Polyphenols are plant compounds that give many fruits and vegetables characterized by bright colors.
These plant compounds are some of the best antioxidants in the diet, and have anti-inflammatory properties that are good for brain, heart, and gut health.
There are more than 8,000 different types of polyphenols, and they are found in a wide range of foods, including green tea, red wine, cocoa, nuts, herbs, and spices.
Listed below are 11 reasons why polyphenols are good for your health.
1. They are powerful antioxidants.
Polyphenols are the most common antioxidants in the diet.
In fact, about 10 times more polyphenols are ingested than vitamin C and 100 times more polyphenols than vitamin E and carotenoids, which are also other antioxidants.
Antioxidants help fight oxidative stress caused by free radicals, which are molecules that can damage cells in the body and contribute to cancer and aging.
They are also very important for general health. In fact, people who eat a lot of antioxidants have lower rates of death and cancer.
A study in 86 overweight or obese people found that following a polyphenol-rich diet for eight weeks significantly reduced oxidative stress.
Also, berry juices and extracts rich in antioxidants and polyphenols have been shown to reduce oxidative stress in humans.
These studies suggest that by reducing oxidative stress, polyphenol-rich foods may reduce the risk of many other diseases such as obesity, diabetes, and cancer.
Summary: Polyphenols are strong antioxidants that can help prevent cell damage caused by oxidative stress.
Learn more about “antioxidants” in our article: How antioxidant foods work .
2. It can help lower cholesterol.
High blood cholesterol is a major risk factor for heart disease, the world’s leading cause of death.
Interestingly, polyphenols can help lower cholesterol, thus reducing the risk of heart disease.
One study found that a diet rich in polyphenols significantly lowered levels of triglycerides and LDL (low-density lipoprotein) or “bad” cholesterol in overweight and obese people.
In particular, cocoa polyphenols are very effective in reducing levels of LDL or “bad” cholesterol, and at the same time increasing levels of HDL (high-density lipoprotein) or “good” cholesterol.
Other polyphenol-rich foods, such as olive oil and green tea, also appear to have similar beneficial effects.
What’s more, a large study of more than 1,200 people showed that eating berries rich in polyphenols could also lower levels of LDL, or “bad” cholesterol.
Abstract: Compelling evidence shows that diets and foods rich in polyphenols, such as berries and olive oil, can reduce levels of LDL or “bad” cholesterol and increase levels of LAD or “good” cholesterol.
Learn more about “lowering cholesterol” in our article: How to lower cholesterol in 5 steps .
3. It can help lower blood pressure.
High blood pressure is another risk factor for heart disease.
It can be caused by a buildup of plaque in the blood vessels or arteries.
This buildup results in increased pressure, which can cause the arteries to thicken, increasing the risk of a heart attack or stroke.
Polyphenols can help the endothelium – the inner layer of blood vessels – to relax, thereby lowering blood pressure.
A large study that included more than 1,300 people showed that drinking green tea rich in polyphenols can significantly reduce blood pressure.
Olives and olive leaves also contain high amounts of polyphenols, and it is one of the reasons why olive oil is one of the healthiest oils.
In fact, one study found that consuming one ounce (30 ml) of olive oil per day for four months can improve the condition of the endothelium.
Additionally, a couple of studies have shown that drinking polyphenol-rich grape, cranberry, or strawberry juice for 6-12 weeks can lower blood pressure in both healthy people and people with high blood pressure.
Another study found that polyphenols from oranges or orange juice could improve the condition of blood vessels.
Summary: Polyphenols can help relax blood vessels. Therefore, foods rich in polyphenols such as olive oil, green tea, and certain fruit juices can help lower blood pressure.
4. It can help prevent certain cancers.
Polyphenols may also help prevent certain cancers by reducing oxidative stress, inflammation, and cancer cell growth.
However, there is very little evidence of this effect in human studies. Rather, most of the evidence comes from observational or test tube studies.
The evidence on cancers of the digestive tract is mixed. Some studies have shown that a higher intake of flavonoids reduces the risk of esophageal and gastric cancer, while others have shown no effect.
The effects of polyphenols in other types of cancer appear to be stronger. In fact, women with higher intakes of various polyphenols may have lower rates of breast, ovarian, and endometrial cancer.
