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
Gout, an inflammatory arthritis that occurs more frequently in aging men, is now becoming increasingly common in women. Sugary sodas may have something to do with the trend. A study of nearly 79,000 women found that those who drank more than two sweetened sodas a day increased their risk of gout 2.4-fold over those who had less than one soda per month. The painful condition is fueled by a buildup of uric acid, a by-product of the fructose in the drinks.
WHO SHOULD EAT SOY?
Soy is known as nature’s estrogen and may affect breast-cancer risk. Studies suggest a woman’s age and soy-consumption level are factors
WHEN: 1998
STUDY OF: Laboratory cells
RESULTS: Phytoestrogens, like those found in soy, increased tumor growth
WHEN: 2008
STUDY OF: Middle-aged and older Chinese in Singapore
RESULTS: Higher dietary soy intake was linked to lower risk of breast cancer
WHEN: 2009
STUDY OF: Chinese breast-cancer survivors
RESULTS: Higher dietary soy intake lowered the risk of death and recurrence over four years
WHEN: 2010
Study of: Pre- and postmenopausal women
RESULTS: Higher soy intake lowered risk of invasive tumors in premenopausal women
More Must-Reads from TIME
- Inside Elon Musk’s War on Washington
- Introducing the 2025 Closers
- Colman Domingo Leads With Radical Love
- Why, Exactly, Is Alcohol So Bad for You?
- The Motivational Trick That Makes You Exercise Harder
- 11 New Books to Read in February
- How to Get Better at Doing Things Alone
- Column: Trump’s Trans Military Ban Betrays Our Troops
Contact us at letters@time.com