Caffeine has numerous short- and long-term effects on the body, including effects on the liver. Caffeine affects the blood sugar function of the liver, and it may help prevent diabetes or diabetes symptoms. Whether or not caffeine can help prevent liver disease is still a subject of much study. Despite these potential benefits, remember that caffeine should not be used medically to treat or prevent any condition unless recommended by a doctor. Caffeine is considered a mildly addictive substance that can be abused and should never be used to replace sleep or a healthy diet.
Coffee & Liver Disease
Many studies have found that coffee has benefits for the liver, although those benefits are not necessarily attributable to the caffeine it contains. For example, a 2004 study reported in "Harvard Women's Health" found that coffee may help reduce the risk of liver damage in those people with a high risk for liver disease. But a 2001 report in the "Annals of Epidemiology" concluded that coffee may reduce risk of developing cirrhosis of the liver, while other beverages with caffeine may not have the same effect.
Caffeine & Liver Disease
A 2004 study by researchers from the National Institute of Diabetes and Digestive and Kidney Diseases found a "positive association" between tea and soft drinks that contained caffeine and liver disease protection. Even the NIDDK researchers, however, noted that these studies are not conclusive on the effects of any active constituents of coffee, nor has the mechanism for coffee and caffeine's potential effects on the liver been determined. It appears from these studies that 2 or more cups of coffee per day yields the most protection.
When caffeine enters the body, the liver releases enzymes to metabolize it before releasing it into the bloodstream. This can temporarily impair the liver's blood sugar uptake and release functions. Therefore, among the short-term effects of caffeine ingestion is an increase in blood sugar and a decrease in liver glycogen stores.
A 2010 study in the "Journal of Agriculture, Food & Chemistry" found that coffee seemed to have an antidiabetic effect on mice, improving the fatty liver and suppressing hyperglycemia, or high blood sugar. The study further found that caffeine in the water given to the mice yielded similar results, suggesting that caffeine may be at least one of the compounds responsible for the antidiabetic properties of coffee.
The same liver enzymes that metabolize caffeine also metabolize hormones related to pregnancy. Women tend to have more of these enzymes in their liver and generally metabolize caffeine faster than men. However when pregnant, women's bodies metabolize their pregnancy hormones first, which means they take longer to metabolize caffeine than they would ordinarily. Whether or not caffeine has detrimental effects on pregnancy is still the subject of much debate and study, with no conclusive evidence pointing in either direction.