muscles as well as bones. The recognition of the importance of vitamin D to developing bone led the FDA to mandate many years ago that dairies fortify milk with 100 units of vitamin D per every 8 ounces of milk. Unfortunately, fewer people are consuming milk today and this, combined with the warnings of dermatologists about the damaging effects of UV rays and the importance of wearing sunscreen, has led to an epidemic of vitamin D deficiency.

Vitamin D’s importance in bone health is particularly important for the young whose bones are developing and for older patients whose bones may be breaking down. But vitamin D has more important contributions outside of bone health. Vitamin D has been shown to preserve muscle strength, and to protect against deadly diseases including diabetes, multiple sclerosis, and even cancer. Vitamin D is a potent force in regulating cell growth, energy metabolism, and immunity. For people living with HIV, bone health is certainly important, as bone loss may be linked to many of the HIV meds that are currently used today. Vitamin D’s role in a healthy immune system is still being defined, but we know that CD4 cells and CD8 cells have vitamin D receptors and activation of those receptors can have major impact on immune function. In addition, vitamin D has an important role in controlling inflammation, which we now know is the underlying cause of many health concerns, especially cardiovascular disease, including diabetes and hypertension. Other inflammatory conditions with an association with vitamin D include irritable bowel disease and rheumatoid arthritis. And neurocognitive dysfunction, a great concern for the aging HIV population, has also been associated with low levels of vitamin D. For these reasons, HIV patients have been targeted specifically to evaluate the role of vitamin D in maintaining good health.

The importance of vitamin D to the HIV treatment community is underscored by the fact that at the 2010 Conference on Retroviruses and Opportunistic Infections (CROI), there was an afternoon session dealing specifically with vitamin D and the importance of vitamin D deficiency in HIV patients. After a brief review of vitamin D metabolism and a summary of the association of low vitamin D levels with a host of serious medical problems, researchers from all over the world presented their own research data on vitamin D.

Data from the SUN Study in the U.S. was presented by Christine Dau from the U.S. Centers for Disease Control and Prevention (CDC). In their study of 672 patients, 71.6% were found to be vitamin D insufficient. Vitamin D insufficiency was associated with black race, Hispanic ethnicity, low UV light exposure, lack of exercise, increased body mass index, renal (kidney) insufficiency, and ritonavir (Norvir) and efavirenz (Sustiva, also in Atripla) exposure.

Efavirenz, through its induction of cytochrome P450 enzymes, is thought to accelerate the breakdown of active vitamin D into inactive compounds. Ritonavir inhibits 1a-hydroxylase, thereby blocking the conversion of vitamin D to its most active form. Thus, two of the most commonly used antiretrovirals can adversely affect vitamin D levels.

Similar data were presented from other countries, including the Icona Foundation Study Group in Italy and the Swiss Cohort Study. In both of these, a high incidence of vitamin D insufficiency was also seen with a similar association with the use of antiretrovirals, especially the NNRTIs. The Italian cohort found an additional association with increasing age and with lower CD4 count. Other data looking at HIV-associated conditions, including wasting and thrush in Africa and bacterial vaginosis in the U.S., were presented showing a strong association with vitamin D insufficiency. In all cohorts, between 50-90% of patients studied demonstrated low levels of vitamin D.

Today, it is not the HIV that presents such a challenge as much
as co-morbidities associated with it, such as cardiovascular disease, diabetes,
bone disease, and cancer. Today nutrition still plays a vital role in HIV care.

So how do we go about addressing the issue of low vitamin D? We know that just 30 minutes of daily sun exposure in summer can generate large quantities of vitamin D and indeed, residents of the tropics typically have ample levels. Having darker skin pigment, however, can severely impair the ability of a person to manufacture vitamin D, and global location (distance from the equator) and seasonal variation have a fixed and marked impact on the ability of a person to maintain adequate levels of vitamin D. The Food and Nutrition Board of the National Academies is currently reevaluating its recommendations regarding vitamin D supplementation and new recommendations are expected in the fall of 2010. Currently, recommendations are that people should get a net of 600 IU (International Units) of vitamin D per day from sun, food, and supplements. Most experts are recommending vitamin D supplementation at 1,000-2,000 IU per day. Vitamin D is a safe supplement to take with relatively little chance of toxicity or overdosage. Hypercalcemia is the biggest risk, but it is only seen with very high serum levels of vitamin D, much higher than what is achieved with routine supplementation.

Conclusion

The management of HIV disease has changed remarkably in the past 30 years. Effective antivirals have changed the natural history of the disease and have allowed patients living with HIV to survive and live with a normal life expectancy. Nutrition was one of the few HIV treatments in the early days that actually impacted the course of the disease by allowing patients to be stronger and healthier as they fought their HIV. Today, it is not the HIV that presents such a challenge as much as co-morbidities associated with it, such as cardiovascular disease, diabetes, bone disease, and cancer. Today nutrition still plays a vital role in HIV care as patients strive to live long healthy lives. Vitamin D insufficiency is an important syndrome that contributes to the co-morbidities that patients face. Recognition of the condition has led to an intense focus on its role and its treatment as we work to keep patients healthy.

Ask your doctor about your vitamin D level. Remember that even people in warm climates can have too little vitamin D and this may negatively affect your overall health. Optimal vitamin D levels are greater than 75 nmol/L (30 ng/ml) and maintaining these levels may require vitamin D supplementation.

Tony Mills, MD, is a leading clinician in HIV disease and men’s health in Los Angeles. He is a nationally recognized speaker and belongs to many professional organizations. Dr. Mills is also principal investigator on more than 50 HIV trials.

REFERENCES

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