According to scientists, broccoli contains a chemical called sulphoraphane, which activates cancer-fighting enzymes inside cells.  Researchers say the richest source of sulphoraphane is contained in sprouts.

In a demonstration of the plant’s anti-cancer properties, investigators smeared broccoli sprout extract on the skin of six volunteers for three days, and then exposed them to high doses of ultraviolet radiation, which is the leading cause of skin cancer.

They found there was an average 37 percent less redness and sunburn in the patches covered by broccoli extract.  Redness and sunburn are an indication of skin damage that could lead to cancer.

The results of the study are published in the journal Proceedings of the National Academy of Sciences.

Paul Talalay is a Johns Hopkins University molecular pharmacologist and the author of the study.  Talalay says sunscreen conferred no protection against the UV rays, but he says that does not mean people should stop using it.

“We want to avoid under all circumstances people doing weird things like making broccoli sprout soup and applying to their skin and thinking that they will be protected against the sun,” he said.  “They will have not have any protection whatsoever, because it’s a totally different mechanism and one cannot possibly substitute for the other.”

Applied as a thick cream, sunscreen protects the skin by deflecting the sun’s harmful rays.  But it must be constantly reapplied to remain effective.

In contrast, Talalay says, a compound made of broccoli sprouts works by penetrating skin cells and stimulating their natural cancer-fighting mechanism.

Observers call the research promising, but say more studies are needed because the results varied considerably among participants, ranging from a low of eight percent to a high of 78 percent protection against sunburn.  Talalay disagrees.

“Everybody knows you go to the beach and you get fried and I go to the beach and nothing happens to me,” he added.  “And we are in the same place.  So, the same experiment if done in a large number of individuals would be much more complex.  But I believe that the evidence certainly from animal studies is that we would get absolutely the same result.”

Talalay believes if it works in the skin, a sulphoraphane extract from broccoli sprouts is very likely to act as a hedge against cancer in other organs.

Meanwhile, researchers say there are a number of challenges in making a sun cream from broccoli sprouts, not the least of which is figuring out how to get rid of the green tint.

New research suggests that a nutrient in red meat, poultry and dairy products may contribute to the development of intestinal polyps, which can lead to colon cancer.

The study, which involved women only, was preliminary, and no one is yet suggesting a change in diet as a result.

However, the research into the nutrient, called choline, could ultimately lead to new dietary recommendations, said Eunyoung Cho, an epidemiologist at Brigham and Women’s Hospital in Boston.

“There may be some impact,” Cho said. “But this is one study, and it’s hard to make any conclusion based on this study.”

The role played by choline, a nutrient required by the body, has been unclear. Some researchers had thought it might provide protection against colon cancer, which kills an estimated 52,000 people in the United States each year, according to the American Cancer Society. The disease is the second biggest cancer killer in the United States after lung cancer.

In the new study, Cho and colleagues looked at nurses enrolled in a large study. They found more than 39,000 women who were free of colon cancer and then underwent at least one endoscopic examination between 1984 and 2002. Polyps — benign growths that can lead to colon cancer — were found in more than 2,400 of the women.

Women who ate the most choline in their food were 1.45 times more likely to have polyps, the team reported in the Aug. 7 online issue of the Journal of the National Cancer Institute.

Having more polyps doesn’t necessarily mean more cancer, and future research will explore whether those who ate the most choline actually developed tumors, Cho said. Studies also need to look into the impact of choline on men.

Why might choline contribute to polyps, and possibly colon cancer, in the first place? The nutrient is a major component of the membranes of cells, Cho said, “and the tumor cell may need choline.”

Currently, health officials recommend that people prevent colon cancer by eating a lot of fiber along with fruits and vegetables. Red meat, meanwhile, is thought to increase risk.

That dietary advice isn’t likely to change even if choline turns out to be a possible villain, said Regina Ziegler, a senior investigator with the National Cancer Institute, who co-wrote a commentary accompanying the new study. “What they’re finding is consistent” with the recommendations, she said.

As for now, “people shouldn’t run out and start either taking more choline or less choline,” she said.