Similarly, large studies in patients with lung and bladder cancer also show that consuming high amounts of polyphenols may have protective effects.
Additionally, polyphenols may help treat prostate cancer by lowering prostate-specific antigen (PSA) levels. Elevated levels of this protein are seen in men with prostate cancer.
For example, one study showed that eating a polyphenol-rich supplement of either pomegranate, green tea, broccoli, and turmeric for six months significantly reduced PSA in men with prostate cancer.
This is an exciting area of research, and more studies may show the importance of polyphenols in preventing or fighting cancer.
Summary: Polyphenols may help reduce certain types of cancer, especially prostate cancer, through their anti-inflammatory and antioxidant effects. However, more studies are still needed to confirm this.
5. Good for intestinal health.
When you eat polyphenols, only 5-10% of them are absorbed into the body in the small intestine.
The remaining 90-95% travel down the colon, where trillions of bacteria break them down into smaller molecules.
As a result, many polyphenols act as a food source for beneficial bacteria in the intestines.
Grapes are a good source of polyphenols, and there are many polyphenols in wine.
A number of studies have shown that red wine extracts help the growth of some beneficial bacteria in the intestines, such as Akkermansia. Akkermansia is a healthy bacteria that can help you lose weight.
Other polyphenols have also been shown to increase levels of Bifidobacteria, which are beneficial bacteria often used as probiotics, and short-chain fatty acids, which are important for gut health.
Abstract: Most polyphenols are not absorbed in the small intestine and instead travel to the large intestine, where they can promote the growth of beneficial intestinal bacteria thus improving intestinal health.
Learn more about “gut health” in our article: How to have a healthy gut .
6. It can lower the risk of blood sugar and diabetes.
High blood sugar can increase the risk of diabetes. Fortunately, polyphenols can reduce the risk of diabetes by helping insulin to remove sugar from the blood.
A large study that included more than 250,000 people found that those with the highest intake of flavonoid polyphenols had a 9% lower risk of diabetes, compared to people with the lowest intakes.
A similar study found that people who ate a lot of polyphenol-rich foods, such as blueberries, apples and pears, also had a lower risk of type 2 diabetes.
Diets rich in polyphenols can reduce the risk of diabetes by lowering blood sugar and increasing the production of insulin, which transports blood sugar into cells.
In fact, polyphenols from green tea, berries, and olive leaves have been shown to improve diabetes risk factors and symptoms.
Summary: There is strong evidence to suggest that different polyphenols can reduce blood sugar and other risk factors for diabetes.
Learn more about “lowering blood sugar” in our article: How to Lower Blood Sugar .
7. Promotes bone health.
Oxidative stress and inflammation can also damage bones.
Bone damage can eventually lead to diseases such as osteoporosis, which increases the risk of bone fractures.
Polyphenols may promote bone health by reducing oxidative stress and inflammation, while supporting bone mineral density through the growth of new bone cells.
Two studies in more than 3,000 Chinese and Scottish people found that those with the highest intake of flavonoid polyphenols had higher bone mineral density.
A type of polyphenol called isoflavones, found in soy products, has been shown to benefit bone health.
A large two-year study found that women who took 120 mg of soy isoflavones each day experienced less bone loss than those who did not take them.
Similar studies have also found that soy polyphenols may benefit bone health, although other studies have found no beneficial effects.
However, a large study that combined the results of 10 other studies found that taking at least 90 mg in soy isoflavone polyphenols daily for six months significantly increased bone density in menopausal women.
Other studies have shown that other polyphenol-rich foods, including green tea, cranberry juice, and olive oil, also have beneficial effects on bone health.
Summary: Polyphenols, particularly soy isoflavones, may support bone health. This is especially true in middle age when the risk of bone diseases such as osteoporosis can be reduced.
8. It can reduce inflammation.
Inflammation occurs when the immune system kicks in to fight an infection.
However, if inflammation persists for long periods, it can contribute to many disorders, including obesity, diabetes, and heart disease.
Polyphenols can help reduce inflammation, with cocoa polyphenols being particularly effective in reducing inflammation.
A number of studies have shown that if cocoa polyphenols are eaten for five days to six weeks, they can reduce inflammation in those at high risk for heart disease and insulin resistance.
Other polyphenols, such as those from whole wheat and non-alcoholic beer, can also reduce inflammation.
