Updated on February 10, 2022.
Of all the juices you can find at the supermarket, orange juice is the one that’s often touted as the healthiest. That’s because it contains substantial doses of vitamin C, a powerful antioxidant.
But research suggests that OJ may not be the only beverage that can help your immune system fight off illness and infection. Purple grape juice may be an immune booster, too.
In a study, people who sipped Concord grape juice daily for 9 weeks had higher blood levels of a specific type of infection-fighting cell.
How might grape juice bolster your defenses?
Published in Journal of Medicinal Food, the 2011 study involved 85 people who were generally healthy to start with. But something interesting happened when researchers added about 1½ cups of grape juice to the daily diet of half the group. After 9 weeks, those people had significantly more T cells compared with the control group.
T cells are a type of white blood cell that fights off infections. In the study, drinking grape juice appeared to increase participants' levels of specialized T cells called surveillance cells, found mostly in the lungs, intestines, and gastrointestinal tract.
Researchers think that T cells act as a first line of defense against invading pathogens. When they detect trouble, they stimulate other immune cells to defend the body.
It’s important to note that the study didn’t check to see if these additional surveillance cells actually translated to fewer bouts of illness in the folks who drank the grape juice. Still, results like these are intriguing.
Cellular soldiers
Researchers suspect that a powerful kind of antioxidant called polyphenols in grape juice can take the credit for these immune-boosting effects. But it’s worth bearing a few things in mind.
For one, the participants in the study were told not to eat any other red, blue, or purple fruits during the study. We don’t know if skipping such healthy foods may have had drawbacks.
In addition, a cup and a half of grape juice adds 217 calories and 53 grams of sugar to a person's day. Although this is natural sugar, not added sugar, it’s still a huge amount to consume all at once—roughly double the American Heart Association’s daily recommended amount of added sugar. What’s more, grape juice usually does not include the fiber found in natural fruit.
So if you’d like to try to take advantage of the nutritional benefit of grape juice, swap it in for other high-calorie, low-nutrition items currently in your diet to help keep your overall calorie intake from inching up. And you can get polyphenols from many other foods, too. Rich sources include dark blue and red berries, coffee, plums, dark chocolate, and black or green tea.
No one food is a magic elixir, either. Good health is all about the big picture. So rather than focusing on specific foods or ingredients, practice a variety of habits to support your immune system, like exercising regularly, getting adequate sleep, and reducing your stress levels.
And if you’re truly feeling sick, stay home to help speed your recovery from colds and flu and avoid spreading your germs to others.
