Early research suggests that a commercially available juice made from a plant used for centuries in Polynesian folk medicine may have heart-healthy benefits, but all agree that larger studies are needed to confirm the finding.
Researchers report that significant reductions in total cholesterol and triglycerides were seen in smokers who drank a product containing juice from the fruit of the noni tree every day for a month. The study was funded by the manufacturer of the product, sold as Tahitian Noni Juice.
The study was presented Thursday at the 46th Annual Epidemiology Conference of the American Heart Association.
American Heart Association spokeswoman Barbara Howard, PhD, called the findings intriguing and said the study is a rare example of good research on a dietary supplement or food that makes health claims.
"Supplement stores are full of products that make health claims that aren't backed up by science," she tells WebMD. "This study was only a first step, but it is a step in the right direction."
Reductions Substantial
Researcher Mian-Ying Wang, MD, says she first became interested in studying noni juice in 1999 after becoming convinced that it helped reduce her pain from a wrist fracture.
She has received more than $800,000 in grants from Utah-based Morinda Corp., which sells the juice via the Internet and through independent distributors. The cholesterol/triglyceride research came from a larger cancer prevention study involving adult smokers.
A total of 106 smokers drank 1 to 4 ounces of the product, made from the juices of the noni plant, blueberries, and grapes, every day for a month. Twenty-six additional smokers drank a similar-tasting juice drink that did not contain noni juice. None of the participants were on cholesterol-lowering medications.
Total cholesterol levels in the noni juice drinkers dropped from 235.2 mg/dL to 190.2 mg/dL after a month; average triglyceride (blood fat) levels dropped from 242.5 mg/dL to 193.5 mg/dL. Cholesterol and triglycerides did not have any significant change during the period in the group that got the drink without noni juice.
Wang tells WebMD that she hopes to do larger studies in both smokers and nonsmokers.
Safety Concerns
Howard expressed concern that the study presented by Wang included no safety data. Noni juice is high in potassium, which can be dangerous to people with chronic kidney disease. As a result, the American Kidney Foundation has listed it as potentially harmful for kidney patients.
"Large studies are needed involving thousands of people, and the basic safety research in animals and humans needs to be done before we really understand the risks vs. benefits of this product," Howard says.
There have also been published case reports of patients who suffered liver damage while taking noni juice.
Unsubstantiated Claims
The Utah-based company that sells the juice has also been in trouble over the years for making unsubstantiated claims about its health benefits.
In August 1998, Morinda Inc. agreed to stop claiming in its advertising that Tahitian Noni Juice could treat, cure, or prevent a wide range of diseases including diabetes, depression, hemorrhoids, and arthritis after the attorneys general of four states cited the company for making the claims. The agreement called for the company, which is also known as Tahitian Noni International, to pay $100,000.
The web site for the product no longer makes claims about its ability to prevent and treat specific diseases. Instead, more vague health claims are found.
The juice is touted on the web site as having "superior antioxidants" and for helping to "maintain a healthy immune system." Athlete and celebrity endorsements also make no mention of specific diseases. Actor Danny Glover claims in one testimonial that after drinking the juice for a few days he "slept better, felt stronger, more refreshed, and more alert."
The web site recommends drinking 1 to 3 ounces of the juice a day. Four liters of the product sell for $168.00, or roughly $3.70 per 3-ounce serving.
Reviewed by Louise Chang, MD
SOURCES: American Heart Association 46th Annual Epidemiology Conference, March 2, 2006. Mian-Ying Wang, MD, research assistant professor, University of Illinois College of Medicine, Rockford . Barbara Howard, PhD, president, Medstar Research Institute, Washington, D.C. Fickert, P. World Journal of Gastroenterology, August 2005; vol 11: pp 4758-4760.
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