The more fat a postmenopausal woman has, the greater chance she will develop breast cancer, according to a study likely to renew debate about whether overall body fat, or belly fat, is the better predictor of the cancer.
At the center of the debate is whether overall fat or belly fat generates the highest levels of hormones and inflammatory factors associated with breast cancer.
Some studies have concluded that overall fat does. Others have sided with belly fat.
The latest research comes down on the side of overall fat. The study, “Association between changes in fat distribution and biomarkers for breast cancer,” was published in the journal Endocrine-Related Cancer.
“It is known that belly fat increases the risk of several chronic diseases, independently of total body fat, but, for reducing sex hormone levels, total body fat seems more important,” Dr. Evelyn Monninkhof, who led the study, said in a news release.
A reasonable weight prevents a woman from producing too much of the hormones associated with breast cancer after menopause, decreasing her risk of developing breast cancer, the study indicates.
“Our next step is to find out how belly fat and total body fat can best be conquered, to identify which nutritional or physical activity programs are optimal for reducing both weight gain and breast cancer risk,” Monninkhof said.
The study looked at the connection between weight loss, hormone levels and inflammatory factors. Two hundred forty-three overweight, postmenopausal women took part in a 16-week weight loss program that generated an average weight loss of 5 to 6 kilograms.
Researchers measured the women’s overall fat and belly fat after the program. “We used more accurate DEXA [dual-energy X-ray absorptiometry] measurements for total body fat, as well as MRI [magnetic resonance imaging] for belly fat,” Monninkhof said.
The team took blood samples from the women who lost weight during the program to assess cancer-related hormone markers and inflammatory factors. The hormones included the sex hormones testosterone and estrogen, plus leptin, which controls a person’s sensation of being full.
By comparing the women’s overall fat, belly fat, hormone levels and inflammatory-factor levels, the researchers concluded that reducing overall fat lowered levels of breast cancer markers better than belly fat.