You may have seen supplements being marketed as liver "detoxification" or "purification" systems. What exactly are these potions? Can they do what their manufacturers claim? Or could they, in fact, be dangerous? By Laurie Barclay         

Dec. 17, 2001 -- We're often tempted to overindulge during the holidays, then wish we could wave a magic wand to undo the damage.

With our liver working overtime to inactivate alcohol and process rich, fatty foods, a potion to heal stressed-out liver cells might just do the trick. But before you stress out your holiday budget on expensive dietary supplements, consider the following facts Most toxins, or poisons, reach our bloodstream when we swallow or inhale them. Others pass through our skin, while still others are released by dying cells or invading bacteria.

Many of these toxins pass through the liver -- the body's waste-purification plant -- where they are broken down and removed from the blood before they can do their dirty work. Poisons are also broken down by the kidney, eliminated in the urine and feces, or exhaled. Drinking six to eight glasses of water daily; eating lots of fresh fruits, veggies, and whole grains; and avoiding tobacco smoke and other fumes can all help keep your body in top working order. So can cutting back on fried foods, animal fats, sugar, and caffeine. We can protect ourselves to some extent by avoiding obvious hazards such as recreational drugs, unsafe sex, and raw shellfish, all of which can cause the liver-damaging disease hepatitis. But even when we're being good to our liver, hidden dangers can damage its cells and interfere with toxin breakdown. Toxins lurk in prescription medications, food additives, and air pollutants, and these may be impossible to avoid completely.

Here's where "liver detoxification" might come in. When the liver is working double-duty to protect you from an onslaught of bad diet, bad judgment, and unavoidable insults, it could benefit from a little extra help.

Antioxidant vitamins such as C, E, and beta-carotene; minerals such as zinc and selenium; B-vitamins that aid alcohol metabolism; and herbs said to "cleanse" the liver such as milk thistle, dandelion root, and schizandra, might help protect liver cells while ridding our body of poisons.

"There is a lot of experimental work in the laboratory and in animals suggesting the beneficial effect of milk thistle extract," Raman Venkataramanan, PhD, FCP, tells WebMD. He is a professor of pharmaceutical sciences and pathology at the University of Pittsburgh.

Laboratory studies by Bharat B. Aggarwal, PhD, a professor of cancer medicine at the University of Texas M.D. Anderson Cancer Center in Houston, and his colleagues also suggest that silymarin, an extract of milk thistle, acts on biochemical pathways to aid in detoxification. "In the laboratory, silymarin is quite protective against liver damage," Aggarwal tells WebMD. "It is approved in Europe for liver damage, especially that induced by alcohol, and seems to have no adverse effects."

But the jury is still out on the ability of supplements like milk thistle to live up to these claims, and to what extent. "Several small, uncontrolled studies indicate some benefit to the use of milk thistle in patients with different types of liver disease without significant side effects," Venkataramanan says. "However, there is no controlled, properly powered, large-scale, convincing study supporting the benefits of milk thistle in patients with liver disease." Another problem is that the FDA does not regulate nutritional supplements. Purity, source, and strength of available products differ widely.

"There is no clear study documenting the actual dose of milk thistle extract and the duration of treatment that is necessary for treating patients with liver disease," Venkataramanan says. "Not all the products available in the market are the same."

There are an endless variety of liver detoxification supplements to choose from, and all the choices can leave you feeling overwhelmed. Milk thistle, for example, is available as powdered seeds at $1.80 per ounce from Cancer Salves, or as "Rainbow Light Milk Thistle Plus" at $20.50 for 60 tablets from Kitchen Doctor.

For those preferring a liquid "cocktail," Native Essence Herb Company offers a concoction of dandelion root, milk thistle seed, Oregon grape root, celery seed, fennel seed, fringetree root bark, licorice root, yellow dock root, Culver's root, cascara sagrada bark, blue flag root, burdock root, barberry root, wahoo root bark, and Turkish rhubarb root. Although these products come with suggested dosages, they don't state how much of the active ingredient is present, or at what strength. Most of the studies thus far have looked at the effects of these supplements individually, not in combination, so there is no experimental evidence justifying use of a specific tonic.

"A lot of products on the market may be useless, as silybin [the active ingredient in silymarin] may not be absorbed from these products," Venkataramanan says. As some ingredients in milk thistle could interact with prescription medications, he warns that patients "must inform their primary care physicians of their use of milk thistle extract so that they can be evaluated for signs and symptoms of potential overdosing of their medications."

More unanswered questions are whether these supplements should be taken daily to maintain normal liver health, whether they should be taken only during alcohol excess or other periods of liver stress, and what their effects are on an already-diseased liver. Now that research organizations like the National Institutes of Health have begun to study alternative therapies, we may get a better handle on how best to use them.

In the meantime, enjoy the holidays. But remember -- the best present you can give your liver is a healthy combination of good judgment and self-restraint.