Vitamin cancer link doubted in study

Press, 18 February 1984, Page 29

Vitamin cancer link doubted in study

NZPA-AP Boston A new American study casts doubt on theories that people can lower their cancer risk by consuming vitamins A and E. The study found, no link between cancer and blood levels of these vitamins or of another highly touted nutrient called carotene, which is a source of vitamin A.

Recently, the American Cancer Society urged people to eat foods high in fibre and vitamins A and C, such as fruit, whole grains, cabbage, broccoli, brussels sprouts, and cauliflower. “It may be that something else in fruits and vegetables helps prevent cancer, as some other studies have suggested,” said Dr Walter Willette, of the Harvard School of Public Health, who directed the study. The society’s nutritional guidelines also suggested low alcohol intake, a fatfree diet, and moderation in smoked or pickled meat or meat cured with salt or nitrite.

The society said its recommendations were based on the best available information, but added that no diet could guarantee prevention of cancer. The National Cancer Institute and the National Academy of Sciences have issued similar guidelines.

Vitamin C, one of the nutrients recommended by the cancer society, was not covered in the new study. Even though the latest

study found no overall impact of vitamins on cancer, the researchers said they could not rule out the possibility that they might protect people against some types of cancer. They said larger studies would be needed to spot small effects of the nutrients. “It does raise doubts about the basis of some of the specific studies relating to vitamin A and carotene that were used in those recommendations,” Dr Willette said.

The results gave cause to question if there would be a reduction in cancer by increased taking of vitamin A or carotene.

“Earlier research suggested that people who eat lots of green or yellow vegetables have lower cancer rates.”

The new study analysed frozen blood samples that were collected 10 years ago in a blood pressure study. No significant differences in the vitamin levels between those who later got cancer and those who remained healthy were found. “The weight of the evidence thus suggests that there is little, if any, overall association between the level of serum (blood) vitamin A and the incidence of cancer in human beings,” the researchers wrote in the latest edition of the “New England Journal of Medicine.”

The findings failed to support claims relating intakes of carotene and vitamin E to the incidence of cancer.