Antioxidants do a lot of heavy lifting — at least in marketing food products and supplements. But are they really a magic bullet for fighting health conditions, including diabetes and its complications?
What Are Antioxidants?
Antioxidants are the umbrella name of substances that defend cells in the body from chemicals called “free radicals,” atoms or molecules made unstable due to unpaired electrons. Free radicals can be beneficial, but an overload of them can be damaging. Essentially, free radicals damage cells and genetic material by grabbing electrons from nearby substances, causing the alteration of those substances’ structure and function. According to Harvard’s T.H. Chan School of Public Health, free radicals are generated as a byproduct of turning food into energy, after exercising or after exposure to external triggers, like cigarette smoke, air pollution, and even sunlight.
Antioxidants are so-called electron donors that may protect cells from damage by free radicals. They are not a single type of substance but vary in their chemical behaviors and biology. According to the Mayo Clinic, substances considered to be antioxidants include vitamins C and E, carotenoids, flavonoids, tannins, phenols, and lignans.
Oxidative Stress and Diabetes
An excessive and chronic amount of free radicals can create what is called “oxidative stress,” which basically is the imbalance between the production of free radicals and antioxidants that curb them.
Oxidative stress attacks healthy cells in the body with the result that the cells lose their function. It has been shown to play a role in the development of a number of chronic diseases, including diabetes.
A 2015 study explained that an excessive level of free radicals helps lead to the development of vascular complications in diabetes, especially type 2 diabetes.
A 2018 paper explained that people with low concentrations of antioxidants are at increased risk of diabetes complications, such as retinopathy, nephropathy, lower extremity amputations, coronary artery, and cardiovascular diseases.
Can Antioxidants Help People With Diabetes?
Scientific studies abound with claims that antioxidants can meaningfully benefit people with diabetes.
The 2018 study mentioned above, for instance, concluded that vitamin E supplementation could be a “valuable strategy” for controlling diabetes complications and enhancing antioxidant capacity. It added that type 2 diabetes patients, with their high risk of micro- and macrovascular complications could also benefit from daily vitamin supplementation as an alternative strategy for metabolic control, alongside diet, exercise, and medication.
A 2023 paper looked at antioxidant phytochemicals as a potential therapy for diabetic complications. Phytochemicals are compounds produced by plants, like fruits, vegetables, grains, and beans. The paper theorizes that since diabetic complications originate and progress in association with oxidative stress and inflammation, phytochemicals that have antioxidant properties (as well as anti-inflammatory and anti-hyperglycemic properties) could help prevent or impede those complications. But there’s a catch: Antioxidant phytochemicals have low bioavailability and are not readily absorbed by the body.
Some researchers believe that antioxidants have broad benefits for people with diabetes. A 2022 paper from Qatari researchers maintains, “Dietary antioxidants that show anti-diabetic effects also improve diabetic status by regulating glucose metabolism, improving insulin secretion and decreasing insulin resistance, improving vascular functions, and regulating the levels of HbA1c and oxidative stress markers.” It touts the benefits of polyphenols, flavonoids, bioflavonoids, and multiple aromatic biophenols.
Studies of these sorts almost universally end, however, with an acknowledgment that more work is needed to strengthen the evidence. And medical authorities don’t seem convinced. The American Diabetes Association doesn’t significantly address the topic of antioxidants in its official literature on nutrition. And Harvard concludes that “studies so far are inconclusive but generally don’t provide strong evidence that antioxidant supplements have a substantial impact on” chronic disease, including diabetes.
Though it may be difficult to evaluate the purported health benefits of antioxidants, it’s worth noting that the foods and ingredients recommended by researchers are typically very healthy, regardless of their antioxidant properties. They include a variety of wholesome foods ranging from fruits, nuts, and berries to leafy green vegetables, olive oil, and herbs.
That may be what makes assessing the benefits of antioxidants directly such a challenge. The foods they derive from are genuinely healthful.
Do Antioxidant Supplements Work?
There is even less evidence in favor of the use of antioxidant supplements in pills or powders. As Harvard noted, the most robust experimental trials “offer little support that taking vitamin C, vitamin E, beta-carotene, or other single antioxidants provides substantial protection against heart disease, cancer, or other chronic conditions.”
It could be that antioxidants just don’t work the same way in isolation. We don’t look just to apples or kale for a healthy diet; we rely on a wide variety of foods to provide us with the nutrients we need. Maybe we should consider antioxidants in the same way. They may need a complex network of other nutrients, plant chemicals, and other antioxidants to do their work.
A Brief Guide to Antioxidant Ingredients
The good news is that you can get plenty of antioxidants just by consuming fresh foods in all their variety. Even if the antioxidants don’t provide obvious benefits for your specific health issues, you’re still getting vitamins, minerals, and fiber.
But if you’re looking for antioxidant-specific nutrients, consider foods with:
Vitamin C
Vitamin E
Carotenoids (beta-carotene and lycopene)
Selenium
Zinc
Phenolic compounds (quercetin, catechins, resveratrol, coumaric acid, and anthocyanins)
The best foods for these antioxidant nutrients are fruits, dried fruits, vegetables, spices and herbs, whole grains, and nuts. And don’t forget lean animal and plant proteins.
According to the Mayo Clinic, blueberries, blackberries, raspberries, strawberries, and cranberries are among the top fruit sources of antioxidants. Colorful produce, from sweet potatoes and carrots to red and green peppers and dark leafy greens are also high in antioxidants. Love nuts? Aim for walnuts, pecans, and sunflower seeds.
For now, the verdict is out on whether antioxidants are actually directly beneficial to chronic conditions like diabetes, or if they can fend off vascular issues that could result from diabetes. Antioxidant supplements or food products that are marketed for antioxidant benefits may not yield the help you think you’re paying for. However, the foods they derive from are plentiful, and delicious, and offer many health benefits on their own.