Is the consumption of oxidized fats contributing to HIV-AIDS progression in South Africa?

Department of Microbial, Biochemical and Food
Biotechnology
University of the Free State
Nelson Mandela Drive
PO Box 339
Bloemfontein 9301
South Africa
E-mail:kockjl.sci{at}mail.uovs.ac.za

Dear Sir:

The findings recently reported by Oosthuizen et al (1) in the Journal were most interesting and of relevance to HIV-AIDS–stricken South Africa. The authors are to be commended on this study, which was performed on black volunteers from the North West province of South Africa. They found that polyunsaturated fatty acid (PUFA) intake is adversely related to liver function in HIV-infected asymptomatic subjects, and they propose further research to determine the optimal safe amounts for intake of n–6 PUFAs by these subjects, especially in countries with traditionally high intake of n–6 PUFA–rich vegetable fats.

I am, however, concerned that some readers may interpret that PUFA-rich fats (traditionally used in South Africa), should be regarded as unsafe until proven otherwise.

Large amounts of heavily oxidized vegetable fats rich in n–6 PUFAs, such as linoleic acid (18:2), have for many years been distributed by frying establishments as waste to the poor black communities across South Africa for use in food preparation. These fats are nicknamed "fish oils" because of their repeated use in frying fish the resulting subsequent fishy taste. In 2002, our group hypothesized that these fats may adversely affect HIV-infected subjects in the black South African population and may lead to oxidative stress and the progression of HIV-AIDS (2). It is therefore not surprising that the independent epidemiologic study of Oosthuizen et al, the THUSA study (1), shows that n–6 PUFA intake by black HIV-infected asymptomatic subjects may be related to liver damage, whereas HIV-uninfected subjects with the same n–6 PUFA intake were not affected. Unfortunately, the oxidative load associated with the dietary fat intake in this study was not measured. Consequently, that aspect should be addressed first.

Such a study is urgently needed, because South Africa is plagued with a very high prevalence of HIV infection. According to the Joint United Nations Programme on HIV-AIDS (UNAIDS), South Africa continues to have the largest number of people living with HIV (1). Some frying establishments in South Africa also produce polyunsaturated n–6 PUFA-rich fat waste ("fish oils") with the highest oxidative free radical–induced breakdown proportions ever recorded—ie, up to 75% polymers (2). It is important that oxidized fats produced from polyunsaturated, monounsaturated, and saturated vegetable fats during the frying process are included in future studies.

ACKNOWLEDGMENTS

The author had no personal or financial conflict of interest with the study of Oosthuizen et al.

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