Flavonoids used in nutritional supplements are derived from foods high in flavonoids, which the body converts to bioflavonoids. Like carotenoids, flavonoids are responsible for the brilliant colours of plants.
Food flavonoids enhance vitamin absorption, and if a supplement you select contains flavonoids, it should also be accompanied by whole food sources of vitamin C.
Many whole food-derived supplements do contain both vitamin C and flavonoids. Other supplements contain ascorbic acid, the synthetic form of vitamin C, along with what are listed as bioflavonoids.
I have also reviewed a lot of other dietary supplements, if you are interested, you might check them out.
There are thousands of various types of flavonoids contained in plants, including their subclassifications. Below is a general breakdown of the most commonly known flavonoids and their whole food sources that commonly occur in nutritional supplements.
- Anthocyanidins – Red, blue, purple berries, red and purple grapes, and red wine.
- Flavanols – Catechins found in green and white teas, cocoa, grapes, berries, apples.
- Flavanones – Citrus fruits and their juices such as grapefruits, lemons, oranges.
- Flavonols (include quercetin, rutin, and hesperidin) – Yellow onions, scallions, kale, broccoli, apples, berries, teas.
- Flavones – Parsley, thyme, celery, hot peppers.
- Isoflavones – Soybeans, soy foods, legumes.
The Health benefits of flavonoids are:
- Strengthen capillaries and enhance their suppleness to prevent brittleness that can result in ruptures and breakages such as bruising or blood vessel damage.
- Prevent excessive inflammatory responses throughout the body and improve the behaviour of the many different immune cells produced by the body.
- Effective against bacteria and viruses, including the HIV and HSV-1 herpes simplex viruses.
- Enhance the action of vitamin C.
- Function as antioxidants to help neutralize free radicals that scavenge healthy cells for electrons, leaving cells damaged and vulnerable to mutagenic occurrences.
- Help increase the body’s own glutathione levels, a powerful antioxidant that boosts the abilities of other antioxidants.
Individuals with a low intake of foods or supplements containing flavonoids may experience:
- Being prone to easy bruising
- Frequency of nose bleeds
- Excessive swelling from injuries
- Frequent viral or bacterial infections
Based on the scientific literature, studies indicate that even in amounts as high as 140 grams per day from nutritional supplements, or if are taken at 10% of total daily calorie intake, flavonoids do not appear to be toxic or put health at risk or produce undesirable side effects, including during pregnancy.