The problem is the milk sugar, not the milk fat, so it is not solved by using non-fat products. In fact, yogurt and cottage cheese seem to be of most concern because the bacteria used in their production increase the production of galactose from lactose. There is a great deal of evidence that dietary factors can help prevent cancer. The evidence is not all in, but there is reason to believe that foods can have an important effect here, too. The immune system is our line of defense against both initial cancers and the spread of cancer.
Substantial evidence shows that certain foods can bolster immune function, while others impair it.
For example, natural killer cells are specialized white blood cells that seek out and destroy cancer cells. A recent German study showed that vegetarians have more than twice the natural killer cell activity of non-vegetarians. It is not yet known whether the immune strength of vegetarians comes from their having double the number of natural killer cells or from each cell having double the killing power. Whichever it is, vegetarians have a defense against cancer cells that is far beyond that of their meat-eating fellows. The immune strength of a vegetarian diet probably comes from its low fat content and from vitamin-rich vegetables and fruits.