What Makes a Polyphenol so Great?
The use of remedies from nature to prevent illness or improve health can be documented as far back as 6,000 years; but it’s safe to say that since human beings have called this planet home, we’ve been utilising plants for their many nutritional, medicinal and health benefits.1
In addition to essential nutrients, vitamins and minerals, plants contain important bioactive compounds which have been developed and are used for the benefit of human health.
A bioactive compound is a compound that has an effect on a living organism, tissue or cell.2 Bioactive compounds are different to essential nutrients in that they can be extremely beneficial but are not essential to the primary functioning of the human body.3
Present in both plant and animal products, bioactive compounds can also be synthetically produced. In the plant world, bioactive compounds are essentially molecular compounds produced by the plant, which have an important role to play in the health and ultimate survival of the plant but are not involved directly in its growth, development or reproduction activity, so not essential to its immediate survival. This type of molecular compound are known as secondary metabolites. These secondary metabolites are often employed in plant activity relating to protection, such as defending the plant against ultraviolet radiation or attack by insects; or providing protection against pathogens.4 Some secondary metabolites are involved in helping the plant to obtain essential nutrients, for example. This often leads to plants that are abundant in bioactive compounds also being a high source of or containing the most essential nutrients and therefore being the most beneficial in terms of human health.5
Of these bioactive plant compounds, polyphenols are one of the most important in terms of medicinal and health benefits. The chemical structure of polyphenols is identified by the existence of more than one phenol unit or building block per molecule. These building blocks are made up of a six-membered aromatic hydrocarbon ring, joined to a hydroxyl group (-OH). The most basic of this group is phenol (C6H5OH) which is employed in various pharmaceutical medication, such as antiseptic. Polyphenols are also known as phenols because they are essentially lots of different clusters of the basic phenol rings.6
Based on difference in molecular structure (namely the number of phenol rings they have and the structural elements that bind these rings to each other) polyphenols can be divided into categories, which include phenolic acids, lignans and flavonoids. Flavonoids can be categorised further into flavonols; flavones; isoflavones; flavanones; anthocyanins; and flavanols (catechins and proanthocyanidins).
The production of these complex molecules in plants is stimulated and sensitive to factors such as light, oxygen and heat, producing notable differences in bioactive concentration. These external factors affect the nutritional or medicinal properties of polyphenols, resulting in a higher flavonol content of one type of fruit, for example, compared to another.7 The antioxidant properties of polyphenols contained in certain types of fruit or plant will vary, for instance, depending on the season it’s harvested, how it’s processed and the specific variety.
Factors such as heat, light and oxygen can all bring about passive oxidation which can change the chemical compounds and alter the molecular nature of the polyphenols present in the plant. For example, when Green tea is subjected to oxidation most of the catechins present are converted into theaflavins and thearubigens, which is essentially how Green tea becomes Black tea. Other examples can be seen in the reduction in the flavonoid content of onions when stored at room temperature and the loss of flavonoids when food is heated, such as when vegetables are boiled.
There are thousands of different beneficial polyphenol compounds, the health effects of which can vary according to the quantities consumed and their individual bioavailability; some polyphenols have better bioavailability than others.
The Power of Polyphenols
Polyphenols have so much beneficial potential because they can act as a powerful antioxidant; able to neutralise free radicals and can also possess anti-inflammatory; anti-aging, anti-carcinogenic; anti-apoptosis; and anti-atherosclerosis capabilities.8 Research has also identified a link between polyphenols and the prevention of diseases brought about by ‘oxidative stress’, for example, cancer and cardiovascular and neurodegenerative diseases. In addition to this, it’s thought that polyphenols can regulate the activity of certain enzymes and cell receptors.Polyphenols can be especially effective in combination with other phytonutrients and antioxidant vitamins and minerals, having a synergistic effect by increasing the overall antioxidant properties.9
Particular health benefits of Polyphenols
Research has shown polyphenols could be particularly beneficial for a range of health issues including:
- Coronary artery disease
- Circulatory disorders
- Inflammatory conditions
- Lung conditions
- Eye conditions related to diabetes.
- Eye conditions related to aging, for example, cataracts and macular degeneration.
