Quercetin shows up in a wide range of fruits, vegetables, herbs, and even some beverages. The average person gets roughly 10 to 100 mg per day from food alone, but the amount varies enormously depending on what you eat and how you prepare it. Some of the richest sources may surprise you.
Herbs With the Highest Concentrations
Fresh herbs dominate the top of the quercetin charts. Lovage contains about 170 mg per 100 grams of fresh leaves, making it the single most concentrated food source measured. Fresh dill comes in around 55 mg per 100 grams, and fresh fennel leaves deliver about 47 mg. Dried Mexican oregano contains roughly 42 mg per 100 grams. Even dried dill holds about 36 mg per 100 grams.
Of course, nobody eats 100 grams of fresh dill in a sitting. These numbers matter more as a ratio: even a small handful of fresh herbs tossed into a salad, soup, or sauce adds a meaningful amount of quercetin that you wouldn’t get from the main ingredients alone.
Vegetables That Deliver Quercetin
Red lettuce is one of the better everyday sources at about 40 mg per 100 grams raw. Bok choy (pak choy) is close behind at 39 mg, and raw yellow chili peppers contain around 33 mg per 100 grams. Onions are probably the most commonly cited source, but the type of onion matters a lot.
Yellow and red onions contain meaningful quercetin, ranging from about 5 to 29 mg per 100 grams of fresh weight depending on the variety. Interestingly, research from the American Society for Horticultural Science found that yellow onions generally contain more quercetin than red ones, despite the common assumption that deeper color means more flavonoids. White onions, on the other hand, contain only trace amounts. If you’re choosing onions partly for their quercetin, skip the white varieties.
Capers: A Concentrated Source
Capers deserve their own mention. They contain about 33 mg of quercetin per 100 grams and are often described as the richest natural source of the compound. Research from UC Irvine found that the pickling process may actually increase quercetin content rather than destroy it. Since capers are typically eaten in small quantities as a garnish or ingredient, you won’t get a huge dose from a single serving, but gram for gram they pack more quercetin than most common foods.
Fruits and Berries
Black elderberries are among the top fruit sources at about 42 mg per 100 grams. Apples are a more practical everyday source, but with an important catch: quercetin in apples is found exclusively in the peel. The flesh contains virtually none. Research published in the Journal of Agricultural and Food Chemistry confirmed that flavonols (the group quercetin belongs to) make up 17 to 39% of the polyphenols in apple skin and are absent from the interior. Peeling your apples removes the quercetin entirely.
Other fruits with notable quercetin include berries (particularly cranberries and lingonberries), cherries, and grapes. Red and purple varieties tend to contain more than their lighter-colored counterparts, following the general pattern that deeper pigmentation often signals higher flavonoid content.
Drinks That Contain Quercetin
Tea is one of the most common dietary sources of quercetin worldwide, particularly black and green tea. Red wine also contributes meaningful amounts. For many people in Western countries, tea and onions together account for the majority of their daily quercetin intake simply because these foods are consumed so frequently, even though their per-serving concentrations are lower than herbs or capers.
How Cooking Changes Quercetin Content
The way you prepare food has a significant effect on how much quercetin ends up on your plate. Frying onions preserves their total flavonoid content, keeping quercetin levels essentially unchanged. Boiling is a different story. When onions are boiled for 30 minutes, about 59% of their quercetin transfers into the cooking water. That quercetin isn’t destroyed, just relocated. If you’re making soup or a braise where you consume the liquid, you still get the benefit. If you’re boiling vegetables and draining the water, you’re pouring most of the quercetin down the sink.
Peeling also removes a large share. Red onions retain only about 79% of one key quercetin compound after typical home peeling, because the outer layers concentrate more flavonoids. The same principle applies to apples and other produce where quercetin sits in or near the skin.
Eating Quercetin With Fat Improves Absorption
Getting quercetin into your gut is only part of the equation. Your body needs to actually absorb it, and that process is heavily influenced by what you eat alongside it. Research published in The Journal of Nutrition found that consuming quercetin with a higher-fat meal boosted its bioavailability by about 30% compared to a low-fat, carbohydrate-heavy meal. The mechanism is straightforward: quercetin dissolves in fat, and dietary fat triggers the release of bile salts that form tiny droplets called micelles, which carry the quercetin across the intestinal wall more efficiently.
This has practical implications. A salad with olive oil dressing, onions sautéed in butter, or an apple eaten alongside nuts will all deliver more usable quercetin than the same foods eaten with no fat present. Protein sources like meat may also improve absorption, partly because a lower-carbohydrate context changes how intestinal transporters handle quercetin compounds.
Putting It All Together
If you want to increase your quercetin intake through food, the most effective strategies are combining several moderate sources rather than relying on one. A meal that includes sautéed yellow onions, a handful of fresh herbs, a side salad with red lettuce, and a cup of tea covers multiple high-quercetin foods in a single sitting. Adding some fat to the meal helps your body absorb more of it. Keep the skins on apples and other produce. Use cooking liquids rather than discarding them. And if you’re adding capers to a dish, know that those tiny pickled buds are doing more nutritional work than their size suggests.