Twelve years ago, we wrote that drinking coffee reduced the risk for type II diabetes, based on a new study then (involving 42,000 healthy men and 84,000 health women from 1980 through 1998) by the Harvard School of Public Health and Brigham and Women’s Hospital published in the Annals of Internal Medicine on January 6, 2004.
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.
Caffeinated coffee was found to be more beneficial than the decaffeinated or the hyped-up mocha, cappuccino, or latte, etc., variety.
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.
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.
How much coffee?
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%.
Effect on longevity
Two recent major international studies (US and European) suggested that coffee lovers may also live a longer life compared to those who do not imbibe coffee.
The International Agency for Research on Cancer (IARC) and Imperial College of London, which reviewed more than half a million people with variable habits and customs across 10 European countries, was the first study. This showed “those who drank about three cups a day tended to live longer than non-coffee drinkers; they also had a lower risk of death from any cause, and specifically for circulatory diseases, and digestive diseases.”
The second one, done in the United States, involved 180,000 subjects of different ethnic, social, and career backgrounds. The findings revealed that drinking coffee “benefits longevity whether the coffee was caffeinated or decaffeinated…and coffee drinkers had a lower risk of death due to heart disease, cancer, stroke, diabetes, and respiratory and kidney disease.” One cup a day drinkers “were 12 percent less likely to die compared to those who didn't drink coffee; those who drank two or three cups per day saw an even higher 18 percent reduced risk of death.”
"We cannot say drinking coffee will prolong your life, but we see an association," stated Veronica Setiawan, lead researcher and an associate professor of preventive medicine at the Keck School of Medicine of University of Southern California.
Drinking coffee is reported to impart anti-oxidant benefits and may improve liver function too, but it is not recommended for pregnant women and children. Also, drinking any very hot beverage in general is suspected to increase the risk for cancer of the esophagus (food pipe).
A professor at the University of Cambridge, David Spiegelhalter,described the research as "huge in size and carefully done," but nevertheless unable to prove cause and effect. "If these estimated reductions in all-cause mortality really are causal, then an extra cup of coffee every day would on average extend the life of a man by around three months, and a woman by around a month," he added.
While drinking coffee appears to help in reducing the risk for Type II diabetes, heart disease, Alzheimer’s, and cancer, and now claimed to prolong life, more clinical studies are still needed to make this an evidence-based medical fact.
Second to water, coffee is one of the world’s most consumed beverages. Over 16 billion pounds of beans are produced in 70 countries annually. More than 2.25 billion cups are consumed each year globally.
The Netherlands (population: 17,035,938) is the highest consumer of coffee in the world at 260.4 liters per capita, compared to 115.2 per capita in the United States (population: 325,416,914), where about 400 million cups of coffee are consumed each day. Almost 85 percent of Americans drink coffee daily. Ninety-three percent of households in the Philippines (population: 105,589,888) drink coffee, the country consuming 100,000 metric tons year. Coffee, “first brought to the Philippines by a Franciscan friar in 1749, is the most consumed beverage next to water, and second most bought item next to sauces and seasonings,” according to one study.
In the United States, McDonald’s “is the leading coffee seller, with 14.32% of the market…second place goes to Dunkin' Donuts with 13.75% share and 185.3 million servings, followed by Starbucks with 11.80% share and 159.1 million servings.”
How many cups are safe?
Since the long term effects of coffee (especially caffeinated) on diabetes, cardiovascular diseases, other illnesses, and longevity are not totally clear, the so called “safe level” becomes an individual issue. One cup of regular coffee may be too much for one person, who might develop heart beat irregularity, like palpitation, or insomnia, when taken before bedtime. Three cups a day may not be enough to satisfy another. This should be tailored to personal tolerance. The final word on this issue is not settled, but the preliminary results as presented above are most encouraging. More long term studies are definitely needed before this becomes a medical dogma.
In the meantime, let me finish my second cup of Columbian espresso.
The main objective of this column is to educate and inspire people live a healthier lifestyle to prevent illnesses and disabilities, and achieve a happier and more productive life. Any diagnosis, recommendation or treatment in our article are general medical information and not intended to be applicable or appropriate for anyone. This column is not a substitute for your physician, who knows your condition well and who is your best ally when it comes to your health.