Although at least one study has linked aspartame consumption to decreased glutathione levels in the liver, the sweetener's connection to liver damage remains unclear, and the U.S. government and public health agencies recognize it as safe. If you're concerned about aspartame's effect on your liver, talk to your doctor or avoid foods and beverages that contain aspartame.
Rumors have swirled around aspartame's safety ever since its approval for food manufacturers' use in the 1980s. However, extensive research has not definitively linked to aspartame to cancer, liver disease or any other health problem. Although several European studies have found increased cancer risks in lab rats fed aspartame, U.S. agencies have generally rejected their findings based on problems in the studies.
Effects on Liver
A study published in "Food and Chemical Toxicology" in 2011 found that long-term aspartame consumption may change the antioxidant status of the liver. Rats given doses of aspartame-laced water over a period of time had lower levels of glutathione, a chemical that helps the body use antioxidants to fight free radicals. However, studies have not established any connections between these findings and liver damage or other specific consequences.
You can prevent liver damage and disease by eating a healthy diet and drinking only moderate amounts of alcohol, if any. Limit your intake of high-fat foods and maintain a healthy weight; obesity, even if you don't drink, can cause nonalcoholic fatty liver disease. Be careful with herbal supplements, as these herbs have the potential to harm the liver: black cohosh, chaparral, comfrey, germander, greater celandine, kava, mistletoe, pennyroyal, skullcap and valerian.
Avoid aspartame if you have a condition called phenylketonuria, or PKU. People with PKU cannot metabolize the amino acid phenylalanine, a component of aspartame. Look for foods and beverages sweetened with other types of artificial sweeteners, such as sucralose or stevia. Even if you can consume aspartame, do not exceed the United States Food and Drug Administration's recommended maximum daily intake of 50 mg for every kilogram of body weight.