These small red and green fruits are loaded with nutrients
By Sally Wadyka
In the nutritional hierarchy of fruits, grapes rarely rank first. Their naturally sweet flavor has earned them an (unjustified) reputation for being an overly sugary fruit. But don’t let their sweetness fool you into thinking they’re unhealthy.
It is true that grapes have more natural sugars and less fiber than other fruits. One cup of grapes contains about 104 calories, 23 grams of sugar and 1.5 grams of fiber. By comparison, one cup of strawberries has only 53 calories, 8 grams of sugar and about 3 grams of fiber. Still, the natural sugars in grapes do not raise blood sugar levels the same way that added sugars do.
“Grapes are nature’s candy, but they’re a healthy kind of candy,” says Lisa Sasson, a registered dietitian and clinical professor of nutrition and food studies at New York University. “If you choose to eat grapes instead of jelly beans whenever you crave sugar, you will improve your health considerably.” This is because grapes really have a lot going for them. Here is the latest information on the health benefits of grapes.
The antioxidant power of grapes
One cup of grapes has about 21% of the daily value for copper, which is important for nervous system and immune system function, and 18% of the daily value for vitamin K, which contributes to improved bone health and helps with blood coagulation. You also get small amounts of potassium, riboflavin, thiamine, and vitamins C and E.
However, what makes grapes stand out is the large amount of polyphenols they contain, such as anthocyanins, flavonoids and quercetin. These compounds are antioxidants, meaning they help protect cells from the damaging effects of reactive oxygen molecules, called free radicals, and reduce inflammation in the body. In some grape varieties, polyphenols are concentrated in the peel and in others they are more abundant in the pulp. Concord grapes and purple grapes have the highest total amount of antioxidants compared to red and green grapes. But all types of grapes are an excellent source of antioxidants.
Polyphenols are well known for their health-promoting qualities. According to a review of a 2017 study that looked at the effects of grape polyphenols and was published in the journal Molecules, grapes improve vascular health, reducing the overall risk of heart disease. Additionally, in an analysis of 10 studies that was conducted in 2015 and published in the journal Plos One, experts found that a low dose of grape polyphenols (733 mg per day or less) contributed to reducing systolic blood pressure by a average of 1.48 mm Hg. That’s about the amount of polyphenols you’ll get from eating a cup of grapes.
The truth about resveratrol
Resveratrol is another type of polyphenol in grapes and the one that receives the most attention. It is found mainly in the skin of red and purple grapes (and in smaller quantities in green ones). You usually hear about resveratrol in the context of red wine (which, of course, is produced from grapes). That’s because, in the 1990s, experts began investigating whether resveratrol could explain the “French paradox,” which suggests that French people who drink a lot of red wine have lower levels of heart disease despite having a relatively high-fat diet. Suddenly, headlines began touting the benefits of drinking red wine to prevent heart disease, and resveratrol supplements flooded the market.
“Wine actually has more concentrated amounts of resveratrol than grapes because during fermentation, alcohol extracts it from the skin,” says Zhaoping Li, MD, PhD, chief of the division of clinical nutrition at UCLA Health. But despite the initial euphoria, decades of research into resveratrol has produced mixed results regarding its ability to help prevent heart disease, cancer and diabetes, or whether on its own it helps promote a longer life. It is best to eat whole grapes. “It’s unlikely that all of the health benefits of grapes come from resveratrol alone; rather, it’s a combination of all the antioxidants and other nutrients they contain,” says Shilpa Bhupathiraju, PhD, assistant professor of nutrition at the University of California. Harvard TH Chan University of Public Health in Cambridge, Massachusetts.
And what’s with the grape and raisin game?
You’ll get the most nutrients for your money by eating whole grapes in a variety of colors. “Drinking grape juice means more calories and concentrated sugar, and you usually lose most of the fiber in the fruit,” says Sasson. An 8-ounce glass of 100% grape juice contains 160 calories, 35 grams of sugar and only half a gram of fiber. Additionally, 2019 testing by Consumer Reports found concerning levels of heavy metals in some brands of grape juice.
Raisins, like all nuts, can be healthy in moderation. “Once the water content is removed, the sugar concentration and calories increase,” says Sasson. “But they are still an excellent source of fiber and are a delicious treat as a snack or as a topping for your cereal and yogurt.” A handful of raisins (1 ½ ounces) contains 129 calories, 28 grams of sugar and 2 grams of fiber.
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