HIV-infected people with raised lipid levels consume more total fat, more saturated fat and more cholesterol than the general population, even though their total calorie intake is no different, write US researchers in the July 31st edition of AIDS.
They stress their findings emphasise the need to make nutritional advice a central part of the management of antiretroviral-associated dyslipidaemia.
A recently presented randomised Brazilian study found that HIV-positive people who received regular dietary counselling after starting antiretroviral therapy were significantly less likely to experience lipid elevations on treatment when compared with people who received a one-off nutritional information intervention before starting treatment.
Taken together, the findings of the two studies strongly suggest that lipid elevations in people on antiretroviral treatment cannot be blamed on the drugs alone.
The US study investigated the relationship between food intake and metabolic parameters in 356 HIV-positive people and 162 HIV-negative controls taking part in metabolism studies at the Massachusetts General Hospital between 1998 and 2005
The HIV-positive group had average CD4 cell counts of 444 cells/mm3, viral loads of 400 copies/ml, and duration of HIV infection of 8.5 years with 89% taking antiretrovirals.
All study participants recorded their food intake by either using four-day food diaries or recalling what they had eaten at the end of each day. Overall calorie intake was similar between the groups- with HIV-positive people consuming on average 2235 kilocalories/day compared to 2065 kilocalories/day in the HIV-negative group.
Levels of dietary carbohydrates and proteins were broadly similar. But dietary fats intake varied significantly with HIV-infected individuals eating more total dietary fat (p < 0.05), saturated fat (p = 0.006), and cholesterol (p = 0.006). They also took in a greater percentage of their calories from more harmful saturated fats (p = 0.002) and trans fats (p = 0.02).
The researchers then compared food intake with the US Department of Agriculture Recommended Dietary Guidelines.
A significantly higher percentage of HIV-infected individuals were above the 2005 USDA recommendation for saturated fat (76% HIV versus 61% controls, p = 0.003), and cholesterol (50% HIV vs. 38% controls, p = 0.04).
That increased fat intake was reflected in the increased risk of dyslipidaemia in the HIV positive group. Compared to the controls, HIV-positive individuals had higher mean triglyceride levels (2.59 vs 1.47 mmol/l, p<0.0001). They also had lower HDL (or “good”) cholesterol levels (1.06 vs. 1.24 mmol/l), p<0.0001). Total cholesterol was 5.06mmol/l on average in the HIV-positive group compared to 4.60 mmol/l in the control p = 0.003.
These associations remained after controlling for protease inhibitor use and other major factors known to influence lipid levels, including gender, alcohol use, race, fibre intake, body-mass index and age.
Exactly why HIV-positive individuals should eat more fat than the general population cannot be explained by this study, say the authors, but it could be due to a number of factors. These include the possibility that HIV-positive people could eat more fat to compensate for increase energy expenditure due to metabolic changes as a result of HIV or antiretroviral treatment, or due to changes in taste or feelings of satiety.
While there has been much research on HIV infection and antiretroviral drug use as factors in blood fat and cholesterol levels in HIV-infected people, the researchers conclude: "Careful assessment of dietary intake and more aggressive dietary intervention may prove to be beneficial to the prevention of cardiovascular disease in this population of patients."