So, it appears the African Journal of Food Sciences is retracting a study because a company complained that the results of the study caused a drop in business. Yes, really.
They come right out and say it. There is no other explanation given, and no reasonable reason for dispute:
The retraction is based on the fact that a Gari processing company has requested the retraction this paper from journal's website and publisher's database since it is crumbling their business inputs to their competitors leading to a drastic reduction in customers and consumers hence affecting their productivity and profitability.
The study found that that foods made with from cassava root (processed or otherwise) causes a significant loss in visual acuity and colour blindness (due to the fact that it naturally contains higher than safe cyanide levels).
The incidence and degree of visual defects was studied among 180 subjects (100 consumers and another 80 non-consumers of gari at Zaria metropolis town). Visual acuity and color vision tests were accessed using the Snellen's chart and the Ishihara's chart, respectively. The visual acuity of consumers of gari showed a significant decrease (P<0.05) when compared with that of the non consumers of gari. The incidence of color blindness is higher in gari consumers than the non consumers. Visual defects are correlated to the frequency of eating gari, for how long gari has been eaten and age. The high prevalence of visual defects among the consumers of gari may be due to the exposure to unsafe amount of cyanide in gari that was consumed over a long period of time. This may consequently contribute to high prevalence of blindness and severe visual impairment especially among those aged ≥ 40 years.
I am not very good at explaining all the statistics above (perhaps some of the more science types around here want to take a crack at it - Mika? neisseria? Doc?) - but the study seems reasonably well done and very conclusive, in spite of a not very large sample size.
It appears garri is a staple food in Africa, especially in Nigeria, where the study took place. Even though it is not very nutritious at all, it is very cheap (and the plant itself is very drought-resistant). Wikipedia says it sells for less than one US dollar. So if the study is correct - the retraction is possibly dangerous for a lot of people, or at least an impediment to consumers making an informed choice.