In nature, more than 6000 flavonoids exist that have several functions as secondary metabolites of plants and fungi, from giving the color of the flowers/fruit to the protection against UV radiation, or pathogens.
Flavonoids, like vitamins, can affect the organisms that consume plants and fungi. Flavonoids of potential importance to humans can be ranked according to 2 criteria of a scientific base.
On the one hand getting into the body and influencing the metabolism, the flavonoids with significant health care or health-enhancing capabilities are more interesting, since they can be used in alternative medicine. On the other hand, those flavonoids got in focus that are in such a large amount in our foods, so after absorption they can appear in the blood in physiologically accountable concentrations.
Unfortunately, this second criterion does not apply to all flavonoids, because some flavonoids are less common or more sensitive to different food processing technologies. In addition, environmental factors such as temperature and duration of sunshine, or the ripeness of vegetables and fruits also affect the flavonoid composition.
In case of the existence of the disease, the further intake of vitamins, and flavonoids considered important in addition to diet should also be considered in order to support the healing process with adequate quality and quantity of flavonoids. This may be particularly important in the case of anorexia, when food intake is already lower.
The best example for the benefit of extra flavonoid-intake is associated with the blood vessel protection effect of flavonoids. Albert Szent-Györgyi, the Hungarian Nobel Laureate, supported the ‘vitamin C treatment’ of scurvy patients with flavonoids. Instead of prescribing a large amount of vegetable and fruit consumption, he gave flavonoid fractions successfully extracted from lemon juice and Hungarian red pepper, along with vitamin C also extract from these plants.
Patients taking both vitamin and flavonoids recovered more quickly from scurvy than those treated with vitamin C alone. The increase in efficiency was due to the fact that the flavonoid fraction, in synergy with the effect of vitamin C, was more effective in reducing capillary fragmentation and leakage.
In the more than 80 years since the discovery of Albert Szent-Györgyi, many other beneficial biological functions have been successfully linked to flavonoids. Flavonoids are general antioxidants, are able to neutralize free radicals, such as reactive oxygen radicals formed under oxidative stress, and may also have anti-inflammatory effects. Thus, they can also contribute to the prevention of the development of cancer and various cardiovascular diseases, such as atherosclerosis, as well as to support their treatment.
In addition, they can be effective in reducing the risk and slowing down the course of neurodegenerative diseases, as evidenced by a number of studies on Alzheimer's disease and other dementias. Flavonoids also function as anti-aging components, so they can contribute to beauty.
In summary, in order to the listed beneficial effects to be achieved a certain level of flavonoids must be present in the blood plasma, which - in many cases – can be achieved only by flavonoid fractions enriched diet, especially in the case of supporting treatments.