Wearables have mastered tracking how we move, breathe and sleep with near-clinical precision. But they still fall short on one of the most important pieces of the health puzzle: diet. Beyond calorie-tracking apps or invasive lab tests, our nutrition has lived mainly outside the smartwatch ecosystem.
Samsung is aiming to change that with the new Antioxidant Index on its new Galaxy Watch 8, Classic, and Ultra. The feature uses an advanced biosensor to measure carotenoids, the natural antioxidants found in fruits and vegetables, directly through the skin (no food diary needed). Samsung believes that this new metric could help unlock a deeper understanding of how lifestyle and diet influence overall health, longevity, and the aging process.
"If we can have a larger proportion of the population just consuming one more serving of fruits and vegetables a day, we're going to see substantial decreases in these chronic conditions over time." says Marcela Radtke, Ph.D., a postdoctoral scholar in epidemiology at Stanford University.
As wearables from Apple, Fitbit and Oura compete to be your one-stop health and wellness hub, with features ranging from advanced vitals tracking to AI health coaches, Samsung is taking a different approach. By honing in on nutrition -- the one health metric that remains largely unconquered -- and combining it with other markers like Vascular Load and sleep guidance, Samsung's approach could provide a competitive edge and deliver a more complete picture of overall wellness.
The Galaxy Watch 8 has a new BioActive sensor that unlocks advanced health metrics like vascular load, and antioxidant levels. Joseph Maldonado/CNET
Why should you care about antioxidants?
Antioxidants play a crucial role in maintaining the body's internal balance. According to the National Institutes of Health, these compounds help remove harmful free radicals, unstable oxygen molecules that form naturally but can multiply due to factors such as a poor diet, alcohol consumption, smoking, stress and even environmental pollution. When free radicals accumulate, they cause oxidative stress, a process that damages cells and can contribute to chronic illnesses, including cancer, heart disease and premature aging.
"Antioxidants neutralize [free radicals] before they cause harm," says Ock K. Chun, professor at the University of Connecticut's Department of Nutritional Sciences. "By increasing antioxidants in the body, you can fend off these diseases, increase longevity as well as quality of life."
While antioxidants come in many forms, including vitamins C and E, Chun, explains that carotenoids -- particularly beta-carotene, the compound measured by the Galaxy Watch -- are among the most reliable indicators of fruit and vegetable intake and the only antioxidants currently measurable through the skin. Beta-carotenoids are commonly found in colorful fruits, grains, oils and vegetables such as carrots and leafy greens, according to the NIH.
According to Radtke, weight is one of the most commonly used indicators for diet in a clinical setting, but it isn't always synonymous with health. Antioxidants can offer a more reliable reflection of nutrition, though measuring them typically requires a blood test -- a procedure that isn't often used for preventive purposes and usually requires a doctor's order once something is already a concern. While antioxidant levels appear faster in the blood, Radtke notes that "carotenoids in the skin are pretty tightly correlated with carotenoids in the blood."
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