Foods rich in plant chemicals called isothiocyanates and quercetin appeared
to offer the best protection against lung cancer, the study showed.
Isothiocyanates are found in cruciferous vegetables such as broccoli,
cabbage, cauliflower, brussels sprouts, and turnips. Apples, grapes, onions,
and broccoli are good sources of quercetin.
Both studies were presented here at the annual meeting of the American
Association for Cancer Research.
Exercise Wards Off Breast Cancer
The exercise study involved about 1,500 women with breast cancer. They were
compared with nearly 5,000 women who didn't have breast cancer.
All the women filled out an extensive questionnaire that asked about their
diet, smoking, and exercise habits.
Overall, women who engaged in recreational exercise 30 to 150 minutes per
week were 50% less likely to have breast cancer than women who exercised less
than a half hour per week.
African-American women benefited the most. They were about 70% less likely
to have breast cancer if they exercised 30 to 150 minutes a week than if they
But Hispanic-American, Tunisian-Arab, and Polish-Caucasian women all
benefited as well, researcher Teresa Lehman, PhD, of BioServe Biotechnologies
in Beltsville, Md., tells WebMD.
The findings held true regardless of whether a woman was premenopausal,
perimenopausal, or postmenopausal, she adds.
Exercising more than 150 minutes per week did not confer additional benefit,
More Exercise May Be Better
The study showed that how long you exercise per workout session also
significantly affects breast cancer risk.
Women who exercised 15 minutes or more per session were 40% less likely to
have breast cancer, compared with women who exercised less than 15 minutes per
The analysis took into account a woman's age, race, and weight as well as
how much she smoked in her lifetime -- all factors that can affect breast
Marji McCullough, ScD, RD, of the American Cancer Society, tells WebMD that
the findings are consistent with the group's recommendation to engage in
physical activity as a means of keeping breast cancer risk down.
But she takes issue with the finding that more is not better.
Women should work out 30 minutes a day, five times a week, to reap the
greatest benefits, McCullough says.
"And even more, like 45 minutes a day, and vigorous activities like
running, will reduce breast cancer risk even further," McCullough says.
Fruits, Veggies Linked to Lower Lung Cancer Risk
For the lung cancer study, Tram K. Lam, PhD, of the National Cancer
Institute, and colleagues analyzed data on 2,120 people without lung cancer and
201 people with lung cancer.