From the book, "Enzyme Nutrition," by Dr. Edward Howell:

EATING REFINED VEGETABLE FAT CAUSED CANCER AMONG 423 MEN

There is a worldwide attempt to control cardiovascular disease by limiting
or excluding the intake of animal fat in all forms, including dairy
products. As substitutes, highly purified vegetable oils are frequently
recommended. These are crystal-clear products, pure fat, with the same
blemished nutritional pedigree that pure, white table sugar has had to
endure these many years. Any isolated, purified, skeletonized food material
must be expected to have adverse, far-reaching effects on the health of
living organisms. This can be predicted by the history of human nutrition.

It need not be unduly surprising to read the report entitled, "Incidence of
Cancer in Men on Diet High in Polyunsaturated Fat." Universities and the
Veterans Administration in the Los Angeles area collaborated in a clinical
trial extending over 8 years to test the efficacy of a diet in which
vegetable oils were substituted for saturated fat. The test involved 846 men
living in government hospitals. Half of them were kept on a diet with
purified, unsaturated fats, while the other half ate a regular diet with
ordinary fats, including butter. Those eating unsaturated purified fat had
lower blood cholesterol levels and fewer deaths from cardiovascular
diseases, 48 versus 70. An unexpected finding after the 8 years of the diet
was that of the 423 subjects eating the purified fat there were 31 cancer
deaths, while in the 423 eating some animal fat there were only 17 deaths
from cancer. In a press conference in 1971, the architects of the program,
Drs. M.L. Pearce and S. Dayton, of the University of California, issued a
warning to go slow both on cholesterol and purified oils.