A BBC World Service news item alerted me this morning to a landmark study hypothesizing a link between consumption of fumonisin-contaminated maize and HIV transmission.
The report suggested that HIV rates in subSaharan Africa could be significantly reduced by altering food
consumption patterns and reducing maize contamination. Mycotoxins are responsible for many afflictions but this seemed to be a first.
The hypothesis is based on statistical analysis of data from the World Health Organization and FAO which showed that, as maize consumption per person in subSaharan African countries rose, so did HIV-infection rates. SubSaharan populations commonly consume food contaminated by mycotoxins, including fumonisins which occur primarily in maize. There is no evidence to suggest that maize consumption would normally increase the susceptibility of humans to HIV infection. The authors identified contaminants as the most likely basis for the association between maize and HIV, of which fumonisins and aflatoxins are the most prevalent. Known features of aflatoxicosis, and consumption patterns of aflatoxin-prone commodities (such as rice and peanuts), suggested that fumonisins rather than aflatoxins are responsible for the HIV-maize link.
Some 1.7 million new infections are estimated to occur annually in subSaharan Africa. The model from this study predicts that addressing the cause of the HIV-maize relationship may prevent up to one million new infections annually. Where maize consumption is a major component of the diet, a significant reduction in the risk of transmission could be possible by reducing maize consumption.
In addition, levels of fumonisin can also be reduced, either preharvest or postharvest. Agricultural practices can have an effect – sowing date, crop density and nitrogen rate can all affect fumonisin contamination. A number of studies have shown that GM insect-resistant maize has lower fumonisin levels than traditional maize. Insect damage tends to encourage fungal contamination and hence higher levels of fumonisins. Postharvest practices for reducing contamination include steeping, which removes the water-soluble toxin, and some types of milling.
It's not clear why fumonisins would affect transmission rates - the most likely mechanism is that fumonisins might increase membrane permeability which could promote HIV transmission.
There is plenty of information in CAB Abstracts on mycotoxins and food safety, including research on agronomic practices for reducing fumonisin contamination in maize. To find records specifically on mycotoxin levels in GM plants, search:
mycotoxins and "transgenic plants"
=138 records, including a CAB Review on Bt corn and impact on mycotoxins which gives an overview of the literature linking Bt corn and mycotoxin reduction, highlighting the benefits of mycotoxin reduction in regions where unprocessed maize is a staple in the diet.