What does science say about the effects of unsweetened coffee on the brain and body?

A recent study from Johns Hopkins University examined what happens inside the body when someone consumes coffee without any added sugar. The research, published in Nature Neuroscience, found that drinking black coffee activates cellular defense systems and alters neuronal signaling — suggesting that its impact goes well beyond caffeine’s usual stimulant effect.

What happens in the body when you drink black coffee?

Researchers observed notable changes in the hippocampus, the brain region responsible for memory and learning. The study indicates that regular, moderate consumption of unsweetened coffee strengthens connections between neurons and may boost cognitive performance. These neural changes appear to support better focus and more efficient memory formation.

From a metabolic standpoint, the findings highlight two ways black coffee can assist with weight management: by increasing thermogenesis and raising the basal metabolic rate. In other words, it helps the body burn more energy and process nutrients faster — potentially supporting weight-loss efforts when paired with balanced eating and physical activity.

Expert views on coffee’s benefits — and potential risks

Coffee beans are rich in antioxidants that help limit oxidative stress and maintain healthy tissues. The analysis also points to cardiovascular benefits: moderate black coffee intake is linked to a lower likelihood of arterial plaque buildup and reduced heart-related risks. These properties position unsweetened coffee as a possible ally for circulation and vascular health.

Another interesting conclusion involves oral health. Black coffee may help slow the growth of cavity-causing bacteria. However, experts caution that adding sugar or artificial sweeteners cancels out this advantage and can even promote enamel damage. The benefit applies only when coffee is consumed plain.

Researchers stress that positive effects come from moderate consumption. Excessive caffeine can lead to adverse outcomes. They also note that the type and quality of coffee — for example, traditional ground coffee versus instant varieties — can influence its chemical composition and, therefore, its impact on the body. For best results, they recommend choosing high-quality beans and classic brewing methods whenever possible.