You can take noni juice, but with a grain of salt

Several family members are urging me to take noni juice. Should I listen?

ZACHARY A.,

Altadena

The product: If taste were everything, noni juice would be about as popular as bottled plague. The extract of the Polynesian noni fruit (scientific name Morinda citrifolia) tastes like fermented death with strong undertones of stomach acid. But flavor has never been noni’s real selling point. Polynesians have used it for centuries to prevent illness and ward off evil spirits, and modern marketers have turned it into a blockbuster health tonic with U.S. sales of at least $250 million in 2005.

The price tag alone shows that noni juice is not just a typical breakfast drink. Whether you find it in a drugstore, health food store or over the Internet, you can expect to pay more than $30 for a 32-ounce bottle. Instructions say to take a couple of tablespoons of the juice at least once daily, but some intrepid people guzzle a quart or more.

The claims: Marketers tout noni juice as “the perfect daily supplement” and “the most incredible natural health breakthrough of the century.” Those are bold words -- even if the century is just 7 years old. The alleged benefits only add to the bravado. Internet sites claim that the juice eases pain from arthritis or injuries, slows aging, lowers cholesterol and treats a wide range of illnesses, including cancer, diabetes, depression and the common cold. No word on whether it still repels evil spirits.

Noni juice, marketers claim, contains a unique blend of antioxidants and other disease-fighting compounds not found in any other health product. Many sites emphasize the powers of xeronine, an “essential nutrient” and the juice’s “active ingredient.” They say xeronine improves the health of every cell in the body by “waking up” enzymes and easing the travels of proteins across cell membranes.

Bottom line: Noni juice really might be a powerful health tonic. It’s loaded with antioxidants, and it contains small amounts of obscure, poorly understood compounds that seem to ease inflammation, shrink tumors and boost the immune system -- at least in mice. For humans, the benefits are far less clear, says Dr. Brent A. Bauer, director of the Complementary and Integrative Medicine Program at the Mayo Clinic, in Rochester, Minn.

The juice’s transformation from an obscure folk remedy to a health-food phenomenon happened so quickly that science hasn’t had a chance to catch up, says A. Douglas Kinghorn, a professor of medicinal chemistry and pharmacognosy (the study of biologically active natural compounds) at Ohio State University. Kinghorn has published two studies on the composition of noni juice, adding to a body of research still in its infancy. “We’re about 10 years behind where we need to be,” he says.

Science so far has punctured one major claim: According to Kinghorn, “xeronine” doesn’t exist, in noni juice or anywhere else. “It would be a marketer’s dream, if only it were true,” he says. And, he adds, the unusual compounds that really can be found in noni juice -- including certain polysaccharides and anthraquinones -- may or may not be abundant enough to really improve health.

For now, many of the claims made for noni juice have the substance of mountain air. But Mark Blumenthal, executive director of the American Botanical Council, thinks future science might prove that the ancient Polynesians were on to something. “It’s hard to dismiss something that has such a long history of traditional use,” he says.

Is there a product you’d like the Healthy Skeptic to examine? E-mail health@latimes.com.