Great news for all you coffee lovers out there! According to a recent study conducted at the University of California in Los Angeles, habitual caffeinated coffee consumption of at least 4 cups a day may decrease your risk for developing type 2 diabetes. This news could not have come at a better time as diabetes, especially type 2 diabetes, is sharply on the rise. The American Diabetes Association estimates that, “nearly 24 million children and adults in the U.S. -- nearly 8 percent of the population -- have diabetes. Type 2 diabetes is the most common form of the disease and accounts for about 90 to 95 percent of these cases”. Many of the risk factors for developing type 2 diabetes are modifiable, especially diet. Can it really be as simple as adding some “java” to your morning routine? Researchers at UCLA say it’s a possibility.
It has long been thought that there is an inverse association between drinking coffee and type 2 diabetes risk but the actual reason as to why this is true has baffled scientists for years. Researchers at UCLA believe they may have finally discovered the mechanism behind this relationship. It is a protein called sex hormone-binding globulin (SHBG). Its job is to regulate the body’s sex hormones which have been associtaed with the development of type 2 diabetes. It appears that the higher the plasma level of SHBG the lower the risk for an individual to develop type 2 diabetes. Coffee it turns out raises the plasma level of SHBG in the blood. The more coffee consumed the higher the plasma level of SHBG. SHBG is also metabolized in the liver and caffeinated coffee alters the activity of liver enzymes. This suggests that SHBG metabolism may be affected by components found in coffee which leads to the increase in plasma SHBG.
The researchers at UCLA drew their test subjects from a Women’s Health Study that was “originally designed to evaluate the benefits and risks of low-dose aspirin and vitamin E in the primary prevention of cardiovascular disease and cancer”. The study spanned 10 years and followed roughly 40,000 women. Out of those subjects 359 postmenopausal women with newly diagnosed type 2 diabetes were matched to 359 control subjects. With the results of this study researchers were able to make a positive association between caffeinated coffee intake and plasma SHBG levels. In fact their results showed that habitual coffee drinkers “were 56 percent less likely to develop diabetes than were non drinkers”.
A previous genetic study conducted by Dr. Simin Liu further supports the proposed association. They found two mutations in the gene coding of SHBG that demonstrate an effect on the risk of developing type 2 diabetes. Carriers of the rs6259 minor allele had a ten percent higher concentration of plasma SHBG which decreased their risk. However, carriers of an rs6257 minor allele had a ten percent lower concentration that put them at greater risk for developing the disease. Liu’s work shows that there is a genetic component as to the propensity for an individual to develop diabetes based on the amount of SHBG in their blood.
Coffee has long been recognized for having a protective effect against type 2 diabetes but the reasoning behind it has been unclear. A high concentration of plasma SHBG has also been shown to have this effect. Upon further investigation it is now proposed that coffee increases plasma levels of SHBG and that this may be the mechanism behind its decreased risk for developing type 2 diabetes. So next time you're debating whether or not to have that extra cup (or four), go for it!
Sources
1. Ding EL, Song Y, Manson JE, et al. Sex hormone-binding globulin and risk of type 2 diabetes in women and men. N Engl J Med 2009;361:1152-1163
2. Jayagopal V, Kilpatrick ES,Jennings PE, Holding S, Hepburn DA, Atikin SL. The biological variation of sex hormone-binding globulin in type 2 diabetes:implications for sex hormone-binding globulin as a surrogate marker of insulin resistance. Diabetes Care. 2004;27:278
3. Wheeler, Mark. University of California - Los Angeles. "Why coffee protects against diabetes." ScienceDaily, 15 Jan. 2011. Web. 17 Jun. 2011 from http://www.sciencedaily.com /releases/2011/01/110113102200.htm
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