• Web
  • Humsa
  • Videos
  • Forum
  • Q2A
rabia shakeel : meri dua hai K is bar imran khan app is mulk k hukmaran hun To: suman(sialkot) 10 years ago
maqsood : hi how r u. To: hamza(lahore) 10 years ago
alisyed : hi frinds 10 years ago
nasir : hi To: wajahat(karachi) 11 years ago
khadam hussain : aslamoalikum pakistan zinsabad To: facebook friends(all pakistan) 11 years ago
Asif Ali : Asalaam O Aliakum . To: Khurshed Ahmed(Kashmore) 11 years ago
khurshedahmed : are you fine To: afaque(kashmore) 11 years ago
mannan : i love all To: nain(arifwala) 11 years ago
Ubaid Raza : kya haal hai janab. To: Raza(Wah) 11 years ago
qaisa manzoor : jnab AoA to all 11 years ago
Atif : Pakistan Zinda bad To: Shehnaz(BAHAWALPUR) 11 years ago
khalid : kia website hai jahan per sab kuch To: sidra(wazraabad) 11 years ago
ALISHBA TAJ : ASSALAM O ELIKUM To: RUKIYA KHALA(JHUDO) 11 years ago
Waqas Hashmi : Hi Its Me Waqas Hashmi F4m Matli This Website Is Owsome And Kois Shak Nahi Humsa Jaise Koi Nahi To: Mansoor Baloch(Matli) 11 years ago
Gul faraz : this is very good web site where all those channels are avaiable which are not on other sites.Realy good. I want to do i..... 11 years ago
shahid bashir : Mein aap sab kay liye dua'go hon. 11 years ago
mansoor ahmad : very good streming 11 years ago
Dr.Hassan : WISH YOU HAPPY HEALTHY LIFE To: atif(karachi) 11 years ago
ishtiaque ahmed : best channel humsa live tv To: umair ahmed(k.g.muhammad) 11 years ago
Rizwan : Best Streaming Of Live Channels. Good Work Site Admin 11 years ago
Boys and Girls May Get Different Breast Milk
By: Editor | 17-12-2013
Total Views:2545

Mother's milk may be the first food, but it is not created equal. In humans and other mammals, researchers have found that milk composition changes depending on the infant's gender and on whether conditions are good or bad. Understanding those differences can give scientists insights into human evolution.

Researchers at Michigan State University and other institutions found that among 72 economically sufficient mothers in rural Kenya, women with sons generally gave richer milk (2.8 percent fat compared with 1.74 percent for daughters).* Poor women, however, favored daughters with creamier milk (2.6 versus 2.3 percent). These findings, published in the American Journal of Physical Anthropology in September, echo previous work that showed milk composition varying with infant gender in gray seals and red deer and with infant gender and the mother's condition in rhesus macaques. The new study also follows findings that affluent, well-nourished moms in Massachusetts produced more energy-dense milk for male infants.

Together the studies provide support for a 40-year-old theory in evolutionary biology. The Trivers-Willard hypothesis states that natural selection favors parental investment in daughters when times are hard and in sons when times are easy. The imbalance should be greatest in polygamous societies, in which men can father offspring with multiple wives, such as the Kenyan villages. In those societies, a son can grow to be a strong, popular male with many wives and children, or he can end up with neither. Well-off parents who can afford to invest in sons should do so because their gamble could give them many grandchildren. Conversely, poor parents should not heavily invest in sons because it is unlikely to pay off—their offspring start at the bottom of the socioeconomic ladder. For those families, daughters are a safer bet because as long as they survive to adulthood, they are likely to produce young.

The new study is “exciting and enthralling,” says Robert Trivers, an evolutionary biologist at Rutgers University and co-author of the hypothesis, who was not involved in the recent work. “It is a Trivers-Willard effect I wouldn't have the guts to predict.”

Even beyond fat and protein, other milk components might vary in humans, says Katie Hinde, an assistant professor in human evolutionary biology at Harvard University. She has found higher levels of cortisol, a hormone that regulates metabolism, in rhesus macaque milk for male infants. Her work shows that milk differences could change infant behavior and might affect growth and development. “Only half the story is what the mom's producing,” Hinde says. “The other [half] is how the infant uses the milk.” These findings could have implications for formula, which could be tweaked to optimize development for both boys and girls.

*Correction/Clarification (11/1/13): This sentence was edited after posting. It originally stated that the amount of fat given by women to their daughters was 0.6 percent, a figure that was later found to be in error by the researchers. It was subsequently corrected in September 2013 to 1.74 percent. The sentence also did not clearly state that the women were, in the researchers' words, "economically sufficient" as compared with the poor women surveyed by the study.


About the Author: Editor
Visit 171 Other Articles by Editor >>
Comments
Add Comments
Name
Email *
Comment
Security Code *


 
Related Articles
By: Editor | 13-12-2012
Magnesium Supplements Could Improve Memory and Cognitive Ability After a decade of research hinting that magnesium supplements could potentially boost your memory and cognitive abilities, it’s finally being put into a small clinical trial. The research is being led by the biopharmaceutical company Magceutics, of Hayward, California, and they began testing the ability of their supplement to boost magnesium ..... Read more
By: Editor | 09-04-2014
The Unforgettable Cars of the '90s Pt. 1 [30 Pics] The World’s Most Mind-Blowing Natural Phenomena March 23, 2013 Source: Blogspot The World’s Most Mind-Blowing Natural Phenomena: Catatumbo Lightning Source: Sodahead Confined to the skies above Venezuela’s Lake Maracaibo, the ceaseless streaks of Catatumbo lightning have captivated the interests of scientists, explorers a..... Read more