A recent study which found that most South Africans should avoid milk has provoked disagreement between researchers at the universities of the Western Cape and Stellenbosch.
The study by Professor Walter Veith of the UWC zoology department created a storm this year when his findings were aired on M-Net's Carte Blanche magazine programme.
Veith did experiments on five vervet monkeys and extrapolated his findings to the human diet, concluding that most South Africans are "lactose-intolerant" and should therefore avoid all milk products.
Now Professor Demetre Labadarios, director of the Nutrition Information Centre at Stellenbosch University, has entered the academic fray, saying it is important to note that Veith did not test his data on humans.
Veith found that milk is associated with various diseases, including heart ailments, osteoporosis, diabetes, cancer and respiratory problems, and is not necessarily the best source of calcium.
Veith found a link between heart disease, infertility and milk and concluded that milk has a negative effect on immunity. He also found that milk proteins are difficult to digest, resulting in a build-up of antibodies which attack the beta-cells and may cause diabetes mellitus.
Labadarios said milk is a valuable if not indispensable component of a healthy diet and contains protein, carbohydrates - particularly lactose - and fat. It is also a good source of vitamins, minerals and trace elements.
He added that a lack of lactose is "common among Africans, Indians and Asians", which would make it inaccurate to say that most South Africans are lactose-intolerant. "It is well known that certain population groups are much less prone to develop osteoporosis. This is not because they do not consume milk and dairy products, but because of differences in their genetic make-up and lifestyles."
By using low-fat and skim-milk products, the saturated-fat content of dairy products can be reduced, thereby lessening the risk of heart disease, he said.
Veith was not available for comment on Labadarios's criticisms, but it is understood that he stands by his findings.