Quercetin is a bioflavonoid found in brightly coloured vegetables and fruit and it has some very interesting health properties. In fact it is currently being used in clinical trials in a supplemental form to test how well it helps the body fight the coronavirus. Quercetin’s antiviral effects are known against influenza strains, other types of coronavirus and DNA viruses such as the virus that causes cold sores. It is an antioxidant (neutralises free radicals that cause cellular and DNA damage), anti-inflammatory, lowers blood pressure, anti-allergic and it aids vitamin C absorption and post-viral healing.
Quercetin is thought by the scientific community to block the binding of the coronavirus to the ACE2 receptor preventing access to the cell, block the break down of proteins needed for viral growth and, it challenges viral replication. Quercetin is found in a number of foods but not all sources are equal. It is better absorbed by the body in the glucoside form found in raspberries, black grapes, red onions, black tea, broccoli and kale. Quercetin from food is more absorbable when eaten with healthy fats such as olive oil, avocado, nuts, oily fish and/or non-digestible/insoluble fibre such as wheat bran, nuts and wholegrain foods.