Sunshine, hot peppers, vitamin D vs. cancer

Researchers show off latest findings in fight against the disease


Spending some time in the sun and eating hot peppers may help fight cancer. And using aspartame to sweeten your coffee probably won't cause the disease.

Those are just a few of the conclusions announced this week at the 97th annual meeting of the American Association for Cancer Research in Washington. About 16,000 scientists attended the event and presented more than 6,000 papers.

One of the most intriguing findings concerned vitamin D. Researchers at the Samuel Lunenfeld Research Institute at Mount Sinai Hospital in Toronto looked at more than 2,000 women, about half of whom had breast cancer.

Through interviews with the subjects, researchers reconstructed how much vitamin D they had been exposed to during their lives.

Exposure to sunlight is the best way to get the body to manufacture its own vitamin D.

Women who had worked at an outdoor job between the ages of 10 and 19 had a 40 percent reduced risk of breast cancer. Those who had an outdoor job between 10 and 29 had a 35 percent lower risk.

Researchers have known for years that vitamin D may decrease the chance of getting cancer, but the study further cemented the link.

The researchers also looked at the effect of dietary vitamin D intake. Taking cod liver oil (which contains large amounts of vitamin D) between the ages of 10 and 19 reduced breast cancer risk by 25 percent, and drinking at least nine glasses of milk (which also contains large amounts of vitamin D) a week between the ages of 10 and 29 lowered the risk by a third. But it only seems to work on the young. In older women, vitamin D intake had no effect on cancer risk.

Epidemiologist Julia Knight, the lead researcher on the study, said vitamin D may "reduce the out-of-control growth that occurs with cancer development."

She suspects that the stage for subsequent cancer may be set during initial breast development in adolescence and the 20s. By limiting abnormal growth during that period, vitamin D may lower breast cancer risk.

As far as sun exposure goes, Knight emphasized that more research is necessary and said she didn't "want to encourage people to get a sunburn." That's the downside: spending too much time in the sun can increase the risk of skin cancer.

"Fifteen minutes to half an hour can give you a fair bit of vitamin D," she said.

Another vitamin D study, by scientists at the University of California at San Diego and Harvard University, found that taking 1,000 international units of the supplement a day may lower breast cancer risk by half. The typical American consumes less than a third of this amount.

Vitamin D may not be the only item to add to your grocery list. Researchers at the University of Pittsburgh reported that capsaicin, the chemical that makes hot peppers hot, may kill certain cancers.

The researchers fed capsaicin to mice that had been implanted with human pancreatic tumors. They found that the spiced mice had significantly smaller tumors than animals that did not receive capsaicin.

In further tests, the scientists found that the substance seems to trigger the release of proteins that induce cancer cells to kill themselves. At the same time, capsaicin did not harm normal cells.

The lead investigator, Sanjay Srivastava, a pharmacologist at the University of Pittsburgh School of Medicine, says capsaicin has the potential to prevent and treat pancreatic cancer, one of the most lethal forms of the disease. Of the 30,000 people diagnosed with it every year, almost all die within 12 months. It is the fifth-leading cause of cancer death in the United States.

Meanwhile, scientists at the National Cancer Institute studied 567,000 Americans of both sexes and reported that aspartame, the widely used artificial sweetener sold most commonly as NutraSweet, does not appear to increase the risk of brain tumors, leukemia or other blood cancers. Some animal studies had suggested that the chemical might be associated with increased cancer risk.

In other research, two scientists from the Johns Hopkins University have discovered evidence that a substance known as cyclopamine may help short-circuit cancer recurrence.

In many cancer patients, initial treatment seems to wipe out the cancer. But the disease often returns, eventually killing the patient.

Dr. William Matsui and Dr. Neil Watkins, assistant professors of oncology at the Johns Hopkins School of Medicine, used cyclopamine to wipe out cancer stem cells, which generate other cancer cells. These cells are thought to be the culprit in many recurrences.

Working with colonies of bone marrow cancer cells, the scientists used cyclopamine to turn stem cells into regular cancer cells, which subsequently died. Matsui says the drug may be a potential treatment.

"[Cancer stem cells] are the factories that the rest of the cancer gets made from," he said. "You want to knock out the factory."

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