Low cholesterol increases cancer risk
Part 1: Introduction
Countries with diets high in saturated fats tend to have high levels of colon cancer.
In 1974 a review of the Framingham data and those from Keys' 'Seven Countries' study was expected to show that the cancer could also be blamed on high blood cholesterol. However, the baffled researchers found the opposite; those with cancer had cholesterol levels which were lower than average.
In 1989, the Renfrew and Paisley Survey, which was studying the lowering of cholesterol levels to prevent heart disease, found that cases of cancer rose as cholesterol levels fell, such that any reduction in heart deaths was more than offset by an increase in cancers, mainly lung cancer.
This was also the case in the World Health Organisation's Cooperative Trial of the cholesterol-lowering drug, clofibrate, which was published in the same year.
We should remember that cholesterol is a vital building block in cell membranes; it is essential for their integrity and stability. It is not, as seems to be suggested, an alien substance that must be reduced at all costs. Professor Michael Oliver pointed to the part that cholesterol played in the integrity of body cell membranes, saying:
'Normal cell activity depends . . . on membrane function and permeability. This is partly dependent on the balance . . . between cholesterol and saturated and polyunsaturated fatty acids. The possibility that normal membrane function is impaired when there is a disproportionate decrease in cholesterol, with resulting loss of resistance to cancerous change, has to remain on the agenda of the risk/benefits of lowering plasma cholesterol.'
1. Isles CG, Hole DJ, Gillis CR, et al. Plasma cholesterol, coronary heart disease, and cancer in the Renfrew and Paisley survey. BMJ 1989; 298: 920-924
2. Oliver MF. Low cholesterol and increased risk. Lancet 1989; ii: 163.