The Flavonols Explained

The Flavonols Explained


The flavonols are a group of health boosting nutrients that can be found in many fruits, herbs and vegetables.  They are part of the flavonoid group of phytonutrients (a group of chemical compounds which occur naturally in plants and have numerous health benefits but are not considered essential nutrients).

The flavonols and the other flavonoids were discovered in 1938 by the Hungarian biochemist Albert  Szent-Györgyi.  He initially referred to the flavonoids as vitamin P but it was later discovered that they are not essential to human health and therefore not technically vitamins.

Although they are not considered essential nutrients, flavonols should still be eaten on a regular basis as they are all powerful antioxidants which can protect your body’s cells from damaging free radicals (harmful by-products of oxygen based reactions), prevent a variety of health ailments and boost overall health.

In this article I will be discussing some of the most well known flavonols in greater detail:


A ginger root plant.Functions:- Gingerol has been linked with strengthening the immune system and preventing multiple types of cancer (including breast cancer, colon cancer and ovarian cancer).  In addition to this, gingerol may reduce inflammation (which can help relieve the painful symptoms of arthritis), relieve migraines and nausea and treat high blood pressure.

Recommended Daily Allowance (RDA):- There is currently no RDA for gingerol.  However, children aged between 2 and 17 years old are advised to consume no more than 1.3 grams (g) a day whilst adults aged 18 years and older are advised to consume no more than 4g a day.

Food Sources:- Gingerol is part of the plan root ginger.  It can be eaten whole but it is often used as a cooking spice or added to herbal infusions (teas).  Gingero is also an ingredient in certain health supplements.

Overdose Symptoms:- There are no reported overdose symptoms associated with natural gingerol.  However, consuming high levels of gingerol supplements can lead to a number of negative symptoms which include confusion, dizziness, irregular heartbeats and sleepiness.


A selection of turnip greens.Functions:- There is only limited research available on isorhamnetin but the early signs are promising.  This powerful phytonutrient has been linked with preventing arteriosclerosis (hardening and loss of elasticity within the arteries), high blood pressure and multiple types of cancer (including esophageal cancer, liver cancer and lung cancer).  It can also relieve a number of diabetes complications and keep the heart healthy (by protecting the heart from damage and keeping the blood healthy).

RDA:- There is currently no RDA for isorhamnetin.

Food Sources:- Isorhamnetin can be found in many plant based foods.  Some of the best sources include almonds (7.05 milligrams (mg) per 100g), chives (6.75mg per 100g), dill weed (43.5mg per 100g) and turnip greens (between 5mg and 10mg per 100g).

Overdose Symptoms:- There are currently no reported overdose symptoms associated with isorhamnetin consumption.


A glass pot of black tea.Functions:- Kaempferol is an antidepressant and a phytoestrogen (a compound which regulates estrogen levels in the body and can help prevent cancer, heart disease, osteoporosis (reduced bone mineral density) and negative menopausal symptoms).  It can also help increase your metabolism (by promoting the production of the metabolism boosting hormone triiodothyronine (also known as T3), prevent arteriosclerosis (hardening and loss of elasticity within the arteries) and prevent heart disease.  Finally, kaempferol can prevent a variety of cancers (including breast cancer, lung cancer, ovarian cancer, pancreatic cancer and prostate prostate cancer).

RDA:- There is currently no RDA for kaempferol but a number of studies suggest consuming between 10mg and 12mg of this phytonutrient each day is adequate.

Food Sources:- Kaempferol can be sourced from a wide variety of fruits, vegetables and even tea.  Apples (0.02mg per 100g), black tea (1.31mg per 100g), blueberries (1.81mg per 100g), turnip greens (11.87mg per 100g) and spinach (7.64mg per 100g) are all excellent sources of this phytonutrient.

Overdose Symptoms:- Consuming extremely high levels of kaempferol may lead to allergic reactions and interfere with other medications and supplements.


