Juicing for fun and profit: taking a good thing too far

Nutrition Forum, Sept-Oct, 1998 by Therese Walsh

They say you can't have too much of a good thing, but as many marketers are proving, you can make too much out of a good thing--if that thing is juicing. Juicing is the consumption of juices from raw fruits and vegetables. Ever since Jay "The Juiceman" Kordich started promoting juicing years ago on television, it has become a trendy alternative to eating the real McCoy. And while juicing itself isn't inherently bad, the claims being made by advocates and companies selling juice extractors are often misleading at best and dangerous at worst.

Overselling Juice

Kordich himself claims that juices contain active enzymes that, by breaking food down in the digestive system, spare our bodies' own enzymes from having to put forth the effort. But the fact is, orally ingested enzymes will not significantly aid digestion and have no enzymatic activity in the human body.

Kordich's worst offense, however, comes from promoting the idea--without evidence--that juice by itself may be able to cure medical conditions including heart disease, impotence, and anxiety. The danger is that some naive people will believe his claims and forego or abandon proven medical treatments to rely instead on an almost exclusively juice diet.

Naturopath Michael T. Murray, ND, makes unsubstantiated claims that specific juices can combat cancer, arthritis, kidney stones, and aging. In his book The Complete Book of Juicing, Murray recommends a true juice fast, just as a few other proponents of juicing do. Nutrition experts, however, point out that although brief fasts may not be harmful, depriving the body of a well-balanced diet on a long-term basis can be very risky.

`Dried Juice'

Even more dubious are the many claims made for dried-juice products. Touted as the effortless way to meet the recommended quota of fruits and vegetables per day (because popping a pill is easier than peeling a banana), these products raise a host of critical questions. The most basic question is: Are there good scientific studies that back up any of the claims? But also: Has research shown that the nutrient content of whole fruits and vegetables is fully maintained through processing? Are there side effects? Unfortunately, there appears to be no solid research to answer these questions.

One company, Juice Plus, has published a study in the Journal of the American Nutraceutical Association, but this rare piece of research is fatally flawed. This study looked at the effect of Juice Plus products or placebo on the body composition of 96 subjects.

The study authors hypothesized that subjects in the experimental group (who were fed two fruit and two vegetable capsules before meals, along with an undefined amount of "nutritionally enhanced protein drink mix" and two fiber chromium-laced wafers) would, by trial's end, have less fat mass and more lean muscle mass than their control group (who were given placebo capsules at unidentified times during the study).

The researchers report that this is exactly what happened. But there are other possible explanations for these results. It is little wonder that the experimental group lost fat mass--the researchers filled the experimental group up with protein drinks and fiber wafers before their meals! And the extra attention bestowed upon that group could have made them more aware of not only their diet, but their exercise habits. Any increase in exercise in this group could easily have resulted in increased lean muscle mass. The researchers apparently did not control for such a possibility.

In addition, the study's design makes it impossible to attribute the results to any experimental component. What do the researchers wish us to believe is the key here? The mystery nutritional drink mix, the Juice Plus capsules, or the chromiumlaced wafers? The manufacturers of Juice Plus capsules, who coincidentally also manufacture the wafers and the drink mix --and who funded the study--would likely have us purchase all of the above.

Juice Plus has also paid a journal called the American Medical Review to publish results of their so-called bioavailability studies. But this research too is seriously flawed.

Juice Plus capsules and many other dehydrated juice capsule products, including those from AIM and Juice For Life, are promoted as having enzymes that aid in digestion. These claims are just as false for juice capsules as for whole juice. Even the claim that juice capsules contain much the same nutritional value as the actual juice is unsubstantiated. It is odd that few, if any, labels for juice capsules list the amount of vitamins, minerals, and fiber that the capsules are supposed to contain.

Noni Juice

Recently, multilevel marketers have been promoting a juice product called Noni. Noni juice comes from the plant Morinda citrifolia, a tropical variety found in Polynesia. Used for hundreds of years by native folk, the juice is said to have special healing powers.

There has been some research conducted with Noni, which shows that it contains a volatile oil that is biologically active. The research, however, has yet to identify how Noni affects the physiology of living things. Laboratory research with mice has shown that Noni can inhibit the growth of cancer cells. Although this may be an interesting preliminary finding, it is a long way from proven usefulness in treating or preventing human cancer. We don't know how Noni inhibits cancer cells, whether it is toxic to normal human cells in much the same way that chemotherapeutic agents are, or what other effects it may have. Many substances that have looked promising in animal studies have proved a bitter disappointment in human research.