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Mainstream, VOL L, No 40, September 22, 2012

Damaging Health Consequences of
 Our Unbalanced Dietary Vegetable Oils

Friday 28 September 2012, by D P Sen


About a month or two back I came to know that my niece, a patient of knee pain, got relief by taking capsule of flax-seed oil (that is, linseed oil) which is highly rich in alpha linolenic acid, ALA. One of her relatives, on the basis of her own experience, had prescribed the same to her. Her regular physician also approved the same without any hesitation. Flax-seed oil capsules are not available at present in India; these are available in the USA. It may be presumed that at a certain stage of her adult or later life she had taken for months together dietary oils overloaded with linoleic acid (LA) only and without any ALA. What my niece had experienced is completely in accordance with our present-day knowledge on metabolic and regulatory roles of dietary oils containing LA with or without ALA unravelled during the last fifty years or so.

It is a pity that the regulatory roles of dietary LA and ALA in several body functions are not well publicised. My niece got the information on the good effect of ALA through personal contact and not based on any massive campaign. LA and ALA imbalance in diet, in addition to knee pain, causes many other disorders and chronic diseases. The ultimate cause of these may be traced to our LA-overloaded vegetable oils and mismatch between our diet and genome (gene). Apart from fats and oils other regulatory processes are involved in many of these disorders. The human body-system is highly complex.

Human Genome and Diet

IN the ultimate analysis, it is the genome of a man (homo sapien) which decides its dietary requirements. The human body expects to be nourished by dietary molecules within a range as determined genetically. Human beings living today are the hunter-gatherers of the stone age displaced through time to a world of civilisation that differs beyond recognition from the one for which our genetic constituents were selected. Our culture, which includes our diet and food, has changed but our genome (gene) has hardly changed. The resulting mismatch has fostered our chronic diet-related diseases. Many of our foods, belonging to the category of fats and oils, do not fit with the requirements of our genes; hence the trouble of chronic diseases

Dietary Fats and Oils and Their Subtypes

FATS and oils are of five subtypes: a) Saturated fats (SFA), b) MUFA, c) Omega-6 PUFA represen-ted by LA, d) Omega-3 PUFA represented by ALA, and e) partially hydrogenated vegetable oil (vanaspati of India) or trans-fatty acids (TFA). There is no need to explain these abbreviations/terms. While SFA and vanaspati are solid or semi-solid at room temperature, MUFA and PUFA oils (that is, LA and ALA-rich oils) are liquid. While vanaspati is industrially made, other fats and oils are extracted from natural sources. LA and ALA cannot be distinguished without special laboratory.

In all the fats and oils, SFA, MUFA, LA and ALA are present but the oil is known by its major component or the source from which it is extracted.

It must be noted that our body cannot synthesise LA and ALA. Our diet must provide them and this is highly important.

Dietary Fats and Oils, and their Regulatory Roles

BOTH LA and ALA are highly important for the diverse and vital regulatory functions of the body. But their roles are completely opposite. LA promotes coagulation (thrombosis) of blood, while ALA is anti-coagulant (antithrombotic). Similarly LA is inflammatory, vasoconstrictor and promotes cancer. ALA has just the opposite regulatory functions. In the absence of ALA, one will be prone to thrombosis, coronary heart diseases, stroke, heart attack, Alzheimer’s disease, arthritis and certain cancers. Our diet must have both LA and ALA in right amounts and proportion. The ratio of dietary LA/ALA is important. It has been variously given as 1, 5 and 10. For men of the hunter-gatherer period it was 1.
Both LA and ALA-rich vegetable oils lower the blood cholesterol responsible for many heart diseases and is a marker for the same.

Both LA and ALA are highly reactive and susceptible to chemical attack in the body promoting many disorders. Our body is made of units called cells and the outer boundary of each cell is mainly made of oily substances. LA and ALA are required to provide the necessary properties to boundaries to function properly. Otherwise, many chronic diseases, such as diabetes, may be promoted. Dietary antioxidants are necessary to stop or minimise this risk.

LA and ALA-rich Dietary Oils of India

MOST of the edible vegetable oils of India are rich in LA and with or without a very small amount of ALA. These oils create a condition which is called: overloaded with LA. This is not good for health. These oils are safflower oil, sunflower oil, rice bran oil, groundnut oil, corn oil, sesame oil and cottonseed oil. Oils containing a fair amount of ALA and also with a good amount of LA are soybean oil, mustard/rapeseed oil and canola. Mustard/rapeseed oil contains a compo-nent which is considered to have bad health effect by many. Flax-seed, that is, linseed, oil contains a very high amount (about 55 per cent) of ALA. In short, dietary fats and oils of our country are highly unbalanced.

Many other food items, such as cereals, vegetables, fruits, dairy, meat, nuts and leafy vegetables, provide us some fat (LA and/or ALA) but the quantity is small. The ALA content of leafy vegetables is proportionately high; in cereals LA is high. Seafoods and freshwater fish are considered a source of EPA which is made in our body from ALA and the good effect of ALA is due to EPA. Thus fish-eaters of West Bengal, Kerala and elsewhere in India get some quantity above fat to an extent. But all these ALA and EPA may not be sufficient quantitatively.

The poor population of India may not have the dietary vegetable oil purchased from the market. Cereal foods they take have small quantities of fat. But this fat is also rich in LA. In other words, these people are also expected to suffer from LA-overload.

Diseases of Mismatched Dietary Oils

AN idea of these diseases has already been given. To elaborate, let us give the corresponding information of the USA. The diet of the USA has all the features similar to ours: a diet with (a) a massive amount of LA with little or no ALA, and (b) a fair amount of vanaspati (TFA). According to an authority on applied nutrition in the USA, the population of the country is in the midst of an explosion of chronic diseases: heart disease, cancer, obesity, diabetis, Alzhei-mer’s disease and arthritis. In addition, we may add thrombosis, heart attack, stroke and hyper-tension. All these diseases are diet-related and also related to dietary fats and oils. Symptoms of these diseases take a long time to appear and escape attention too; nobody thinks that common edible fats and oils are promoters of many chronic ailments.

Statutory Guidelines

THE authorities of India are completely indifferent to the problem which demands attention from the public health consideration. The Food Safety and Standards Act, 2006 with the Amendment of 2008 and different Rules and Regulations, 2011 are now in force in India. This does not throw any light on the subject. The Indian authorities do not recognise different subtypes of fats and oils, not to speak of the difference between LA and ALA. It allows linseed, that is, flax-seed, oil as edible oil in our country. The Indian system of the use of edible oil involves cooking. This will change the oil and make it unsuitable as food. The linseed oil of the Indian market used for the paint industry and other non-food uses is not suitable for edible purposes.

Academic Bodies and NGOs

DIFFERENT academic bodies and NGOs associated with applied nutrition are rather reticent on the issue. Many a scientist in their individual capacity have thrown light on the damaging effect of unbalanced edible oils. This is also known to a large number of medical men, physicians, nutritional scientists and several of those in authority.

We know the massive campaign against smoking. We also know that in our country the cultivation of khesari dhal was discouraged when it was found to have adverse health conse-quences.


IT is necessary that we should have statutory guidelines for balanced dietary fats and oils. As a beginning the government may form an expert committee for the purpose. At the same time it may advocate promotion and marketing of mixed edible oils containing balanced amounts and proportion of LA and ALA. The mixed oils should have appropriate amount of antioxidant. One may also take soybean oil which contains both LA and ALA in the ratio of 7.5.

Dr D.P. Sen is a retired scientist of the Central Food Technological Research Institute, Mysore. He can be contacted by e-mail at: dhrubasen1921@

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