Energy drinks are an increasingly popular beverage in the U.S., consumed by at least 17 percent of the population as of 2012, according to the market researcher Packaged Facts. Marketed as products that boost mental and physical performance, these drinks contain caffeine and sweeteners, along with ingredients such as B-vitamins, amino acids and herbal stimulants. Because of the potential for excessive caffeine or sugar intake, or the risks of combining these drinks with alcohol, the safety of these drinks have been questioned, including their impact on liver function.
Impact of Alcohol
Energy drinks mixed with alcohol have become more commonplace in bars and nightclubs. Combining alcohol -- a depressant -- with a stimulant such as caffeine masks the symptoms of intoxication, which can encourage a person to drink even more. Since the liver is the primary organ responsible for breaking down alcohol, the liver is particularly vulnerable to health effects of this known toxin. Initially, liver damage from alcohol or other factors is noticed by blood tests such as elevated liver enzymes. Any progression to more severe liver damage -- including fatty liver and cirrhosis -- is dependent on factors including the frequency and duration of alcohol use.
Impact of Sweeteners
Energy drinks are either artificially sweetened or contain a nutritive or calorie-containing sweetener such as glucose, sucrose or high fructose corn syrup -- in amounts similar to sweetened soda. Compared to other sugars, fructose is preferentially handled by the liver, so this sweetener in particular has been linked to fatty liver -- an abnormal accumulation of fat that can progress to scarring and liver damage. However, all nutritive sweeteners appear to be problematic when consumed in excess. An August 2015 article published in “Journal of Hepatology” studied more than 5,900 adults, finding those who drank a sugar-sweetened beverage daily had a 56 percent increased risk of fatty liver disease compared to those who didn’t drink these beverages. There was no relationship between fatty liver disease and artificially sweetened drinks.
Impact of Caffeine and Other Ingredients
Most of the negative health effects of energy drinks are blamed on the high caffeine intake, as a result of excessive consumption. In addition to traditional caffeine, ingredients such as guarana, kola nut and yerbe mate also contain caffeine, and their presence may not be included in the calculated caffeine content. While excessive caffeine can lead to symptoms such as insomnia, increased heartbeat, restlessness and anxiety, caffeine is not known to negatively impact the liver, according to a January 2016 review in “Therapeutic Advances in Gastroenterology.” Other common ingredients -- ginseng, taurine, carnitine and B-vitamins -- are not known to cause liver problems. Less is known about the health impact of the varying forms and concentrations of these ingredients and the combination of energy drink components.
Reports of animal research have shown mixed results. One study showed that rabbits fed energy drink powder for 36 days had lower levels of liver enzymes compared to rabbits given water, according to research published in the January-March 2011 issue of “Nigerian Quarterly Journal of Hospital Medicine.” However, another study published in the March 2013 issue of “Advanced Pharmaceutical Bulletin” showed that rats fed an energy drink alone or mixed with alcohol for 30 days showed an increase in liver enzymes. Unfortunately, there is a lack of human research on the effects of energy drinks on liver health. Since the liver and gastrointestinal tract are exposed to much greater concentration of energy drink ingredients compared to other organs, more human research is warranted to understand the safety of energy drinks.
Warnings and Precautions
While limited or infrequent consumption of energy drinks is unlikely to affect the liver, frequent and long-term consumption of sugar-sweetened or alcoholic beverages may pose risks to liver health.
Despite the lack of research on liver effects, there have been a few case reports suggesting excessive energy drinks may cause liver damage. Hepatitis or liver inflammation was diagnosed in a woman who consumed 10 energy drinks daily for 2 weeks, and a man was diagnosed with liver failure after consuming 3 sugar-free energy drinks daily for a year, according to an October 2015 issue of “International Journal of Health Sciences.”
If you are a healthy adult and plan to consume energy drinks, limit your use and avoid them if they cause any unwanted symptoms. If you are a child or teenager, it's best to avoid these drinks unless your doctor specifically approves moderate use. Finally, if you have any medical problems, get advice from your doctor before consuming these beverages.
Reviewed and revised by Kay Peck, RD, MPH