REPORTING POINT 02/11
HEALTH NEWS
“Live healthy...Live well”
Dedicated to providing pertinent information on health, fitness, and nutrition to foster a culture of wellness among Southwest Airlines flight crews and their families.
by Larry Kline
email: livehealthy-livewell@cox.net
LOWERING BREAST CANCER RISK – hundreds of studies show that avoiding weight gain, getting exercise, and limiting alcohol can lower breast cancer risk. Here are four steps that are most likely to lower the risk:
1. Watch your weight. Probably the single most important thing women can do to reduce their risk of breast cancer is to avoid weight gain in adult life. Ironically, obesity is protective at young ages. Premenopausal women who are heavy have a lower risk of breast cancer. Extra pounds only matter in postmenopausal women who are not taking hormones. In women who take no hormones, being overweight increases risk two- to three-fold. The increased risk is not of much significance with a 10- to15- pound weight gain like it is with diabetes, but gaining 20 to 30 pounds after age 18 certainly increases the risk.
HOW DO EXTRA POUNDS HARM THE BREAST?
Estrogen. Estrogen, which travels through the bloodstream largely as estradiol, promotes breast cancer. That partly explains why extra pounds boost the risk. In the postmenopausal period, the ovaries are no longer producing estrogen. That means the main source of estrogen is fat cells, so the more fat cells you have, the higher the levels of estrogen.
But being overweight has little impact on women who take hormones after menopause because the estrogen in the pills swamps the estrogen that their fat cells produce. So for women taking hormones, the little extra addition of estrogen from fat cells has little effect.
Estrogen may also explain why heavy young women have a lower risk of breast cancer. For reasons that are unclear, they have lower estrogen levels than normal-weight young women.
Whether you start out fat or thin or medium at age 20, putting on weight increases the risk of postmenopausal breast cancer…and a majority of American women put on weight.
Insulin. Women with high fasting insulin levels have nearly 2 ½ times the risk of breast cancer of those with low insulin levels.
Obesity is highly correlated with high insulin levels. In overweight people, the pancreas pumps out high levels of insulin because the insulin does not do a good job of moving blood sugar into cells. The cells are resistant to insulin.
Some studies show that perhaps 15 to 25 percent of postmenopausal women could be insulin resistant, and that could grow with the obesity epidemic in this country.
Insulin is a potent growth factor, particularly in breast tissue. Studies have suggested that women who have diabetes and then get breast cancer do much better if they are treated with metformin than if they are treated with insulin (Metformin is a diabetes medicine that makes cells less resistant to insulin.) Research is now moving beyond estrogen and looking at insulin.
2. Avoid taking hormones. In July, 2002, the National Institutes of Health announced that it was halting the Women’s Health Initiative trial early because women taking hormones after menopause had more breast cancer than those taking a placebo. (There was a 26 percent increase in breast cancer risk.)
Women who took estrogen plus progestin were 29 percent more likely to have a heart attack, 41 percent more likely to have a stroke, twice as likely to have a blood clot, and 47 percent more likely to show a marked drop on test of memory and other mental abilities. The only benefit found was that hormone takers were about 35 percent less likely to be diagnosed with colorectal cancer or hip fracture.
Prolonged hormone replacement therapy strongly elevates postmenopausal breast cancer risk. The Nurses’ Health Study several years ago revealed that the combination of HRT and weight gain during adult life explains about half of breast cancer mortality in the
Weight and hormones also partly explain why
3. Exercise. Active women have a lower risk of breast cancer. An American Cancer Society study tracked more than 72,000 postmenopausal women who answered a questionnaire about leisure activities like walking, running, swimming tennis, bicycling, aerobics, and dancing. After five years, the most active women had a 29 percent lower risk of breast cancer than those who exercised the least.
Exercise protecting the breast seems true for pre- and postmenopausal breast cancer.
Most studies have found that women who engage in physical activity tend to lose fat mass even if their weight remains stable. There is also evidence that staying active may help women who have been diagnosed with breast cancer.
4. Minimize alcohol. One of the best proven ways to lower the risk of breast cancer is to keep alcohol consumption low…and low is pretty low. Even at one drink a day, there is a modest but significant increase in breast cancer risk.
In the Million Women Study, which tracked more than 1,280,000 women for seven years, each daily alcoholic drink raised the risk of postmenopausal breast cancer by 12 percent.
From the standpoint of cancer risk, the message of this report is clear; there is no level of alcohol consumption that can be considered safe for women.
And that is critical even if alcohol helps lower the risk of heart disease. Although it is true that cardiovascular disease is the leading cause of death among women overall, this primarily applies to women older than 75 years. Among women, the major cause of death by far during the middle years is cancer.
FOLATE IF YOU DRINK?
Early studies suggest that women who consumed more folate (largely from fruits, vegetables, and beans) had a lower risk of breast cancer, especially if the women drank alcohol regularly.
OTHER RISK FACTORS
Age. The average age at which women are diagnosed with breast cancer is 62, but the highest rates are in women aged 70+.
Family history. Risk is twice as high in women who have one first-degree relative (mother, sister, or daughter) with breast cancer than in women with none. Women who have two first-degree relatives with breast cancer have five times the risk (especially if the cancers were diagnosed before age 50).
Genes. So far there has not been a clear genetic explanation for most breast cancer. Genes are the major cause of only about 5 to 10 percent of breast cancer cases. Genes like BRAC-1 and BRAC-2 give you about a 60 percent lifetime chance of getting the disease, but not many women have them.
Breast density. Women whose mammograms show a larger area of light (dense) tissue have three to five times the risk of women whose breast are more fatty. Exercise does not appear to reduce the proportion of dense tissue.
Benign breast disease. Hyperplasia (extra cells) raises the risk, possibly because cells are more likely to become abnormal when they multiply.
Jewish ethnicity. Jewish women-especially those of Ashkenazi (European) descent-have a higher risk because they are more likely to have gene mutations linked to the disease.
Menstrual periods. Women who started menstruating early (before age 12) or who went through menopause late (after age 55) have a higher risk, possibly because they had more menstrual periods.
The cycling of estrogen and progestin during menstrual cycles kicks up breast cancer risk because it makes breast cells multiply.
Births. Women who gave birth to fewer than two children or who had their first child after age 30 have a higher risk. An early pregnancy may protect the breast by making breast cells specialize.
Breastfeeding. Women who breastfed children for at least a year (all babies combined) have a lower risk in some studies. Breastfeeding may help by cutting the number of menstrual periods.
Height. Taller women have a higher risk of breast cancer. Researchers suspect that greater height may mean that growth factors were operating during adolescence.
WHAT DOES NOT RAISE YOUR RISK
Little or no evidence supports the claims that antiperspirants, underwire bras, abortions, or breast implants raise breast cancer risk. Nutrition Action Healthletter 7/10.
HEALTHY LIFESTYLE DIVIDENDS – when people embrace a healthy lifestyle, which includes eating at least five servings of produce a day, exercise regularly, and drink alcohol in moderation, they can expect to add 14 years to their lives. Men’s Health 4/08.
