Does the inside of your fridge resemble a psychedelic rainbow these days — with bottles of ruby, amethyst, tangerine and chartreuse juices? We love our fruit juices — those seemingly perfect solutions for the overly busy but nutritiously alert. Just uncap and pour health, flavor and convenience. But while some juices may deserve a place in your fridge, not all are the liquid manna we seek.
Pomegranate for Healthy Arteries
Among the celebrated new juices, pomegranate boasts some respectable credentials. The whole fruit of Punica granatum was a staple among desert nomads of the Middle East for centuries — who counted upon it to travel well and deliver a refreshing pickup. The juice, derived from pomegranate’s soft seeds and red pulp, is a modestly good source of potassium (about 430 mg in an 8-ounce glass). But its real value may be in combating cardiovascular disease and other health problems. A darling among researchers, pomegranate is the focus of many clinical studies that buzz with praise.
Pomegranate juice reduces cholesterol buildup on artery walls. In coronary patients with restricted blood flow to the heart, a daily cup of the juice for three months significantly improved circulation, based on a double-blind study published in the American Journal of Cardiology. And a small study in Clinical Nutrition says drinking the juice for a year induced a 30 percent reduction in clogging of the carotid artery, which shuttles blood to the brain and can cause a stroke if blocked. These patients also had a 21 percent drop in systolic blood pressure.
The cholesterol-lowering action of pomegranate may come from antioxidant polyphenols called ellagitannins. But how they work is a subject of debate. They may directly prevent LDL cholesterol from degrading to its artery-clogging oxidized form, or they may be converted by colonic bacteria into metabolites whose protective actions are not yet fully understood.
Preliminary test-tube research also suggests anti-cancer activity and cartilage-preserving benefits from the juice or other fruit extracts. The juice acts against prostate cancer tumors, and fruit extracts fight breast cancer cells and lessen bone cartilage decay in osteoarthritis. Clinical results with humans are not yet available.
While pomegranate is considered safe, too much juice may be risky because the fruit contains small amounts of potentially toxic compounds like protocatechuic acid, ursolic acid and gallic acid. How much pomegranate is too much isn’t known, but, based on the studies, an 8-ounce glass a day seems safe unless you’re also taking blood pressure-lowering medication — pomegranate juice may intensify the drug’s action.
Wolfberry for Eyes and Liver
Wolfberry is a traditional Chinese tonic for the eyes, liver, kidneys and blood. It is frequently taken for diabetes and as a general body strengthener, often combined with other medicinal plants. It is common for a traditional Chinese diet to include about an ounce of the dried orange-red berries daily or a few fresh leaves in soups and other dishes. Of the many species of wolfberry, Lycium chinense and L. barbarum are used most often — they provide nutritious berries with a tart-sweet flavor. The berry juice is a relatively modern offering that lacks substantial research or a strong tradition of medicinal usage, though it is confidently marketed for health purposes.
The science indicates wolfberry may help protect the eyes and liver and may support cancer therapies. The berries are a superb source of apigenin, an antioxidant that protects human cells from radiation damage. They also are rich in zeaxanthin dipalmitate, a carotenoid antioxidant postulated to lessen the risk for age-related macular degeneration. One-half ounce (15 grams) of wolfberries taken daily over a month has been shown to increase plasma zeaxanthin levels 2.5-fold in humans, and an animal study has shown the antioxidant accumulates mainly in the macula of the retina and also in the liver. Other animal studies indicate wolfberry helps protect and repair damage to liver and red blood cells. Wolfberry contains betaine, a known liver-protectant. It also possesses unique polysaccharides, which a human trial has suggested may make it a useful adjuvant treatment for some cancers.
Recommended doses for the juice are small — roughly an ounce (about 2 tablespoons) per day. How much of the nutrient and phytochemical strength of wolfberry fruits is realized in pure wolfberry juice is unclear, as nutrient and phytochemical profiles for wolfberry juices tend to be for blends with other fruits. Human studies with the juice are lacking. Wolfberry juice may well be worth a try, but I prefer to stick with the dried berries for now.
