Featured Research

from universities, journals, and other organizations

Male maturity shaped by early nutrition; Differences between the sexes affected by environment during first six months of life

Date:
September 13, 2010
Source:
Northwestern University
Summary:
A new study makes a strong case for nurture's role in male to female differences -- suggesting that rapid weight gain in the first six months of life predicts earlier puberty for boys. Males who experienced rapid growth as babies -- an indication that they were not nutritionally stressed -- also were taller, had more muscle and were stronger, and had higher testosterone levels as young adults.

New research suggests that male maturity is shaped by early nutrition.
Credit: iStockphoto/Chuck Schmidt

It seems the old nature versus nurture debate can't be won. But a new Northwestern University study of men in the Philippines makes a strong case for nurture's role in male to female differences -- suggesting that rapid weight gain in the first six months of life predicts earlier puberty for boys.

Males who experienced rapid growth as babies -- an indication that they were not nutritionally stressed -- also were taller, had more muscle and were stronger, and had higher testosterone levels as young adults. They had sex for the first time at a younger age and were more likely to report having had sex in the past month, resulting in more lifetime sex partners.

The researchers think that testosterone may hold the key to understanding these long-term effects.

"Most people are unaware that male infants in the first six months of life produce testosterone at approximately the same level as an adult male," said Christopher W. Kuzawa, associate professor of anthropology in the Weinberg College of Arts and Sciences and author of the study. "We looked at weight gain during this particular window of early life development, because testosterone is very high at this age and helps shape the differences between males and females."

The study provides more evidence that genes alone do not shape our fate.

"The environment has a very strong hand in how we turn out," Kuzawa said. "And this study extends that idea to the realm of sex differences and male biology."

The study found men, on average, tend to be taller and more muscular than females, and the magnitude of that difference appears to be the result of nutrition within the first six months of an infant male's life, according to the study.

"There is a perennial question about how important heredity is versus the environment as shapers of who we turn out to be," said Kuzawa. "In the last 20 years, a lot has been learned about a process called developmental plasticity -- how the body responds early in life to things like nutrition and stress. Early experiences can have a permanent effect on how the body develops, and this effect can linger into adulthood. There is a lot of evidence that this can influence risk of diseases like heart attack, diabetes and hypertension -- really important diseases."

Kuzawa and his collaborators applied the same framework in this study and found evidence that male characteristics -- such as height, muscle mass and testosterone levels as opposed to disease characteristics -- also relate back to early life developmental plasticity.

"Another way to look at it is that the differences between the sexes are not hard wired, but are responsive to the environment, and in particular to nutrition," Kuzawa said.

Testosterone has long been known to increase muscle mass and puts a person on a higher growth trajectory to be taller. The Northwestern study suggests that the age of puberty also is influenced by events in the first six months of life.

The study, which was funded by the National Science Foundation and the Wenner Gren Foundation, was conducted among a group of 770 Filipino males aged 20 to 22 who have been followed their entire lives. Since 1983 a team of researchers in the United States and the Philippines (including Kuzawa for about the last 10 years) has been working to understand how early life nutrition influences adult health, such as risk for cardiovascular disease and diabetes.

The study was published Sept. 13 in the Proceedings of the National Academy of Sciences. The study's co-authors are Thomas W. McDade, associate professor of anthropology, Northwestern University, Linda S. Adair, University of North Carolina at Chapel Hill, and Nanette Lee, University of San Carlos of the Office of Population Studies in Cebu City, Philippines.


Story Source:

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


Journal Reference:

  1. Christopher W. Kuzawa, Thomas W. McDade, Linda S. Adair, Nanette Lee. Rapid weight gain after birth predicts life history and reproductive strategy in Filipino males. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1006008107

Cite This Page:

Northwestern University. "Male maturity shaped by early nutrition; Differences between the sexes affected by environment during first six months of life." ScienceDaily. ScienceDaily, 13 September 2010. <www.sciencedaily.com/releases/2010/09/100913153635.htm>.
Northwestern University. (2010, September 13). Male maturity shaped by early nutrition; Differences between the sexes affected by environment during first six months of life. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2010/09/100913153635.htm
Northwestern University. "Male maturity shaped by early nutrition; Differences between the sexes affected by environment during first six months of life." ScienceDaily. www.sciencedaily.com/releases/2010/09/100913153635.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
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.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

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