Can fibre help fight fat gain? By Sean R. Hosein

From: Alice - January 2004, Volume7, Issue 1
(reprinted from www.catie.ca. Cet article est disponible en francais)

Although highly active antiretroviral therapy (HAART) can help maintain and improve the health of people with HIV/AIDS (PHAs), these drugs have side effects, particularly the HIV lipodystrophy syndrome. Features of this syndrome can include the following:

  • loss of fat just under the skin (subcutaneous fat) in the face, arms and legs
  • fat gain in the belly, breasts (in women) and, less commonly, at the base of the neck, forming a "buffalo hump"
  • increased levels of sugar and the hormone insulin in the blood
  • increased levels of fatty substances - cholesterol and triglycerides - in the blood

Together these changes increase the risk of diabetes and cardiovascular disease in HAART users. For more information about dealing with these side effects, please see CATIE's Practical Guide to HIV Drug Side Effects at http://www.catie.ca/sideeffects_e.nsf.

One of the features of the lipodystrophy syndrome is fat accumulation, particularly in the belly. Researchers at several research centres in Boston, including Harvard University, have been studying nutritional factors that may be linked to the issue of fat gain. According to the team's results, an "overall high-quality diet, rich in fibre and adequate in energy [calories] and protein" may help prevent fat gain.

Study details

As part of their research, scientists in Boston collected nutritional and medical information on PHAs between 1995 and 2000. This information was entered into a database and later analysed. One of these analyses has been used to study vitamin B12 levels (for more information on that study, please see TreatmentUpdate 138 at http://www.catie.ca/tu.nsf).

Subjects were trained by a nutritionist how to keep accurate records of the types of food they eat on a regular basis. Also, subjects were interviewed regularly about their eating habits and had blood work and other tests performed. The research team was looking at the time period six to 24 months before subjects developed fat deposits to try to find which nutritional factors may have had an impact on this. In the current study on fibre, researchers reviewed the information in their database and identified 94 PHAs with the following profile who were divided into two groups:

  • 47 subjects with fat gain (and who were not "obese")
  • 47 subjects without fat gain (and who did not have fat wasting)

In the data analysis, each subject with fat accumulation was paired or matched with another subject without fat accumulation and who also had similar age, race, CD4+ cell count and HAART use. On average, most of the 94 PHAs were white, about 42 years old and male. Thirty-eight percent of the entire group had more than 200 CD4+ cells and 81% were taking HAART. Initially, the researchers (all women) began to include women in their analysis but later found that they did not have enough women to serve as matched controls and produce statistically meaningful results (Kristy Hendricks, written communication), so the study focused entirely on men.

Results - Diet Researchers found the following:

  • PHAs with fat deposits ate significantly less fibre than PHAs without fat deposits.
  • PHAs with fat deposits consumed significantly less protein and fewer calories than PHAs without fat deposits.
  • When it came to the consumption of carbohydrates, fats or alcohol, there were no differences between both groups.
  • Although not significant, PHAs with fat deposition tended to consume less omega-3 fatty acids (found in canned tuna, herring, mackerel, sardines and salmon) than PHAs without fat deposits.

Results - Lifestyle factors

In comparing the two groups of PHAs, researchers found two other factors not related to diet that may have played a role in whether or not fat deposits occurred:

  • Lifting weights (resistance training) - this was done by significantly more PHAs without fat deposits than those with fat deposits.
  • Smoking tobacco - more PHAs who smoked developed fat deposits compared to non-smoking PHAs.

The researchers noted that these last two factors (weight-lifting and not smoking) were not linked to an increased intake of fibre in the diet.

Fibre in perspective

In this study, high intake of dietary fibre was associated with a reduced risk of developing fat deposits in men with HIV/AIDS, most of whom were taking HAART. Similar results were found in another study of both men and women with HIV/AIDS. In the current study, an increase in the intake of dietary fibre - as little as one gram - was associated with a 7% reduction in the risk of developing fat deposition.

Fibre has many other potential benefits. Previous studies in HIV negative people found that a high intake of fibre is linked to reductions in blood sugar and reduced levels of the hormone insulin and lipids in the blood. Good sources of fibre include whole grains, fruit and vegetables.

The study would have been strengthened if additional information, such as the type of drugs used in HAART regimens and the length of time PHAs were taking HAART, were included in the analysis. Nonetheless, the researchers found that diets high in fibre may be beneficial in preventing the development of fat deposition in PHAs. Additionally, good nutritional habits, including adequate intake of protein and calories are also important. Lastly, not smoking tobacco and engaging in resistance exercise may also be useful.