One popular recommendation for a healthy diet is to “eat the rainbow.” This strategy highlights the importance of eating a variety of fruits and vegetables to get the nutrients you need.
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According to dietitian Joyce Prescott, MS, RD, LD, the chemicals that give plants their bright colors can be especially good for your health. And fruits and vegetables on the purple end of the spectrum contain a chemical called anthocyanin that packs a nutritional punch.
What are anthocyanins?
Anthocyanins (an-tho-SY-uh-nins) are a group of deep red, purple and blue pigments found in plants. They’re part of a larger category of plant-based chemicals called flavonoids. Flavonoids are abundant in all parts of plants: fruits, seeds, shoots, flowers and leaves. They help plants reproduce by attracting pollinators and protect plants from environmental stressors like UV (ultraviolet) light, drought and cold.
“Research shows that flavonoids are also powerful nutrients and may help explain why plant-based diets are consistently associated with health benefits,” says Prescott. “We think this is due, in part, to their antioxidant properties.”
Antioxidants destroy unstable molecules called free radicals that can damage your cells. Free radicals occur naturally as a by-product of metabolism, as well as from environmental exposure to pollution, cigarette smoke, alcohol, sunlight and harmful chemicals.
Among about 6,000 known flavonoids, there are six main types of anthocyanins:
Where are anthocyanins found?
Fruits, vegetables and grains with red, purple, blue or black hues tend to be rich in anthocyanins. Berries have the highest levels, particularly black elderberries and aronia berries (chokeberries). Blueberries, blackberries, raspberries and strawberries are also great sources. Additional foods with a high anthocyanin punch include:
- Fruits: Black plums, blood oranges, cherries, black and red grapes and pomegranates.
- Vegetables: Red cabbage, red onions, red radishes, purple cauliflower, purple corn and the skin of purple eggplant.
- Legumes and rice: Black beans, black rice and black soybeans.
- Beverages: Grape juice and wine.
“Fresh and frozen forms of the foods listed retain the highest levels of this colorful flavonoid,” notes Prescott. “You’ll also find many types of anthocyanin-containing supplements. Extracts of elderberry, aronia, tart cherry and blueberry are just a few that have become popular.”
What are the health benefits of anthocyanins?
Anthocyanin-rich foods are an important part of a healthy diet. But researchers are still investigating their role in treating and preventing specific diseases. Overall, evidence suggests that anthocyanins may provide a range of health benefits.
Here are some of the latest findings:
1. Lowers blood pressure
Anthocyanins may help reduce blood pressure, according to a review of 66 studies. Study participants with hypertension took a variety of extracts and preparations from anthocyanin-containing plants. The study found there was a consistent lowering effect on blood pressure. In other studies, however, researchers identified many factors that led to mixed results, such as:
- Dosage and type of anthocyanin (food, juice, freeze-dried powder or extract).
- Number of doses (single vs. long term).
- Patient characteristics (a person’s baseline blood pressure and other health conditions).
This study highlights the need for more research to establish a dosing regimen and determine who might benefit from anthocyanins.
2. Reduces risk of heart disease
Atherosclerosis is when plaque builds up on the inside of your arteries. This buildup can cause high blood pressure, heart attack, stroke, peripheral artery disease or kidney failure.
The formation of plaque is a multi-stage process that depends on many factors. Prescott says that research shows that anthocyanins can intervene at different stages in the process by reducing:
- Cholesterol, a main part of plaque.
- High blood pressure, which can damage blood vessels and make them more likely to develop atherosclerosis.
- Inflammation, which leads to plaque formation.
4. Prevents neurological diseases
Research shows that anthocyanins can help protect and improve your brain function:
- One study found that a daily dose of cherry juice improved speech and memory in people aged 70 and over with mild or moderate dementia.
- Another study reported anthocyanins increased blood flow to and activated brain areas that control memory, language and attention.
Researchers believe that anthocyanins’ antioxidant and anti-inflammatory properties are responsible for these improvements.
5. Slows cancer growth
Anthocyanins may act in many ways to slow or stop cancer. Studies suggest that anthocyanins might:
- Block the changes in DNA that cause cancer.
- Destroy cancer cells or stop their growth.
- Prevent tumors from becoming malignant (cancerous).
- Reverse drug resistance and increase tumors’ sensitivity to chemotherapy.
However, Prescott cautions that the research on anthocyanins and cancer has mainly happened in the laboratory. There are only limited data from clinical trials on people. Researchers need to continue to investigate these findings so they can determine exactly how anthocyanins affect cancer growth and treatment.
How much anthocyanin should I have each day?
While the results of many of these studies are promising, they don’t offer clear guidance on how much anthocyanin you should consume each day. Unlike essential vitamins and minerals, there isn’t a daily recommended value.
“Your best strategy is to include anthocyanin-rich foods as part of your regular meal pattern,” says Prescott. “We know these foods are safe and can help boost your overall nutrition.”
Should I take anthocyanin supplements?
There’s no clear evidence supporting the use of anthocyanin supplements. While supplements are widely available and claim many health benefits, data guiding the use of these products is generally nonexistent.
Prescott recommends talking to your healthcare provider if you’re considering taking an anthocyanin supplement. It’s important to make sure the supplement won’t interfere with your current medications. Your healthcare provider can also help you decide if a supplement is the right choice based on your health and medical history.