SIGNIFICANCE OF RICE BRAN OIL
Shashank R Joshi MD,DM,FICP,FICN Endocrinologist, Lilavati Hospital Hon
Grant Medical College, Mumbai Hon Editor, JAPI
OF COMMON VEGETABLE OILS
Fat is an important ingredient of human diet. The functional role of fat
in the diet is manifold. Fat is a most concentrated source of energy.
One gram of fat gives 9 kcal of energy.
Carbohydrates and proteins provide only 4 kcal of energy per gram. Hence
fat provides calorie density to the diet. Secondly, fats are essential
in the diet for the absorption and mobilization of fat-soluble vitamins
such as vitamin A, vitamin E and fat-soluble antioxidants. These vitamins
are not utilized by the body if fat is not available in the diet.
Thus fat works as a vehicle to carry the fat-soluble vitamins, nutrients
and antioxidants in the body. Thirdly, vegetable oils are the only sources
of essential fatty acids to the body.
Essential fatty acids (EFA) are those fatty acids, which the body cannot
synthesize and need to be supplied through diet. EFA's are the precursors
for a group of chemically related compounds, known as prostaglandins that
are synthesized in the body from EFA. If EFA is not supplied through diet
to the body, the body cannot synthesize prostaglandins. Prostaglandins
play a key role in regulating many physiological processes in the body,
such as controlling blood pressure, vascular damage in the brain and the
heart, preventing blood clot in the arteries, lowering cholesterol, uterine
contractions during child birth and menstrual cycles, inflammation and
Fourthly, fat also helps in raising HDL the so-called good cholesterol.
Low-fat diets can result in reduction of HDL cholesterol. Fifthly, fat
in the diet imparts certain textural qualities, taste and palatability
to the food. Fats and oils are integral lubricants of foods in two ways:
through use as release agents as a part of the cooking process and as
a lubricant during mastication (chewing). Fats and oils modify flavor
release and improve palatability.
Thus fat is an essential nutrient in our balanced diet. Since several
studies in literature have directly implicated the amount and type of
fat intake to specific diseases such as cardiovascular disease, cancer,
high blood pressure and obesity, so one has to be very particular as to
quantity as well as quality of fat in the diet to maintain good health.
The quantity and quality of fats determine the intakes of various fatty
acids in the total diet. Several studies have indicated that the hypocholesterolemic
action of a dietary fat depends on the fatty acid composition and also
to some extent on the micronutrients like tocopherols and tocotrienols
present in them. The optimal balance of saturated, polyunsaturated and
monounsaturated fatty acids make an ideal oil.
Quantity of fat
According to the American Heart Association, the optimum intake of fat
for an adult is 30% of its total caloric intake. Therefore for an adult
man consuming 2000 calories, the upper limit of total fat (visible and
non-visible) is 65 gm/day.
Apart from visible fat some amount of fat is present in food items like
cereals, pulses, milk, eggs, meat etc. as invisible fat. From the data-base
generated on fatty acid composition in Indian foods and National Nutrition
Monitoring Bureau diet surveys, the daily invisible fat intake is estimated
to be 15gm in rural poor and 25gm in the urban middle and high-income
groups. Thus the daily requirement of visible fat intake works out to
be some where between 20 to 50 gms depending upon physical activity and
Quality of fat
Choice of a healthy cooking oil is a controversial subject. The ideas
keep on changing as new evidence accumulates. Desi Ghee (butter Oil) used
to be the conventional cooking oil of the Indians. There was nothing wrong
with this most favourite cooking medium of Indian households. But the
problems started with the change in our eating and living habits. Desi
Ghee being rich in saturated fats has the tendency to increase total cholesterols
including HDL (so called "good cholesterols") and LDL & VLDL (so called
"bad cholesterols"). As such consumption of desi ghee coupled with fibre
rich diet which reduces LDL bad cholesterol & physical activity which
reduces VLDL bad cholesterol brings about a favourable lipid profile.
In the good olden days, our forefathers used to take fibre rich diet such
as chapattis made out of flour of wholegrains & lots of leafy vegetables
along with desi ghee and the nature of work involved lots of physical
labour. All this used to neutralize the adverse effects of desi ghee on
LDL & VLDL while retaining its positive effects on HDL and thereby
this favourite cooking medium used to bring about a favourable lipid profile.