Sources of Polyphenols
Over 4,000 plant polyphenols have been identified and can be found in fruits, vegetables, tea, chocolate, spices, herbs, wine, cereals, nuts, grains, algae, olives, seeds, dark berries and extra virgin olive oil, for example. A range of dietary supplements are also a great source of polyphenols, such as Green tea; Acai; Bilberry; Grape seed; Garlic; Vitamin A; Lutein; Astaxanthin; Sage; Spirulina and Chlorella to name just a few!
Flavonoids are a particular and diverse type of Polyphenol best known for their antioxidant and anti-inflammatory health benefits. The antioxidant properties of flavonoids are known to be effective in limiting free radical damage to cells and other components in body tissue. Studies have shown flavonoids also hold particular value in supporting the cardiovascular and nervous systems.10 Research has shown that flavonoids could help to regulate blood flow in the brain, which could result in improved cognitive function.11
Green tea tablets: Green tea is a wonderful natural source of Flavanols, a type of flavonoid. The flavonoids contained in Green tea are known as Catechins, of which EGCG is the one that glitters with particular goodness. It’s an effective antioxidant recognised for its anti-inflammatory, anti-thrombogenic and anti-hypertensive qualities. As a health supplement, Green tea extract can provide many of the essential minerals and vitamins vital to optimum human health. Plant polyphenols often have high levels of astringency which can be felt as that dry mouth sensation and bitter taste. A bonus of the Green tea tablets is you get to ‘pass’ on this experience and cut straight to the chase of getting the goodness.
Anthocyanins are a special and diverse type of flavonoid which helps to keep our hearts healthy. Anthocyanins are adept at stopping the oxidation of cholesterol, helping to prevent high blood pressure and generally beneficial for vascular health. They have amazing antioxidant value, preventing free radical damage, protecting the immune system and reputed to protect against a host of diseases and thought to be particularly beneficial for promoting healthy skin and to the health of the eye by protecting the microvascular systems. Anthocyanins are thought to have anti-inflammatory, anti-viral, and anti-cancer properties and particularly effective for the treatment of colds and urinary tract infections.12 The powerful antioxidant properties of anthocyanins assist the body to burn more fat, increasing metabolism, meaning anthocyanins can work well in supporting weight loss, as part of a healthy balanced lifestyle.
Acai tablets, Bilberry tablets and Grape seed tablets: These three extracts contain a fantastic amount of flavonoids; which fall into the category of anthocyanins. Try pairing acai with Green tea for an extra antioxidative kick; Studies have shown that some plants containing large quantities of phenolics and flavonoids, such as Acai and Bilberry, when combined with Green tea can synergistically enhance antioxidant activity.13
Lignans are thought to play a crucial role in optimal health of the body and are believed to play a part in the reduction of cholesterol and help protect against cardiovascular disease. Lignans are reported to help regulate hormone levels in the body, so could aid menopausal symptoms and can help lessen levels in the body of the stress hormone, Cortisol. Lignans have been cited as containing properties that could benefit ovarian, uterine and prostate and colon health. Lignans are also believed to help promote healthy hair, skin and teeth.14 Algae such as spirulina and chlorella are fantastic sources of lignans.
Spirulina tablets: Spirulina is a type of algae. Algae is believed to have a host of health benefits and particularly noted as a great source of the polyphenols that come under the umbrella of lignans. The polyphenols in spirulina act as a super antioxidant tasked with protecting the body against free radicals and oxidation. By preventing oxidation it will protect the tissues and cells DNA and lipid membranes, thus, maintaining the health of the cell. In addition, it’s thought to assist the vitality of the immune system. Spirulina is also recommended for diabetics as it aids glycaemic control, maintains sugar levels, and promotes decreased energy intake.15
Chlorella powder: Chlorella is a small single celled algae and is considered a “wholefood” which means it provides the majority of nutrients a human would need for a healthy existence. Chlorella is a great benefit to our immune system, by acting as a detoxing agent particularly in the gallbladder, liver, and kidneys, where it promotes metabolism and enhances vitality. Chlorella also has benefit to the health of our digestive system and its contribution is beneficial to gut microflora. It helps to maintain normal colonic function, which too beneficially affects sugar and cholesterol levels. There has also been evidence to show that Chlorella can help to reduce irritation found in the gut wall.16
Nutriceutical Allicin is an organic sulphur based phenolic compound found in species of the Alliaceae family. As a secondary metabolite, allicin is the plant’s defence mechanism against attacks by pests. Allicin has been shown to be very beneficial to human health and exhibits antifungal, antibacterial, anti-hypertensive, antioxidant, anti-platelet, anti-inflammatory and apoptotic functions.17 It’s natural healing properties have been used to treat skin conditions such as athlete’s foot and it’s believed to help lower blood cholesterol and blood glucose levels.
