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What We Know About Cancer Risk and Coffee

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Coffee beans are seen in a roaster at a stand at the Coffee Fair in Lima, Peru. VOA
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Trouble is brewing for coffee lovers in California, where a judge ruled that sellers must post scary warnings about cancer risks. But how frightened should we be of a daily cup of joe? Not very, some scientists and available evidence seem to suggest.

Scientific concerns about coffee have eased in recent years, and many studies even suggest it can help health.

“At the minimum, coffee is neutral. If anything, there is fairly good evidence of the benefit of coffee on cancer,” said Dr. Edward Giovannucci, a nutrition expert at the Harvard School of Public Health.

The World Health Organization’s cancer agency moved coffee off the “possible carcinogen” list two years ago, though it says evidence is insufficient to rule out any possible role.

ALSO READ: International Coffee Day: Let’s Debunk Some Coffee Myths

coffee
Roasting beans naturally produces a carcinogen called acrylamide. A California judge found that companies must warn their consumers. VOA

The current flap isn’t about coffee itself, but a chemical called acrylamide that’s made when the beans are roasted. Government agencies call it a probable or likely carcinogen, based on animal research, and a group sued to require coffee sellers to warn of that under a California law passed by voters in 1986.

The problem: No one knows what levels are safe or risky for people. The U.S. Environmental Protection Agency sets acrylamide limits for drinking water, but there aren’t any for food.

“A cup of coffee a day, exposure probably is not that high,” and probably should not change your habit, said Dr. Bruce Y. Lee of Johns Hopkins Bloomberg School of Public Health. “If you drink a lot of cups a day, this is one of the reasons you might consider cutting that down.”

Here’s what’s known about the risks.

ALSO READ: A Pilgrim Smuggled Coffee Beans To India: The Intriguing History behind the Development of Coffee Culture

Drinking Coffee reduces mortality in Kidney patients
Drinking reduces mortality in Kidney patients. Pixabay

The chemical

Start with the biggest known risk factor for cancer — smoking — which generates acrylamide. In the diet, French fries, potato chips, crackers, cookies, cereal and other high-carbohydrate foods contain it as a byproduct of roasting, baking, toasting or frying.

Food and Drug Administration tests of acrylamide levels found they ranged from 175 to 351 parts per billion (a measure of concentration for a contaminant) for six brands of coffee tested; the highest was for one type of decaf coffee crystals. By comparison, French fries at one fast-food chain ranged from 117 to 313 parts per billion, depending on the location tested. Some commercial fries had more than 1,000.

Even some baby foods contain acrylamide, such as teething biscuits and crackers. One brand of organic sweet potatoes tested as having 121 parts per billion.

What’s the risk?

The “probable” or “likely” carcinogen label is based on studies of animals given high levels of acrylamide in drinking water. But people and rodents absorb the chemical at different rates and metabolize it differently, so its relevance to human health is unknown.

A group of 23 scientists convened by the WHO’s cancer agency in 2016 looked at coffee — not acrylamide directly — and decided coffee was unlikely to cause breast, prostate or pancreatic cancer, and that it seemed to lower the risks for liver and uterine cancers. Evidence was inadequate to determine its effect on dozens of other cancer types.

ALSO READ: Californian Court Warns “Coffee Causes Cancer!”

Since 1986, businesses have been required to post warnings about chemicals known to cause cancer or other health risks — more than 900 substances are on the state’s list today — but what’s a “significant” risk is arguable.

Sellers and other defendants in the lawsuit that spurred Thursday’s ruling have a couple of weeks to challenge it or appeal.

bulletproof coffee
The law “has potential to do much more harm than good to public health,” by confusing people into thinking risks from something like the drink are similar to those from smoking, Giovannucci said. Pixabay

The International Food Information Council and Foundation, an organization funded mostly by the food and beverage industry, says the law is confusing the public because it doesn’t note levels of risk, and adds that U.S. dietary guidelines say up to five cups of coffee a day can be part of a healthy diet.

Dr. Otis Brawley, the American Cancer Society’s chief medical officer, said, “The issue here is dose, and the amount of acrylamide that would be included in coffee, which is really very small, compared to the amount from smoking tobacco. I don’t think we should be worried about a cup of coffee.”

