What Are Anthocyanins?

Anthocyanins are a group of bioactive pigments naturally found in certain plants. These pigments account for red, blue, and purple colors in many fruits and vegetables.

Anthocyanins belong to a class of compounds called flavonoids, many of which are thought to contain antioxidant effects, including anthocyanins. Antioxidants fight unstable molecules, called free radicals, that have the potential to damage cells and increase the risk of certain diseases.

Some contend that anthocyanins can also boost the immune system and help fight inflammation, diabetes, viral infections, and cancer.

There are many different anthocyanins, with the six most common being:

• Cyanidin
• Delphinidin
• Malvidin
• Peonidin
• Petunidin
• Pelargonidin
  

This article will explore the research surrounding the potential uses of anthocyanins. It will also review any side effects, precautions, drug interactions, and other things you should know regarding anthocyanins.

Uses of Anthocyanins

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian (RD), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease. 

In herbal medicine, anthocyanins are thought to be useful for several health conditions, including:

• Alzheimer's disease
• Flu and other viral infections
  
• Enlarged prostate
• Eye diseases like retinopathy (damage to the blood vessels of the retina) and glaucoma
• Fatty liver disease
• High cholesterol
• High blood pressure
  
• Certain cancers
• Stroke
  
• Urinary tract infections

It should be noted that this is not an exhaustive list. Anthocyanins continue to be researched for many other health conditions.

While it is clear that anthocyanin-rich foods play a role in human nutrition, it remains unclear if they can prevent or treat any health condition independently. Evidence is lacking, and even where there is evidence that anthocyanins are beneficial, it is unknown how much is needed for anthocyanins to be considered preventive.

Below is a look into some of the research on anthocyanins.

Heart Disease

Some research suggests that anthocyanins may reduce the risk of heart disease.

A 2021 review on the effect of anthocyanin-rich berries on heart disease showed promising results. The review included 44 studies and evaluated anthocyanin-rich berries such as cranberries, blueberries, bilberries, and blackcurrant. According to the review, regular intake of anthocyanins may improve blood lipids while reducing inflammation that can lead to the development of heart disease.

Anthocyanins are also believed to have potential blood pressure–lowering effects. However, study results have been mixed, which means anthocyanins may only help lower blood pressure in some cases.

Cancer

Although some researchers believe that anthocyanins may possess protective properties against certain types of cancer, no human studies have found any significant benefit.

Lab studies have shown that anthocyanins extracted from various sources were able to shrink, kill, or inhibit cancer cells. This was demonstrated in colon, bladder, breast, and thyroid cancer cells, among others.

Animal studies have had similar results, yet human trials on anthocyanins and cancer remain limited.

One small human study looked at the effect of anthocyanins on colon cancer. Despite positive findings from preliminary research, anthocyanins were found to have no significant impact on colon cancer in the human trial.

More research is certainly needed in this area.

Diabetes

There is research that suggests anthocyanins may be beneficial for diabetes management.

In a small human study cited in 2015, 58 people with type 2 diabetes were given either placebo (an intentionally given ineffective substance) or 160 milligrams (mg) of anthocyanins twice daily for 24 weeks. By the end of the study, those taking anthocyanins had decreased fasting blood sugar. The anthocyanins were also thought to improve insulin resistance (when cells stop responding to insulin, causing glucose to build up in the blood) in the study participants.

In another study performed on women with diabetes, intake of anthocyanins was associated with lower levels of inflammation. This study also found an association between a high intake of anthocyanin-rich foods and improved insulin resistance.

It should be noted that no large-scale studies looking at the effects of anthocyanins on diabetes have been performed to date. Larger and better-designed studies on the subject certainly are needed.

What Are the Side Effects of Anthocyanins?

As a natural substance in many foods, anthocyanins are not thought to have side effects when eaten in normal amounts. For this reason, it is recommended to take a food-first approach to the intake of anthocyanins.

Supplements containing high doses of anthocyanins may be more likely to cause mild or severe side effects.

Common Side Effects

You may experience side effects when taking supplements that contain anthocyanins. However, anthocyanins in supplement form are thought to be generally safe.

In the human trials that we do have on anthocyanins as supplements, little to no adverse events have been reported. In the few cases where side effects have occurred, they have mostly been mild. Reported side effects include eczema and gastrointestinal (stomach) upset.

Severe Side Effects

Evidence suggests that side effects occur only when anthocyanins are taken in doses that are too large. Despite this belief, there are still no reports of severe side effects caused by anthocyanins.

To avoid all side effects, choose to obtain anthocyanins through food. If you do take supplements containing anthocyanins, use them only as directed, and never take more than you should.

Precautions

Some people may need to take extra precautions when using anthocyanins in supplement form.

Anthocyanins are thought to be safe when consumed through food.

However, the safety of anthocyanin supplements in certain populations has not been established at this time. Children, people who are pregnant or breastfeeding, and those with medical conditions should seek advice from their healthcare provider before using anthocyanin supplements.

Dosage: How Much Anthocyanins Should I Take?

