Tuesday, August 11, 2009

Apetite - it is all hormonal

Here is an interesting study. It all depends on the hormones.......normal weight and obese people has different hormonal reactions to food and different resultant appetites.......

Pre- and post- prandial appetite hormone levels in normal weight and severely obese women

Appetite is affected by many factors including the hormones leptin, ghrelin and adiponectin. Ghrelin stimulates hunger, leptin promotes satiety, and adiponectin affects insulin response. This study was designed to test whether the pre- and postprandial response of key appetite hormones differs in normal weight (NW) and severely obese (SO) women.

Twenty three women ages 25-50 were recruited for this study including 10 NW (BMI = 23.1 +/- 1.3 kg/m2) and 13 SO (BMI = 44.5 +/- 7.1 kg/m2). The study was conducted in a hospital-based clinical research centre. Following a 12-hour fast, participants had a baseline blood draw, consumed a moderately high carbohydrate meal (60% carbohydrate, 20% protein, 20% fat) based on body weight. Postprandially, participants had six blood samples drawn at 0, 15, 30, 60, 90, and 120 minutes. Primary measures included pre- and post-prandial total ghrelin, leptin, adiponectin and insulin. A repeated measures general linear model was used to evaluate the hormone changes by group and time (significance p < 0.05).

There were significant differences between the NW and the SO for all hormones in the preprandial fasting state. The postprandial responses between the SO versus NW revealed: higher leptin (p< 0.0001), lower adiponectin (p=0.04), trend for lower ghrelin (p=0.06) and insulin was not different (p= 0.26). Postprandial responses over time between the SO versus NW: higher leptin (p<0.001), lower ghrelin and adiponectin (p=0.004, p=0.015, respectively), and trend for higher insulin (p=0.06).

This study indicates that significant differences in both pre- and selected post- prandial levels of leptin, ghrelin, adiponectin and insulin exist between NW and SO women. Improving our understanding of the biochemical mechanisms accounting for these differences in appetite hormones among individuals with varying body size and adiposity should aid in the development of future therapies to prevent and treat obesity.

1 comment:

Eugene Thong said...

Chris -

Neat-o study. But I think I'm actually going to disagree with your headline on this. I don't think appetite is as mechanistic as "insulin, ghrelin, and leptin." Certainly hormonal factors play a huge part (particularly when talking about sound approaches to losing fat), but they are far from telling the whole "hunger" story.

You can experience hunger as a psychological function as well. Meeting with a group of friends; family dinners and gatherings; as a response to other psychological difficulty such as a divorce, bereavement, or displacement; all those situations can have stimulating effects on your hunger.

Also, it's possible what are perceived as hunger symptoms may be something else (the oft-quoted example of thirst being mistaken for hunger).

Doesn't mean I don't think keeping insulin low isn't a high priority, tho.