Tandul-Nature's way to good health

DR.SHASHANK R.JOSHI, CONSULTANT, ENDOCTRINE &
METABOLIC PHYSICIAN, LILAVATI HOSPITAL, MUMBAI

Basics
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 mobilisation of fat-soluble vitamins such as Vitamin A, Vitamin E and fat-soluble antioxidants. These vitamins are not utilised 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 other conditions.

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 part of the cooking process and as a lubricant during mastication (chewing), Fats and oils modify flavour 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 fat 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 database generated on fatty acid composition in Indian Foods and National Nutrition Monitoring Bureau diet surveys, the daily invisible fat intake is estimated to be 15 gm in rural poor and 25 gm in the urban middle and high-income groups. Thus the daily requirement of visible fat intake works out to be somewhere between 20 to 50 gms depending upon physical activity and physiological status.

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 neutralise 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 food grains, consumption of desi ghee started raising 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 poly-unsaturated fats had the ability to reduce the total cholesterols as such the recommendations tilted in favour of PUFA rich oils such as Sunflower oil & Safflower oil.

In due course of time evidence began to accumulate establishing that although poly-unsaturated fats were effective in reducing LDL cholesterol, very high content of poly-unsaturated fats had the undesirable affect of reducing HDL cholesterol as well. It further came to light that since oils with high levels of poly-unsaturated fats oxidise faster than those with MUFA or SFA profiles, therefore, the excessive intake of these oils 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 resect to the earlier recommendations and a delicate balance between cholesterol balancing (instead of cholesterol lowering) properties and oxidative stability has become an important concern now-a-days.

The American Heart Association now recommends use of oils having an equal proportion of saturated, monosaturated and polyunsaturated fats. The World Health Organisation(WHO) recommends poly-unsaturated fatty acid (PUFA) saturated fatty acids (SFA) ratio of 0.8 to 1.0 and linoleic acid(Omega-6) alpha linolenic acid(Omega-3) ratio of 5-10 in the diet. The most recent recommendations according to the National Reseach Council, Washington DC are 10% saturates, 12 to 13% for monounsaturates, not more than 7 to 8% for poly-unsaturates. Japan’s Ministry of Health & Welfare suggests that fatty acid ratio of saturated/mono-unsaturated/poly-unsaturated as 1:1.5:2 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 unsaturated/mono-unsaturated/poly-unsaturated fatty acid, ratio of essential fatty acids (Omega-6/Omega-3) 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.

Oil	Fatty Acids			Essential Fatty Acids	Antioxidants
	SFA	MUFA	PUFA	Omega-6/Omega-3
Mustard Oil/ Rapeseed Oil	6	67	27	2	Tocopherols
Sunflower Oil	12	21	67	57	Tocopherols
Safflower Oil	10	15	75	69	Tocopherols
Soyabean Oil	16	24	60	10	Tocopherols
Groundnut Oil	20	50	30	32	Tocopherols
Rice Bran Oil	18	45	37	15	Tocopherols, Tocotrienols & Oryzanol
RECOMMENDED	Below 33%	Above 33%	About 33%	5-10	Maximum possible

The use of any one of the oils like Safflower, Sunflower and Soyabean furnish very high PUFA/SFA ratio. The use of Safflower & Sunflower also provide high ratio of Omega-6/Omega-3. 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 Omega-6/Omega-3 ratio contains three categories of natural antioxidants i.e. tocopherols, tocotrienols & oryzanol as against only one category i.e. tocopherols found in 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 shelf life 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 Oil.

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.

Effect of lowering serum cholesterol level by various vegetable edible fats:

This graph indicates the percentage of decrease of serum cholesterol concentration against anti ingestion after taking 60 gms of vegetable edible oil per day for a week.

Abstracted from a Japanese Journal of Nutrition Vol.20 No.4 P.11-13.

Human trials conducted by the National Institute of Nutrition, Hyderabad, have confirmed significant reduction in total cholesterols particularly on the triglyceride levels by using Rice Bran Oil as compared to conventional cooking oils. In this study, 21 subjects with high 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 cholesterol 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.

Subjects	Cholesterol (mg/dl)	Triglycerides (md/dl)
Control Group Basal	244.0 +/- 14.0	298.5 +/- 33.0
After 30 days	249.6 +/-16.1	286.3 +/- 34.9
% change from Basal	2.3	-3.1
Experimental group Basal	247.3 +/- 10.5	349.8 +/- 42.4
15 days after RBO	204.0+/-6.6	236.5+/- 31.9
30 days after RBO	182.7+/-8.4	212.9 +/- 20.0
% Change from Basal after 15 days	-17.5	-32.4

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 upto 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 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 founding any other edible oil. This fat has been reconfirmed 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 reduce bad cholesterols due to “Oryzanol” present in the rice bran oil. Serum lipid levels of rats fed with diet containing 10% groundnut oil & refined ricebran oil containing about 10,000 ppm of oryzanol produced through the latest techniques of refining, were reported as under after 11 weeks of feeding.

Parameters(mg/100 ml)	Groundnut Oil(control)	Refined Rice Bran Oil
HDL Cholesterol (Good Cholesterol)	33.8+6.69	50.57+3.57
LDL +VLDL (Bad Cholesterol)	23.48+8.51	15.75+6.68
Triglycerides	272.8+59.7	118.7+34.55

Besides beneficially influencing the lipid profile, oryzanol is also known to have anti-itching, anti-dandruff & anti-ageing properties. 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 other conventional Indian oil, besides being a cholesterol reducing agent & a powerful antioxidant are also known to have anti-thrombotic, anti-cancer & anti-ageing properties.

Thus rice bran oil is the healthiest cooking oil having desirably fatty acid composition with higher oxidative stability along with 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 world’s healthiest oil” is also the best tasting. A properly refined rice bran oil has a pale yellow colour and is completely odourless & tasteless. In a blind taste test at the University of Oregon USA, 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 “Heart Oil” in Japan. In recent years, US 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 Americans.

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 planning 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.