Health Benefits of Soybean
Isoflavonoids and Related Phenolic
• Soybeans are a well-known dietary staple of
Asian countries such as Japan and are now
consumed worldwide.
• Soybeans cannot be eaten raw, because they
contain trypsin inhibitors, which can disrupt
digestion activities in the stomach, leading to
cramping and associated discomfort.
• Soybeans are usually fermented to produce
distinct cultural or ethnic foods or food
ingredients.
• East Asian populations that regularly consume soybeans
as a part of their dietary intake seem to have lower
incidences of cancers and oxidation linked diseases of old
age than are prevalent in Western populations.
• The Japanese are estimated to consume 25–100 mg of
isoflavonoids per day. Chinese women are estimated to
consume 39 mg of isoflavonoids per day.
• The consumption of isoflavonoids in Western diets is
much lower, at less than 1 mg/day in the U.S. and U.K.
• Numerous epidemiological studies have
demonstrated an association between the
consumption of soybeans and improved health,
particularly as a reduced risk for cancers or
diseases, such as breast cancer, cardiovascular
disease, and atherosclerosis.
• Consumption of soy foods has also been
associated with a reduced risk of prostate cancer.
• Although soybean protein was first suspected to
potentiate the health-promoting benefits of
soybean consumption, these properties have
more recently been linked to the biological
activities of a specific group of phenolic
compounds, found mainly in soybeans, known as
isoflavonoids.
• While the chemopreventive properties of purified
and synthetic isoflavonoids have been heavily
investigated, a fermented soybean extract was
recently shown to perform better at reducing the
incidence of mammary tumor risk than a similar
mixture of its constituent isoflavonoids,
suggesting that the food background may play a
positive role in the chemopreventive actions
associated with soybean consumption, in
addition to that of isoflavonoids.
Soybean Isoflavonoids
• Isoflavonoids are found mainly in soybeans, and possess a
chemical structure that is similar to the hormone estrogen.
• The chief isoflavonoids found in soybeans are genistein
and daidzein.
• Because their structures resemble estrogen and they can
interact with the estrogen receptor, soybean isoflavonoids
are sometimes referred to as phytoestrogens.
• Phenolic compounds normally occur as glucoside
bound moieties called glycones. However, it is
the aglycone (glucoside free) form that is
metabolically active.
• After consumption, microbial enzymes in the
intestine cleave the glycoside moieties from
glycone isoflavonoids and release the biologically
active health-promoting aglycone isoflavonoids.
• Aglycone phenolic compounds possess higher antioxidant
activity and are absorbed faster in the intestines than
glucoside bound forms. Interestingly, fermented soy foods
are rich in phenolic aglycones due to microbial
bioprocessing during fermentation.
• However, once inside the bloodstream, biologically active
aglycone genistein travels to the liver were it is converted
back into an inactive glycone (b-glucuronide). Cellular
glucuronidases must remove the glycone moiety before
genistein can exert its biological activity.
• Isoflavonoids have been well studied and possess
numerous biological activities. For example,
genistein possesses inhibitory activity against
topoisomerase II, tyrosine kinase, NF-κB, cancer
cell proliferation, and nonoxidative pentose–
phosphate pathway ribose synthesis in cancer
cells.
• Many of the health-promoting benefits of
isoflavonoids have been linked to the ability of
phenolics to serve as antioxidants.
Health benefits of soybean isoflavonoids
• Soybean isoflavonoids may be useful for the treatment of
somatic, mood, and cognitive disturbances associated
with the onset of menopause.
• Soybean isoflavonoids may also have potential in natural
chemoprevention therapies against long term health
problems associated with menopause, particularly for
osteoporosis.
• Estrogen positively affects the metabolism of calcium, lack
of sufficient estrogen can lead to bone loss and
osteoporosis.
• Soybean isoflavonoids also possess various biological
activities that may help to explain the cancer
chemopreventive properties associated with the
consumption of soybean foods.
• In in vitro studies, daidzein was reported to stimulate the
apoptosis, Genistein can stimulate antioxidant enzyme
activities.
• Soybean consumption has also been linked to a reduced
risk for cardiovascular disease.
• Addition of soybean into diets has been shown to result
in reduced cholesterol isoflavonoid rich soybean in diets
was also reported to protect against coronary heart
disease by causing reductions in blood lipids, oxidized
LDL, homocysteine, and blood pressure.
Probiotics
• Probiotics are feed and food supplements that beneficially
affect the host’s health.