When it comes to anthocyanin supplements, there are no guidelines for recommended dosage. More research is needed to establish safe dosage information for all people.

There is also no Dietary Reference Intake (DRI) for anthocyanins from food.

However, a joint committee comprising the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) has established 2.5 milligrams per kilogram (mg/kg) of anthocyanins as an acceptable daily intake. However, this recommendation applies to anthocyanins from grape skin extracts, not anthocyanins in general. The committee found this to be a safe, nontoxic dose.

If necessary, your healthcare provider can help determine the right anthocyanin dose for you.

What Happens If I Take Too Much Anthocyanins?

You may be more likely to experience side effects if you take a dose of anthocyanins that is too high. However, anthocyanins are generally considered safe, especially when consumed through food.

Reports of anthocyanin toxicity or overdose have not been made. Anthocyanins have also been labeled as having low to no toxicity.

Regardless, it's still important to be safe and only use anthocyanin supplements as directed. You should also only consume anthocyanins through food in normal amounts.

Interactions

Anthocyanins may interact with certain nutrients and medications.

Some research suggests that anthocyanins interfere with various enzymes and protein transporters responsible for helping the body absorb some nutrients, like thiamine and folic acid. Anthocyanins may also affect enzymes or transporters needed to metabolize certain medications.

Unfortunately, anthocyanin interactions are not well-documented or understood.

It is also important that you carefully read the ingredients list and nutrition facts panel of a supplement. This will ensure you know which ingredients are in the product and how much of each ingredient is included in the supplement. For best practice, please speak with your healthcare provider regarding the potential for interactions between anthocyanins and any other supplements or medications you take.

How to Store Anthocyanins

Anthocyanin supplements should be stored in a cool, dry place. Keep them out of direct sunlight. Foods containing anthocyanins should be stored normally.

To ensure proper shelf life, always keep supplements in their original bottle or packaging. You should also keep anthocyanins out of the reach of pets and children to prevent accidental ingestion.

Discard all supplements once they reach their expiration date.

Similar Supplements

Various supplements have been researched for similar uses to anthocyanins. These include:

• Berberine: A natural substance found in certain plants, berberine has been researched for its potential use in lowering cholesterol. A review of various studies on the subject found that berberine showed a positive effect on both LDL (low-density lipoprotein) cholesterol (considered "bad" cholesterol) and triglycerides (a fat in the blood).
• L-arginine: There is evidence that suggests L-arginine, an amino acid, may help lower blood pressure. In one 2021 review, L-arginine supplementation was found to have a modest effect in people with hypertension, or high blood pressure.
• Chromium: Although nothing can replace a well-balanced diet and lifestyle, chromium may be beneficial for people with type 2 diabetes. Similar to anthocyanins, chromium is thought to improve fasting blood sugar levels.
• Vitamin D: Vitamin D supplements are similar to anthocyanins in a few ways. Like anthocyanins, vitamin D has been studied for complementary uses in cancer, heart disease, diabetes, and inflammation.

Talk with your healthcare provider about which supplement is best for you.

Sources of Anthocyanins & What to Look For

Although supplements are available, the best way to get anthocyanins is through food.

A food-first approach to anthocyanins ensures better absorption and utilization of nutrients. However, supplements may be necessary in certain cases.

Food Sources of Anthocyanins

Anthocyanins are found in many plant foods, most of which are fruits or vegetables.

Plants that are rich in anthocyanins include:

• Corn
• Sweet potatoes
• Blackberries
• Grapes
• Blueberries
• Black currants
• Chokeberry
• Tart cherry
• Soybeans
• Wild berries
  
• Black rice
  
• Bilberries
• Pomegranate

Some foods, like baked goods, dairy products, and beverages may even be fortified with anthocyanins.

You can also purchase anthocyanin-rich supplements, including tart cherry extract, blueberry extract, bilberry extract, and black raspberry extract.

Anthocyanin Supplements

Anthocyanin supplements are mostly available as various berry extracts. These may come in the form of capsules, soft gels, tablets, or gummies.

Keep in mind that supplements containing anthocyanins typically have additional nutrients and ingredients.

If you choose to take an anthocyanin supplement, you should also note that supplements are not regulated in the United States as strictly as drugs and conventional food products. Because of this, they can vary in quality and may contain ingredients you may not want.

To better ensure quality and purity, look for products that have been independently certified by ConsumerLab, USP, or NSF International. Certification doesn't mean that supplements are safe or effective but that they contain the ingredients listed on the product label and in the advertised amounts.

Summary

Anthocyanins are natural pigments in certain plants that give them their purple, blue, or red color. Anthocyanins are rich in antioxidants and other bioactive ingredients that may offer health benefits.

Anthocyanin-rich foods are highly nutritious and an excellent part of a well-balanced diet, but it is still unknown if anthocyanin supplements provide any true benefits.

If you're thinking about taking an anthocyanin supplement, talk with your healthcare provider first. Remember that supplements cannot cure or prevent any health condition and that nothing beats nutrition from whole food sources.