Amy Trenton-Dietz, public health specialist at the University of Wisconsin-Madison, said the California ruling contrasts with what science shows.

“Studies in humans suggest that, if anything, coffee is protective for some types of cancer,” she said. “As long as people are not putting a lot of sugar or sweeteners in, tea and water are the best things for people to be drinking.” VOA

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Immunotherapy Drugs Show Significant Improvement Against Breast Cancer: Study

Side effects need a close look, both doctors said. Nearly all study participants had typical chemo side effects such as nausea or low blood cell counts.

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Breast Cancer
This undated fluorescence-colored microscope image made available by the National Institutes of Health in September 2016 shows a culture of human breast cancer cells. For the first time, one of the new immunotherapy drugs has shown promise against breast cancer in a large study that combined it with chemotherapy to treat an aggressive form of the disease. VOA

For the first time, one of the new immunotherapy drugs has shown promise against breast cancer in a large study that combined it with chemotherapy to treat an aggressive form of the disease. But the benefit for most women was small, raising questions about whether the treatment is worth its high cost and side effects.

Results were discussed Saturday at a cancer conference in Munich and published by the New England Journal of Medicine.

Drugs called checkpoint inhibitors have transformed treatment of many types of cancer by removing a chemical brake that keeps the immune system from killing tumor cells. Their discovery recently earned scientists a Nobel Prize. Until now, though, they haven’t proved valuable against breast cancer.

Breast Cancer
Weight loss may lower breast cancer risk for post-menopausal women. Pixabay

In the study

The new study tested one from Roche called Tecentriq plus chemo versus chemo alone in 902 women with advanced triple-negative breast cancer. About 15 percent of cases are this type, their growth is not fueled by the hormones estrogen or progesterone, or the gene that Herceptin targets, making them hard to treat.

Women in the study who received Tecentriq plus chemo went two months longer on average without their cancer worsening compared with those on chemo alone, a modest benefit. The combo did not significantly improve survival in an early look before long-term follow-up is complete.

Failed protein test

Previous studies found that immunotherapies work best in patients with high levels of a protein that the drugs target, and the plan for the breast cancer study called for analyzing how women fared according to that factor if Tecentriq improved survival overall.

breast cancer
FILE – A patient receives chemotherapy treatment for breast cancer at the Antoine-Lacassagne Cancer Center in Nice, July 26, 2012. VOA

The drug failed that test, but researchers still looked at protein-level results and saw encouraging signs. Women with high levels who received the combo treatment lived roughly 25 months on average versus about 15 months for women given chemo alone.

That’s a big difference, but it will take more time to see if there’s a reliable way to predict benefit, said Dr. Jennifer Litton of the MD Anderson Cancer Center in Houston. She had no role in running the study but enrolled some patients in it and oversees 14 others testing immunotherapies.

“We’re really hopeful that we can identify a group of women who can get a much bigger and longer response,” she said.

Another breast cancer specialist with no role in the study, Dr. Michael Hassett at Dana-Farber Cancer Institute in Boston, said he felt “cautious excitement” that immunotherapy may prove helpful for certain breast cancer patients.

Breast Cancer
Breast cancer cell, Wikimedia Commons

Side effects and cost

Side effects need a close look, both doctors said. Nearly all study participants had typical chemo side effects such as nausea or low blood cell counts, but serious ones were more common with the combo treatment and twice as many women on it stopped treatment for that reason.

Three of the six deaths from side effects in the combo group were blamed on the treatment itself; only one of three such deaths in the chemo group was.

Also Read: New DNA Tool To Predict People’s Height And Risk For Cancer

Cost is another concern. Tecentriq is $12,500 a month. The chemo in this study was Celgene’s Abraxane, which costs about $3,000 per dose plus doctor fees for the IV treatments. Older chemo drugs cost less but require patients to use a steroid to prevent allergic reactions that might interfere with the immunotherapy. Abraxane was chosen because it avoids the need for a steroid, said one study leader, Dr. Sylvia Adams of NYU Langone Health.

The study was sponsored by Roche and many study leaders consult or work for the company or own stock in it. (VOA)