Flavonoid

A flavonoid is a type of natural chemical called a phytonutrient. They are found in many plants and plant products. They help protect the plants from bugs, germs, mold, and fungi. Humans who consume plants are also provided some of the flavonoids' protections. They support the immune system and help the body resist inflammation. They may also play a significant role in fighting cancer and other diseases, such as heart and nervous system disorders.

Background

The word flavonoid comes from the Latin flavus, which means "yellow." It refers to the fact that many of the plant materials where flavonoids are found are yellow. Flavonoids are found in fruits and vegetables, grains, and the roots, bark, stems, and flowers of many plants. There are more than six thousand types of flavonoids, making them the largest and most diverse group of phytonutrients.

In addition to providing the bright colors of the fruits and vegetables in which they are found, they also help regulate plant growth, absorb harmful radiation from ultraviolet light, protect against pests, inhibit infectious agents, and help plant cells communicate. Flavonoids also affect the tastes and smells of fruits and vegetables and provide the astringency of some teas and wines. They also have a very low toxicity level, which means that people can usually eat a lot of them with little or no ill health effects.

Overview

It has long been known that eating a diet rich in fruits, vegetables, and other natural products supports good health. Interest in flavonoids grew in the 1990s as many researchers began looking into exactly why fruits and vegetables had such healthy effects. They began to uncover evidence that plant-based products not only provided nutrients that the human body needed for survival but also provided many nutrients that, while not essential to life, were very beneficial. Flavonoids were one of these nutrients.

Scientists do not completely understand how and why flavonoids work, but they have determined that flavonoids can play a key role in the management of a number of diseases. In addition to their anti-inflammatory and antioxidant properties, flavonoids also have properties that help control cell mutation (antimutagenic properties) and some that help stem cancer formation and growth (anticarcinogenic properties). They support healthy cell growth and regrowth and reduce or limit harmful enzymes and other substances. They also help combat viruses. As a result, flavonoids show great potential to help in the treatment of heart disease, diabetes, degenerative diseases of the brain and nerves such as Alzheimer's and Parkinson's disease, and certain cancers. They could also help with weight management. Regular intake of flavonoids through a diet rich in fruits, vegetables, tea, wine, and cocoa products (especially dark cocoa or chocolate) has been shown to play a role in longevity as well.

There are twelve major subclasses of flavonoids. Six of these provide value in the human diet. They include anthocyanidins, flavones, flavonones, isoflavones, flavanols, and flavonols. Within the flavonol group, there are also subgroups of flavonoids.

Anthocyanidins such as cyanidin, malvidin, pelargonidin, and peonidin are found mostly in red and purple fruits. These include berries, pomegranates, and grapes. Anthocyanidins are also found in products that are made from these fruits, such as red wine. Anthocyanidins help with heart health, diabetes prevention, and weight management. They are also antioxidants, which means they help counteract the effect of oxidation on cells in the body. Oxidation is part of the natural process of the body using oxygen. However, the process also produces substances known as free radicals, which can cause damage to cells. Antioxidants help prevent this damage.

Flavones are also antioxidants. In addition, they are known to slow down the rate at which the body metabolizes certain medications. Flavones such as apigenin and luteolin are found in herbs, celery, and hot peppers.

Flavonones are found in oranges, grapefruits, and other citrus fruits. They include eriodictyol, hesperetin, and naringenin. Like other flavonoids, they are known to have antioxidant and anti-inflammatory properties and can promote relaxation and heart health.

Isoflavones are phytoestrogens, which means that they are plant-based but act like the hormone estrogen that is made by the body. They are found in soybeans and the products made from them and in some legumes. Researchers are not sure if isoflavones work as antioxidants but do think they might possibly help with some types of cancer as well as with bone loss and some of the other conditions related to menopause, the time after a woman's monthly menstrual cycle stops.

Flavonols such as quercetin and kaempferol have powerful anti-inflammatory properties. Inflammation is the body's response to injuries and/or infections, and it is a factor in many acute and chronic diseases and conditions. Kaempferol also has antioxidant properties, and quercetin is an antihistamine that helps with asthma and allergic reactions, including hay fever, eczema, and sinusitis. Kaempferol, quercetin, and other flavonols are found in tea, berries, apples, beans, onions and leaks, and green vegetables such as broccoli, kale, and brussels sprouts.

There are several varieties of flavanols: polymers, dimers, and monomers, which are often called catechins. Catechins provide known benefits for neurological and cardiovascular health and may help with chronic fatigue syndrome. Dimers show promise in the treatment of cancers. Some flavanols occur in both a monomer and polymer form. These are found in tea and cocoa in all their forms.

All of these potential benefits have made flavonoids a popular addition to many products intended to boost health. These include pharmaceuticals, nutraceuticals (dietary supplements intended to treat or prevent disease), and cosmetics. Although they have many benefits, there are a few potential side effects to consuming flavonoids. They can affect how the body absorbs vitamin C and iron, so people who are taking supplements of either of these are often advised to use care when eating foods containing certain flavonoids. Two chemicals in the body that are important to how the body uses drugs (cytochrome P450 and P-glycoprotein) are also negatively affected by flavonoids.

Bibliography

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