Health promoting effects of fermented foods against cancer: an updated concise review
1 Introduction
Approximately half of the global burden of cancer cases
occur in Asian countries. It has been projected that ~10.6 million
cancer cases may occur in 2030 (Sankaranarayanan et al., 2014).
The incidence of cancer will increase due to urbanization, lifestyle
changes (unhealthy lifestyle such as use of tobacco, alcohol
consumption, and unhealthy diet), aging (one of the key factors
of cancer), and socioeconomic development. The incidence and
mortality rate of the ten most common cancers (the cancer types
include lung, stomach, liver, colorectum, oesophagus, prostate,
bladder, leukaemia, lip and oral cavity, and non-Hodgkin
lymphoma in men; the cancer types include breast, cervix uteri,
lung, stomach, colorectum, liver, corpus uteri, oesophagus,
ovary, and leukaemia in women) will increase by the year 2030
(Sankaranarayanan et al., 2014).
Diet is one of the influential environmental factors associated
with cancer risk. A proper dietary pattern may reduce the risk
of cancer development (Vera-Ramirez et al., 2012); importantly,
diet plays a critical role in breast cancer risk (Ewertz & Gill, 1990;
Sieri et al., 2008). The American Cancer Society proposed some
nutritional guidelines (categorized as diet, physical activities, and
weight management) for cancer prevention based on scientific
evidence; the recommendations are also updated based on the
recent scientific reports (Bail et al., 2016).
1 Introduction
Approximately half of the global burden of cancer cases
occur in Asian countries. It has been projected that ~10.6 million
cancer cases may occur in 2030 (Sankaranarayanan et al., 2014).
The incidence of cancer will increase due to urbanization, lifestyle
changes (unhealthy lifestyle such as use of tobacco, alcohol
consumption, and unhealthy diet), aging (one of the key factors
of cancer), and socioeconomic development. The incidence and
mortality rate of the ten most common cancers (the cancer types
include lung, stomach, liver, colorectum, oesophagus, prostate,
bladder, leukaemia, lip and oral cavity, and non-Hodgkin
lymphoma in men; the cancer types include breast, cervix uteri,
lung, stomach, colorectum, liver, corpus uteri, oesophagus,
ovary, and leukaemia in women) will increase by the year 2030
(Sankaranarayanan et al., 2014).
Diet is one of the influential environmental factors associated
with cancer risk. A proper dietary pattern may reduce the risk
of cancer development (Vera-Ramirez et al., 2012); importantly,
diet plays a critical role in breast cancer risk (Ewertz & Gill, 1990;
Sieri et al., 2008). The American Cancer Society proposed some
nutritional guidelines (categorized as diet, physical activities, and
weight management) for cancer prevention based on scientific
evidence; the recommendations are also updated based on the
recent scientific reports (Bail et al., 2016).
2 Anti-cancer property of fermented products
The mechanism behind the anti-cancer activity of fermented
foods varies depending on the type of food, phytochemical
composition, type of fermentation, and microbial composition of
the food. Induction of apoptosis, suppression of cell proliferation,
cell cycle arrest and inhibition of inflammatory reaction are the
most possible mechanisms by which fermented foods confer
protective activity against cancer occurrence and development
(Supplementary Material - Figure. S1). The supplementation
of fermented foods protects healthy cells via improvement of
anti-inflammation and antioxidant mechanisms (Figure. S2).
The predominant outcomes of in vitro and in vivo studies on
anti-cancer properties of fermented foods are listed in Table S1.
2.1 In vitro studies
Kim et al. (2003) studied the anti-cancer property of the
solvent extracts of Manda Enzyme® (a fermented product)
in vitro. Bioactivity varied among the extracts (the extracts of
the fermented product were prepared by 55% ethanol extraction
and then the concentrated supernatant was fractionated into
chloroform, ethyl acetate, n-hexane, methanol-insoluble and
methanol-soluble extracts) and cell types. The n-hexane extract
(400 μg/ml) showed high anti-proliferative activity against human
rectal cancer cell line (HRT-18), human hepatoma cell line
(HepG2), and human colon cancer cell line (HCT48). The results
suggested that Manda Enzyme® has bioactive compounds with
anti-cancer activity (Kim et al., 2003).
2.2 In vivo studies
Kefir is a probiotic fermented milk product with several
health benefits. Melo et al. (2018) studied the health beneficial
effect of fermented kefir milk on azoxymethane (AOM)-induced
ACF in BALB-c mice. The supplementation of 5 ml/kg of kefir
for 8 weeks significantly suppressed the formation and size of
AOM-induced ACF in BALB-c mice. The bioactivity of kefir
greatly depends on its microbial composition, especially the
presence of probiotic strains. Ultra-high temperature treated
kefir milk enhanced the growth of L. acidophilus more compared
with pasteurized kefir milk. The study suggested that ultra-high
temperature treated kefir milk enhanced the growth of probiotic
strains, and regular consumption of kefir could prevent the
occurrence of colon cancer (Melo et al., 2018). The fermentation
conditions, especially fermentation period, significantly influenced
the anti-proliferative effect of kefir (Hatmal et al., 2018).
2.3 Results of human studies
Demidov et al. (2008) conducted a randomized, open-label,
pilot, phase II clinical trial and revealed that supplementation of
Avemar™ (fermented wheat germ extract) during dacarbazine-based
adjuvant chemotherapy improved the overall health status and
reduced the mortality rate of high risk stage III skin melanoma
patients. The mortality of the patients was 34.6% in the Avemar™ supplemented group, which was significantly lower compared
with that of the control group (61.5%). The experimental group
showed a reduction in disease progress and improvement in overall
health status. The study recommended that Avemar™ could be
included in adjuvant melanoma therapy (Demidov et al., 2008).
A case-control study was conducted by Sonoda et al. (2004) in
Japan based on the relation between the diet and prostate cancer
and suggested that the consumption of fermented soy product and
fish greatly reduced the risk of development of prostate cancer.
Consumption of vegetables, fruits and milk are not associated
with cancer incidence (Sonoda et al., 2004). Similarly, another
case-control study showed that the consumption of miso soup and
other soya foods reduced the risk of occurrence of hepatocellular
carcinoma in Japanese A-bomb survivors (Sharp et al., 2005).
Recently, Barrubés et al. (2018) reported that high consumption
of dairy products and low-fat milk is associated with a reduced
risk of development of colorectal cancer in older Mediterranean
individuals (Barrubés et al., 2018).
3 Conclusion
Acknowledgements
We wish to thank Faculty of Pharmacy, Chiang Mai
University, Chiang Mai, Thailand for the support. P.K. and B.S.S
acknowledge the Chiang Mai University-Post-doc grant for the
necessary support.
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