Why Americans Need Coffee

The Effects of Coffee on Type 2 Diabetes and Hyperglycemia

Americans consume around 400 million cups of coffee per day, which totals to 146 billion cups of coffee per year! Most people consume coffee to get an extra kick in the morning but there is another reason more Americans should be joining the trend. In a nation where type 2 diabetes and high blood sugar (hyperglycemia) is on the rise, the need to maintain blood sugar levels is critical and there have been several world-wide studies done in the past decade supporting the idea that coffee decreases blood sugar levels. Normally, when the body consumes energy in the form of glucose (carbohydrates), it is able to regulate the amount of glucose in circulation because insulin, a hormone released by the pancreas, signals cells to take up glucose and use it as energy. Too much glucose, however, will result in cells unable to release insulin or cells that are resistant to insulin and do not take up glucose. This disease is known as diabetes and the result is hyperglycemia, which, if left untreated, leads to nerve damage and kidney failure. A large 2015 study in Brazil, looks deeper into the effects of coffee on type 2 diabetes as well as hyperglycemia and glucose metabolism.

The study focused primarily on middle-aged and elderly people who are most commonly affected by hyperglycemia and type 2 diabetes. Statistical analyses were performed to examine the associations between different rates of coffee consumption with newly diagnosed diabetes as well as previously diagnosed diabetes. The study found that the effect of coffee consumption during and after lunch or dinner (postprandial) has a greater effect on glucose levels than after a period of fasting (2 or more hours after a meal). Furthermore, the study showed that participants who drank 2 or more times per day displayed the lowest odds of developing diabetes.

Figure 1: The association between the frequency of coffee consumption and newly diagnosed diabetes and intermediate hyperglycemia.

This study provides evidence for the protective effect of coffee against adult-onset diabetes, however, this effect appears to act primarily, if not exclusively, through postprandial glucose homeostasis, as opposed to drinking coffee after a period of fasting. Figure 1 shows that moderate consumption (1 or more cups per day) of coffee was not consistently associated with glucose levels measured but participants who consumed coffee 2 or more times per day showed a 23-26% lower odds ratio (OR) of being diagnosed diabetes as well as a lower impaired glucose tolerance. Analyses produced similar results when coffee consumption was measured base on both quantity and frequency consumed. However, for people previously diagnosed with diabetes, there were no associations between coffee and improvements of glucose regulation during two-hour post-meal tests.

Although the effects of coffee on diminishing the risk for type 2 diabetes and insulin resistance has been thoroughly showed, there is an inconsistent understanding of how coffee affects glucose metabolism and insulin resistance and secretion. The study found a significant inverse association between coffee and post-meal insulin concentrations, but no associations with markers of insulin resistance in the fasting state. Some studies have suggested that caffeine is the major component in glucose metabolism; however, some data exists showing the same effects of both caffeinated and decaffeinated coffee. The protein in coffee that provides the largest case is adiponectin, a protein shown to regulate glucose metabolism and fatty acid breakdown by acting through another protein that modulates glucose uptake. However, more research is needed before this claim can be substantially proven as fact.

Overall, drinking a cup of coffee during or after a meal more than once a day a potential way to naturally decrease your risk of developing type 2 diabetes and hyperglycemia with few unknown side effects. Although this effect has yet to be substantially proven, the number of studies showing similar results is increasing. The only issue is confirming the mechanism through which coffee regulates blood sugar levels and the molecules involved. From what we do know of coffee could bring us closer to a final consensus. Coffee contains caffeine, which studies have shown burns fat and boost metabolic rate, as well as vitamin B₂ and B₅, potassium, and magnesium, which are essential for converting food into fuel, allowing us to stay energized throughout the day and while these may not provide significant results their benefits to human health is inarguable. As Dr. Frank Hu, a professor of nutrition and epidemiology professor at the Harvard School of Public Health, states, “There is certainly much more good news than bad news, in terms of coffee and health.”