Alcoholic and Toxic Liver Disease: Nutritional Considerations

High doses of preformed vitamin A and other supplements with potential or suspected hepatotoxicity should be avoided. Most cases of chronic hypervitaminosis A are the result of self–administration of preformed vitamin A (i.e. retinol, not provitamin A carotenoids).² Hepatotoxicity can occur with doses of more than 100,000 IU per day. However, rare cases have occurred with dosages of 25,000 IU per day, and alcohol potentiates the hepatotoxicity of vitamin A. Steatosis, perisinusoidal fibrosis, chronic hepatitis, and cirrhosis may result from chronic overadministration.³ Niacin also has hepatotoxic potential, although this may be limited to sustained–release preparations.⁴

Several botanical supplements are sources of hepatotoxic pyrrolizidine alkaloids (eg, comfrey). Kava, a botanical used for anxiolytic effects, was withdrawn from the market after suggestions of hepatotoxicity. Certain herbal products that are freely available to consumers (eg, pennyroyal, skullcap, and chaparral) and Chinese herbal formulas that are not commercially distributed are associated with hepatotoxic effects. The U.S. Food and Drug Administration has issued warnings regarding the hepatotoxicity of certain formulas touted for weight loss, such as LipoKinetix, although the active hepatotoxins in this product have not yet been identified.⁵ A surprising number of patients with acute hepatitis or acute liver failure have no identifiable cause of illness other than the use of herbal weight–loss products, particularly those containing hepatotoxins such as usnic acid, a lichen alkaloid. Ephedra alkaloids, which are also used for weight loss by millions of people, are associated with development of severe hepatic dysfunction and even fulminant hepatic failure.⁶

A botanical extract, called milk thistle, has shown promise, but has yet to be proven effective in clinical trials. Silymarin, the active principle of milk thistle, has antioxidant, radical–scavenging, anti–inflammatory, and liver–regenerative effects that have partly validated its history of use for toxic liver disorders.Treatment was associated with decreased levels of gamma–glutamyl transferase (GGT) activity and procollagen III peptide, and with normalization of serum bilirubin, AST, and ALT levels.⁷ However, there are several reasons to be cautious with silymarin. First, the majority of previously published studies are limited by a lack of high–quality evidence.^7,8 Second, isolated compounds from milk thistle, such as silymarin, may not have the same effect as the full mixture of flavanolignans found in the milk thistle plant.⁷

Orders

See Basic Diet Orders.

What to Tell the Family

Liver damage most often results from excessive habitual alcohol intake. However, it can also be caused by several prescription medications, in addition to self–medication with over–the–counter (OTC) supplements. The family can support patients by providing an environment that discourages alcohol consumption, by making sure medications are taken only as directed, and by checking with qualified healthcare personnel, such as a physician and a pharmacist, before allowing the use of OTC supplements. If these conditions are met, recuperation of liver function may be expected.