Allicin is incredibly beneficial to health as it’s believed to promote balance of the healthy microbiota in the gut.
Garlic tablets: Garlic is a gigantic source of Nutraceutical Allicin. Garlic is rich with antioxidant properties that lead to a decrease in cell damage and onset of disease. There is also evidence to show the beneficial effects of Garlic on respiratory health, by regulating its function.Garlic has also been linked with the therapeutic regulation of blood glucose concentration, promotion of insulin secretion and maintenance of healthy carbohydrate metabolism.18
Carotenoids are a subgroup included as part of the broad term Vitamin A and a source of Vitamin A only found in plants. There are over 600 different types of Carotenoids, but very few are beneficial to health. Once the Carotenoids have entered the body they are converted to all-trans-retinol where it is active for use in the body. Sources of Carotenoids include dark leafy green vegetables, peppers, sweet potato, broccoli, kale, parsley and carrots. Carotenoids are generally thought to decrease the risk of disease, particularly certain cancers and eye disease.19
Vitamin A tablets: Vitamin A is a fat-soluble vitamin that is predominantly stored in the liver. Vitamin A also contributes to the maintenance of mucous membranes and thus strengthening the immune system. Lastly, Vitamin A is used for the normal metabolism of Iron.20
Lutein tablets: Lutein is a natural carotenoid and one that has a host of health benefits. Oxford Vitality extracts their Lutein from Marigold Flowers. Vitamin A substances such as the Lutein carotenoids have been shown to contribute to gastric membrane mucosa protection and support the efficient function of the digestive system, this helps to eliminate digestive discomfort.21
Astaxanthin tablets: Astaxanthin is molecule rich in carotenoids, a yellow/orange pigment and a derivative of the lipid soluble Vitamin A. The source used by Oxford Vitality is from the microalgae Haematococcus Pluvialis. Haematococcus Pluvialis is the richest natural source of Astaxanthin with 40,000ppm. Astaxanthin is colloquially known as “The King of the Antioxidants”, due to its high level of active antioxidants. It has been shown to be x6000 stronger than Vitamin C activity and x11 stronger than beta-carotene. This is taken to maintain cell integrity. In addition, it prevents feelings of fatigue.22
Sage leaf tablets: Sage is bursting at the seams with antioxidants and coveted for its carotenoid properties. Sage can help protect the body from free-radical damage and the presence of carotenoids is thought to help protect against heart disease and possibly cancer; aid digestion; boost immunity and reduce the risk of bacteria in food. Sage can contribute to normal hormonal balance, particularly in women during the menopause. It eases and subdues symptoms brought about by hormonal imbalance, such as excessive sweating. Sage is also responsible for the health of the digestive system, stimulating normal stomach and intestinal tract function. Finally, sage has antiseptic and anti-oxidising properties which help to contribute to the body’s natural defenses.23
So plant polyphenols are a very diverse group of bioactive compounds which are pretty precious for a profusion of reasons. Polyphenols work hand in hand with the many essential nutrients, vitamins and minerals our bodies require to function properly and have proven to have properties beneficial to the prevention of disease and maintenance of good health.
2 Medical Definition of Bioactive: MedicineNet 14 June 2012. http://www.medicinenet.com/script/main/srchcont.asp?src=compound+medical+definition
7 The American journal of Clinical Nutrition: Polyphenols: food sources and bioavailability. 2004. Retrieved from:http://ajcn.nutrition.org/content/79/5/727.full#aff-1
9 The American journal of Clinical Nutrition: Polyphenols: food sources and bioavailability. 2004. Retrieved from:http://ajcn.nutrition.org/content/79/5/727.full#aff-1