By Linda Conlin, Pro to Pro Managing Editor
Grapes are a sweet, juicy, handy snack high in antioxidants. While antioxidants have been shown to have overall health benefits, they are especially good for eye health. Grapes, and red grapes in particular, are sources of lutein, zeaxanthin, and resveratrol, which studies have shown to improve macular pigment optical density (MPOD). Macular pigments are known as carotenoids that provide protection from the damaging effects of blue and near-ultraviolet light.
News Medical Life Sciences reported a recent randomized, controlled human study, that found consuming grapes for 16 weeks improved key markers of eye health in older adults. Researchers at the National University of Singapore conducted a 16 week, double-blind, randomized, placebo-controlled trial. (Yes, I wondered, too, what they used for placebo grapes, but they found a solution.) Thirty-four Singapore older adults were randomized into regularly consuming either 46 g day of freeze-dried table grape powder (the intervention group) or the same amount of placebo powder (the control group). The intervention group (grape eaters) showed a significant increase in MPOD, plasma antioxidant capacity, and total phenolic (a category of antioxidants found in foods) content compared to those on placebo. Those who didn't consume grapes saw a significant increase in harmful advanced glycation end products (AGEs). AGEs may contribute to many eye diseases by damaging the vascular components of the retina, impairing cellular function, and causing oxidative stress. (Hu, W., et al. (2023) Impacts of regular consumption of grapes on macular pigment accumulation in Singapore older adults: a randomized, controlled trial. Food & Function. doi.org/10.1039/d3fo02105j.)
While there is no recommended daily allowance (RDA) for resveratrol, studies have shown that 100 – 500 mg per day is beneficial. One cup of red grapes has approximately 0.24 – 1.25 mg. Neither is there an RDA for lutein and zeaxanthin, but 10 mg of lutein and 2 mg of zeaxanthin per day have shown MPOD improvement. Four ounces, about 2/3 cup, of red grapes have 50 mg lutein and 10 mg zeaxanthin. Red grapes have the most antioxidants, but other grape varieties - green, black, yellow, pink, and purple – also are rich in these nutrients. In addition to grapes, good sources of resveratrol are raisins (dried grapes) peanuts, cocoa, and some berries. Green leafy vegetables are good sources of lutein and zeaxanthin. Consuming a variety of these foods boosts levels of these important nutrients. And we’ve all heard about the benefits of red wine. Made from grapes, of course, it’s also a good source for resveratrol with an 8 ounce serving having 1-2 mg, as well as 12 micrograms of lutein and zeaxanthin. White and rose wines have less antioxidants but are still considered beneficial.
So grab some grapes for a tasty and nutritious snack or relax with a glass of wine. It’s good for you and your eyes!