What is healthy oil for our healthy bodies

Published: Sunday 15 February 2009

What is healthy oil for our healthy bodies

-- (Credit: AGNIMIRH BASU)Commercial interests determine content

The oil we eat is essential for our body to function. We cannot do without it. Thus it is important to understand its chemistry. It is agreed that healthy oil is one which has less saturated fat, more monounsaturated fat (mufa) and polyunsaturated fats (pufa) is balanced between the two. It should also be rich in omega 3, 6 and 9 fatty acids (see box mufa, pufa and omega).

But what does this mean to us, when we go out to buy our oil?

Which one is the best?
It is impossible to say with certainty, which oil is the best. The reason is partly to do with commercial interests, which makes some oils bad and some good.

While sunflower and safflower oils are considered the best for the heart, because they are rich in pufa, recent research suggests it is omega 3, a part of pufa, which is the best for preventing ischemic heart diseases. Both sunflower and safflower are low on omega 3. Mustard oil is high on omega 3.

The marketing of good and bad
Certain good oils have been given a bad name. For example, coconut oil was considered unhealthy because it has high amount of saturated fats. But studies found that the oil is healthy because its carbon chains are shorter in length than other saturated fats. A study in Kerala in 1995 on 64 volunteers showed that adding coconut kernel to the diet did not bring about any change in the total cholesterol, hdl cholesterol or ldl cholesterol, in the serum.

Happy meals

In 2002, fast-food giant McDonald's announced in the US it would phase out trans fats from its food. When it failed to comply, a non-profit, Ban Trans Fats, filed a case in 2003.

Succumbing to pressure, McDonald's agreed to place notices in all its restaurants that it had not changed to the lower trans fats cooking oil. It also agreed to pay US $7 million to the American Heart Association for a trans fats programme. Ban Trans Fat also filed a suit against Kraft Foods for marketing trans fats-rich Oreo cookies to children. Kraft agreed to eliminate trans fats in all its products.

In 2007, another US non-profit, the Center for Science in the Public Interest, filed suits against KFC and Burger King. KFC agreed and reduced its trans fats but Burger King did not. The non-profit found that a regular-size order of chicken tenders with a large order of French fries has eight grammes of trans fats, more than what someone should consume in four days.

Research has also found that coconut oil has antimicrobial components and leads to normalization of body lipids, protects against alcohol damage to the liver and improves the immune system's anti-inflammatory response.

But it is still not the preferred medium for the market because coconut oil is expensive; it is shunned by the food industry. The industry prefers oils like canola (rapeseed), says Mary Enig, a nutritionist in the US, who writes on fats and their impacts on human bodies.

She says this industry-friendly oil was marketed as being "as healthy as olive oil" because it is similarly rich in mufa. But then research found that about two-third of the mufa in rapeseed is erucic acid, which was associated with fibrotic lesions in the heart. To fix this Canadian plant breeders developed a variety of rapeseed, low on erucic acid and high on omega 3 and oleic acid, which is an omega 9 fatty acid.

This new oil, sold as lear oil, bombed in the US as farmers and consumers shunned it. Industry then went to town to sell and decided to change the name--from 'rape', 'lear' to canola, to give a healthy image for what Enig calls the Cinderella oil.

All of a sudden canola oil began to appear in recipe books, which was perfect for Mediterranean diets, replacing olive. Research and recipes were pushed, this time extolling omega 3, which suited canola, because it was high on this fatty acid as well.

Enig notes that this hard-sell was not right. A large numbers of studies point to the "fact that canola oil is definitely not healthy for the cardiovascular system". She points out that these studies also find that the use of this oil retards growth, which is why the US Food and Drug Administration does not allow it in infant formula.

Should we be eating what we are eating?

Anoop Misra, director, department of diabetes and metabolic diseases, Fortis Hospital, New Delhi, and his colleagues recently reviewed the oils and fats that South Asians are consuming and the linkage with human health. They found several studies had reported diets, which had higher intake of carbodydrate, high saturated fatty acid and high omega 6 in India. These studies also found low intake of mufa, omega 3 and fibre. Intervention studies, which added omega 3 to the diet, improved the lipid profile, but did not show a beneficial effect on insulin resistance. The problem, the study points, is that South Asians, particularly Indians, are prone to develop insulin resistance and the metabolic syndrome. Therefore, current diet is contributing to the development of metabolic syndrome and diabetes. The doctors advise it is critical for Indians to replace unhealthy fast food with healthy options.

