Tea phytochemicals are color blind

Q. What is red tea and is it as healthful as green tea?

A. Red tea, also called South African red tea or rooibus (roy-boss) tea, is a caffeine-free herbal tea. Unlike green, black and white teas, which all come from the camellia sinensis tea plant, red tea is made from the red bush plant.

Red tea and green tea are both rich in phytochemicals called polyphenols that are strong antioxidants. Researchers say these antioxidants can protect cells from damage that could lead to health problems including cancer and heart disease. Limited laboratory studies suggest that both types of tea may act in additional ways to stop or slow cancer development.While there are human studies that have reported on the effects of green tea, the results have been inconsistent; human studies of red tea are very limited.

The bottom line: Although these teas may confer some health benefits, they are likely most beneficial as beverage alternatives to replace high-calorie, high-sugar beverages like soft drinks.

Q. Does diet have any impact on ED (erectile dysfunction)?

A. According to researchers, weight control, regular physical activity and tobacco avoidance all play a role in reducing risk of erectile dysfunction (ED).

There are several theories on how excess weight may impact ED. Some studies note that ED may be related to inflammation and damage to blood vessels that can increase with excess body fat; other studies suggest it could be linked to a drop in testosterone levels that may result from obesity.

A study published in 2006 followed healthy men without ED for over a decade. According to the researchers, after 14 years, obese men were almost twice as likely to have developed ED. Men who smoked were about 50 percent more likely to develop ED. And men who were most physically active were 30 percent less likely to develop the problem compared to the least active men.

There's less evidence on the impact of eating habits beyond how they support weight control. Some experts speculate that a diet rich in vegetables, fruits and whole grains may help. Promising results have also been seen in one intervention that promoted healthier lifestyle choices in a group of obese men with ED.

According to the researchers, after two years, the men who participated in the intervention lost more weight and showed a greater drop in a marker of inflammation than men who did participate. Most notable: The incidence and severity of ED also decreased in the intervention group.

Q. Since being overweight increases risk of several kinds of cancer, does risk go back down if overweight people lose weight?

A. More research is needed to help experts answer this very important question. For now, some limited data on breast cancer risk suggests that losing weight may have a positive impact.

In both the Iowa Women's Health Study and the Nurses' Health Study, overweight women who lost more than about 20 pounds (and kept it off) showed significantly lower risk of postmenopausal breast cancer than women whose weight remained stable.

Because weight loss reduces levels of hormones and growth factors that have been linked with cancer risk, many researchers speculate that dropping pounds may lower risk of other cancers that are linked to excess body fat as well, including cancer of the colon, kidney, pancreas, esophagus and endometrium.

• Karen Collins, registered dietian writes this column for the American Institute for Cancer Research. Send questions to her at webaicr@aicr.org.