WHAT IS QUERCETIN?
Quercetin is one of the many flavonols that can be found in plant based foods and is part of the phytonutrient family (a group of chemical compounds that occur naturally in plants and have multiple health benefits but are not considered essential to human health). Like many of the other flavonols, quercetin is highly protective and may help fight cancer and inflammation whilst also boosting heart health. In this article I will be dicussing quercetin in more detail.
WHEN WAS QUERCETIN DISCOVERED?
Quercetin was discovered in 1938 by the Hungarian biochemist Albert Szent-Györgyi as part of the flavonoid family. 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.
HOW DOES YOUR BODY USE QUERCETIN?
Quercetin is one of the most well known phytonutrients. As discussed above, it acts in a protective capacity throughout the body and supports a number of vital organs. The list below highlights some of the main roles of quercetin in the human body:
– Acting as an antihistamine (a substance that counters the effects of histamine and fights against allergies and inflammation).
– Acting as an antioxidant and protecting the body from damaging free radicals (harmful by-products of oxygen related reactions).
– Preventing heart disease (by reducing blood pressure and low density lipoprotein (LDL) cholesterol levels).
– Preventing the production of fat cells.
– Reducing blood pressure in hypertensive patients.
– Reducing levels of LDL cholesterol (a type of cholesterol that can build up in the artery walls and cause blockages).
– Treating diabetes (by reducing blood glucose levels and increasing blood insulin levels).
In addition to the above, quercetin may also have further health benefits but more research needs to be done to validate these. The list below highlights these possible health benefits of quercetin:
– Possibly increasing endurance and energy levels during exercise.
– Possibly preventing multiple types of cancer (including breast cancer, colon cancer, gastric cancer, ovarian cancer and prostate cancer).
HOW MUCH QUERCETIN DO YOU NEED?
Quercetin is not currently considered an essential nutrient in humans so no official recommended daily allowance (RDA) has been specified. However, most sources suggest that consuming between 200 milligrams (mg) and 500mg of quercetin per day will provide the health benefits listed above. Consuming up to 1 gram (g) per day is thought to be safe.
WHICH FOODS CONTAIN QUERCETIN?
Quercetin can be found in a wide selection of plant based foods. Apples, tea (both black and green), onions and peppers are all excellent sources. The table below highlights a selection of the best quercetin foods:
| FOOD | MILLIGRAMS (MG) OF QUERCETIN PER 100 GRAMS (G) |
| Apples | 4.42 |
| Black Tea (brewed with tap water) | 1.99 |
| Cranberries | 14.02 |
| Dill Weed | 55.15 |
| Green Tea (brewed with tap water) | 2.69 |
| Red Onions | 19.93 |
| Yellow Wax Hot Peppers | 50.63 |
WHAT ARE THE SYMPTOMS OF GETTING TOO MUCH QUERCETIN?
Quercetin is generally safe and overdose symptoms normally only develop when amounts of more than 1g per day are consumed. The symptoms of quercetin overdose include:
– Diarrhea.
– Headaches.
– Interference with anticoagulants (blood thinners) (which can lead to uncontrollable bleeding).
– Kidney damage.
– Stomach problems.
QUERCETIN SUMMARY
Quercetin is one of the most well publicised flavonols due to its links with both improved health and improved performance during exercise. Fortunately, it can be found in many of the natural foods that we eat every day. So if you want to start enjoying all these quercetin benefits, make sure your diet contains some of the quercetin rich foods listed in this article.
Sources:
List Of Phytochemicals In Foods (Wikipedia)
Quercetin (Phytochemicals.info)
Quercetin (University of Maryland Medical Centre)
What Is Phytochemical? (Juicing For Health)
USDA Database for the Flavonoid Content of Selected Foods