Reducing fat intake during puberty lowers blood levels of hormones in young girls that are linked to breast cancer in adult women, according to researchers at the Fox Chase Cancer Center in Philadelphia.

However, the researchers said further study will be needed to determine whether a low-fat diet during adolescence actually results in a reduction in the risk of the breast cancer later in life.

The study involved 286 girls aged between 8 and 10, about half of whom were counseled on following a low-fat diet, in which 28 percent of calories came from fat and no more than 8 percent from saturated fat.

Researchers measured the girls’ blood sex hormone levels at the start of the study and over a seven-year period.

Reporting in the Journal of the National Cancer Institute, the researchers said that after five years, girls in the low-fat group had lower levels of specific forms of estrogen linked to breast cancer.

Estradiol levels were about 30 percent lower and estrone levels were about 20 percent lower, the researchers reported. Levels of progesterone, which may also increase breast cancer risk, were also lower.

"Although we do not know if lower hormone levels during adolescence will influence breast cancer risk in adulthood, adolescence is a time of rapid growth and maturation of the breasts. Estrogens and progesterones contribute to the regulation of this process," lead researcher Dr. Joanne F. Dorgan said.

Other sources: Journal of the National Cancer Institute