Antioxidants are compounds produced in your body and found in foods. They help defend your cells from damage caused by potentially harmful molecules known as free radicals.
When free radicals accumulate, they may cause a state known as oxidative stress. This may damage your DNA and other important structures in your cells.
Sadly, chronic oxidative stress can increase your risk of chronic diseases such as heart disease, type 2 diabetes and cancer (1).
Fortunately, eating a diet rich in antioxidants can help increase your blood antioxidant levels to fight oxidative stress and reduce the risk of these diseases.
Scientists use several tests to measure the antioxidant content of foods.
One of the best tests is the FRAP (ferric reducing ability of plasma) analysis. It measures the antioxidant content of foods by how well they can neutralize a specific free radical (2).
The higher the FRAP value, the more antioxidants the food contains.
Here are the top 10 healthy foods that are high in antioxidants.
1. Dark Chocolate
Lucky for chocolate lovers, dark chocolate is nutritious. It has more cocoa than regular chocolate, as well as more minerals and antioxidants.
Based on the FRAP analysis, dark chocolate has up to 15 mmol of antioxidants per 3.5 ounces (100 grams). This is even more than blueberries and raspberries, which contain up to 9.2 and 2.3 mmol of antioxidants in the same serving size, respectively (3).
Moreover, the antioxidants in cocoa and dark chocolate have been linked to impressive health benefits such as less inflammation and reduced risk factors for heart disease.
For example, a review of 10 studies looked at the link between cocoa intake and blood pressure in both healthy people and those with high blood pressure.
Consuming cocoa-rich products like dark chocolate reduced systolic blood pressure (the upper value) by an average of 4.5 mmHg and diastolic blood pressure (the lower value) by an average of 2.5 mmHg (4).
Another study found that dark chocolate may reduce the risk of heart disease by raising blood antioxidant levels, raising levels of “good” HDL cholesterol and preventing “bad” LDL cholesterol from becoming oxidized (5).
Oxidized LDL cholesterol is harmful because it promotes inflammation in the blood vessels, which can lead to an increased risk of heart disease (6).
Pecans are a type of nut native to Mexico and South America. They are a good source of healthy fats and minerals, plus contain a high amount of antioxidants.
Based on a FRAP analysis, pecans contain up to 10.6 mmol of antioxidants per 3.5 ounces (100 grams) (3).
In addition, pecans can help raise antioxidant levels in the blood.
For example, a study found that people who consumed 20% of their daily calories from pecans experienced significantly increased blood antioxidant levels (7).
In another study, people who consumed pecans experienced a 26–33% fall in oxidized blood LDL levels within two to eight hours. High levels of oxidized LDL cholesterol in the blood is a risk factor for heart disease (8).
Although pecans are a great source of healthy fats, they are also high in calories. So it’s important to eat pecans in moderation to avoid consuming too many calories.
Although they are low in calories, blueberries are packed with nutrients and antioxidants.
According to a FRAP analysis, blueberries have up to 9.2 mmol of antioxidants per 3.5 ounces (100 grams) (3).
In addition, research from test-tube and animal studies has shown that the antioxidants in blueberries may delay the decline in brain function that tends to happen with age (11).
Researchers have suggested that the antioxidants in blueberries may be responsible for this effect. They’re thought to do this by neutralizing harmful free radicals, reducing inflammation and changing the expression of certain genes (11).
Additionally, the antioxidants in blueberries, especially a type called anthocyanins, have been shown to reduce risk factors for heart disease, lowering LDL cholesterol levels and blood pressure (12).
Based on a FRAP analysis, strawberries provide up to 5.4 mmol of antioxidants per 3.5 ounces (100 grams) (3).
Moreover, strawberries contain a type of antioxidant called anthocyanins, which give them their red color. Strawberries that have a higher anthocyanin content tend to be brighter red (14).
A review of 10 studies found that taking an anthocyanin supplement significantly reduced LDL cholesterol among people who had either heart disease or high LDL levels (17).
Artichokes are a delicious and nutritious vegetable not very common in the North American diet.
But they have a long history — people in ancient times used their leaves as a remedy to treat liver conditions like jaundice (18).
Artichokes are also a great source of dietary fiber, minerals and antioxidants (19).
Based on a FRAP analysis, artichokes contain up to 4.7 mmol of antioxidants per 3.5 ounces (100 grams) (3).