But then how were people in China, Japan and India, where rapeseed oil has been traditionally used, coping? Research has found that these adverse impacts of rapeseed oil can be mitigated if it is combined with butter or ghee. The problem is not with the content of the erucic acid but with the high levels of omega-3 in the absence of saturated fats. In other words, explains Enig, the advice to Indian housewives not to use butter and ghee, which was previously used in combination with rapeseed oil, is the real problem. Also, it concerns the processing of the oil. In the past, rapeseed oil was cold pressed in thousands of small neighbourhood mills and it was consumed fresh. This, she says, gave it its added benefits.

Cold pressed is hot
This is another debate in the science of oil and nutrition. Olive oil is considered the best for the heart, only when it is cold pressed. Research published in the open-source journal BMC Cancer done by Spanish researchers found that the major complex phenols present in extra-virgin olive oil also prevent cancer. These are not present when the oil is extracted through solvents.

In India, there is a similar perception that the cold-pressed mustard oil is better for health. "In the last year, the sales of mustard oil has increased suggesting that people are more health conscious," said S K Shukla, director, Data Group, a company specializing in mustard oil. It is because of these reasons that the interest is growing in traditional oils like rice bran, coconut and mustard, shunned by the modern oil industry.

Diet of essential fatty acids
There is increased attention on the omega factors in oil. But researchers cannot agree on what works best in which circumstance. It is accepted that the human body needs a ratio of 5-10 1 of omega 6 to omega 3.

A P Simopoulos from the Center for Genetics, Nutrition and Health, Washington DC, in the September 1999 issue of American Journal of Clinical Nutrition found that over the past years there has been an enormous increase in the consumption of omega 6 fatty acids due to the increased intake of vegetable oils from corn, sunflower seeds, safflower seeds, cottonseed and soybeans.

As a result, today's western diet has a ratio of omega 6 to omega 3 of 301.

Mahtab S Bamji, one of India's most eminent nutrition scientists, suggests this ratio should not exceed 101.

Then what should we buy?
There are no straight answers. In spite of all the hard sell for one type of oil being best, nutritionists are of the view that the best oil is an oil used in moderation and switched frequently to get the maximum nutrition value.

D Prabhakaran, executive director of the Centre for Chronic Disease Control in Delhi suggests combining mustard, canola and peanut oil. Swati Bhardwaj, nutritionist and diet consultant with the Diabetes Foundation (India), says canola, olive and rice bran oils are the best options available in the market for Indians.

S K Kalia, general manager, quality control of Dhara (manufacturer of many refined oils), said the best option would be to use oils rich in mufa, like olive, mustard and groundnut as well as those rich in pufa, like soyabean and sunflower.

But the choice must be yours (and not the company's) to make.

MUFA, PUFA and omega

We know that fats and oils are made up of chains of carbon atoms. The bonds between the carbon atoms classify the oil into saturated and unsaturated fats.

Saturated fats have a single bond between carbon atoms (they have more hydrogen atoms).

Down to Earth Unsaturated fats have double bonds between the carbon atoms. Where double bonds are formed, hydrogen atoms are eliminated and energy is released.

The unsaturated fats are further classified into monounsaturated fats (MUFA), containing one double bond and polyunsaturated fats (PUFA) containing more than one double bond.

MUFA includes omega 9. PUFA includes omega-6 and omega-3.

The body needs these essential fatty acids to manufacture and repair cell membranes, to enable the cells to obtain optimum nutrition and expel harmful waste products. It is now accepted that omega-9 found in MUFA, could be the best.

In relation to our health, it is broadly accepted that PUFA protects against cardiovascular disease by providing more membrane fluidity than MUFA.

On the other hand, it is also found that foods with MUFA lower LDL (bad) cholesterol, while possibly raising the HDL (good) cholesterol.

Down to Earth Trans fats are produced when unsaturated fats are partially hydrogenated. These hydrogen atoms saturate the double bonds and also change the configuration to trans.

While both MUFAand PUFA oils can give rise to trans fats, oils rich in PUFA have more double bonds and result in fats rich in trans-fats.

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