Red meat links to higher risk of breast cancer¹

Exercise and keeping a healthy weight are two things that doctors say might help women lower their risk of breast cancer.

Mothers may reduce their risk if they breastfeed for at least four months. For older women, hormone replacement therapy² can lower the risk of some other diseases. But it has been found to increase the risk of breast cancer. So women should consider their choices carefully. The same may be said for diet.
    New findings show that younger women who eat a lot of red meat have higher rates of breast cancers called hormone-receptor positive.³ The growth is fed by the levels of estrogen or another hormone, progesterone, in the body.

Researchers at Brigham Women's Hospital in Boston, Massachusetts, reported the findings as part of a health study of nurses. The researchers followed the health of more than 90,000 women from 1991 to 2003. Those who ate the most red meat ate more than one and one-half servings a day. A serving was defined as roughly 84 grams. Those who ate the least red meat ate less than three servings a week. This is what the study found about breast cancers that were hormone receptor-positive: The women who ate the most red meat were almost two times as likely to get them as the women who ate the least of it.

Eunyoung Cho, the lead author of the report, says more research is needed to know the reason for the link. But in the past, researchers have suggested that three things may play a part. One is the way meat is cooked or processed. Another is the use of growth hormones in cows. And the third is the kind of iron in red meat. The study appears in the Archives of Internal Medicine.

And now we have more to tell you about our subject -- resveratrol. We discussed a study in the United States that found that large amounts of this plant compound helped fat mice live longer. The mice were fed much more resveratrol than people could get from red wine, one of the foods that contains it.

Now, scientists in France say resveratrol also improves muscle performance -- again, at least in mice. They were able to run two times as far in laboratory treadmill tests⁴ as mice normally could. The study at the Institute of Genetics and Molecular and Cellular Biology⁵ appeared in the journal Cell.

词汇：

breast n 胸；乳房

breastfeed v. 哺乳，喂奶

hormone n. 激素，荷尔蒙

therapy n. 疗法，治疗

receptor n. 接受器，感受器；受体

estrogen n. 雌激素

progesterone n. 黄体酮, 孕酮 (孕激素类药)

serving n. 一份饭菜

process vt. 处理；加工

resveratrol n. 白藜芦醇（抗肿瘤药）

compound n. 混合物；化合物；复合物

treadmill  n. （古时罚囚犯踩踏的）踏车；（喻）单调的工作

genetics n. 遗传学

molecular adj. 分子的

cellular adj. 细胞的

cell n. 细胞