Mediterranean Diet as a Shield against Male Infertility and Cancer Risk Induced by Environmental Pollutants: A Focus on Flavonoids

Abstract

The role of environmental factors in influencing health status is well documented. Heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, dioxins, pesticides, ultrafine particles, produced by human activities put a strain on the body's entire defense system. Therefore, together with public health measures, evidence-based individual resilience measures are necessary to mitigate cancer risk under environmental stress and to prevent reproductive dysfunction and non-communicable diseases; this is especially relevant for workers occupationally exposed to pollutants and/or populations residing in highly polluted areas. The Mediterranean diet is characterized by a high intake of fruits and vegetables rich in flavonoids, that can promote the elimination of pollutants in tissues and fluids and/or mitigate their effects through different mechanisms. In this review, we collected evidence from pre-clinical and clinical studies showing that the impairment of male fertility and gonadal development, as well as cancers of reproductive system, due to the exposure of organic and inorganic pollutants, may be counteracted by flavonoids.

Keywords: Mediterranean diet; bisphenols; cancer; dioxins; flavonoids; heavy metals; male infertility; phthalates; pollution; polycyclic aromatic hydrocarbons.

Figure 1

Decrease rates of sperm concentration worldwide. Sperm concentration declines in several areas of the world from 1980 to 2015 (A), and from 1940 to 1990 (B).

Figure 2

Basic structures of the six classes of flavonoids. The lead compound benzopyrone can be variously substituted to form the derivative structures of flavonols, flavones, flavanones, flavanonols, anthocyanins and isoflavones. The hydroxyl groups can be linked to monosaccharides, in case of glycosides, or methoxylated. The radicals, expressed as R, can be either methyl or methoxy groups, depending on the structure.

Figure 3

Effects of flavonoids against environmental pollutant-induced carcinogenesis and male infertility. Physiological processes of normal cells can be altered by pollutants leading to cancer and sperm cell damage. Flavonoids can protect cellular functions from environmental insults via targeting a wide plethora of mechanisms.