Researchers at UC Davis Medical Center this week announced results of an in vitro study that found antioxidants in apple juice help reduce levels of bad cholesterol and may protect against heart disease. The discovery is reported in the April 16 issue of Life Sciences.
Apples, long considered part of a healthy diet, contain phenols or chemical compounds in their juice that are also found in other fruits and vegetables. Those phenolic compounds have been shown to act as antioxidants that help protect the body from injury, including the injuries of eating fat in your diet. The antioxidants work by preventing the oxidation of low density lipoprotein (LDL), or bad cholesterol, and have the potential to guard the body against chronic heart disease, the leading cause of death in this country.
Researchers tested six commercial apple juices, and the peel, flesh and whole fruit of Red Delicious apples for various phenolic compounds. Only juices containing 100 percent apple juice and no sugar were included in the study. The juices and fresh apple extracts varied in the amount of phenolic concentrations, but all inhibited LDL oxidation. While further research is needed to determine which juice components and extracts specifically contribute to the antioxidant activity, the study shows that 100 percent apple juice is a nutritious addition to any healthy well-balanced diet.
Previous in vitro studies have indicated that several beverages including wine, tea and grape juice have antioxidant components that may help reduce levels of LDL. Now apple juice has been added to this list. It remains unclear if and to what degree these phytochemicals, or plant-derived compounds, are absorbed in the body in a metabolically active form, but researchers agree that fruits and vegetables containing these beneficial compounds contribute to healthy diets.
"While most people don't start paying attention to heart disease until they are older, good nutrition is important at any age," says co-author Eric Gershwin, chief of the Division of Rheumatology, Allergy and Clinical Immunology at UC Davis School of Medicine and Medical Center. "In addition to improving health, good nutrition helps young kids stay awake, do homework, and have enough energy to exercise. All of these come from eating sound diets including fruits and vegetables."
Dianne Hyson, a dietitian at UC Davis Medical Center, emphasizes that this study is another reason for instilling a heart-healthy lifestyle in young children as they are establishing habits that can make a big difference in their health later.
"Children tend to like apple juice, and this new information indicates there are more health benefits to drinking it than we thought previously," she says. "Past studies have focused on identifying antioxidants in other foods. These new findings give us even more reason to emphasize apple juice as a fruit serving."
As we age, our bodies produce harmful materials in our cells known as oxidants; they affect arteries, skin and other organs in the body. Gershwin compares these oxidants to sparks that age cells and cause damage. Antioxidants, such as those found in apple juice, are able to prevent those sparks from hurting the body.
"We found the amount and activity of antioxidants in apple juice to be significant," Gershwin says. "In fact, if you went out and ordered a hamburger, drinking apple juice or other phytonutrient-rich beverage would help to protect your body against the fats in that burger."
He also stresses the importance of eating these healthy nutrients as foods rather than trying to consume them in the form of a pill. "The importance of phytonutrients comes down to the expression, you are what you eat," he says. "And eating something that contains all sorts of natural substances is so much more healthy than taking a handful of different pills which aren't digested or absorbed the way something natural like apple juice would be. If you drink apple juice, you're getting everything in the juice, not one single thing that might come in a pill."
A wide range of chronic diseases including heart disease and cancer result from oxidation events; for example, the oxidation of LDL leads to atherosclerosis.
"This study showed that we can actually reduce the oxidation of LDL cholesterol," Hyson says. "So that has a significant impact on potentially reducing the risk of that disease."
Hyson says that consumers tend to look for products by identifying one particular nutrient, whether it is vitamin C in oranges or folic acid in green leafy vegetables. "Our message has been to look at the whole picture of what a food can do for you before you judge its health value. The potential benefit of apple juice and fruit-based juices can go beyond vitamins we've seen before. We're identifying new phytochemicals every day, and the health benefits can have quite an impact."
The old saying 'an apple a day keeps the doctor away,' has more support with this new research, Gershwin says. "In fact, we're showing that apple juice contains some good antioxidants, excellent vitamins and good nutrition - things that protect you from illness. If I could give just one piece of advice to families, every time you eat fast food, drink something like apple juice or some other beverage containing antioxidants with that meal to help prevent damage from the fatty foods."
This study was funded by a grant from the Processed Apples Institute in Atlanta, Georgia. Co-authors of the study include Debra Pearson, Christine Tan and Bruce German from the Dept. of Food Science and Technology at UC Davis, and Paul Davis with the Departments of Nutrition and Internal Medicine at UC Davis School of Medicine and Medical Center.