In a previous column, we reported that drinking coffee regularly “reduces the risk for the development of Type II (adult onset) diabetes.” Subsequently, we have also published reports of later clinical studies that alluded to other health benefits of coffee-drinking in warding off migraine headaches, Alzheimer’s, degenerative diseases, gallstones, liver cirrhosis, and possibly cancer.
New study released by researchers at the US National Cancer Institute (part of National Institutes of Health) and American Association of Retired Persons (AARP) says “older adults who drank coffee, caffeinated or decaffeinated, had a lower risk of death overall than others who did not drink coffee.”
This encouraging recent report went on to say “coffee drinkers were less likely to die from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections, although the association was not seen for cancer.” To minimize errors in the interpretation, this large study adjusted for the effects of others risk factors on mortality, such as smoking and alcohol intake.
Published in the May 17, 2012 issue of the New England Journal of Medicine, this new revelation included a caution that the researchers were not certain that the observed associations really “mean drinking coffee actually makes people live longer.”
The subject of this study involved 400,000 American men and women ages 50 to 71 who joined the NIH-AARP Diet and Health Study from 1995 to 1996, where the individuals were followed up by Neal Freedman, Ph.D., Division of Cancer Epidemiology and Genetics, NCI, and his colleagues until participants died or to December 31, 2008, whichever came first.
The report observed that “there was an association between coffee and reduction in risk of death increased with the amount of coffee consumed…. Relative to men and women who did not drink coffee, those who consumed three or more cups of coffee per day had approximately a 10 percent lower risk of death.”
Since coffee contains about 1,000 compounds, it is not clear as to which of them, caffeine or the other antioxidants in it, confers the protection and health benefits.
Which type of coffee?
A previous research conducted by the Harvard School of Public Health and Brigham and Women’s Hospital showed that caffeinated or decaffeinated coffee are both beneficial in lowering the risk for the adult onset diabetes, but the decaffeinated brew is somewhat weaker.
How about tea?
In a separate report, and not a part of this Harvard study, tea has been found to improve insulin activity up to 15 times, making it more effective. This includes green, black or oolong teas, but not herbal tea (which does not have this beneficial effect). Since the active ingredients do not last long in the body, one should drink a cup every few hours to benefit from it. Also, no milk (not even soy milk) must be added, because this renders the “good chemicals” useless to the body.
How was the study done?
Different from the NIH-AARP study, the Harvard research included about 42,000 healthy men and more than 84,000 healthy women from 1980s through 1998, sending them questionnaires every 2-4 years for 18 years, to assess their intake of both regular and decaffeinated coffee and the development of diabetes. Compared to those who did not drink coffee, men who had more than 6 cups of caffeinated coffee a day lowered the risk of developing Type II diabetes by 50%. Among women, there was a 30% reduction in the risk. “This is good news for coffee drinkers; however, it doesn’t mean everyone should run out for a latte,” Frank Hu, an associate professor at the Harvard School of Public Health, stated in a release. “We still don’t know exactly why coffee is beneficial for diabetes, and more research is clearly needed.”
How does coffee do it?
The exact mechanism is still unclear. In another research (Nurses Health Study), it shows that the 2000 women coffee drinkers in its survey had significantly lower (13%-14%) levels of C-peptide hormone, a component of insulin in our body, compared to non-coffee drinkers. Higher level of C-peptide, which indicates the body is unable to use insulin (called insulin resistance) are linked to the increased risk of developing adult-onset diabetes. The good effect was more apparent among obese and overweight women, 22% and 18%, respectively. So, if coffee reduces C-peptide, then the risk is reduced.
Is this hormone working alone?
This is still not fully understood. Both regular and decaffeinated coffees have a lot of antioxidants in them, like chlorogenic acid (the ingredient that gives the “addicting” coffee flavor), phyto-estrogens, and magnesium. These chemicals improve sensitivity to insulin and may play a vital role in lowering adult onset diabetes. Caffeine itself is also known to affect insulin secretion. Coffee also induces urination. As for the other benefits, they could be from the antioxidants in coffee, but the more studies are being conducted to find out for sure.
How much coffee is needed?
The Harvard study stated 6 or more cups per day. The research on the same subject in Finland (which has the highest per capita coffee consumption in the world), involving 15,000 healthy men and women (ages 35-64), as reported in The Journal of American medical Association, showed that women who consumed 10 or more cups a day had 79% lower risk, and men, about 55%.
Why are coffee and soft drinks bad for children?
Caffeine in coffee and soft drinks, in general, affect children’s nutrition since they reduce the appetite by its central nervous system effects and at the same time these beverages “replace” the nutrient dense foods such as regular food and milk. Since coffee and cola drinks are of no essential nutritional value, these may be wisely omitted from their diet. Cola beverages also contain high doses of sugars (carbohydrates), which is bad for children. Soft drinks also increase the risk for metabolic illnesses, especially among children. Pregnant women are also advised against drinking beverages with caffeine since this cause central nervous system stimulation effects in the baby in the womb and also tends to affect their birth weight. In some cases birth defects have been reported. There are many medications which should not be taken during pregnancy and during breast-feeding as they adversely affect the health of the baby. They include, among many others, nicotine (tobacco), alcohol, insulin, caffeine, cocaine, theophylline (asthma drug), and a long list of prescription drugs.
With this recent clinical study from NIH-AARP, we can at least say that coffee has no adverse health effects in general and could even be most beneficial for most of us.
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Philip S. Chua, MD, FACS, FPCS, Cardiac Surgeon Emeritus in Northwest Indiana and chairman of cardiac surgery from 1997 to 2010 at Cebu Doctors University Hospital, where he holds the title of Physician Emeritus in Surgery, is based in Las Vegas, Nevada. He is a Fellow of the American College of Surgeons, the Philippine College of Surgeons, and the Denton A. Cooley Cardiovascular Surgical Society. He is the chairman of the Filipino United Network – USA, a 501(c)(3) humanitarian foundation in the United States. Email: [email protected]
