A day without orange juice is like a day without sunshine, went an old TV commercial. Now we're more concerned with the health benefits of juice than a sunny start to our day. You've seen the ads and read the headlines. Cranberry juice prevents urinary tract infections. Pomegranate juice may clear clogged arteries. Grape juice lowers risk of blood clots. But are these claims valid? And if so, does that mean the more juice you drink, the healthier you'll be?

The answer to the first question is -- in many cases -- yes. Scientific studies have shown that certain juices can indeed offer protective health benefits. But that doesn't mean, however, that drinking more juice will make you healthier. As with most things in life, moderation is in order.

While most nutrition experts would prefer you eat whole fruit rather than drink its juicy equivalent, 8 ounces a day of 100% juice is acceptable, says Michael D. Ozner, MD, president of the American Heart Association of Miami and author of The Miami Mediterranean Diet: Lose Weight and Lower Your Risk of Heart Disease.

"Is juice as good as whole fruit?" he asks. "No. Fruit has more fiber, fewer calories, and more phytonutrients than juice." For the sake of convenience, however, Ozner admits that it's often easier to drink a glass of juice than, say, start peeling an orange on your way out the door.

Lots of Juice Choices

And many juices are indeed worthwhile, says Ozner. Despite the fact that The Federal Trade Commission filed a complaint against Tropicana Products, Inc., alleging that the company had misled consumers with claims that drinking two to three glasses a day of its "Healthy Heart" orange juice would reduce the risk of heart disease and stroke, orange juice is, in fact, a healthy juice choice, says Ozner. OJ -- especially with pulp -- is loaded with vitamin C, potassium, and folic acid. (The basis of the complaint by the FTC was not that orange juice didn't offer health benefits, but that Tropicana went overboard with its health claims. The company has been prohibited from making similar health-related claims in the future unless they can be substantiated by reliable scientific evidence.)

Ozner's other juices of choice are purple grape juice, cranberry juice, and especially pomegranate juice, all of them loaded with antioxidants which may offer protection against cardiovascular disease and cancer. "Fruit juice certainly has a role to play in healthy living," agrees Ann Kulze, MD, a family doctor specializing in nutrition and wellness and author of Dr. Ann's 10-Step Diet: A Simple Plan for Permanent Weight Loss and Lifelong Vitality.

No matter how healthy a juice, though, Kulze cautions those who are watching their calorie intake to watch their juice consumption as well. Indeed, a study in the Journal of Clinical Endocrinology and Metabolism suggests that fructose, a sweetener found naturally in fruit juice, may induce a hormonal response in the body that promotes weight gain.

Choose Colorful Juices

Juices made from deep purple, red, and blue fruits (such as grapes, cranberries, pomegranates, and blueberries) are high in anthocyanins, says Kulze, which have been shown in lab and animal studies to have antioxidant and anti-inflammatory properties.

"Richly colored juices are your best choice," Kulze says, and advises that when selecting a juice, you choose one where you can see sediment at the bottom of the bottle. "That means the skin has been used in making the juice," she explains. "The skin of any fruit is where you find the highest concentration of beneficial properties." (Make sure you shake the bottle vigorously before pouring so you get some of that sediment in your serving, says Kulze.)

Don't be thrown off by labels that say juice "beverage," "drink," or "cocktail," says nutrition consultant Carla McGill, RD. "Look for a label that says 100% juice," she advises, which means that it is not a sweetened beverage. The exception to this is cranberry juice, which is much too tart to drink unsweetened, but even in this case, there are degrees of sweetened cranberry juice from which to choose.

New Juices on Market

One of the newer fruit juices that is capturing our attention is black currant juice. For 100 years it was illegal to commercially grow black currants in the U.S, but that law has now been overturned, thanks to the efforts of Greg H. Quinn, president of The Currant Company, which is the first, and at the moment, the only domestic producer of a currant product in the U.S., a nectar known as CurrantC. (Growing black currant was banned in the early 1900s because it was found to promote the spread of white pine blister rust, which threatened the booming timber industry.)

Research conducted in countries such as New Zealand, Japan, Sweden, and Finland has shown that black currants have many benefits. They have been shown to have twice the antioxidants of blueberries, four times the vitamin C of oranges, and twice the potassium of bananas. These overseas studies have also reported that black currants can lower blood pressure, improve skin disorders such as dermatitis and psoriasis, and improve eye function.

In this country, researchers at Tufts University found that anthocyanins and polyphenolics, compounds found in black currants (as in other deeply colored fruits), may help protect against Alzheimer's disease. The study was published in the January 2006 issue of Chemistry & Industry magazine.

Also new on the juice scene is Tahitian noni juice, made from a fruit grown only in tropical climates and first discovered by two food scientists in the 1990s. The U.S.-based company Tahitian Noni International now distributes juice (and other noni products) through direct sales in 35 countries and promotes the drink's antioxidant properties, its support to the immune system, and its ability to increase energy and physical performance levels.

In a literature review conducted by the University of Illinois College of Medicine, researchers cited a statistical clinical survey of noni's medicinal benefits undertaken by Neil Solomon, MD, PhD, former Secretary of Health and Mental Hygiene for the State of Maryland. After reviewing results of 10,000 noni users, Solomon reported that noni possesses a variety of medical benefits including lessening of symptoms in cancer patients, significant drops in blood pressure, decrease in pain for those experiencing chronic pain, decrease of symptoms among heart patients, and more. Nearly all the data, however, comes from users of the company's juice, and the research project itself was supported by a grant from Morinda Inc., the parent company of Tahitian Noni International.

Same Benefits, Cheaper Price

Independent studies published in the scientific community have more validity than a company's own sponsored research, says nutrition consultant Carla McGill. But McGill acknowledges that we are discovering new substances in food -- and even new foods themselves -- all the time that do have beneficial effects. "As technology improves, as we find foods with which we have been unfamiliar, we continue to learn more."

Still, counters Shawn Talbott, PhD, chief scientific officer for SupplementWatch, for less money (Tahitian noni juice sells for $42/liter), you can find the same antioxidant, cancer-fighting, heart-protecting, and immune-boosting benefits in juices sold at your local grocery store.

"Yes, it is true that many of these exotic plants have a variety of antioxidants and polysaccharides - but so does EVERY plant and fruit juice. For every test tube study showing a chemical benefit of mangosteen or aloe or gac (as an antioxidant, immune stimulator, etc) - we can show the SAME effect in studies of other 'regular' plant extracts and juices (grape juice, orange juice, cranberry juice, tomato juice, etc.)," Talbott writes in his SupplementWatch newsletter.

The juicy bottom line, say the experts, is that juices can be part of a healthy lifestyle, especially when it's inconvenient or impractical to eat the whole fruit. But drinking more doesn't translate into more health benefits, so limit your juice to 1 serving a day (if you'd like to spread that out over the day, dilute a serving with sparkling water), make sure you stay well hydrated with other beverages like water, coffee, or tea (the latter two also have antioxidant properties), and don't make the mistake of thinking that a glass of juice takes the place of a balanced diet and healthy lifestyle.

Published Feb. 27, 2006.