The question of what—if any—effect coffee has on health has long been a topic of debate. Conflicting studies abound, and when it comes to coffee and diabetes the issue is even more confusing. The reality is that coffee may have both beneficial and negative effects, and the deciding factor may be your unique physiology and individual habits. Here’s what you need to know:
Coffee may lower your risk of type 2 diabetes if you don’t already have it
The Harvard School of Public Health makes a compelling case for the benefits of coffee. In a meta-analysis examining 28 other studies and over a million people in total, researchers found that increasing or decreasing coffee consumption can have a significant effect on diabetes risk.
People who increased their coffee intake by one cup per day were 11% less likely to develop type 2 diabetes than those who made no changes. And those who decreased the amount of coffee they drank increased their diabetes risk by 17%. Another large study, done in 2009, found that people who drank three cups of coffee or black tea per day had a 40% lower risk of type 2 diabetes than those who didn’t.
All in all, it appears that moderate coffee consumption may have a protective effect against type 2 diabetes in people who do not already have the disease. For those already living with type 2 diabetes, however, the evidence is less clear.
Caffeine does appear to raise blood sugar
Numerous studies have found that coffee does tend to raise blood sugar—in come cases dramatically. But this evidence may not be as cut-and-dried as it appears at first glance. Most of these studies have been very small, and at least one tested pure caffeine rather than coffee itself. In one, coffee consumption was increased dramatically—to roughly 13 cups of coffee per day—for four weeks, a situation unlikely to be replicated in real life.
Yet another study found that while coffee did raise insulin levels, those who combined coffee with 40 minutes of exercise dramatically decreased bIood sugar levels compared to those who drank no coffee. In addition, habitual coffee-drinkers show less effect than non-coffee drinkers or those who drink coffee infrequently. This suggests that long-term coffee drinkers may build up a tolerance which could balance the negative effects of caffeine.
…But there’s more to coffee than caffeine
Most studies on coffee and diabetes have focused on caffeine—one of the primary chemical compounds in coffee. However, there is more to coffee than its caffeine content. Coffee also contains polyphenols, anti-oxidant compounds which prevent free-radical damage and may reduce inflammation.
Polyphenols are widely believed to have both anti-inflammatory and anti-cancer effects. Coffee has been shown to lower the risk of heart disease and strokes, Parkinson’s disease, some types of cancer, and even Alzheimer’s disease, probably due to these anti-inflammatory compounds.
If you’re a regular coffee drinker, there’s no compelling reason to cut it out of your diet. If you’re not diabetic, it may lower your risk of developing the disease. If you are diabetic and are a long-time coffee drinker, its effects are probably negligible. If you are concerned about its effects, monitor your blood sugar after drinking coffee and discuss your results with your doctor.