Fructose interferes with brain's appetite regulation

Thursday, March 28, 2013 by: David Gutierrez, staff writer
Tags: fructose, brain, appetite regulation

(NaturalNews) Fructose fails to trigger activity in regions of the brain associated with feelings of fullness and satiety, according to a preliminary study conducted by researchers from Yale University and published in the Journal of the American Medical Association. In contrast, consumption of glucose leads directly to stimulation of those areas.

The findings are of particular concern given the rising consumption of fructose in recent decades, driven by the popularity of sugary beverages, particularly those sweetened with high fructose corn syrup.

"These findings support the conceptual framework that when the human brain is exposed to fructose, neurobiological pathways involved in appetite regulation are modulated, thereby promoting increased food intake," wrote Jonathan Q. Purnell and Damien A. Fair of Oregon Health & Science University in an accompanying editorial.

"The implications of the study .. as well as the mounting evidence from epidemiologic, metabolic feeding, and animal studies, are that the advances in food processing and economic forces leading to increased intake of added sugar and accompanying fructose in U.S. society are indeed extending the supersizing concept to the population's collective waistlines," they wrote.

Does fructose trick the brain?

The researchers used magnetic resonance imaging (MRI) to monitor the cerebral blood flow (CBF) to the hypothalamus after 20 participants drank both glucose and fructose beverages.

They found that after consumption of a glucose drink, CBF to the hypothalamus significantly decreased, implying a reduction in appetite. In contrast, no such change was seen following the consumption of fructose.

"Glucose but not fructose ingestion reduced the activation of the hypothalamus, insula, and striatum - brain regions that regulate appetite, motivation, and reward processing; glucose ingestion also increased functional connections between the hypothalamic-striatal network and increased satiety," researchers wrote.

The researchers noted that consumption of fructose was associated with lower levels of the hormone inulin, which triggers satiety.

"Increases in fructose consumption have paralleled the increasing prevalence of obesity, and high-fructose diets are thought to promote weight gain and insulin resistance," they wrote.

"Fructose ingestion produces smaller increases in circulating satiety hormones compared with glucose ingestion, and central administration of fructose provokes feeding in rodents, whereas centrally administered glucose promotes satiety.

"Thus, fructose possibly increases food-seeking behavior and increases food intake."

Heart and liver damage

The study is only the latest in a line of studies implicating fructose in bypassing the brain's fullness and satiety mechanisms. In addition, consumption of fructose has also been linked with other forms of health damage.

For example, a study published in the journal Hepatology in late 2012 found that consumption of fructose appears the affect the availability of the energy-transferring chemical ATP in the liver, thereby increasing the risk of liver cell malfunction and death.

Another study, published in the Journal of Nutrition in early 2012, found that adolescents who consumed high levels of fructose had lower blood levels of cardiovascular protective compounds, such as HDL cholesterol and adiponectin. Higher consumption of fructose led to higher levels of fat around the midsection, a significant risk factor for diabetes and cardiovascular disease.

Sources for this article include:http://www.sciencedaily.com/releases/2013/01/130101182010.htm ; http://www.naturalnews.com ; http://www.naturalnews.com ; http://www.sciencedaily.com/releases/2011/02/110209131951.htm ; www.sciencedaily.com/releases/2009/03/090325091811.htm