Gender affects brain's response to food

[Guest guest]

An interesting article from this week's Science News:

Week of July 6, 2002; Vol. 162, No. 1

His-and-Her Hunger Pangs: Gender affects the brain's response to food

Cobb

Women have higher rates of obesity and eating disorders than men do, but scientists don't know why. New findings offer clues to the root of sex differences in eating behaviors. The study showed that men's and women's brains react differently to hunger, as well as to satiation.

This is the first research to document sex-specific brain activity related to eating, says study author Angelo Del Parigi of the Phoenix branch of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The report appears in the June American Journal of Clinical Nutrition.

Using positron emission tomography (PET), Del Parigi and his colleagues at NIDDK monitored the brains of 22 men and 22 women. A PET scan identifies areas where there are surges in blood flow that reflect activity. The scientists performed the scans after the participants endured a 36-hour fast and again after they drank a liquid meal to quench their hunger.

The scans revealed many similarities between the men's and women's brains during hunger and satiation. But they also found significant differences.

For example, when hungry, men had more activity than women did in the paralimbic region of the brain, an area involved in processing emotion. When sated, women had more activity than men did in the occipital cortex, the seat of vision, and men had more activity than women did in an area of the prefrontal cortex associated with feelings of satisfaction.

These and other results of the study hint at several specific ways that men and women may process hunger and satiation differently and how these differences could influence their food intake. For example, men may derive a more rewarding feeling from eating than women do, the researchers speculate.

"It will take many more experiments to find the neurophysiological explanations of sex differences in eating behavior," Del Parigi emphasizes. But he hopes his group's research will spur further studies.

"The area is under intense investigation right now," says neuroscientist Yijun Liu of the University of Florida in Gainesville. Liu notes that the NIDDK team turned up no gender differences in the hypothalamus, the brain area responsible for basic physiological responses to hunger and satiation. The researchers also found no gender differences in blood-chemical signals controlled by the hypothalamus.

Rather, he says, the newly observed brain patterns suggest that men and women differ in how they think and feel about what they eat rather than in the way they process food compounds.

"This is a very important finding for the future study of obesity," Liu concludes. He says the work should encourage scientists to recognize that gender is central to obesity and eating disorders and to develop sex-appropriate treatments.

References and Sources

References:

Del Parigi, A., et al. 2002. Sex differences in the human brain's response to hunger and satiation. American Journal of Clinical Nutrition 75(June):1017-1022. Abstract available at http://www.ajcn.org/cgi/content/abstract/75/6/1017.

[Guest guest]

Hi All,

/message/3676 describes

some nice studies for which the PDF can be provided. For men and

women, it was very impressive and convincing to see the differences in

the brain in response to hunger and satiation.

This is the second of this list of studies by the first author on the

first two.

1: Del Parigi A, Gautier JF, Chen K, Salbe AD, Ravussin E, Reiman E,

Tataranni PA.

Neuroimaging and obesity: mapping the brain responses to hunger and

satiation in humans using positron emission tomography.

Ann N Y Acad Sci. 2002 Jun;967:389-97.

PMID: 12079866 [PubMed - in process]

Results in lean individuals indicate that the neuroanatomical

correlates of hunger form a complex network of brain regions including

the hypothalamus, thalamus, and several limbic/paralimbic areas such

as the insula, hippocampal/parahippocampal formation, and the

orbitofrontal cortex. Satiation was associated with preferentially

increased neuronal activity in the prefrontal cortex. Our studies also

indicate that the brain responses to hunger/satiation in the

hypothalamus, limbic/paralimbic areas (commonly associated with the

regulation of emotion), and prefrontal cortex (thought to be involved

in the inhibition of inappropriate response tendencies) might be

different in obese and lean individuals.

2: Del Parigi A, Chen K, Gautier JF, Salbe AD, Pratley RE, Ravussin

E, Reiman EM, Tataranni PA.

Sex differences in the human brain's response to hunger and satiation.

Am J Clin Nutr. 2002 Jun;75(6):1017-22.

PMID: 12036808 [PubMed - indexed for MEDLINE]

In response to hunger, the men tended to have greater activation in

the frontotemporal and paralimbic areas than did the women (P <

0.005). In response to satiation, the women tended to have greater

activation in the occipital and parietal sensory association areas and

in the dorsolateral prefrontal cortex than did the men (P < 0.005); in

contrast, the men tended to have greater activation in the

ventromedial prefrontal cortex than did the women (P < 0.005).

CONCLUSIONS: Despite extensive similarities in the brain responses to

hunger and satiation between the men and women, our study showed

sex-specific brain responses to a meal that indicate possible

differences between men and women in the cognitive and emotional

processing of hunger and satiation.

In conclusion, we observed extensive similarities in the brain

responses to hunger and satiation between the men and the women.

Nonetheless, the results of our study indicate that 1) hunger elicits

greater activation of brain regions mainly involved in processing

emotion in men than in women, 2) satiation elicits more extensive

activation of neocortical areas involved in sensorial association and

behavioral planning in women than in men, and 3) satia-tion elicits

greater activation of cortical areas involved in process-ing

association between stimuli and responses in men than in women. This

study provides a foundation for investigating the brain regions and

cognitive processes that distinguish normal and abnormal eating

behavior in men and women.

3: Gautier JF, Del Parigi A, Chen K, Salbe AD, Bandy D, Pratley RE,

Ravussin E, Reiman EM, Tataranni PA.

Effect of satiation on brain activity in obese and lean women.

Obes Res. 2001 Nov;9(11):676-84.

PMID: 11707534 [PubMed - indexed for MEDLINE]

4: Tataranni PA, Baier L, on C, Harper I, Del Parigi A,

Bogardus C.

A Ser311Cys mutation in the human dopamine receptor D2 gene is

associated with reduced energy expenditure.

Diabetes. 2001 Apr;50(4):901-4.

PMID: 11289060 [PubMed - indexed for MEDLINE]

Cheers, Al.

Alan Pater, Ph.D.; Faculty of Medicine; Memorial University of

Newfoundland; St. 's, NF A1B 3V6 Canada; Tel. No.: (709) 777-6488;

Fax No.: (709) 777-7010; email: apater@...

> An interesting article from this week's Science News:

>

> Week of July 6, 2002; Vol. 162, No. 1

>

>

> His-and-Her Hunger Pangs: Gender affects the brain's response

to food

>

> Cobb

>

> Women have higher rates of obesity and eating disorders than

men do.....

> References:

>

> Del Parigi, A., et al. 2002. Sex differences in the human

brain's response to hunger and satiation. American Journal of Clinical

Nutrition 75(June):1017-1022. Abstract available at

http://www.ajcn.org/cgi/content/abstract/75/6/1017.