Lab Report: Health, Science and Medicine

MOTHERHOOD

Breast-Feeding Moms Get Just as Much Sleep

Score another point for advocates of breast-feeding. A new study found that mothers who breast-fed their newborns during the first three months got just as much (or as little) rest as their bottle-feeding counterparts.

Although some previous studies showed that breast-fed babies were more likely to wake during the night and slept less overall than formula-fed infants, meaning less sleep for Mom, the new data suggests that the method of feeding has little impact on mothers' rest. Among 80 new mothers studied--some who breast-fed, some who used formula and some who relied on a combination of the two--researchers found no differences in objective measures of mothers' sleep, recorded by a motion-detection device the women wore on their wrists, or in subjective assessments of how well the women slept and how rested they felt. On average, the mothers reported getting a total of about seven hours of sleep per night.

The results should help convince new moms concerned about losing sleep to breast-feeding--which is known to confer health and immunity benefits to babies--that choosing formula may not necessarily lead to more z's.

CANCER

Understanding the Links Between Obesity, Breast Cancer and Race

Studies have hinted that obesity may play a key role in breast cancer, particularly in postmenopausal women. Fat cells release a form of estrogen that can promote tumors; they also prevent the absorption of estrogen circulating in the body. But those studies primarily involved Caucasian women, and the interplay of obesity and cancer may differ by race.

A new study of Mexican-American women underscores the point. For every 11 lb. (5 kg) the women gained, their risk of breast cancer dropped 8%. Though counterintuitive, the findings can be explained by differences in reproductive history, the researchers suggest: the women in the study hit menopause earlier than white women do, sparing them two additional years of cancer-triggering estrogen exposure.

FROM THE LABS

Hard Work Makes Food Taste Better

A study of mice in which some were forced to work harder than others for the same sweet treat suggests that effort can change the way animals--and possibly people--perceive and taste food. When the mice in the study were given a choice of foods, they continued to prefer the treats they had labored for previously.

Turning Skin Cells Into Blood

In a development that may someday help patients with blood disorders like anemia or those undergoing cancer therapy, researchers in Canada have figured out how to transform skin cells directly into blood cells--without first reverting them to an embryo-like stem-cell stage. The scientists produced various types of blood cells by inserting a single gene and exposing the skin cells to specific growth factors.

DIET