A selection of blueberries on a white background.Functions:- Myricetin can protect your body against numerous types of cancer (including breast cancer, colon cancer, lung cancer, pancreatic cancer and prostate cancer).  It can also protect the important genetic information carrier deoxyribonucleic acid (DNA) from damage, reduce inflammation within the body and treat diarrhea.  In addition to this, myricetin can reduce low density lipoprotein (LDL) cholesterol levels within the body (which indirectly improves blood flow within the body and keeps the heart healthy).  Myricetin may also possibly assist in the treatment of certain mental disorders (such as Alzheimer’s disease and Parkinson’s disease) and relieve the negative symptoms associated with diabetes but further research is needed to validate this.

RDA:- There is currently no RDA for myricetin.

Food Sources:- Myricetin can be found in most fruits, herbs and vegetables.  Some of the richest food sources of this phtyonutrient are blueberries (2.66mg per 100g), blackberries (0.67mg per 100g), cranberries (6.78mg per 100g) and red onions (2.7mg per 100g).

Overdose Symptoms:- Consuming extremely high levels of myricetin may lead to allergic reactions and interfere with other medications and supplements.


A wooden scoop full of buckwheat.Functions:- Rutin can improve blood circulation, enhance the effectiveness of vitamin C, strengthen the capillaries (the smallest blood vessels in the human body) and treat venous edema (a condition which causes swelling in the lower legs).  It can also prevent atherogenesis (the formation of plaques on the artery walls), cancer, heart disease, haemophilia (a condition which causes uncontrollable bleeding) and inflammation.  Finally, rutin keeps the eyes healthy and protects the collagen (the main protein in animal connective tissues) within the body from damage (which helps keep the skin firm and reduces the formation of wrinkles).

RDA:- There is currently no RDA for rutin but sources suggest that consuming between 200mg and 600mg each day is adequate.

Food Sources:- Buckwheat is the richest food source of rutin.  Apple peel, apricots, blackberries, black tea, citrus fruits, green peppers, onions and prunes are also very good sources.

Overdose Symptoms:- Eating too much rutin is extremely rare and is normally caused by excessive supplement consumption.  When a rutin overdose does occur it can cause dizziness, fatigue, headaches, muscle stiffness, rapid heartbeats and stomach upsets.


A clear, glass cup of green tea.Functions:- Quercetin is an antihistamine (a substance that counters the effects of histamine and fights against allergies and inflammation) which prevents heart disease and prevents the production of fat cells.  It also reduces blood pressure in hypertensive patients, reduces levels of LDL cholesterol and can be used as a treatment for diabetes (by reducing blood glucose levels and increasing blood insulin levels).  In addition to this, quercetin may increase endurance and energy levels during exercise and prevent certain types of cancer (including breast cancer, colon cancer, gastric cancer, ovarian cancer and prostate cancer) but more research needs to be done to confirm this.

RDA:- There is currently no RDA for quercetin but most sources suggest consuming between 200mg and 500mg each day is adequate.  Consuming up to 1g of quercetin per day is thought to be safe.

Food Sources:- Quercetin can be found in many different plant based foods.  Apples (4.42mg per 100g), black tea (1.99mg per 100g), cranberries (14.02mg per 100g), dill weed (55.15mg per 100g), green tea (2.69mg per 100g) and yellow wax hot peppers (50.63mg per 100g) are all great sources.

Overdose Symptoms:- Quercetin overdose is extremely rare and only develops when more than 1g of this phytonutrient is consumed each day.  The symptoms of quercetin overdose include diarrhea, headaches, interference with anticoagulants (blood thinners) (which can lead to uncontrollable bleeding) and kidney damage.


The flavonols have countless health benefits.  They can fight cancer, strengthen your immune system, reduce inflammation, keep your heart healthy and more.  Fortunately, you can get your fill by adding natural plant based foods (such as fruits, herbs and vegetables) to your diet.  Try having berries with your breakfast, have a meat and pepper salad for lunch, add some onions to your evening meals and snack on fruits and nuts throughout the day.  Doing this will ensure that your diet is rich in all these health boosting flavonols.


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