Project Lead(s): Gregor Reid
Man-made and environmentally derived toxins cause acute and chronic illness and death to millions of humans and animals in Africa.
Environmental toxins, such as aflatoxins and heavy metals, contaminate food and can lead to neurological problems in infants.
Since 2004, about 477 cases of aflatoxin poisoning associated with eating contaminated maize have been documented in eastern Kenya, with a fatality rate of 40%.
The main goal of this project was to develop a special probiotic yogurt that is consumed to reduce environmental toxin uptake in humans.
Fermented foods that contain lactobacilli bacteria can lower adsorption of environmental toxins, as the cell wall of the organism can bind to the toxins and, in some cases, degrade them.
The project team had previously introduced probiotic yogurt through community kitchens in Tanzania, and Kenya, and shown that the probiotic strain Lactobacillus rhamnosus GR-1 can decrease adsorption of arsenic and mercury in children and pregnant women. The basis of the new work was that the GR-1 strain and one recovered from fermented millet in Kenya (strain NN20) could bind to aflatoxin.
The first objective was to set up a community kitchen in rural Kenya near Embu, where aflatoxin poisoning is known, and to test whether ingestion of probiotic yogurt containing GR-1 and NN20 could reduce aflatoxin uptake in school children known to be exposed, despite warnings to avoid the contaminated maize.
Each participant received 200ml of this probiotic yogurt for 14 days in a calibrated cup every morning, and samples of blood and urine were collected for aflatoxin analysis. Samples of maize from the source used by families were also collected and tested for aflatoxin.
The second objective was to design and create a sachet that contains a dried Streptococcus thermophilus bacterium that effectively ferments milk, and the complementary probiotic Lactobacillus rhamnosus GR-1 strain. This is a critical innovation, as it provides a means to deliver the probiotic to a wider audience. With one sachet, a person or group can produce 100 litres of probiotic yogurt all by themselves, rather than relyinh on a separate entity (university, institute, hospital, clinic) to have to grow the probiotic. Through extensive collaboration with Yoba-for-Life and analysis of over 100 strains, a S. thermophilus was discovered with ideal properties, and this has now successfully been added to L. rhamnosus GR-1.
When tested with school children, the yogurt was well received, with only one suspected adverse event attributed to lactose intolerance.
Using a dietary recall, the children consumed maize on an average of 9.5 of the 28 days of study.
On average, the children’s body mass index Z score of 14.8 kg/m2 was indicative of malnutrition. This increased to normal levels (average 16.3 kg/m2) following probiotic yogurt intake for two weeks.
The percentage of urine samples post-treatment testing positive for aflatoxin was 21% for controls and 9% for those consuming the probiotic yogurt.
Levels of aflatoxins were generally low, so it was not possible to conclude that these children were at risk of liver cancer or that daily consumption of probiotic yogurt would reduce that risk.
The successful creation and production of 20,000 sachets allows expansion to community kitchens around Mwanza, Tanzania, and Nairobi, Kenya. This empowers women and provides income for social business groups and farmers; the kitchen provides nutritional food, especially to growing children.
With the success of this project, and collaboration with Heifer International, Yoba-for-life and Jomo Kenyatta University of Agriculture and Technology (JKUAT), the team received follow-on funding from the International Development Research Centre (IDRC) to enable the distribution of these probiotic yogurts to access one million adults and children in east Africa.