Flavonoids and hypertension

Plant compounds (polyphenols and flavonoids) have been reported to exert beneficial effects in the treatment of cardiovascular disease, including hypertension.

Flavonoids can be found in fruits, vegetables, nuts, seeds, in coffee, wine, or tea, with significant antioxidant effects. Flavonols, flavanols, and anthocyanidins are the main members of the group of natural phenolic compounds called flavonoids.

It is well known that nitric oxide (NO) from the endothelium plays a crucial role in regulating vascular tone and blood pressure. Nitric oxide causes vascular smooth muscle relaxation by activating soluble guanylate cyclase29 and by increasing cyclic guanosine 30 ,50-monophosphate (cGMP), which inactivates the release of intracellular calcium.

Flavones, a subgroup of luteolin-rich flavonoids, exert their antihypertensive effect by signaling and activating the cAMP/protein kinase A cascade, which will further activate NO synthase, the final result being the increased concentration of endothelial NO. Through this mechanism, vasodilation takes place, a process modulated by potassium and calcium channels.

A number of studies have shown that consumption of fruit, vegetables, wine and tea may protect against stroke, for which hypertension is the major risk factor.

Flavonoid’s antioxidant activity is well established, and epidemiologic studies have suggested associations between flavonoid intake and a lower risk of cardiovascular disease.
Flavonoids and hypertension

Fruits and vegetables reduce the risk of hypertension

The medical term for high blood pressure is hypertension. Hypertension is a major cause of morbidity and mortality, with many studies indicating it has been strongly associated with the risk of cardiovascular disease, stroke, and kidney failure.

For several decades, researchers have mainly focused on the potentially adverse or preventive effects of various dietary factors. The DASH (Dietary Approaches to

Stop Hypertension) eating plan includes whole grains, poultry, fish, and nuts, and has low amounts of fats, red meats, sweets, and sugared beverages. It is also high in potassium, calcium, and magnesium, as well as protein and fiber.

Among these, fruit and vegetable intake have a special powerful association with lower blood pressure (BP).

Regular frequent intake of fruits and vegetables was found to reduce the risk of hypertension, cardiovascular disease and stroke. Those foods are high in fiber, and eating more of them may temporarily cause bloating and diarrhea.

Flavonoids are polyphenolic anti-oxidants which occur in a variety of foods of vegetable origin, such as tea, onions and apples. Prospective studies indicate an inverse association of dietary flavonoids with CHD. Studies also shows that quercetin one of the abundant flavonoids in food and vegetables reduced blood pressure in several experimental models.

Fruits and vegetables also contain other phytochemicals that may have protective properties, including isothiocyanates and indoles (found in cruciferous vegetables), sulphides (found in onions and garlic), terpenes (found in citrus oils) and phytoestrogens.

Furthermore, the dietary intake of polyphenols has been linked to higher adherence to a healthy dietary pattern, namely the Mediterranean diet, that has been adopted worldwide.
Fruits and vegetables reduce the risk of hypertension