But with the lack of physical activity in the recent years coupled with
intake of diet devoid of fibre such as chappaties and other snack foods
made from flour of decorticated foodgrains, consumption of desi ghee started
raising total cholesterol levels. Therefore, the search started for an
alternative cooking oil which could reduce the cholesterol levels. Short-term
scientific studies conducted in this regard found that vegetable oils
rich in polyunsaturated fats had the ability to reduce total cholesterols
as such the recommendations tilted in favour of PUFA rich oils such as
In due course of time evidence began to accumulate establishing that although
polyunsaturated fats were effective in reducing LDL cholesterol, very
high content of polyunsaturated fats had the undesirable affect of reducing
HDL cholesterol as well. It further came to light that since oils with
high levels of polyunsaturated fats oxidize faster than those with MUFA
or SFA profiles, therefore, the excessive intake of these oil could impair
the ability of the anti-oxidants in the human system to control free radicals
and thereby enhance the risk of certain cancers, cataracts, rheumatoid
arthritis, Parkinson's disease and contribute to the ageing problem. All
these findings have led to a change with respect to the earlier recommendations
and a delicate balance between cholesterol balancing(instead of cholesterol
lowering) properties and oxidative stability has become an important concern
The American Heart Association now recommends use of oils having an equal
proportion of saturated, monounsaturated and polyunsaturated fats. The
World Health Organization (WHO) recommends polyunsaturated fatty acid
(PUFA)/saturated fatty acids (SFA) ratio of 0.8 to 1.0 and linoleic acid
(Omega6) alpha linolenic acid (Omega3) ratio of 5-10 in the diet. The
most recent recommendations according to the National Research Council,
Washington DC are 10% saturates, 12 to 13% for monounsaturates, not more
than 7 to 8% for polyunsaturates. Japan's Ministry of Health & Welfare
suggests fatty acid ratio of saturated/monounsaturated/ polyunsaturated
as 1:1.5:1 and a 4:1 ratio of omega 6 to omega 3 fatty acids. A further
noteworthy point in this recommendation is that the intake of polyunsaturated
fat should be accompanied by vitamin E, vitamin C or carotene consumption
to help prevent lipid peroxidation.
A perusal of these recommendations would reveal that there are basically
three parameters to adjudge any oil as the healthiest cooking oil. i.e.
ratio of saturated/ monounsaturated/ polyunsaturated fatty acid, ratio
of essential fatty acids (Omega6/Omega3) and presence of natural antioxidants.
If we look to the composition of the various vegetable oils commonly used
in India, we shall find that no single oil could meet the requirement
of these recommendations but some are nearer to the recommendations.
The use of any one of the oils like safflower and soyabean furnish very
high PUFA/SFA ratio. The use of safflower & sunflower also provide high
ratio of Omega6/Omega3. Though the levels of Omega3 will be in the desirable
range when mustard and rapeseed oils are used, these oils furnish very high
levels of erucic acid. The use of groundnut or rice bran oils ensure optimal
intake of MUFA and ratio of PUFA/SFA. But rice bran oil a unique cooking
oil produced from rice, is the only oil which besides having balanced fatty
acid composition and an ideal Omega6/Omega3 ratio contains three categories
of natural anti-oxidants i.e. tocopherols, tocotrienols & oryzanol as
against only one category i.e. tocopherols found in all other conventional
oils. These natural anti-oxidants help in controlling production of free
radicals in the body which can cause injury to the inner lining of blood
channels and initiate coronary diseases, certain cancers, cataracts, rheumatoid
arthritis, parkinson's disease and contribute to the ageing process.
High content of natural anti-oxidants present in the rice bran oil, impart
higher oxidative stability and a longer selflife as compared to other edible
oils. In a recent study conducted by the Central Food Technological Research
Institute, Mysore, oxidative stability of natural anti-oxidants enriched
refined rice bran oil has been found to be five times more than the groundnut
Although the PUFA content of rice bran oil is much lower than the other
conventional oils, but it has higher cholesterol reduction power than even
the PUFA rich oils.
Human trials conducted by the National Institute of Nutrition, Hyderabad,
have confirmed significant reduction in total cholesterols particularly
the triglyceride levels by using rice bran oil as compared to conventional
cooking oils. In this study 21 subjects with high total cholesterols (>225
mg/dl) or high triglycerides(>190 mg/dl) were randomly divided into experimental
and control groups. Twelve subjects, who constituted experimental group,
were instructed to use rice bran oil in place of their usual cooking oil
which they were using earlier. The remaining nine who served as controls,
were allowed to continue the use of their habitual edible oil. There was
a significant reduction in total cholestrol and triglyceride levels 15 and
30 days after the use of rice bran oil. However, in control subjects there
were no changes in serum lipids.
