Featured Research

from universities, journals, and other organizations

Human Breast Milk Contains Obesity Hormone, Researchers Find

December 22, 1997
Purdue University
Leptin, a hormone that appears to play an important role in body metabolism and obesity, has been found for the first time in human breast milk.

WEST LAFAYETTE, Ind. -- Leptin, a hormone that appears to play an important role in body metabolism and obesity, has been found for the first time in human breast milk.

In a study of 23 lactating women, researchers at Purdue University, the University of Idaho and Washington State University found that the hormone is present in human breast milk in levels that are lower than, but correlate with, levels in the mother's bloodstream.

The research also found that the amount of leptin in the breast milk correlates with the amount of body fat of the mother; obese mothers produce large amounts of leptin, thin mothers produce almost no leptin in their breast milk. The study was published in the current issue of the scientific journal Biochemical and Biophysical Research Communications.

Leptin is produced by fat cells and the placenta in the body. Since its discovery in the early 1990s, researchers have been racing to learn more about the protein. The reason is simple: Obese mice that are injected with leptin soon lose their excess weight. Scientists are hoping that by learning more about leptin, they can control the problems of obesity and its related maladies, such as diabetes and heart disease.

Karen Houseknecht, assistant professor of animal science at Purdue and adjunct assistant professor of endocrinology and metabolism at the Indiana University School of Medicine, is interested in the role of leptin during transitional periods of the body. She decided to investigate whether this newly discovered hormone was in breast milk, because lactation is an obviously important physiological transition for many women.

Although the researchers found leptin in the milk, at this point they aren't sure what role the hormone plays for mothers and infants. "Like many hormones in breast milk, it is difficult to determine what it is doing," Houseknecht says. "It may be that leptin is doing nothing; it may be that the leptin is just there."

On the other hand, there are reasons to believe that leptin could be important to neonatal development. "We know that breast milk contains many bioactive hormones and peptides. Research by many groups has shown that breast-fed infants have many health advantages over formula-fed infants," Houseknecht says. "Experiments in suckling rats have shown that rat newborns respond to leptin injections by increasing their metabolic rates.

"Leptin in breast milk could mean lots of things to the infant's development. There are receptors for leptin throughout the gastrointestinal tract of adults. If leptin is important to the neonate, we know there is a mechanism for it to get from the intestine to the bloodstream."

No one knows yet if leptin is present in cow's milk, or if the pasteurization process damages the hormone, Houseknecht adds.

Researchers don't know whether leptin offers any advantages or disadvantages for infant development, but they do know that infants whose nursing mothers have significant fat tissue will be exposed to more leptin in the milk. "Leptin levels reflect the mom's leptin levels," Houseknecht says. "Very thin mothers don't produce very much leptin. This adds another interesting twist to this story, because if leptin is important for infant development, these varying levels may mean that some infants are at a disadvantage."

Another theory about how leptin could be important is that leptin may play a role in passing obesity from one generation to the next. An obese mother who produces high levels of leptin and passes the hormone on to her infant may influence the child's metabolism into adulthood. "This is a possibility, but we have no data on this," Houseknecht says. "We know from studies of identical twins that have been separately adopted that there is a huge genetic component to obesity. The animal studies cause us to wonder if milk-borne leptin may play a role, too."

Another possibility is that leptin is important for the lactating mother and not important for the infant. Research has found that leptin levels in mothers are elevated during the pregnancy, and that it may be involved in milk production. "We also know that obesity plays a role in lactation, because obese mothers don't breast-feed as well as other women. Studies have shown that obese women start breastfeeding later and don't stay with it as long," Houseknecht says. "So it may be that the leptin is in the milk because in some way it is involved in lactation."

Houseknecht has discovered previously that leptin circulates in the bloodstream bound to specific proteins, and this binding process is saturated -- or at its upper limit -- in obese people. The next step for the researchers is to see whether breast milk has leptin-binding proteins that may influence the amount of active leptin available for the infant.

Story Source:

The above story is based on materials provided by Purdue University. Note: Materials may be edited for content and length.

Cite This Page:

Purdue University. "Human Breast Milk Contains Obesity Hormone, Researchers Find." ScienceDaily. ScienceDaily, 22 December 1997. <www.sciencedaily.com/releases/1997/12/971222043035.htm>.
Purdue University. (1997, December 22). Human Breast Milk Contains Obesity Hormone, Researchers Find. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/1997/12/971222043035.htm
Purdue University. "Human Breast Milk Contains Obesity Hormone, Researchers Find." ScienceDaily. www.sciencedaily.com/releases/1997/12/971222043035.htm (accessed July 31, 2014).

Share This

More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News


    Free Subscriptions

    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile

    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?

    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins