Tuesday, January 26, 2010

Liquid gold - All about oils (by Geraldine Ling in Mind your body of the Straits Times dated 21 Jan 2010)

Oils are essential for our health and beauty. But this liquid goodness has to be used and consumed with care for too much of it can wreak havoc on the bodyBy Geraldine Ling

A dash of aromatic sesame oil can do wonders for a hasty stirfry dish. Likewise, a slice of warm toast dipped in herb-infused olive oil has that extra zing.

Food, when spiced up with cooking oils, magically smells, looks and tastes better.
There is a wide variety available today and you might wonder about the properties of the different types of oil.


In the kitchen, most of the oils we use are vegetable-based.

"To make these oils, there is a process of crushing, refining, bleaching and deodorising the plants," said Ms Sulina Tsai, senior marketing manager of oil producer Lam Soon Singapore.
But edible oils are not limited to vegetable sources alone.


Fish oil is commonly taken as a supplement, said Ms Jaclyn Reutens, a dietitian from Aptima Nutrition and Sports Consultants.

Good for health

Edible oils, if used correctly, can have tremendous health benefits. Most vegetable and fish oils are rich in essential fatty acids (EFAs), which are vital to life.

Commonly known as omega-3 and omega-6, these EFAs are not produced by the body and are commonly found in certain foods.

Said Dr Alvin Ng, a consultant cardiologist at Raffles Hospital: "Omega-3 fatty acids have been shown to improve heart health, reduce cholesterol and triglycerides and are present in fish and olive oil."

Omega-6 is reportedly important for brain function and is found in many vegetable oils, including sunflower and peanut.

Dr Ng said having a good balance in the ratio of omega-3 to omega-6 acids consumed makes a significant difference in improving heart health.

"It should ideally be no more than 4:1 (omega-6 to omega-3). In fact, consuming more omega-3 acids would be better," he added.

However, most people tend to consume far more omega-6 than omega-3, noted Mrs Sheeba Majmudar, a nutritionist in private practice.

An unbalanced ratio skewed towards too high a proportion of omega-6 may lead to health problems, like prostate and breast cancers, said Dr Ng. However, such findings are quite ambiguous as there are varying outcomes from different studies, he added.

Good vs bad fats

Unlike saturated fats like butter and lard, oils are liquid at room temperature. This is because they are high in mono- unsaturated and polyunsaturated fats, or the good fats, said Ms Reutens.
Monounsaturated fats help to increase high-density lipoproteins, or good cholesterol.


Polyunsaturated fats help to increase HDL and decrease low-density lipoproteins, or bad cholesterol.

However, Ms Reutens cautioned that not all oils are made equal.

Some oils, despite containing good fats, have a high percentage of the bad fat, or saturated fat.
"Palm and coconut oil are sources of saturated fat. Consuming too much of such oils increases our bad cholesterol," she said.


Palm oil - a common ingredient in blended vegetable oils - is made up of 51 per cent saturated fat while coconut oil, also common, contains 87 per cent of saturated fat.

Dr Ng said: "When bad cholesterol accumulates in the walls of the arteries, atherosclerosis, or the formation of plaque, results.

"When plaque builds up, blood vessels are narrowed, leading to angina pectoris (chest pains) or heart attacks."

For a healthier alternative, Ms Reutens recommends using oils low in saturated fat, like sunflower and olive oils. The latter is also high in monounsaturated fat.

Not too much

While oils have health benefits, they can wreak havoc on the body if they are consumed too often.

Ms Reutens said: "Oil is a concentrated source of calories. Containing 9 calories per gram, it has twice the amount of energy compared to carbohydrates and proteins. It is easy to over-consume oil as foods cooked in oil taste better.

"Sometimes we may be eating oils without realising it," she added, citing the example of a sugary cake. Although its sweet appearance creates the impression that sugar is the main ingredient, it is actually made with a lot of fat.
Eating too much fat may cause weight gain, which in turn, can cause heart problems, cancers and diabetes.


Ms Reutens recommends consuming no more than 50-60g of fat a day based on a 1,500 to 1,800 calorie diet. Of this, no more than 10 per cent should come from saturated fat.

Trans fats trouble

Another concern is the presence of trans fats, commonly found in commercially baked and deep-fried foods.

Trans fats are a man-made product that results from high temperature treatment, pressure and hydrogenation, said Mrs Majmudar.

Hydrogenation is a process of adding hydrogen to oils to solidify them at room temperature.
Trans fats, also known as hydrogenated fats, spell double trouble for your heart health because they increase bad cholesterol and decrease good cholesterol.


While oil may sometimes be given a bad name, we all need fat to live.

Said Ms Reutens: 'Oil helps us to absorb the fat-soluble vitamins like A, D, E and K. We definitely need oil, but we need to control the amount we consume.'


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