484
cancer risk. Soy intakes yield a reduced risk for prostate cancer and breast cancer in
recent meta-analyses, among Asian population, although the dose-response relationship is not clear (Qin et al. 2006; Yan and Spitznagel 2009; Dong and Qin 2011).
However, the protective effect of soy isoflavones is not significantly found among
non-Asian populations who soybeans and soy-related products intake is not frequent (Yan and Spitznagel 2009; Dong and Qin 2011). After stratification for fermentation, non-fermented soy is only a significant preventive effect for breast
cancer (Dong and Qin 2011). Soy food intake was associated with not only prevention of breast cancer, but also longer survival and low recurrence among breast
cancer patients (Zhu et al. 2011; Kang et al. 2012; Zhang et al. 2012).
The effect of isoflavones for gastric cancer is more complicated and it depends
on food processing. Both Korean and Japanese populations have high incidence
rates of gastric cancer and frequently eaten a wide variable soy food. In recent metaanalyses, among Korean and Japanese population, non-fermented soy foods show a
protective effect for gastric cancer, whereas fermented soy foods present no effect
in reducing risk for gastric cancer (Kim et al. 2011). Fermented soy foods, including
fermented soy sauce and soybean pastes such as Doenjang and miso, which Korean
and Japanese are used to add for making foods with high salt content, and therefore
fermented soy foods can be associated with higher risk of gastric cancer due to
effect and high salt and N-nitroso compounds. There are few human studies using
blood concentrations of isoflavones. In Korean study, isoflavones, including genistein, daidzein and equol have an effect of reducing gastric cancer risk, and the higher
concentration of three isoflavones is much lower to facilitate gastric cancer risk (Ko
et al. 2010). This protective effect against gastric cancer can be explained as an antiinflammatory, anti-tumorogenic, and anti-oxidative effect of isoflavones. Although,
the effect of isoflavones for other cancer prevention has little compelling evidences
up to date, a Japanese recent study using a nested case-control reports an inverse
effect for lung cancer (Shimazu et al. 2011) and possible preventive effects of isoflavones for other cancers are expected to be released in future studies.
22.4.4 Breast Cancer Prevention
Estrogen is known to induce breast cancer progression, and interventions, such as
dietary modifications, that block or reduce estrogen production are likely to result
in favourable prognoses for breast cancer patients. A population-based, prospective
study confirmed that frequent isoflavone consumption was inversely associated with
the risk of breast cancer (Yamamoto et al. 2003). In another study, researchers found
that soy isoflavones did not have estrogenic effects in humans and concluded that
such a diet may be safe for breast cancer survivors (Fritz et al. 2013), chemoprotective and can prevent recurrence in breast cancer patients. Numerous other plants of
the Fabaceae family have been reported to possess anticancer activities. For instance,
one study by Arul et al. (2018) demonstrated that the ethanolic extracts of Pisum
sativum seeds exhibited cytotoxic activity against human breast adenocarcinoma
S. Das et al.
cancer risk. Soy intakes yield a reduced risk for prostate cancer and breast cancer in
recent meta-analyses, among Asian population, although the dose-response relationship is not clear (Qin et al. 2006; Yan and Spitznagel 2009; Dong and Qin 2011).
However, the protective effect of soy isoflavones is not significantly found among
non-Asian populations who soybeans and soy-related products intake is not frequent (Yan and Spitznagel 2009; Dong and Qin 2011). After stratification for fermentation, non-fermented soy is only a significant preventive effect for breast
cancer (Dong and Qin 2011). Soy food intake was associated with not only prevention of breast cancer, but also longer survival and low recurrence among breast
cancer patients (Zhu et al. 2011; Kang et al. 2012; Zhang et al. 2012).
The effect of isoflavones for gastric cancer is more complicated and it depends
on food processing. Both Korean and Japanese populations have high incidence
rates of gastric cancer and frequently eaten a wide variable soy food. In recent metaanalyses, among Korean and Japanese population, non-fermented soy foods show a
protective effect for gastric cancer, whereas fermented soy foods present no effect
in reducing risk for gastric cancer (Kim et al. 2011). Fermented soy foods, including
fermented soy sauce and soybean pastes such as Doenjang and miso, which Korean
and Japanese are used to add for making foods with high salt content, and therefore
fermented soy foods can be associated with higher risk of gastric cancer due to
effect and high salt and N-nitroso compounds. There are few human studies using
blood concentrations of isoflavones. In Korean study, isoflavones, including genistein, daidzein and equol have an effect of reducing gastric cancer risk, and the higher
concentration of three isoflavones is much lower to facilitate gastric cancer risk (Ko
et al. 2010). This protective effect against gastric cancer can be explained as an antiinflammatory, anti-tumorogenic, and anti-oxidative effect of isoflavones. Although,
the effect of isoflavones for other cancer prevention has little compelling evidences
up to date, a Japanese recent study using a nested case-control reports an inverse
effect for lung cancer (Shimazu et al. 2011) and possible preventive effects of isoflavones for other cancers are expected to be released in future studies.
22.4.4 Breast Cancer Prevention
Estrogen is known to induce breast cancer progression, and interventions, such as
dietary modifications, that block or reduce estrogen production are likely to result
in favourable prognoses for breast cancer patients. A population-based, prospective
study confirmed that frequent isoflavone consumption was inversely associated with
the risk of breast cancer (Yamamoto et al. 2003). In another study, researchers found
that soy isoflavones did not have estrogenic effects in humans and concluded that
such a diet may be safe for breast cancer survivors (Fritz et al. 2013), chemoprotective and can prevent recurrence in breast cancer patients. Numerous other plants of
the Fabaceae family have been reported to possess anticancer activities. For instance,
one study by Arul et al. (2018) demonstrated that the ethanolic extracts of Pisum
sativum seeds exhibited cytotoxic activity against human breast adenocarcinoma
S. Das et al.