Polyphenols in food; what are they good for?

What are antioxidants and why we need them?

Polyphenols are phytochemicals, compounds that are abundantly found in medicinal plants. They are known for phenomenal antioxidant properties and have a very important role in maintaining overall health.

There are 8,600 known polyphenols and can be found in foods such as tea, wine, chocolate, fruit, vegetables and olive oil (extra virgin). These antioxidants protect the cells of our body from damage caused by free radicals, thus preventing heart disease, cancer, Alzheimer's disease, slow down aging. Read on to learn for what we need plant polyphenols.

How are these valuable antioxidants divided in groups?

All polyphenols have a similar ring chemical structure and are divided into the following subgroups:

Flavonoids - antioxidants that are found in fruits, vegetables, legumes, red wine and green tea;

Flavones - can be found in celery, parsley, carrots, rosemary and basil;

Flavonols – found in berries, apples, black and green tea;

Isoflavones - the best source is soy;

Anthocyanins - are found in black grapes, eggplant, oranges raspberries, and cherries;

Chalcones – found in medicinal plants, such as liquorice;

Catechins – found in tea, coffee and cocoa;

Stilbenes - can be found in red wine and peanuts, and most polyphenol resveratrol;

Lignans – found in flax seeds, legumes, grains, fruits, algae and certain vegetables;

Phenolic acid;

Hydroxybenzoic acid - found in tea;

Hydroxycinnamic acid – found in cinnamon, coffee, blueberries, kiwi, plums, apples and cherries.

Why are these antioxidants important?

The polyphenols in foods such as berries, fruits and vegetables provide vibrant colour and acidity, aroma, flavour and oxidative stability. They protect the plants from ultraviolet radiation, pathogens, oxidative damage and harsh climatic conditions.

In the human body, polyphenols have different biological roles:
  1. They fight against cancer cells and inhibit angiogenesis (the growth of blood vessels that feed the tumour);
  2. Protect the skin from ultraviolet rays;
  3. They fight free radicals and reduce the signs of aging;
  4. Protect the brain from dementia;
  5. Decrease inflammation;
  6. Maintain normal blood sugar levels;
  7. Protect the cardiovascular system and regulate blood pressure.
What are the foods rich in polyphenols?

To fully take advantage of all the benefits of these healthy compounds, it is important to eat a variety of foods rich in polyphenols and more.

High-quality spices, raw vegetables and seeds are among the best sources. However, there is a problem of bioavailability, or how well your body can absorb the nutrients contained in the food.

The interesting thing about the polyphenols is that they break down the fat. This means that they should be consumed with fat or they will not be easily absorbed.

The way of cultivating plants may also affect the potential health benefits. As noted in a scientific work from 2004, industrial processes reduce the health effects of polyphenols in foods, e.g. Organic food contains a higher percentage of these compounds as compared with that grown in the usual way.
Also, freezing immediately after plucking retains a high percentage of antioxidants.

Among the top twenty foods that contain the highest percentage of polyphenols are: garlic, mint, anise, raw cocoa beans, Mexican oregano, celery seeds, dark chocolate, flax seed, elderberry, chestnut, sage, rosemary, thyme, red grapes, blueberries, capers, black olives, nuts and pecan.

What are the health benefits of polyphenols?

An extensive research which included more than 8,000 different subspecies of polyphenols confirmed their importance to human health:

They prevent type 2 diabetes

Tests on animals and some studies which involved people have shown that polyphenols in foods stabilize blood sugar levels and fat metabolism, reduce insulin resistance and inflammation in the body. This can prevent future complications of diabetes such as cardiovascular disease, neuropathy and retinopathy.

Prevent the occurrence of cancer

Several different studies have demonstrated that valuable polyphenols protect against cancer. The researchers believe that their antioxidant effects protect DNA from damage caused by free radicals, which can be a trigger for the development of cancer. They can also reverse epigenetic markers in DNA and how it is thought to slow down tumour growth.

Prevent many cardiovascular diseases

Scientific studies have shown that the polyphenols in wine are an excellent prevention of cardiovascular diseases and even help in their treatment. Flavonoids reduce the number of platelets circulating in the blood and contribute to the better functioning of the cells that form a protective surface on veins and arteries. Also they prevent thrombocytes from sticking together, and hence prevent thrombosis, inhibit inflammatory processes in the body and prevent the deposition of plaque on artery walls.

Reduce the risk of Alzheimer's

The researchers found that polyphenols have a huge role in delaying dementia and reduce the risk of Alzheimer's. For example, a polyphenol resveratrol, which is located in the skin of red grapes and red wine, has a neuroprotective effect. Other studies have shown that their daily intake slows down the development of dementia, alleviating changes in the neurological system that cause this disease.

Strengthen brittle bones and prevent osteoporosis

Because of its antioxidant effect, polyphenols in foods have a positive effect on bone health and significantly reduce the risk of osteoporosis.

Be sure to consume organically grown berries

With spices, berries are one of the best sources of polyphenols and contain low levels of fructose, and will not significantly affect the level of insulin and contribute to insulin resistance.

One of the best benefits of this fruit is that it is, due to its high content of anthocyanins, extremely beneficial for the heart. Anthocyanins nourish and protect the endothelium, and thereby improve blood flow and blood pressure, reduce oxidative stress and inflammation, strengthen capillaries, prevent platelet production and accumulation of plaque in the arteries.

A study published in the popular scientific journal with the participation of high-risk postmenopausal women found that one serving of blueberries a day for eight weeks lowers blood pressure and relaxes the arteries, and this is thanks to the increased production of nitric oxide. The conclusion is that the polyphenols in foods, particularly from berries have many beneficial effects and improve health.

The women who ate weekly more than three servings of blueberries and strawberries reduced the chance of having a heart attack by as much as 32 percent. One serving of wild fruit a day lowers blood pressure and increases the level of good cholesterol. Blueberries still protect against type 2 diabetes by stabilizing blood sugar levels and increase insulin sensitivity.

Plant polyphenols from green tea improve digestion

Without a healthy intestinal flora, our body would not be able to function. Microorganisms in the intestine are contained ten times more than in the cells of the body. They play an important role in the protection and prevention of cancer, obesity, diabetes, neurological disorders, allergies and mood swings.

Recent research has shown that plant polyphenols also regulates the intestinal flora because they have a probiotic effect, e.g. they feed good bacteria that are found in the intestines. This was confirmed by testing conducted on green tea which is rich in these compounds.

Also, it was shown that the intestinal flora can be improved by the moderate consumption of red wine and dark chocolate, which are also rich in polyphenols.

Be careful with the consumption of supplements

Various extracts of grape seeds, grape skins and pulp of olives are used in the production of supplements, which are representative of polyphenols. However, although these supplements are made from natural ingredients, it does not mean it is safe to take them in large quantities.

Research has shown that too much polyphenol supplements may interfere with the effect of drugs, cause disorder in the thyroid gland and a lack of iron in people who otherwise do not have it in sufficient quantities.

A well-balanced diet rich in polyphenols reduces the ability to consume more micronutrients than you need for your body.

We hope that you found out how useful polyphenols are in the diet, and you will be sure to include them more in your daily menu.