Coffee drinkers are less likely to suffer from type 2 diabetes, Parkinson's disease and dementia than are non-coffee drinkers. Coffee drinkers also have fewer cases of certain cancers, heart rhythm problems and strokes. However, coffee containing caffeine can cause insomnia, nausea and vomiting, as well as an increased heart rate. According to WebMD, consuming large amounts of coffee might also cause headaches, ringing in the ears and irregular heartbeats.
Caffeine and its metabolites have been proven to help proper cognitive functionality. Coffee lipids act as a safeguard against some malignant cells by modulating the detoxifying enzymes. According to About.com, men who drank six cups of coffee a day reduced their chances of developing type-2 diabetes by half, and women who drank the same amount cut their risk by 30 percent.
However, higher levels of caffeine raise serum cholesterol and pose threats to coronary health such as myocardial and cerebral infarction, insomnia and cardiovascular complications. According to PubMed, caffeine withdrawal is accompanied with muscle fatigue in those addicted to coffee. Further evidence shows that pregnant women should avoid excessive consumption of coffee, as should postmenopausal women because of coffee's interference with postmenopausal hormones. The caffeine in coffee is the addictive chemical that accounts for the majority of coffee's disadvantages.