by Craig Weatherby
When Dr. Philipp Scherer discovered a hormone called adiponectin in 1994, research into this fat-handling hormone soon grew into a flood.
Adiponectin controls our cells’ sensitivity to insulin—loss of which causes diabetes—and plays a critical role in regulating fat storage.
When adiponectin levels are high, the body stores excess fat in fat cells (adipocytes), to protect against possible starvation during lean times… hence its nickname, the “starvation hormone.”
Fat deposited because of the actions of adiponectin lie primarily in the subcutaneous tissue located, as the name implies, under the skin.
As a person accumulates more fat, adiponectin levels decline and the body begins storing fat in dangerous places such as the heart, liver and muscle tissues—where it can cause inflammation and pave the way for heart disease.
(Needless to say, it’s better to avoid accumulating excess body fat anywhere, including the belly, which is a risk factor for diabetes. Big bellies start with excess calorie intake, and adiponectin is just doing what it is designed to do when it creates belly fat in times of “plenty,” to build up stores for the starvation season that never comes… for most Americans.)
Many researchers think that measuring people’s adiponectin levels could help predict their risk for diabetes and heart disease.
Now, findings from Dr. Scherer’s group at UT Southwestern Medical Center help explain how adiponectin affects several key biological systems… with implications for preventing insulin sensitivity and the diabetes that follows.
Significantly, recent human, cell, and animal studies show that certain of the polyphenol compounds in berries and onions—which occur in many other plant foods—have recently been shown to boost body levels of adiponectin (Kobori M et al. 2010).
For more on the berry part of the story, see “Fruit Antioxidants May Help Deter Diabetes” in this issue of Vital Choices.
Study finds that adiponectin converts villains to heroes
For this study, the researchers examined cellular “suicide” in the pancreatic beta cells that produce insulin—and in muscle cells called cardiomyocytes, located in a part of the heart known as the myocardium—to determine how the single hormone appears to exert influences in such different places (Holland WL et al. 2010).
And as Dr. Scherer said, “This paper shows that the common theme among all these different activities relies on adiponectin’s interaction with a specific subset of lipids known as ceramides” (UTSMC 2010).
Ceramides are a family of lipid (fat) molecules known to promote cell suicide, or apoptosis.
Apoptosis is a good thing when it comes to preventing cancer from growing... but high levels of ceramides seem to promote death of healthy cells.
And high body levels of ceramides have been shown to promote diabetes by sabotaging the work of insulin and pancreatic beta cells.
When the researchers introduced adiponectin into cells, they found that the hormone triggers the conversion of ceramides from a destructive force into one that helps cells survive and inhibits inappropriate cell death.
“Adiponectin essentially provides a makeover of this ugly cousin,” Dr. Scherer said (UTSMC 2010).
These findings suggest that diets high berries—and possibly other polyphenol-rich foods—can help maintain healthful levels of adiponectin and prevent fat from accumulating in unhealthful places.
- Holland WL, Miller RA, Wang ZV, Sun K, Barth BM, Bui HH, Davis KE, Bikman BT, Halberg N, Rutkowski JM, Wade MR, Tenorio VM, Kuo MS, Brozinick JT, Zhang BB, Birnbaum MJ, Summers SA, Scherer PE. Receptor-mediated activation of ceramidase activity initiates the pleiotropic actions of adiponectin. Nat Med. 2010 Dec 26. [Epub ahead of print]
- Kobori M, Masumoto S, Akimoto Y, Oike H. Chronic dietary intake of quercetin alleviates hepatic fat accumulation associated with consumption of a Western-style diet in C57/BL6J mice. Mol Nutr Food Res. 2010 Dec 15. [Epub ahead of print]
- UT Southwestern Medical Center (UTSMC). New clues uncover how 'starvation hormone' works, investigators at UT Southwestern report.Dec. 26, 2010. Accessed at http://www.utsouthwestern.edu/utsw/cda/dept353744/files/621927.html
- Wang A, Liu M, Liu X, Dong LQ, Glickman RD, Slaga TJ, Zhou Z, Liu F. Up-regulation of adiponectin by resveratrol: The essential roles of the Akt/FOXO1 and AMPK signaling pathways and DsbA-L. J Biol Chem. 2010 Oct 27. [Epub ahead of print]