querQuercetin food sources

  • Elderberries
  • Apples
  • Peppers
  • Red wine
  • Dark cherries and berries (blueberries, bilberries, blackberries and others)
  • Tomatoes
  • Cruciferous veggies, including broccoli, cabbage and sprouts
  • Leafy green veggies, including spinach, kale
  • Citrus fruits

Title: Quercetin, not caffeine, is a major neuroprotective component in coffee.
Authors: Lee M, McGeer EG, McGeer PL.
Journal: Neurobiol Aging. 2016 Jul 5;46:113-123.
PMID: 27479153

As we said above, for the longest time people have believed that caffeine was the active ingredient in the miraculous ability of coffee to reduce the risk of Parkinson’s disease.

The researchers who published this report were particularly interested in the neuroprotective role for coffee in Parkinson’s disease and they decided to break coffee down into some of its basic components.


  • Caffeine
  • quercetin
  • flavone
  • Chlorogenic acids (CGAs)

They tested each of these coffee components on cells (grown in petri dishes) that had been exposed to a toxin, and then assessed cell survival. Curiously, although caffeine did exhibit neuroprotective effects on the cells, it was beaten by the far superior protective effects of quercetin.

What is quercetin?

Quercetin is a flavonoid (a type of plant pigment) that is found in many fruits, vegetables, leaves and grains. Flavonoids are potent antioxidants. Antioxidants scavenge particles (called free radicals) in the body which can damage cell membranes, affect DNA, and even cause cell death. Antioxidants neutralize these free radicals. (For more on flavonoids – click here).

What does this mean?

The results are very interesting, especially if they provide us with a new potential target for therapeutic drug development. It also raises the age-old idea of antioxidants being potentially useful in the treatment of Parkinson’s disease (the previous history of this therapeutic approach has been disappointing – click here to read more on this).

But before you rush out and load up on quercetin, there are a few things to consider:

Quercetin is generally considered pretty safe. Fruits and vegetables are the primary dietary sources of quercetin, particularly citrus fruits, apples, onions, parsley, sage, tea, and red wine.

That said: excessive use of quercetin can have side effects, which may include headache and upset stomach. Very high doses of quercetin can cause damage to the kidneys (doses greater than 1 g per day), and regular periodic breaks from taking quercetin is advised. Importantly, pregnant women, breastfeeding women, and people with kidney disease should avoid quercetin.