What is something that dark chocolate, green tea, red wine, blueberries, flaxseed, and coffee all have in common? Polyphenols!
Polyphenols are a natural compound found in countless plants. They are actually responsible for the bright coloring of many fruits and vegetables. Polyphenols also protect the plants against insects, UV radiation, and bacterial and fungal infections. More than that, however, polyphenols have amazing health benefits for humans (1).
There are thousands and thousands of different types of polyphenols found in just as many fruits, nuts, vegetables, herbs, spices, and more. Some polyphenol names you may be more familiar with include flavonoids, catechins, anthocyanidins, stilbenes, reseveratrol, phenolic acid, hydroxycinnamic acids, flavanones, isoflavones, and etc.
Here are 11 of the best reasons to incorporate polyphenol-rich foods into your diet:
1. Found in Healthy, Yummy Foods
First and foremost, you’re not going to eat ‘healthy’ foods unless they are at least a little appetizing. Luckily, most foods high in polyphenols tend to be delicious and easy to find (herbs and spices included, of course) (2).
Some of the most popular polyphenol foods include:
- Dark Chocolate (70%+)
- Red Onions
- Fermented Soybeans
- Red Wine
- Green, Black, White Teas
- Olive Oil
You may recognize some of these foods as “superfoods” or staples of some of the healthier diet plans out there. Both are true. In addition to containing polyphenols, consuming a wide variety of these foods (and reducing or eliminating your intake of processed foods) will benefit your overall health and well-being in countless ways. Best of all, you can enjoy many of the foods on the above list without feeling like you’re depriving yourself.
For example: Enjoy a hot cup of coffee in the morning with a veggie omelet. Have some green or black tea with a heart-healthy lunch and/or with some mixed nuts as an afternoon snack. For dinner, enjoy a colorful salad with spinach, red onion, dried currants, and olive oil/vinegar dressing. Indulge in some dark chocolate covered almonds or blueberries for dessert or a glass of red wine.
Doesn’t sound too bad, right?
2. Gut Health
The importance of intestinal health to your physical and emotional well-being cannot be overstated (3).
As much as 95 percent of your body’s serotonin (your brain’s happiness neurotransmitter) and as much as 80 percent of your immune system is derived directly from your intestines (4,5). Those numbers are huge! So, what do polyphenols have to do with this?
When talking about gut health, we’re referring to the microbiome contained in your intestines. This is all of the good and healthy bacteria that helps break down food, absorb nutrients, and even aid in the production of chemicals and compounds your body needs (like serotonin) (6).
Polyphenols serve as a food source for your good bacteria. With the right food source, the beneficial bacteria can multiply, keeping out bad bacteria that contribute to illness and infections.
Have trouble losing weight? Suffer from stomach issues? Depressed? Try looking inside your body first, and you may be able to heal yourself from the inside out.
3. Rich in Antioxidants
Polyphenols are actually a type of antioxidant – the most common type in the human diet. Antioxidants is the generic term for any chemical compound that fights against free radical damage. Free radicals are byproducts of certain processes in the body.
The issue with free radicals is that they can cause damage to DNA and the instructions within it by stealing electrons from anything near them (7). This is called oxidative stress and can lead to a host of health problems, cancer included.
Antioxidants provide free radicals with a source of electrons to steal from without damaging cells. Studies have found that reducing oxidative stress and free radical damage through a healthy diet may also reduce the risk of heart disease, obesity, diabetes, and certain types of cancer.
4. Cancer Prevention
As mentioned above, polyphenols are important for reducing free radical damage that can lead to cancer. In addition to preventing against oxidative stress, polyphenols have shown promising results against inflammation and cancer cell growth. The mechanisms of these actions are still being studied, but the effects are clear: polyphenols have anti-cancer effects (8).
There is a caveat: polyphenols seem to react differently depending on the type of cancer. Polyphenols seem to have a preventative effect on bladder and lung cancers (9,10).
Consuming a polyphenol-rich diet is also associated with a lower risk of breast, endometrial, ovarian, prostate, and esophageal cancers (11,12,13,14,15).
In other cases – such as with gastric cancers – polyphenols may also increase the survival rates of those recovering from cancer.
Studies also found that not all polyphenols are the same: certain polyphenols were more effective at preventing against certain types of cancers. Some polyphenols have no impact, while others are remarkably effective. For example: the polyphenols in turmeric, green tea, and red grapes show incredible anticancer activity for both prostate and HPV-related cancers (16,17).
5. Reduce Inflammation
Inflammation has an important role in the body: it lets you know when there’s an illness or injury present. Inflammation brings healing white blood cells to the area, often accompanied by swelling with lymphatic fluid. For temporary illness and injury, this is a good thing. However, chronic inflammation can be a sign of a bigger problem – such as an autoimmune disease (18).
Some health problems are even directly related to chronic inflammation, from something as simple as hay fever and tooth/gum problems, to conditions as serious as cancer and heart disease.
Polyphenols have powerful anti-inflammatory properties – some more than others. For example: cocoa polyphenols are particularly effective in reducing inflammation in those at risk for (or that already have) heart disease (19).
Polyphenols from wheat grains (such as in beer or whole grain breads) have shown anti-inflammatory properties in clinical trials for digestive health. For best results (and a better overall diet) consume a variety of polyphenol-rich foods (20).
6. Help Control Blood Pressure
When it comes to the benefits of polyphenols, its effects on high blood pressure is perhaps one of the most well-studied. Clinical research on the subject seems to indicate that some polyphenols help lower blood pressure by relaxing blood vessel walls; others work by improving the condition of endothelium and blood vessel walls (21).
