Despite the success of highly active antiretroviral treatment (HAART), people with HIV may still be at higher risk for nutritional deficiencies and abnormalities.
In two different studies, researchers at the Nutrition/Infection Unit in the Department of Public Health and Family Medicine at Tufts University School of Medicine, and colleagues examined the incidence of metabolic syndrome and existing micronutrient deficiencies among participants in the Nutrition for Healthy Living (NFHL) study, a cohort with HIV. Both studies were published in the December 1st issue of the Journal of Acquired Immune Deficiency Syndromes, reporting that a high percentage of people with HIV have the same two defining characteristics of metabolic syndrome, and that people with HIV may be at risk for zinc deficiency.
Metabolic syndrome is defined as having three or more of the following medical conditions; low levels of high-density lipoprotein (HDL or 'good') cholesterol, hypertension, abdominal obesity, high levels of serum glucose (blood sugar), and/or hypertriglyceridemia, which is an elevation of triglycerides (fatty compounds) in the blood. Metabolic syndrome is often associated with obesity and related diseases like diabetes, but characteristics of metabolic syndrome have been observed among patients with HIV both before and after the introduction of HAART.
To investigate the prevalence of metabolic syndrome in populations with HIV, corresponding author Denise Jacobson, PhD, MPH, assistant professor at Tufts University School of Medicine, along with Christine Wanke, MD, and Sherwood Gorbach, MD, both of the Nutrition/Infection Unit and senior authors on the study, worked with colleagues to compare the incidence of metabolic syndrome among nearly 500 participants in the NFHL study to the population as a whole, using data from 1,900 participants in the National Health and Nutrition Examination Survey (NHANES).
"We determined that almost one fourth of the NFHL participants had metabolic syndrome, although this is lower than the incidence of metabolic syndrome in the population as a whole," says Jacobson. "Strikingly, 77 percent of people with metabolic syndrome in the NFHL study had the same two defining characteristics, low HDL cholesterol and hypertriglyceridemia."
"It appears that HIV viral load and metabolic syndrome are associated, as people with both HIV and metabolic syndrome were likely to have a clinically relevant increase in viral load within six months of developing components of metabolic syndrome," says Gorbach, who is a professor at Tufts University School of Medicine and at the Friedman School of Nutrition Science and Policy at Tufts. "An increased viral load is also linked to a decrease in HDL cholesterol levels, so this may be what drives metabolic syndrome in people with HIV."
Both HAART and non-HAART users in the NFHL study had a higher incidence of low HDL than the NHANES population. However, only HAART users demonstrated high triglyceride levels, leading the researchers to conclude that certain anti-retroviral therapies may also increase the risk for components of metabolic syndrome.
"We have seen that people with HIV have an increased prevalence of two of the characteristics of metabolic syndrome, components that are also associated with cardiovascular disease (CVD) and diabetes," says Wanke, a professor at Tufts University School of Medicine. "People with HIV are also living longer due to advances in treatment, and their risk of CVD and diabetes increases with age as it does in the general population. Since people with HIV are already at higher risk for low HDL cholesterol and hypertriglyceridemia, it might be important for health care providers to monitor risk for metabolic syndrome, as these risk factors may increase the likelihood of additional medical complications."
Using the same NHFL population, Clara Jones, MD, MPH, an assistant professor at Tufts University School of Medicine, and colleagues analyzed micronutrient levels of nearly 300 people infected with HIV on HAART, since little is known about the nutrient status of people taking anti-retroviral drugs. Jones determined that HAART users were unlikely to have low levels of selenium or vitamins A and E. However, despite these improvements in micronutrient levels (as compared to previous studies conducted before the widespread use of HAART), Jones found that HAART users still have an increased risk for zinc deficiency. Zinc, commonly found in seafood, meat, and dairy products, is crucial to many aspects of cellular metabolism, including immune and neurological function, as well as cell reproduction.
"We found that 40 percent of men and 36 percent of women in the study had low zinc levels," says Jones. "It has been thought for some time that low levels of micronutrients are associated with an increased viral load. This was demonstrated in the study, as people with lower levels of zinc had higher viral load levels, particularly women. However, we were also surprised to find that women with the highest levels of vitamin A in their blood had higher viral loads than those with the lowest levels of vitamin A. More studies are needed to confirm this observation. One could speculate that there is an optimal range of serum vitamin A needed for people with HIV that could contribute to maintaining lower viral loads."
The Nutrition/Infection Unit of the Department of Public Health and Family Medicine at Tufts University School of Medicine was established in 1986 to research the relationship between nutrition and various diseases. Since 1994, this group, originally led by Gorbach and now by Wanke, has specialized in the relationship between nutrition and HIV.