How do Antioxidants Work?

You may have heard about the importance of antioxidants, but do you know exactly what they are or how they benefit you?

Some common dietary antioxidant nutrients include vitamin C, vitamin E, carotenoids like beta-carotene, and flavonoids. Antioxidants are responsible for vibrant colors in fruits and vegetables; flavonoids produce red and purple pigments in berries and carotenoids produce the orange pigment in carrots and the red in tomatoes.

Antioxidants help to limit the potentially damaging side effects of our metabolic processes; we use oxygen in our energy metabolism, and this naturally generates free radicals (we are also exposed to free radicals due to environmental factors such as cigarette smoke exposure or a poor diet).  The purpose of antioxidants is to  protect your cells against the negative effects of free radicals. Free radicals are molecules with unpaired electrons, making them unstable and highly reactive. Over time, free radical damage (also called oxidative damage) can lead to aging and diseases like cancer and heart disease. Antioxidants slow or stop the reactions of free radicals, counteracting these effects. ¹

“Free radical scavenging” is not the only mode of disease-protection for many antioxidants. Flavonoids, for example, do not have strong antioxidant activity after they are ingested, but they benefit health by affecting cell signaling, activating the body’s natural detoxification system, and reducing inflammation—these effects are unrelated to their antioxidant properties.²

Some antioxidants are naturally present and produced by the body in response to plant phytochemicals, and we take in other direct antioxidants through our diet. You can help your body tip the balance—to build up sufficient antioxidant defenses needed to counteract free radical production—by ensuring that you are loading your body with plenty of antioxidant-rich, high-nutrient foods. An easy way to do this is to make sure you are eating the colors of the rainbow, since antioxidants are responsible for the vibrant colors in fruits and vegetables. The greater the amount and variety of nutrients you consume, the better for your immune function and resistance to disease.

Berries, cherries and pomegranates are wonderful sources flavonoids, which are concentrated in their skins and give rise to their deep colors of red, blue, and purple. Flavonoids affect cell signaling pathways leading to changes in gene expression, detoxification, inhibition of cancer cell growth and proliferation, and inhibition of inflammation and other processes related to cancer and heart disease.³ 

Berries also support brain function. Substances present in blueberries reduce oxidative stress and improve communication between brain cells. In animal studies, blueberries, strawberries and blackberries have all been shown to slow or reverse age-related cognitive decline. In a small study in humans, older adults with mildly impaired memory were given wild blueberry juice as a supplement and after 12 weeks they showed improvement in learning and memory.⁴ In people with mild memory complaints, those who drank pomegranate juice daily performed better on memory tasks and displayed an increase in brain activity on a functional MRI as compared to those who were given a placebo.⁵ Antioxidants in cherries have also been shown to protect brain cells against oxidative stress, implying that eating cherries may help prevent neurodegenerative diseases like dementia.^{6, 7}  

Adding some of these fruits to your daily diet may provide protective benefits, reducing your risk of disease. Adding some berries, cherries or pomegranate seeds to a smoothie is a convenient and delicious way for your body to absorb all the beneficial antioxidants that the fruit has to offer.  Download my formula for making the perfect smoothie to help you create your own special blends or try one of my four favorite smoothie recipes, including the ultimate Chocolate Cherry Smoothie, found here in this infographic. 

1. Gordon MH: Significance of dietary antioxidants for health. Int J Mol Sci 2012;13:173-179.
2. Higdon J, Drake VJ: Flavonoids. In An Evidence-Based Approach to Dietary Phytochemicals and Other Dietary Factors. New York: Thieme; 2012: 83-108
3. Stoner GD: Foodstuffs for preventing cancer: the preclinical and clinical development of berries. Cancer Prev Res (Phila) 2009;2:187-194.
4. Krikorian R, Shidler MD, Nash TA, et al: Blueberry supplementation improves memory in older adults. J Agric Food Chem 2010;58:3996-4000.
5. Bookheimer SY, Renner BA, Ekstrom A, et al: Pomegranate juice augments memory and FMRI activity in middle-aged and older adults with mild memory complaints. Evid Based Complement Alternat Med 2013;2013:946298.
6. Kim DO, Heo HJ, Kim YJ, et al: Sweet and sour cherry phenolics and their protective effects on neuronal cells. Journal of Agricultural and Food Chemis ry 2005;53:9921-9927.
7. Traustadottir T, Davies SS, Stock AA, et al: Tart cherry juice decreases oxidative stress in healthy older men and women. J Nutr 2009;139:1896-1900.