What antioxidants are and why they matter
Antioxidants are compounds that counter oxidants—substances that can damage crucial cellular components such as proteins, lipids, and DNA. A key group, free radicals, are highly reactive oxidants that can contribute to inflammation and cellular wear over time. To support health, your body relies on a balance: enough antioxidants to neutralize oxidants while avoiding excessive exposure to harmful free radicals.
As a nutrition researcher and clinician, I’ve seen a broad consensus emerge: oxidative stress, driven by imbalances between antioxidants and oxidants, is linked to aging and several chronic diseases, including cancer, diabetes, cardiovascular disease, and dementia. The practical takeaway is simple: adopt a diet rich in antioxidants and minimize unnecessary exposure to oxidants, especially free radicals.
Food, not supplements: the case for dietary antioxidants
Some everyday processes—breathing, digestion, keeping warm—produce oxidants as a natural byproduct of metabolism. Other sources of oxidants include inflammation, pollution, and radiation. Because of this inevitability, everyone benefits from antioxidant-rich foods. Antioxidants come in many forms: enzymes, minerals, vitamins, and phytochemicals such as carotenoids and flavonoids.
Two phytochemical groups deserve emphasis. Carotenoids are pigments responsible for yellow, orange, and red hues and include beta-carotene, lycopene, and lutein. Flavonoids such as anthocyanins give some foods blue, purple, or red colors. While the body manufactures some antioxidants, the strongest protection comes from whole foods rather than supplements.
In several studies, antioxidant supplements have not reduced mortality and, in some cases, may increase risk when taken in high amounts. Many of these trials tested single antioxidants at levels far exceeding daily recommendations, which likely skews outcomes. The consensus remains: foods, not pills, should be the primary source of antioxidants.
Measuring antioxidants: why foods vary
Quantifying antioxidants in foods is complex. Variables such as growing conditions, harvest timing, processing, storage, and even the specific variety of a food (for example, different apple varieties) affect antioxidant levels. In 2018, researchers created the first comprehensive antioxidant database, assessing more than 3,100 foods by how much oxidants they neutralize per 100 grams.
Some representative findings show blueberries, for instance, delivering the highest antioxidant capacity among common berries (about 9 millimoles per 4-ounce serving). Pomegranates and blackberries also rank highly, around 6.5 millimoles per the same serving. Among vegetables, cooked artichoke, red kale, and cooked red cabbage show notable values, while everyday staples like orange bell pepper and coffee contribute meaningful amounts as well. Nuts and seeds also pack antioxidants, with walnuts and pecans offering substantial amounts per serving. Even herbs and spices can deliver powerful antioxidant boosts in small portions.
Practical tips to boost antioxidant intake
How should you apply this knowledge to your plate? Start by reading nutrition labels and looking for vitamins and minerals associated with antioxidant activity—A, C, E, D, B2, B3, B9—plus minerals like selenium, zinc, and manganese. Be aware that not every nutrient is required on labels, and some may be omitted.
Focus on color: eat a rainbow of fresh produce. Dark leafy greens, deeply colored berries, and richly hued vegetables tend to be higher in antioxidants. Heat can affect antioxidant levels—sometimes cooking improves the availability of certain compounds in leafy vegetables, while storage and processing can degrade others. Diversity is key: incorporate a variety of fruits, vegetables, nuts, seeds, whole grains, and herbs to maximize the range of antioxidants you receive.
Local, seasonal produce often offers the best balance of flavor and antioxidant content. While blueberries, red kale, and pecans are excellent, a varied diet will provide a broader spectrum of antioxidant compounds that work together to support health over a lifetime.
