Wearable technology has made impressive strides in monitoring various aspects of health, such as movement, breathing, and sleep, often with precision approaching clinical standards. However, one critical area has remained largely uncharted within this ecosystem: diet. Despite the proliferation of calorie-counting apps and periodic lab tests, nutrition tracking has yet to become a seamless part of wearable health monitoring. Samsung aims to address this gap with an innovative new feature called the Antioxidant Index, introduced on its latest Galaxy Watch 8 lineup, including the Classic and Ultra models. This advancement represents a significant step toward integrating diet into wearable health metrics, allowing users to gain deeper insight into how their lifestyle choices impact overall wellness, longevity, and aging.
The Antioxidant Index leverages an advanced biosensor built into the Galaxy Watch 8 series to measure carotenoids—natural antioxidants found in fruits and vegetables—directly through the skin. This approach eliminates the need for manual food diaries or invasive blood tests, offering a nonintrusive, user-friendly way to gauge diet quality. Marcela Radtke, Ph.D., a postdoctoral scholar in epidemiology at Stanford University, highlights the potential public health benefits of such technology, noting, "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." This underlines the profound impact even small dietary improvements can have on long-term health.
While major wearable brands such as Apple, Fitbit, and Oura have focused on expanding vital signs monitoring and incorporating AI-driven health coaching, Samsung’s strategy is distinct. By honing in on nutrition—a relatively untapped metric in the wearable space—and combining it with other health indicators like vascular load and sleep quality, Samsung aims to provide a more holistic and nuanced picture of wellness. This integrated approach could give Samsung a competitive advantage, appealing to consumers looking for a comprehensive health tracking solution.
The Galaxy Watch 8 introduces a new BioActive sensor that enables these advanced health measurements, including the Antioxidant Index and vascular load metrics. Antioxidants play a crucial role in maintaining the body’s internal balance by neutralizing free radicals—unstable oxygen molecules that naturally occur but can increase due to poor diet, stress, pollution, smoking, and alcohol consumption. When free radicals accumulate unchecked, they cause oxidative stress, damaging cells and contributing to chronic diseases such as cancer, heart disease, and accelerated aging.
Ock K. Chun, a professor at the University of Connecticut’s Department of Nutritional Sciences, explains the protective role antioxidants play: "Antioxidants neutralize [free radicals] before they cause harm. By increasing antioxidants in the body, you can fend off these diseases, increase longevity as well as quality of life." Among antioxidants, carotenoids—including beta-carotene—are particularly reliable markers of fruit and vegetable intake. Beta-carotene is found in a variety of colorful produce, such as carrots, leafy greens, grains, and oils. According to the National Institutes of Health (NIH), carotenoids are the only antioxidants measurable through the skin, making them ideal candidates for noninvasive tracking.
In clinical settings, weight is often used as a proxy for diet quality, but this metric is imperfect and can be misleading. Radtke points out that antioxidant levels provide a more direct reflection of nutritional status. Traditionally, measuring antioxidants required blood tests—procedures that are invasive, costly, and typically reserved for diagnosing existing concerns rather than preventive care. However, carotenoid levels in the skin correlate closely with those in the blood, offering a promising alternative for monitoring diet noninvasively.
Before Samsung’s implementation, the only comparable noninvasive device was the Veggie Meter, launched in 2018. This standalone instrument measures skin carotenoid levels at the fingertip but has not seen widespread clinical adoption. Samsung’s innovation lies in integrating this capability into a popular wearable device, harnessing multiple colored LEDs—yellow, blue, violet, and infrared—to detect carotenoids based on light absorption and reflection patterns on the skin.
Unlike most wrist-based health sensors, the Galaxy Watch’s carotenoid measurement requires the user to place their thumb over the sensor for about five seconds. Dr. Jinyoung Park, principal engineer on Samsung’s Digital Health Team, explains that the fingertip is optimal for this measurement due to its thicker skin and lower melanin interference, which can affect accuracy: "By pressing hard on the