Resveratrol, a polyphenol found in red grapes, seems to be among the most effective for reducing blood pressure (22).
Another meta-study review of 13 different trials found that drinking green tea (which is very rich in polyphenols) daily helped reduce blood pressure significantly. Other polyphenol-rich food options for reducing blood pressure include olive oil, strawberries, and oranges. Consider adding all of these to your regular diet if you have high blood pressure or a family history of heart disease. (23,24,25)
7. May Prevent Neurodegeneration
Our brains and cognition are subject to degeneration just like the rest of the body. Consuming foods with neuroprotective properties can help prevent and slow the progression of degenerative conditions like dementia and Alzheimer’s disease.
As previously discussed, polyphenols have wonderful anti-inflammatory effects and also reduce oxidative stress associated with free radicals – both of which contribute to neurological degeneration (26).
Multiple studies over the last few decades confirm: individuals with polyphenol-rich diets show less cognitive impairment and have a much lower risk of developing Alzheimer’s disease or dementia.
This does not mean that the cognitive benefits are only long-term; on the contrary, one will experience improved learning and memory in a matter of weeks (27,28,29).
The same studies found that those who supplemented with polyphenol rich grapes, blueberries, green tea, or similarly beneficial foods experienced improved mood and decreased blood glucose levels.
As with most plant-based clinical studies, there is some conflicting data. Most of this has to do with the type of polyphenol used in the study. They have, however, led to other discoveries: one such study found that polyphenol-rich diets increased brain-derived neurotrophic factor (BDNF). BDNF is absolutely vital to the areas of the brain that control memory, learning, and high-level thinking (30).
8. Lower Cholesterol
High cholesterol is considered one of the major risk factors for cardiovascular disease. When too much LDL (bad) cholesterol builds up in your blood vessels, it can lead to heart attacks, stroke, loss of circulation, and ultimately death. HDL (good) cholesterol helps by keeping LDL in check, removing the excess and keeping your veins and arteries from clogging up.
High triglyceride levels also contribute to heart disease, though through a different mechanism.
Polyphenols have been shown to significantly reduce both triglyceride levels and LDL levels in obese and overweight individuals (one of the highest risk groups for heart disease) (31). At the same time, polyphenols help boost HDL cholesterol levels.
Cocoa polyphenols seem to be the most effective of those studied. If you’d rather stick to fruits, deep-colored berries will also do the trick (32).
9. Contribute to Healthy Weight
Given all of the above listed benefits, It should come as no surprise that polyphenol-rich foods can also help you lose and maintain a healthy weight.
A recently released massive study of nearly 125,000 people found that individuals with higher intake of polyphenol-rich food had much better body compositions and lower weight than those who didn’t (33).
Noting that this is a correlation and not necessarily a cause – it still makes sense. Polyphenol-rich foods would give you a variety of fruits and vegetables that are also high in fiber and low in glycemic index.
Some polyphenol foods help prevent weight gain, like green tea.
In fact, consuming green tea daily may help reduce overall food intake, increase your metabolism, and help prevent free radical damage and inflammation – all of which contribute to a healthy body composition (34).
In a separate meta-analysis on the weight loss benefits of green tea, researchers found that those who drank green tea consistently for 12 weeks lost an average of 2.2 lbs (without changing anything else) and were able to keep the weight off in the long run (35). That’s a huge win!
10. Help Control Blood Sugar
We’ve touched on this one briefly in a few other sections – polyphenol-rich diets are associated with a markedly lower risk of diabetes.
In an analysis of several studies with over 250,000 participants, the risk of type 2 diabetes was 9% lower in those who ate polyphenol-rich diets compared to those with the lowest intake of polyphenols (36).
Furthermore, not all of these foods were considered truly low-carb: blueberries, pears, apples, and other fruits work remarkably well in these diets due to a combination of the polyphenols (which help prevent inflammation) and the high fiber content in fruit (which slows the digestion of the sugars, preventing a high insulin spike).
It is theorized that polyphenols encourage insulin production and early release of insulin, improving insulin sensitivity (37). For those with insulin resistance, such a mechanism of action is incredibly important as it may help prevent the onset of type 2 diabetes.
Some of the best foods to help naturally lower blood glucose levels are olive oil, green tea, ginger, blackberries and strawberries, cinnamon, oregano, and rosemary. (38,39,40)
If you have diabetes, insulin resistance (pre-diabetes) or type 2 diabetes, incorporate these and other high-fiber, low-GI foods into your diet. Coupled with proper exercise, you may be able to prevent (or reverse) your condition.
11. Healthy Bones
Inflammation and oxidative street impact more than your joints and muscles – they have an effect on bone health as well (41).
Diets rich in polyphenols consist of a variety of fruits and vegetables with countless other beneficial nutrients, some of which are critical for bone growth and remodeling after damage.
Polyphenols are also associated with enhanced bone formation and decreased bone density loss, in addition to their antioxidant and anti-inflammatory properties (42).
Oxidative stress from free radicals can interfere with the healing and remodeling processes, which makes it even more important to consume polyphenols. As an antioxidant they act as an electron donor, preventing free radicals from taking electrons from healthy cells – which in turns disrupts the healing process.
As for inflammation, think of it this way: if your bones are damaged or beginning to lose some of their density, your body needs to fix it. However, if there is a more immediate need in the form of inflammation elsewhere, then your body will prioritize accordingly. If the bone repair/maintenance is put on the back burner enough, then osteopenia and osteoporosis are more likely to occur.
Polyphenols are found in most healthy foods. Chances are, you’re already eating large quantities of them every day. And if you’re not, you’ll