Need one more reason to enjoy a cup of joe every day? Sip on this! Researchers from the University of Nottingham have found that “brown fat,” our body’s fat-fighting defense, may be stimulated by drinking a cup of coffee. Brown fat may be key to fighting obesity and diabetes.The study, published in the journal Scientific Reports, is one of the newest to be done on humans to find ways that could have a direct impact on how brown fat functions, since brown fat is a vital part of our bodies that plays an important role in how fast we burn calories into energy.Brown fat, technically brown adipose tissue (BAT), is one of the two types of fat found in humans and other mammals. It was first only associated with babies and hibernating mammals, but it was discovered in recent years that adults possess brown fat, too. The main function of brown fat is to create body heat by burning calories. White fat, on the other hand, mostly stores excess calories. Those with a lower body mass index (BMI) tend to have higher amounts of brown fat.According to Professor Michael Symonds (from the University of Nottingham and who co-directed the research) brown fat acts differently than other fat in our bodies and makes heat by burning fat and sugar, often as a response to cold. Blood sugar control and improved lipid levels are observed through its activity. Additional calories burned aid with weight reduction. Until now, no one has discovered an acceptable method to stimulate BAT activity in humans.Symonds’s study is the first in humans to find that a simple cup of coffee can have a direct impact on how brown fat functions. As obesity is a major health concern in society and diabetes is a growing epidemic, brown fat could be a potential ally in fighting both.The research team initiated a series of studies on stem cells to evaluate if caffeine would stimulate brown fat. Once the correct dose was found, they continued on to human subjects to see if the results were the same.A thermal imaging technique was used by the team to follow the body’s reserves of brown fat. The technique is non-invasive and helps the team find brown fat and evaluate its ability to produce heat.Based on previous research, Symonds notes that brown fat is primarily located in the neck region, so they were able to image a person right after drinking coffee to check if brown fat got hotter. Given the positive results, the team now needs to evaluate if caffeine or another active ingredient in coffee is impacting the activation of brown fat. Caffeine supplements are being tested to see if the effect is the same.Once the researchers have pinpointed the responsible component, it could likely be utilized as part of a weight management or blood sugar control program to help reduce the risk of diabetes.Now that we've reviewed the research, let's explore some takeaway messages for dietitians.

• Coffee is not a magic bullet. While the study is promising, calorie control and regular exercise still remain the gold standards for weight management and diabetes prevention. While black coffee is calorie-free, coffee with cream, sugar or other add-ins (syrup, whipped cream, chocolate shavings, liquor), may contain quite a few calories and could pack on pounds. Coffee with skim milk or plant-based milks will provide calcium in addition to caffeine.
• Remember that caffeine is a drug and it affects people differently. When abused, it may increase anxiety, heart rate, nervousness and risk for insomnia. According to the FDA, four to five cups of coffee per day (roughly 400 mg caffeine per day) is deemed safe for most.

By Lisa Andrews, MEd, RD, LDReferences:

1. Ksenija Velickovic, Declan Wayne, Hilda Anaid Lugo Leija, Ian Bloor, David E. Morris, James Law, Helen Budge, Harold Sacks, Michael E. Symonds, Virginie Sottile. Caffeine exposure induces browning features in adipose tissue in vitro and in vivo. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-45540-1
2. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much