HIV and nutrition are intimately linked. HIV infection can lead to malnutrition, while poor diet can in turn speed the infection’s progress. As HIV treatment becomes increasingly available in the poorest parts of the world, critical questions are emerging about how well the drugs work in people if they are short of food. Uncertainty also surrounds the role of vitamins and other supplements. And for those already receiving treatment, side effects such as body fat changes are a daily concern.
Understandably, HIV positive people and those who care for them are interested in whatever might benefit their health. This article looks at what is known about the relationships between HIV and nutrition.
HIV and AIDS is well known for causing severe weight loss known as wasting. In Africa, the illness was at first called “slim” because sufferers became like skeletons. Yet body changes are not only seen during AIDS; less dramatic changes often occur in earlier stages of HIV infection.
Whereas starving people tend to lose fat first, the weight lost during HIV infection tends to be in the form of lean tissue, such as muscle. This means there may be changes in the makeup of the body even if the overall weight stays the same.
In children, HIV is frequently linked to growth failure. One large European study found that children with HIV were on average around 7 kg (15 lbs) lighter and 7.5 cm (3 inches) shorter than uninfected children at ten years old.
What causes these changes?
One factor behind HIV-related weight loss is increased energy expenditure. Though no one knows quite why, many studies have found that people with HIV tend to burn around 10% more calories while resting, compared to those who are uninfected. People with advanced infection or AIDS (particularly children) may expend far more energy.
But faster metabolism is not the only problem. In normal circumstances, a small rise in energy expenditure may be offset by eating slightly more food or taking less exercise. There are two other important reasons why people with HIV may lose weight or suffer childhood growth failure.
The first factor is decreased energy intake or, to put it simply, eating less food. Once HIV has weakened the immune system, various infections can take hold, some of which can affect appetite and ability to eat. For example, sores in the mouth or throat may cause pain when swallowing, while diarrhoea or nausea may disturb normal eating patterns. Someone who is ill may be less able to earn money, shop for food or prepare meals. Stress and psychological issues may also contribute.
Secondly, weight loss or growth failure can occur when the body is less able to absorb nutrients – particularly fat – from food, because HIV or another infection (such as cryptosporidium) has damaged the lining of the gut.