Flavonoids are compounds found in fruits, vegetables and grains that have many effects on the body. It has been hypothesized that
the lower risk of certain types of cancer associated with a diet heavy in vegetables is in part due to the activities of the
flavonoid compounds that are contained in these foods. While flavonoids provide many benefits for bodybuilders.
Particularly with regard to recovery and cellular response, you're probably better off getting your flavonoids from whole foods rather than taking them in supplement form.
These little biological wonders are plant-produced compounds that function as signaling agents to soil microbes and insects. When consumed by mammals, these chemical agents often interact with mammalian enzymes and signaling pathways, usually disrupting or diminishing them, so as to attenuate cellular activation. These activities are believed to account for the anticancer, anti-inflammatory and anti-cell-proliferation effects that have been observed during in vitro experiments using various flavonoid compounds.
As far as bodybuilding goes, getting a good daily dose of flavonoids from natural sources provides several benefits. Their chemical structure makes flavonoids excellent antioxidants. Not only do they scavenge free radicals floating around the cell, they wedge themselves between cell membranes, protecting membranes from oxidative damage. Coupled with their antioxidant effects is their ability to protect DNA. Carcinogens often work by attacking the DNA. Flavonoid compounds hang out around the DNA and combine with carcinogens, neutralizing their chemical toxicity to genetic material. Another anticancer effect is suppression of cell-proliferation response. This is a function of intracellular signaling. Hormones combine with receptors, which then signal cellular response. For the most part, flavonoid compounds inhibit transmission of intracellular signals, which is great if you are a bodybuilder suffering from an inflammatory response to training. It's also effective in calming cells that are out of control or cells that are inclined to excessively reproduce themselves.
Another mechanism by which flavonoid compounds modify certain biological functions and reactions is through what is referred to as competitive inhibition. For example, many flavonoid compounds are antiestrogenic. They combine with estrogen receptors but do not produce a receptor-mediated response related to estrogen - at least not to the same degree that estrogen does. Other flavonoid compounds are considered antiestrogenic because they inhibit the enzyme responsible for converting testosterone to estrogen, an effect that decreases serum estrogen.
Flavonoid compounds affect many enzyme systems, and these pathways can be negatively or positively affected by a flavonoid compound. So how do we separate one response from another? We don't. You have to take the bad with the good. Flavonoids are not pharmaceuticals with specific applications. These are compounds ww found in food that, taken in the context of a healthy diet, may have many healthful benefits. However, when taken as a supplement in high concentrations perhaps hundreds of times greater than what is derived from eating a healthy diet, there are questions regarding the spectrum of effects these chemicals can have on the body.
For instance, some isoflavones may be estrogen antagonists while others are estrogen agonists. Most flavonoids decrease intracellular-signaling pathways, an effect that is believed to be protective against certain types of cancers. However, the muscle-building effects of insulin and IGF-I (growth factor) are dependent on effective intracellular signaling.
Blunting these signaling pathways may cause insulin resistance, inhibit IGF-I receptor response and decrease creatine transport into muscle.
The bottom line is that while flavonoids taken in the context of a healthy diet, as a part of whole foods, may help to keep you healthy as you age, there are no peer-reviewed studies supporting the use of pharmaceutical doses of one or more flavonoid compounds as muscle-building agents. There is always the chance that high doses of flavonoids may actually limit muscle growth through their effect on dampening cellular-signaling pathways.