Health Effects of Soy Isoflavones and Green Tea Catechins on Cancer and Cardiovascular Diseases Based on Urinary Biomarker Levels

Abstract

Plant polyphenols have various health effects. Genistein, which is abundant in soybeans, and epigallocatechin-3-gallate, which is abundant in green tea, are major flavonoids, a subclass group of polyphenols. Several epidemiological studies have shown that these flavonoids have beneficial effects against cancer and cardiovascular diseases. However, other studies did not show such effects. Several confounding factors, including recall bias, are related to these inconsistent findings, and the determination of metabolites in the urine may be useful in reducing the number of confounding factors. Equipment, which can be used by research participants to collect samples from a portion of voided urine within 24 h without the help of medical workers, has been developed for epidemiological investigations. Previous studies, in which flavonoid metabolites in these urine samples were measured, revealed that soy intake was correlated with a reduced risk of certain types of cancer and cardiovascular diseases worldwide. Although soybeans and green tea consumption may have protective effects against cancer and cardiovascular diseases, further clinical studies that consider different confounding factors are required to provide evidence for the actual impact of dietary flavonoids on human diseases, including cancer and cardiovascular diseases. One possible mechanism involved is discussed in relation to the downregulation of reactive oxygen species and the upregulation of 5′-adenosine monophosphate-activated protein kinase elicited by these flavonoids.

Anti-Inflammatory Effects of Dietary Polyphenols through Inhibitory Activity against Metalloproteinases

“…Recent comprehensive review articles have also discussed the role of MMPs in rheumatoid arthritis (RA) and musculoskeletal diseases [10,11]. Our research group has focused on the health effects of dietary polyphenols such as chlorogenic acid (CGA), curcumin (CUR), EGCG, genistein (GEN), quercetin (QUE), and resveratrol (RES) (Figure 1) and published several review articles including recent ones [12,13]. This review provides updated information on effects of these dietary polyphenols on MMPs in relation to their anti-inflammatory effects with mechanistic aspects including evidence from molecular docking studies.…”

“…Recent comprehensive review articles have also discussed the role of MMPs in rheumatoid arthritis (RA) and musculoskeletal diseases [ 10 , 11 ]. Our research group has focused on the health effects of dietary polyphenols such as chlorogenic acid (CGA), curcumin (CUR), EGCG, genistein (GEN), quercetin (QUE), and resveratrol (RES) ( Figure 1 ) and published several review articles including recent ones [ 12 , 13 ].…”

Preliminary Results on the Effects of Soybean Isoflavones on Growth Performance and Ruminal Microbiota in Fattening Goats

“…Numerous studies have demonstrated that phytoestrogens can benefit the growth performance and intestinal health of livestock [7][8][9]. Among the phytoestrogens, isoflavones extracted from bean products (SIFs) are considered natural plant estrogens [10] that can interact with endogenous estrogens in the animal thereby enhancing growth and improving feed conversion efficiency [11]. In the longissimus muscle of Chinese mini-pigs, SIFs enhanced fat deposition and modulated mRNA abundance of myokines and lipogenic genes, underscoring its potent biological activities [12].…”