You have likely heard the adage, “An apple a day keeps the doctor away.” Apples are amazing for many nutritional reasons- and in particular have been noted to support heart health with their high antioxidant content. But apples contain an important antioxidant that you may have never “heart” of- quercetin. If you follow our blog, you have recently read about undercover antioxidants, and quercetin is another secret antioxidant agent whose cover you’ll want to blow wide open. Read on to learn more about this amazing antioxidant, where you can find it in your diet, and why we suggest it is a smart supplemental addition to any regimen to cover your health bases.

The Power of Plant Pigments 

Most commonly discussed antioxidants are either plant pigments or vitamins found in plants. You may have heard people say “Eat a Rainbow” to reduce your risk of cancer by improving your antioxidant intake, which is a great recommendation because plant pigments act as antioxidants. Some plant pigments, like chlorophyll, can both trap electrons from light and store them as usable chemical energy (sugar) as well as reduce oxidative damage to the plant. Other plant pigments function exclusively as antioxidants, like the anthocyanins in blueberries. A given plant can have several types of pigments, even if one dominates what you see. You may have noticed that most plants protect their ovaries and eggs (fruits, nuts, seeds, and legumes) from damage with colorful pigments and hard outer shells. This passive protection guards plants from oxidation brought on by heat, light, and oxygen. Pigments also help to tip off pollinators in search of their preferred meal. Plant-produced antioxidants include:

  • Chlorophylls (Green) – These make the bright blue-tinted colors in green leaves and algae. They protect the plant from damage by using light energy to make sugar. Find them in all green plants.
  • Carotenoids (Yellow, Orange, Red) – These are hidden by the green chlorophyll (until fall!) in many plant leaves but also shine on their own in flowers. Like chlorophylls, they both make energy and protect the plant. Find them in carrots, sweet potatoes, and golden cauliflower. Vision-supportive lutein and zeaxanthin are in this category as is heart-friendly lycopene (tomato, watermelon, pink grapefruit).
  • Flavonoids (Red, Blue, and Purple; White and Pale Yellow). Anthocyanins are red, purple, and blue and can be found in purple cabbage and blueberries. White and pale yellow flavonoids include the flavonol compounds quercetin, rutin, and kaempferol. Betalains are another group of flavonoids that come in two flavors – the red-violet (betacyanin) of beets and a yellow pigment (betaxanthin).

Your New Favorite Flavonoid

Quercetin is one of the most powerful antioxidants on the planet. While there has been some research into its effectiveness for specific metabolic challenges and more research is needed, most research into therapeutic uses of quercetin has involved heart disease, cancer, or infection. In addition to being a powerful scavenger of free radicals which can improve overall health, clinical research continues concerning:

  • High Blood Pressure. Preliminary research has shown that high dose quercetin (730 mg per day) may be effective to reduce blood pressure in those with untreated, mild hypertension.[1] More research is needed, however, to evaluate the safety of using high dose quercetin for longer than 12 weeks.[2] In addition, population-level research following a cohort of elderly men from 1985 to 1990 indicated that boosting dietary quercetin from foods such as tea, onions, and apples is associated with a significantly reduced risk of death from heart disease.[3]
  • Cancer Prevention. Epidemiological studies have indicated that diets rich in quercetin are associated with a reduced risk of lung cancer (especially in male smokers),[4] ovarian cancer,[5] and pancreatic cancer.[6]
  • Exercise-Induced Respiratory Infections. Quercetin has been shown to reduce rates of upper respiratory tract infections in a small study of long distance cyclists.[7]
  • Neurological Health. A study published in the journal Experimenal Biology and Medicine found that quercetin was one of two compounds that helped reduce cellular death that is caused by oxidation and inflammation of neurons.[8]

We recommend getting quercetin in your diet and covering your bases with smart supplementation given our oxidation-prone world because antioxidants work in concert, like a beautiful symphony- not as solo performances.

Increase your Intake

Let’s examine how to boost your quercetin intake from delicious dietary changes and safe supplementation as well as adjusting your lifestyle to reduce oxidative stress.

