April 25, 2014
Increased Coffee Consumption May Help Lower Type 2 Diabetes Risk
Brett Smith for redOrbit.com - Your Universe Online
New research led by researchers from the Harvard School of Public Health (HSPH) has found that increasing coffee consumption over four years leads to a lower risk for type 2 diabetes; while decreasing coffee consumption over the same time span increases risk for the metabolic condition.
The study, published in the journal Diabetologia, was based on three big prospective, US-based studies and included over 120,000 men and women. The Harvard team found that an average increase of more than one cup of coffee per day led to an 11 percent lower risk of type 2 diabetes and a reduction of more than one cup led to a 17 percent higher risk.
"Our findings confirm those of previous studies that showed that higher coffee consumption was associated with lower type 2 diabetes risk," said study author Shilpa Bhupathiraju, a lead nutritionist at HSPH. "Most importantly, they provide new evidence that changes in coffee consumption habit can affect type 2 diabetes risk in a relatively short period of time."
The researchers also found that those with highest coffee intake, around 3 cups daily, had the smallest risk of type 2 diabetes, 37 percent lower than those who drank 1 cup or less each day.
The study team said lower risk for type 2 diabetes might be due to reverse causation – whereby those with health risks for type 2 diabetes, such as high blood pressure, might decrease their coffee intake after receiving their diagnosis. However, when cardiovascular disease or cancer diagnoses were excluded at follow-up, the findings were comparable.
The Harvard researchers also considered any potential effects of tea and decaffeinated coffee consumption. They found baseline decaffeinated coffee intake was linked to a lower type 2 diabetes risk, but the changes in decaffeinated coffee intake did not change this risk. The researchers said they found no evidence of a connection between 4-year increases in tea intake and ensuing risk of type 2 diabetes.
“This finding may have potentially been due to the relatively low number of participants who made significant changes to their tea consumption over a 4-year period thereby limiting statistical power to detect true associations,” the study authors wrote. “The overall low levels of tea consumption in this group may also be responsible for these findings."
"In these 3 large prospective cohorts with more than 1.6 million person-years of follow-up, we observed that increasing coffee, but not tea, intake over a 4-year period was associated with a lower type 2 diabetes risk in the next 4 years,” the researchers concluded. “These changes in risk were observed for caffeinated, but not decaffeinated coffee, and were independent of initial coffee consumption and 4-year changes in other dietary and lifestyle factors."
Study author Frank Hu, a professor of nutrition and epidemiology at HSPH, warned against reading too much into the study’s findings.
"These findings further demonstrate that, for most people, coffee may have health benefits," Hu said. "But coffee is only one of many factors that influence diabetes risk. More importantly, individuals should watch their weight and be physically active."