Wolfberry consumption is generally safe, but avoid it if you’re on blood-thinning medication as the risk of dangerous internal bleeding may increase. Also, because wolfberry belongs to the nightshade family (with peppers, eggplants, potatoes and tomatoes), allergies to this group may extend to the herb as well.
Elderberry Soothes Colds and Flu
Winter is a good time to try a little elderberry juice. The mucilage in elderberry (Sambucus canadensis, S. nigra) soothes mucous membranes of the digestive and respiratory tracts, providing modest relief from colds or flu and serving as a gentle laxative. Elder also contains unique compounds called alpha- and beta-amyrin palmitates, which are anti-inflammatory and have sedative effects. Initial lab studies suggest elderberry targets other viral infections, including HIV and herpes, but human trials are needed.
In general, the juice seems to be a mild cleansing tonic for the body. It is a good source of antioxidants — in fact, one of the best. A comparison of the antioxidant capacities of 14 common European fruit and vegetable juices placed it near the top, just behind lingonberry and blueberry juices. Some researchers say elderberry juice may reduce “bad” (LDL) cholesterol. The berries contain campestrol and rutin, which have anti-cholesterol action — but clinical results are inconclusive.
Elderberry juice, when boiled before consuming, poses no health risks for most adults, but tolerance by young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established. A typical daily dose is about 4 teaspoons of juice. If the fruit is not fully ripe before juicing, mildly toxic glycosides and alkaloids can cause upset stomach and diarrhea.
Noni: Hype or Miracle Cure?
Noni (Morinda citrifolia), also known as Indian mulberry, is a Polynesian plant whose juices and extracts are promoted by manufacturers as a cure-all. A couple of tablespoons of juice daily promises to deal a death blow to everything from cancer to bad breath. As yet, there is no solid clinical proof for the claims, prompting Food and Drug Administration warnings to manufacturers to tone down the hype. We do know it is a shrubby tree that produces visually unappealing fruit with a cheesy odor when ripe, and a taste considered unpalatable. Granted, this would seem the stuff of dynamite medicine, but who knows? Some say that only the most desperate, starving Polynesians would force themselves to eat noni. But we should recognize that it was a traditional
Polynesian remedy for various conditions including cancer, hypertension and diabetes, so there might be something to the noni story after all — although only you can decide if the potential warrants paying up to $85 for a month’s supply of juice!
Noni contains some beneficial compounds, as seen in animal and test-tube studies. For example, asperuloside, a substance that is converted into hormone-like prostaglandins by the body, has anti-inflammatory, antimutagenic and blood pressure-lowering action. And a noni polysaccharide called noni-ppt helps stimulate the immune system and enhance production of an anti-tumor factor. Animal studies show anti-tumor and immune-enhancing properties for noni juice extracts, but very high doses have been used that would necessitate drinking much more than the daily few ounces of juice typically recommended.
Noni also contains toxic anthraquinones, a possible factor in two cases of liver toxicity — one requiring transplant — attributed to the juice. Do not take noni if you are pregnant or nursing. Given the questions regarding effectiveness, appropriate doses and safety, I?cannot yet recommend noni juice.
Juice or Whole Fruit?
While juices are convenient, some antioxidants are bound to be lost during processing and heat pasteurization. Juices also lack the fiber and nutrition of whole fruits. And watch out for sweeteners like high fructose corn syrup, ubiquitous in commercial juices and implicated in North America’s current epidemic of obesity and possibly even diabetes. Fructose — normally considered a friendly carbohydrate because it is prevalent in fruit — turns out to be not as well-managed by the body as glucose, and it may impede insulin action and trigger fat accumulation. Even unsweetened fruit juices naturally contain a lot of fructose.
So while a little juice may be fine, don’t overdo it, and remember to enjoy whole fruit whenever possible — with the possible exception of noni!
Gina Mohammed, Ph.D., is a plant physiologist in Sault Ste. Marie, Ontario, Canada. She is the author of Catnip and Kerosene Grass: What Plants Teach Us About Life (www.CandlenutBooks.com).