STEP ONE – FOOD: Boost your dietary quantity of quercetin- and its awesome antioxidant partners- to maximize your defense against free radicals.

  • Fill up on Flavonoids. Because light stimulates quercetin production in plants, higher levels of quercetin are found in the leaves and outer skins of plant foods such as red grapes, tea, onions, kale, tomatoes, broccoli, green beans, asparagus, apples, and berries.
    • Berries highest in quercetin (in decreasing order) include elderberries, lingonberries, goji berries, chokeberries, blueberries, and cranberries. Capers, an edible flower, boast high levels as well.
    • Vegetables highest in quercetin (in decreasing order) include lovage, radish leaves, wild arugula, onions, ancho peppers, kale, asparagus, serrano and chili peppers, cowpeas, mizuna, red leaf lettuce, chicory, brussel sprouts, chives, tomatoes, green leaf lettuce, broad beans, butterhead lettuce, collard greens, and broccoli. Carob and cocoa powder are also high in quercetin.
    • Dried herbs such as dill weed, coriander, oregano, tarragon, and bay leaves contain appreciable amounts, as do medicinal herbs such as Gingko biloba, St. John’s Wort, and American Elder.[9]
  • Drink up! Find meaningful doses of quercetin in black tea (2-14 mg in 12 oz), green tea (about 3 mg in a 12 oz serving), or red wine (about 3 mg in a 5 oz serving).

STEP TWO – LIFESTYLE. Mind your medications, reduce your exposure to compounds that cause oxidative stress, and relax.

  • Mind your Medications. Quercetin can extend the half life of certain medications such as warfarin (coumadin), quinolone antibiotics, pravastatin, midazolam, or cyclosporine, so you may want to avoid taking quercetin if you are using these medications. Moreover, because quercetin is a powerful antioxidant that has been shown to lower blood pressure in some people, it can enhance the effect of other therapies to lower blood pressure. If you take pills to do so, we recommend informing your doctor and taking appropriate caution that your blood pressure does not fall too low should you decide to supplement quercetin.
  • Avoid Environmental Toxins. We cannot (oxidative) stress this enough. We live in a toxic world. Overfill your inbox and no matter how many antioxidants you have on board, you will be at a loss dealing with free radical damage. So take control of your environment where you can- clean with less damaging chemicals, choose whole, organic produce and food raised close to nature, avoid artificial fragrances, preservatives, and plastics, and be mindful of the medications, supplements, and “food” you put in your body.
  • Take it Easy. Emotional stress causes physical stress, and physical stress can lead to inflammation that can exhaust your protective mechanisms, including your antioxidants. Strive for work-life balance, boost your ability to deal with sudden stressors by eating well and living well, and don’t forget to step back, take stock, and breathe deeply throughout this extraordinary journey we call life.

STEP THREE – SUPPLEMENTATION. Current research has not ruled out that high dose quercetin can damage your kidneys, so we recommend limiting your supplementation to levels found in food sources.

  • Safe to Supplement. While up to 500 mg per day of supplemental quercetin is safe to use according to ongoing clinical research, we add 50 mg to our Nutrience formulation to ensure you get enough quercetin to compliment your healthy, antioxidant-rich diet without excessive intake. In fact, it is actually the quercetin that gives nutreince that gorgeous orange color!
  • Like all antioxidants, quercetin works best with its antioxidant allies. In food, one finds quercetin alongside vitamin C, grape seeds, and other antioxidants. So, we combine it with vitammin C and grapeseed extract and a host of other powerful antioxidants in our Nutreince multivitamin too, so you can expect peak performance from your antioxidant add-ins.

Our toxic world abounds with free radical damage, and having more antioxidants to heal you than oxidants that harm you is critical to dodging the bullet of metabolic disease. We live in a chemical soup among very sick people- but you can be your best self and an example to others with some meaningful changes. Clean up your environment, boost your free-radical-fighting-flavonoids, and cover your bases with smart supplementation- your future self will thank you!