SERUM LIPIDS IN CONTROL & EXPERIMENTAL SUBJECTS
Control Group Basal
change from Basal
Experimental group Basal
days after RBO
days after RBO
change from Basal after 15 days
Similar findings have been reported in the animal studies coupled with the
human clinical trials recently completed and published by the University
of Lowell, USA. These studies have confirmed that rice bran oil has the
ability to reduce blood cholesterol levels up to 40 percent and has significantly
better cholesterol lowering than the popular olive oil. Experiments conducted
by the Human Nutrition Res. CTR., WASHINGTON ST., showed a greater reduction
in the total & LDL cholesterol in animals fed with the RBO diet than
those consuming CANOLA Oil diet.
All these studies conducted in India & abroad have attributed the cholesterol
reducing properties of rice bran oil to the presence of a unique component
in this oil known as "Oryzanol" which is not found in any other edible oil.
This fact has been re-confirmed in a most recent study conducted by the
Central Food Technological Research Institute, Mysore. In this study it
was observed that although the fatty acid composition of groundnut oil and
rice bran oil is almost similar but use of rice bran oil significantly raises
good cholesterols and reduces bad cholesterols due to "Oryzanol" present
in the rice bran oil. Serum lipid levels of rats fed with diet containing
10% groundnut oil & refined rice bran oil containing about 10,000 P.P.M.
of oryzanol produced through the latest techniques of refining, were reported
as under after 11 weeks of feeding :-
Rice Bran Oil
Besides beneficially influencing the lipid profile, oryzanol is also known
to have anti-itching, anti-dandruff & anti-ageing properperties. It
is effective in treating a broad range of gastrointestinal disorders including
stress-induced gastric and duodenal ulcers. Oryzanol is also sold abroad
as an agent for body building in humans & for treatment of nerve imbalance
and disorders of menopause.
Tocotrienols which are found only in rice bran oil and in no other conventional
Indian oil, besides being a cholestrol reducing agent & a powerful antioxidant
are also known to have anti-thombotic, anti-cancer & anti-ageing properties.
Compared to other edible oils, rice bran oil has high content of squalene
which is reported to be a quencher of singlet oxygen and a free radical
scavenger and it has been shown to maintain the texture of skin. It is well
known for its anti-wrinkle properties.
Thus rice bran oil is the healthiest cooking oil having desirable fatty
acid composition with higher oxidative stability alongwith better cholesterol
reducing power than all other edible oils. It contains certain unique micro-nutrients
which are important for promotion and maintenance of good health.
"The Worlds' Healthiest oil" is also the best tasting. A properly refined
rice bran oil has a pale yellow colour and is completely odourless &
taste less. In a blind taste test at the university of Oregon U.S.A., comparing
refined rice bran oil, palm oil, safflower oil, soyabean oil, corn oil,
and sunflower oil, rice bran oil won hands down.
Rice Bran Oil is extensively used in Japan, Korea, China, Taiwan and Thailand
as a premium edible oil. It is the conventional & the most favourite
cooking medium of Japanese, the longest living human beings on this earth
and is popularly known as a "Heart Oil" in Japan. In recent years U.S. Scientists
have also shown a tremendous interest in the cholesterol lowering properties
of rice bran oil & this oil has acquired the status of health food with
Only recently some of the Indian markets too have started witnessing some
brands of refined rice bran oil. As India is the second largest producer
of crude rice bran oil in the world, some of the leading national &
multi-national players in this field are having an eye over this largely
untapped potential and are planing to enter in a big way in the branded
refined rice bran oil segment. The time is not very far when the leading
brands of refined rice bran oil will be available in all the markets of
India & consumers in India too could enjoy the benefits of this unique
gift from the mother nature.
It will be the cooking medium of first choice and preferance to Bypass bypass
the dietary way.Our group is doping evidence based work on the oil to prove
its real benefits.Its is equivalent to oilive oil which is the oil of choice
for the Italian Europeans.Therefore for Indians we have Indian made Rice
T.N.B. Kaimal, Why Rice Bran Oil, OTA Journal, vol.30, No.2, dated
Rukmani, Nutritional Significance of Rice Bran Oil, Indian J. Med.
Res. 102, November, 1995,pp 241-44.
R. Campen, Research Shows promise for Rice Bran Oil, www.usarice.com/branoil.html
T.N.B. Kaimal, r-oryzanol from rice Bran oil, OTA Journal vol.31,
No.2, April-June 1999.
SR. Bypass/Bypass: Rice Bran Oil. Proceedings of 33rd Annual Conference
General Practitioners' Association - Greater Bombay.
views of the expert are on good quality Oryzanol Rich Rice Bran oil and
/or its blends and not for any specific brand.