However, the combination of polyphenols can be even more effective. A recent study found that eating a polyphenol blend for 15 days reduced inflammation in women.
Summary: Polyphenols, especially those from cocoa, have anti-inflammatory properties. They can benefit a variety of conditions.
Learn more about “dark chocolate benefits” in our article: Dark Chocolate Benefits .
9. It can help prevent weight gain.
Polyphenols may help prevent weight gain in people who are obese, overweight, or normal weight.
A recent study found that a higher intake of polyphenols was associated with significantly reduced weight in more than 100,000 people.
Green tea is high in polyphenols and is the most commonly consumed drink in Asian countries, after water.
Importantly, green tea can help prevent weight gain and even lose weight naturally. This can be done by reducing food intake and fat cell formation, as well as increasing energy expenditure, all of which help prevent weight gain.
A large study that combined the results of 10 other studies found that taking green tea polyphenols for at least 12 weeks led to more than 2.2 pounds (1 kg) of weight loss. More importantly, these people did not regain the lost weight.
Summary: Some polyphenols, especially those found in green tea, can help you lose weight and keep it off.
10. It can help reduce brain degeneration.
As you age, your brain health begins to decline, possibly leading to diseases like Alzheimer’s.
Polyphenols may help prevent brain health from degenerating by reducing oxidative stress and inflammation, two important factors that characterize brain health from degenerating.
Some studies have examined the polyphenol intake of people over the age of 65 and evaluated their brain health 5 and 10 years later.
These studies have found that those with the highest intake of polyphenols had a significantly reduced risk of dementia and cognitive decline.
Grapes contain a number of important polyphenols. One study showed that older people with mild cognitive decline showed significantly better verbal learning after drinking grape juice for 12 weeks.
A study in healthy older people examined the effects of drinking cranberry juice and found similar results.
Another study found that after eating a diet high in polyphenol-rich fruits and vegetables or drinking a polyphenol-rich cocoa drink might increase a chemical called brain-derived neurotrophic factor (BNF) in young and old people.
FNDC is an important chemical involved in learning. This study also found that diets rich in polyphenols improve cognition.
Similar studies have shown that polyphenols can beneficially alter other chemicals involved in brain health in patients with Alzheimer’s disease.
However, other studies have shown that some polyphenols do not improve brain health. Therefore, the evidence remains somewhat uncertain.
Summary: Some evidence suggests that polyphenols may improve brain health in the elderly by reducing inflammation and oxidative stress. However, further studies are needed.
11. They are found in many common and delicious foods.
One great thing about polyphenols is that they are found in many delicious foods.
Since there are many types of polyphenols, it’s important to eat a wide variety of foods that contain them, especially fruits and vegetables.
One study identified the 100 richest dietary sources of polyphenols. Below are some of these foods and their polyphenol content.
- Cocoa powder: 3,448 mg of polyphenols per 100 grams
- Dark chocolate :1,664 mg of polyphenols per 100 grams
- Flaxseed: 1,528 mg of polyphenols per 100 grams
- Dried rosemary: 1,018 mg of polyphenols per 100 grams
- Blueberries :836 mg of polyphenols per 100 grams
- Black olives: 569 mg of polyphenols per 100 grams
- Hazelnuts: 495 mg of polyphenols per 100 grams
- Strawberries :235 mg of polyphenols per 100 grams
- Coffee :214 mg of polyphenols per 100 grams
- Almonds :187 mg of polyphenols per 100 grams
- Red wine: 101 mg of polyphenols per 100 ml
- Green tea: 89 mg of polyphenols per 100 grams
This list is only a sample, and there are many other sources of polyphenols, so it is easy to ingest a wide variety of polyphenols through a regular diet.
Summary: Polyphenols are found in many delicious foods, such as red wine, dark chocolate, and berries, so it’s easy to consume plenty of them through a regular diet.
Polyphenols are plant compounds that are extremely important to your health.
Their main health-promoting property is their antioxidant effect, but they also have a number of beneficial health effects, including reducing inflammation.
Many studies have shown that polyphenols can reduce the risk and improve symptoms of many diseases, including diabetes, heart disease, and bone health.
Fortunately, these healthy compounds are found in many delicious foods, including dark chocolate, coffee, berries, and red wine.
By eating a wide range of these foods in moderation, you can reap many healthy benefits that polyphenols provide.