Wetenschap - 15 maart 2001

Fungus in peanut butter causes liver cancer in Sudan

Fungus in peanut butter causes liver cancer in Sudan

The incidence of liver cancer in subtropical areas of Asia and the Sahel zone in Africa is strikingly high. The disease is deadly. The majority of patients in whom doctors find the disease are dead within a year. PhD candidate Ragaa El Hadi Omer discovered that half of the cases are caused by contaminated peanut butter.

Farmers in Sudan often store peanuts in mud huts. Conditions inside the huts are humid, the ideal environment for some Aspergillus bacteria types to mature, during which process they give off dangerous poisons: aflatoxins. El Hadi Omer discovered that peanuts in Sudan contain twenty times more aflatoxins than the WHO safety guidelines allow.


Aflatoxins cause liver cancer in some people. "Almost half of the Sudanese population do not manufacture the enzyme glutathione-s-transferase," explains the PhD candidate. "This is the enzyme that makes the aflatoxins harmless. If you don't have this enzyme then the aflatoxins are converted into compounds that damage the DNA of liver cells." Sudanese who consume large amounts of aflatoxins and are not capable of making the enzyme are seventeen times more likely to develop cancer of the liver than the average, according to El Hadi Omer's research.

An additional risk factor is hepatitis infection. People who have had this viral disease are fifteen times more likely to develop liver cancer. Hepatitis and contaminated peanuts together are responsible for 80 percent of all Sudanese cases of liver cancer.

Agricultural practices

El Hadi Omer indicates the improvements that can be made on the basis of her research: vaccination against hepatitis, improved on-farm storage of peanuts, use of resistant varieties and other methods of harvesting. In Sudan at present there is little knowledge of the fact that improvements in agricultural practices can lead to big improvements in health. "First people have to become aware of the problem. Most Sudanese at present are unaware of the risks they face. We saw for example that farmers make the lower quality peanuts into peanut butter for their own consumption, while they sell the higher quality peanuts."

Willem Koert

The quality of peanuts in Sudan can be improved by the introduction of a number of agricultural and post-harvest measures, which would lead to considerable improvements in the health of the population.

Biopsy being carried to determine whether a patient has liver cancer. One of the main causes of the high rate of liver cancer in Sudan is aflatoxin contamination of peanuts. Photos | Ragaa El Hadi Omer