• Strain identity is important in order to link a strain to a
specific health effect and to enable accurate surveillance
and epidemiological studies.
• The term “probiotic” includes a large range of
microorganisms, mainly bacteria but also yeasts.
• Because they can stay alive until the intestine and provide
beneficial effects on the host health, lactic acid bacteria
(LAB), non-lactic acid bacteria and yeasts can be
considered as probiotics.
• LAB are the most important probiotic known to have
beneficial effects on the human Gastro-Intestinal (GI)
tract. These bacteria are Gram-positive and usually live in
a non-aerobic environment but they also can support
aerobic conditions.
• Bifidobacteria are also Gram-positive and can grow at a
pH range of 4.5 – 8.5 but the most important
characteristic is the fact that they are strictly anaerobic.
• Each species covers various strains with varied benefits
for health. The probiotic health benefits may be due to
the production of acid and/or bacteriocins, competition
with pathogens and an enhancement of theimmune
system.
• Dose levels of probiotics depend on the considered strain,
but 106 – 107 CFU/g of product per day is generally
accepted.
• Probiotics have been reported to play a
therapeutic role by modulating immunity,
lowering cholesterol, improving lactose tolerance
and preventing some cancers.
– Probiotics may influence the immune system by means
of products such as metabolites, cell wall components
or DNA.
– The second mechanism of action can be described by a
direct effect on other microorganisms which can be
commensal and/or pathogenic.
– Probiotics have the ability to affect some microbial
products such as toxins and host products like bile salts
and food ingredients.
Synbiotics
a combination of the probiotics and prebiotics positives effects
• Prebiotics can be defined as ‘non-digestible food ingredients that,
when consumed in sufficient amounts, selectively stimulate the
growth and/or activity of one or a limited number of microbes in the
colon resulting in documented health benefits.
• When considering probiotics, viability and dose level are important
parameters for their efficacy and prebiotics have the potential to
improve probiotic’s viability and vitality, its survival in the GI tract
and its further attachment and growth in the intestine.
• Inulin and fructo-oligosaccharides are the most common prebiotics
used, because of their resistance against gastric acid and pancreatic
enzymes.
• The synbiotic concept can be defined as ‘a
mixture of probiotics and prebiotics that
beneficially affects the host by improving the
survival and implantation of live microbial
dietary supplements in the GI tract, by selectively
stimulating the growth and/or activating the
metabolism of one or a limited number of health
promoting bacteria, and thus improving host
welfare’.
Rice bran oil
• Interest in rice bran oil has been growing from the
nutritional point of view.
• Rice Bran Oil contains three different kinds of natural
antioxidants -- namely Tocopherol, Tocotrienol, and
Oryzanol --.
• The unique components, such as oryzanol or tocotrienol,
have been drawing people's attention.
• Numerous studies show rice bran oil reduces the harmful
cholesterol (LDL) without reducing good cholesterol
(HDL).
• In those studies, Oryzanol is reported as the key element
responsible for that function.
• Tocotrienol, on the other hand, is highlighted as
the most precious and powerful vitamin E
existing in nature and is said to have an anticancer effect, too. As a Vitamin-E source, rice
bran oil is rich not only in alpha Tocopherol but
also has the highest amount of Tocotrienol in
liquid form vegetable oils.
Oryzanol
• Oryzanol is one of the several minor components
found in the unsaponifiable fraction of rice bran
oil. It is a mixture of two or more ferulic acid
ester of triterpene alcohols, cycloartenyl ferulate,
-methylene cycloartanyl ferulate, b-sitosteryl
ferulate and campesteryl ferulate. The ferulic acid
is 4-hydroxy-3-methoxy cinnamic acid.
• Most of the biological activities of oryzanol are
because of its excellent antioxidant property.
Studies indicate that this phenolic antioxidant
scavenges free radicals and prevent their
formation inside our body metabolic process.
The benefits resulting from this antioxidant
activity are prevention against cancer, protection
against heart disease by maintaining optimum
cholesterol level and other factors like combating
respiratory problems, diabetic health etc.
• This particular unsaponifiable material is
considered to be an important factor in
hypocholesterolemic and hypolipidemic action of
rice bran oil.
• Studies indicated that oryzanol fed to humans
and animals reduced LDL cholesterol and
increased HDL cholesterol.
• It has been reported that hypertriglyceridaemia
induced by fructose was significantly lower in
animals which had been maintained on a diet
containing 0.5% of this compound.