Artichokes are especially rich in the antioxidant known as chlorogenic acid. Studies suggest that the antioxidant and anti-inflammatory benefits of chlorogenic acid may reduce the risk of certain cancers, type 2 diabetes and heart disease (20, 21).
The antioxidant content of artichokes can vary, depending on how they are prepared.
Boiling artichokes may raise their antioxidant content by eight times, and steaming them may raise it by 15 times. On the other hand, frying artichokes may reduce their antioxidant content (22).
6. Goji Berries
Goji berries are the dried fruits of two related plants, Lycium barbarum and Lycium chinense.
They have been a part of traditional Chinese medicine for more than 2,000 years.
Based on a FRAP analysis, goji berries contain 4.3 mmol of antioxidants per 3.5 ounces (100 grams) (3).
In addition, goji berries contain unique antioxidants known as Lycium barbarum polysaccharides. These have been linked to a reduced risk of heart disease and cancer, and may help combat skin aging (25, 26).
Moreover, goji berries may also be very effective at raising blood antioxidant levels.
In one study, healthy elderly people consumed a milk-based goji berry drink every day for 90 days. By the end of the study, their blood antioxidant levels had risen by 57% (27).
While goji berries are nutritious, they can be expensive to eat on a regular basis.
Moreover, there are only a handful of studies on the effects of goji berries in humans. Though these support their health benefits, more human-based research is needed
Raspberries are soft, tart berries that are often used in desserts. They are a great source of dietary fiber, vitamin C, manganese and antioxidants (28).
Based on a FRAP analysis, raspberries have up to 4 mmol of antioxidants per 3.5 ounces (100 grams) (3).
Several studies have linked the antioxidants and other components in raspberries to lower risks of cancer and heart disease.
One test-tube study found that the antioxidants and other components in raspberries killed 90% of stomach, colon and breast cancer cells in the sample (29).
A review of five studies concluded that the anti-inflammatory and antioxidant properties of black raspberries may slow down and suppress the effects of a variety of cancers (30).
That said, most of the evidence for the health benefits of raspberries is from test-tube studies. More research in humans is needed before recommendations can be made.
Kale is a cruciferous vegetable and a member of the group of vegetables cultivated from the species Brassica oleracea. Other members include broccoli and cauliflower.
However, red varieties of kale such as redbor and red Russian kale may contain nearly twice as much — up to 4.1 mmol of antioxidants per 3.5 ounces (3).
This is because red varieties of kale contain more anthocyanin antioxidants as well as several other antioxidants that give them their vibrant color.
Kale is also a great plant-based source of calcium, an important mineral that helps maintain bone health and plays roles in other cellular functions (35).
9. Red Cabbage
Red cabbage has an impressive nutrient profile. Also known as purple cabbage, it is rich in vitamins C, K and A, and has a high antioxidant content (36).
According to a FRAP analysis, red cabbage provides up to 2.2 mmol of antioxidants per 3.5 ounces (100 grams) (3).
That’s more than four times the amount of antioxidants in regular cooked cabbage (3).
This is because red cabbage contains anthocyanins, a group of antioxidants that give red cabbage its color. Anthocyanins are also found in strawberries and raspberries.
These anthocyanins have been linked to several health benefits. They may reduce inflammation, protect against heart disease and reduce the risk of certain cancers (37).
Interestingly, the way red cabbage is prepared can also affect its antioxidant levels.
Boiling and stir-frying red cabbage may boost its antioxidant profile, while steaming red cabbage may reduce its antioxidant content by almost 35% (40).
Beans are a diverse group of legumes that are inexpensive and healthy. They are also incredibly high in fiber, which can help keep your bowel movements regular.
In addition, some beans such as pinto beans contain a particular antioxidant called kaempferol. This antioxidant has been linked to impressive health benefits, such as reduced chronic inflammation and suppressed cancer growth (41, 42).
However, because most of the research supporting the benefits of kaempferol has been in animals or test tubes, more human-based studies are needed.
Antioxidants are compounds that your body makes naturally. You can also get them from foods.
They protect your body from potentially harmful molecules known as free radicals, which can accumulate and promote oxidative stress. Unfortunately, oxidative stress raises the risk of heart disease, cancers, type 2 diabetes and many other chronic diseases.
Fortunately, eating a diet rich in antioxidants can help neutralize free radicals and reduce the risk of these chronic diseases.
By eating a wide variety of the foods in this article, you can boost your blood levels of antioxidants and reap their many health benefits.