I recently attended the AIDS Impact Conference in Gaborone, Botswana, where HETN was presenting a poster.
Very few presenters even mentioned the subject of nutrition. When we raised it, there was interest, but the consensus seemed to be:
- (From the scientists) – Yes, nutrition is important, but it is complex, so we would rather concentrate on things we can understand.
- (From the agencies) – Yes, nutrition is important, but it is complex and we cannot get into ‘feeding the world’.
One of the plenary speakers, Dr Gita Ramjee of the Medical Research Council, gave an excellent presentation on all possible biomedical interventions, with their strengths and weaknesses. She questioned whether the randomised control trial was always an appropriate assessment tool, but she never mentioned the role of micronutrients.
No one I spoke to had even heard of the importance of selenium.
In 1979, Chinese scientists reported that selenium had been linked to Keshan disease, an endemic juvenile cardiomyopathy (disease of heart muscle) found in the Keshan district of China. This often fatal disease has since has been found elsewhere (including New Zealand and Finland) where soil selenium levels are low.
However, certain epidemiological features of the disease could not be explained solely on the basis of inadequate selenium. Fluctuations in the seasonal incidence suggested the involvement of an infectious agent.
Indeed, a coxsackie virus isolated from a Keshan disease victim caused more heart muscle damage when inoculated into selenium-deficient mice than when given to selenium-replete mice. Vitamin E status had a similar effect on viral virulence.
Keshan disease seems to be the result of several interacting factors, including a dominant nutritional deficiency (selenium), other nutritional deficiencies (vitamin E and polyunsaturated fatty acids) and an infectious agent (virus).
Turning to HIV infection, the estimated adult prevalence rate (2007) in Bolivia was 0.2. In Senegal it was 1.0. These two countries have the highest naturally occurring soil selenium levels in the world. Comparable figures for South Africa and Swaziland, where soil selenium levels are very low, were 18.1 and 26.1 respectively. Finland had low soil selenium levels, but has been adding selenium to fertilisers since 1984. There, the estimated adult HIV prevalence rate (2007) was 0.1, whereas in neighbouring Russia and Estonia it was 1.1 and 1.3 respectively.
Kupka studied the relationship between death from AIDS and plasma selenium levels in pregnant women in Tanzania. Blood was collected from 949 pregnant women and saved for 5.7 years, by which time 306 of them had died. Statistical analysis showed that the lower the original plasma selenium level, the more likely the woman was to die of AIDS. The relationship was statistically significant.
Has selenium been shown to benefit AIDS patients? Yes. Randomised controlled trials in Nigeria (Odonukwe) and in the US (Hurwitz) have shown significant benefit.
Both these studies used selenium rich yeast. Many selenium studies show little benefit, but I have talked elsewhere about the importance of form. Where there is deficiency, it has become commonplace to fortify bread or salt with sodium selenate or selenite. This is unlikely to have the desired benefit because these salts are toxic, poorly absorbed, and the little that is absorbed does not act as an antioxidant. It is a mad world that bans mineral water that is contaminated with sodium selenite – an industrial pollutant – and then puts it in the bread! Selenomethionine is better absorbed and has some antioxidant properties. In contrast, selenium rich yeast is non-toxic, well absorbed and has powerful antioxidant properties. One would expect this, as yeast is a natural food and the selenium in it is complexed with natural carrier proteins.
In my naivety, I thought that the scientific method was about noticing something, developing a hypothesis and testing it. There is certainly much to notice about HIV prevalence and selenium status.
Sadly, there seems little interest. This is indeed strange. AIDS is about immune deficiency. The commonest cause of immune deficiency is micronutrient deficiency. Surely any AIDS intervention should start with ensuring that populations are micronutrient replete?
HETN’s poster was about TB, which kills more adults than any other infectious disease, and is often found with HIV. Ensuring that patients are micronutrient replete improves TB cure rates by 39% and only costs £1.50 per month. So cost is not the issue – but perhaps it explains the lack of interest?
CEO – Health Empowerment Through Nutrition