The juice that claims to be good for all ailments

DOES IT WORK?Noni juice and general health

NONI JUICE IS one of several new fruit juices swept along by the recent interest in fruits and juices. Since 2003, noni juice has been approved in the European Union as a novel food. The juice is made from the fruit of the morinda tree ( Morinda citrifolia), a small evergreen that grows primarily among lava flows in the Pacific islands, southeast Asia and Australia.

The morinda has a long and diverse history of medicinal usage in Polynesian cultures. All parts of the tree and fruit are used to treat almost every ailment known. For the most part, however, these remedies were applied externally to treat wounds and infections.

In 1985, western interest began with a report in a botany journal claiming that unique chemicals had been identified in noni juice. The author claimed that noni juice contained a chemical called “proxeronine”, which was broken down in the body to release “xeronine”.

This xeronine was said to enter the cells of the body and heal any damage present. All of a sudden, noni was not just an exotic juice, but was said to have medicinal properties. However, the author of this report did not reference his sources and no one has ever identified proxeronine or xeronine.

Nevertheless, interest in noni juice has continued. The juice is said to be good for almost all ailments, but especially for gastric complaints. The claims got so out of hand that in 2004 the Food Safety Authority of Ireland issued a warning to consumers about the many unsubstantiated claims being made about noni juice.

Although the hype has decreased, websites can still be found today offering noni juice to Irish customers, claiming it will reduce cholesterol, boost energy levels, stimulate the immune system and support most of the body’s normal functions.

Research has begun looking at noni juice, but most has focused on identifying its ingredients. Noni juice contains a rich assortment of vitamins and minerals, especially potassium, vitamin C, carotene, vitamin A and fatty acids.

Several other compounds have been identified that have biological activity, but whether the juice contains enough of them to have specific medicinal effects has not been established. One evaluation of more than 170 different noni brands found that the amounts of these ingredients varied considerably between manufacturers.

Despite these preliminary investigations, controlled clinical studies have not been conducted to determine whether noni juice prevents or treats any condition.

No side effects have been reported in settings where people have been monitored while taking noni juice. However, much controversy exists over a small number of case studies in which patients developed liver problems after drinking noni juice daily for several weeks.

The reports suggested that noni juice might cause or exacerbate liver problems in some people, but a clear connection has never been demonstrated. Research conducted with human liver cells and published last month found no evidence that noni juice damages the liver.

Noni juice is high in potassium, which could be problematic for some people taking certain medications for high blood pressure. If you take such medications, ask your doctor or pharmacist whether you should avoid fruits containing potassium.

Noni juice can contain a wide range of important vitamins and minerals. As such, the juice may be nutritious, although its taste is not to everyone’s liking. It also remains relatively expensive, with some brands costing more than €60 a litre.

However, different brands contain different amounts of nutrients. This may arise because different parts of the plant may be used in preparing different products. As for any specific health benefits from the juice, evidence does not exist to support such claims.

• Dónal O'Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University. He is author of Alternative Medicine: The Christian Handbook, Updated and Expanded Edition, Zondervan, 2007