Trans-fat levels in products will be limited and labelled on packaging from May next year.
By Ng Wan Ching, The Straits Times, 22 Mar 2012
Fat is such a dirty word people will pay large sums of money to siphon it out of their bodies.
But everyone needs it in their diets. It provides essential fatty acids, keeps skin soft, helps the body absorb nutrients, and is a good source of energy.
If consumed in excess amounts, fat contributes to weight gain, heart disease and certain types of cancer.
But not all types of fat are created equal. Some types promote health while others increase the risk of heart disease.
The health authorities here have trained its sights on trans fat, one of the worst types of fat around.
Trans fat occurs naturally in small amounts in dairy products and meats. All deep-fried food also contains trans fat because all types of oil can be converted into trans fat under high and prolonged heat.
But the main source of trans fat is vegetable oil that has had hydrogen added to it. This process of hydrogenation hardens the oil for the production of solid fat such as hard margarine and shortening. These are then used in food products including cakes, cookies and pastries.
The Ministry of Health is working with the Agri-Food & Veterinary Authority (AVA) to step up measures to limit trans-fat consumption. From May next year, AVA will require that trans fat be limited to no more than 2g per 100g of fat in oil products supplied to local food-service establishments and food manufacturers, and sold in retail outlets.
WHY TRANS FAT IS SO BAD
Cholesterol is carried in the blood by two types of lipoproteins: low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
The LDL or 'bad' cholesterol transports cholesterol throughout the body. In excess, cholesterol builds up slowly in the arteries, contributing to the narrowing of the arteries.
On the other hand, HDL or 'good' cholesterol picks up excess cholesterol and prevents cholesterol build-up in blood vessels.
High intake of saturated fat such as lard and butter can raise LDL cholesterol levels, which increases the risk of heart disease.
Trans fat not only raises LDL cholesterol levels, but also lowers HDL cholesterol levels, thus increasing even more the risk of heart disease, said Ms Loh Yet Hua, head of the department of dietetics at Singapore General Hospital.
That is not all. Trans fat also promotes inflammation and endothelial dysfunction, a condition in which the inner lining of a blood vessel does not function normally, said Ms Loh.
The World Health Organisation says trans fat consumption from partially hydrogenated oil contributes to multiple cardiovascular risk factors and increases significantly the risk of heart disease. Studies have shown that eating 4g of fat a day raises the risk of coronary heart disease by 23 per cent.
Ms Liong Suet Mei, senior dietitian at the National University Hospital, said a study of 80,000 female nurses showed that eating trans fat doubled the risk of heart disease in women compared with those who rarely eat trans fat.
While the experts Mind Your Body spoke to all agreed that trans fat is the worst type of fat, they pointed out one should also be mindful of saturated fat, which is widely found in food.
Sources of saturated fat include animal fat such as lard, ghee and butter, and plant sources including coconut oil, milk and cream.
Some people claim that virgin coconut oil does not affect blood cholesterol and even helps in weight loss. But this has not been proven in large-scale studies, Ms Liong said.
Other common types of fat found in food are polyunsaturated fat and monounsaturated fat.
They can lower LDL cholesterol if they replace saturated fat in the diet, said Ms Liong.
Monounsaturated fat is present in canola, olives, avocados and most nuts.
Polyunsaturated fat can be found in cooking oil such as sunflower, soya bean and corn oil. Omega3, a type of this fat, can be found in nuts, seeds and oily fish. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the unique types of omega 3 found in fish such as salmon, cod and sardine.
Studies have suggested that EPA and DHA can help lower the risk of cardiovascular disease by reducing triglycerides and inflammation, said MsLiong.
EVERYTHING IN MODERATION
But even with good fat, moderation is still the best policy.
Ms Loh said: 'As part of healthy eating, one must still watch the total amount of fat that one consumes. Too much fat, even the good ones, will still provide excess calories.'
Dr Kenneth Ng, a consultant cardiologist at Novena Medical Centre, said too much fat can lead to raised triglyceride levels.
All types of fat contain triglycerides. Too much fat will lead to insulin resistance and fat breakdown and increase triglyceride levels, cautioned Dr Ng.
High triglyceride levels can raise the risk of heart disease and may be a sign of metabolic syndrome.
The syndrome is the combination of at least three of these conditions: high blood pressure, high blood sugar, too much fat at the waist, low HDL and high triglyceride levels. The syndrome increases the risk of heart disease, diabetes and stroke.
But how much fat is too much?
It depends on how active a person is, his weight, age and, most importantly, the state of his health.
The Health Promotion Board and United States Department of Agriculture (USDA) recommend that the average person keeps total fat intake to 20 to 35 per cent of calories a day.
They advise limiting saturated fat to less than 10 per cent of calories, which is about 200 calories for a typical adult diet of 2,000 calories.
The USDA goes further to say trans fat should be limited to 1 per cent of calories - 2g a day for a 2,000 calorie diet. The rest of the fat should be polyunsaturated and monounsaturated fatty acids.
Fat facts
Myth: All types of fat are the same and equally bad for you.
Fact: Saturated fat and trans fat are bad for you because they raise your level of 'bad' cholesterol and increase your risk for heart disease.
But monounsaturated fat and polyunsaturated fat are good for you, lowering your 'bad' cholesterol level and your risk of heart disease.
Myth: Lowering the amount of fat intake is what counts.
Fact: The mix of types of fat eaten, rather than the total amount in the diet, is what matters most. The key is to eat more good types of fat and less bad types of fat.
Myth: Fat-free equals being healthy.
Fact: Many types of fat-free food are high in sugar, refined carbohydrates and calories.
Myth: Eating a low-fat diet is the key to weight loss.
Fact: Cutting calories is the key to weight loss and since fat is filling, it can help curb overeating.
Myth: All body fat is the same.
Fact: Where you carry your fat matters. The health risks are greater if your weight tends to accumulate around your abdomen, as opposed to your hips and thighs.
A lot of belly fat is stored deep below the skin surrounding the abdominal organs and liver, and having too much of belly fat is closely linked to insulin resistance and diabetes.
Source: Helpguide, a non-profit website in collaboration with Harvard Health Publications, the consumer health publishing division of Harvard Medical School
GOOD FAT
Monounsaturated fat
- Olive, canola, sunflower, peanut and sesame oil
- Nuts such as almonds, peanuts, macadamia nuts, hazelnuts, pecans and cashews
- Peanut butter
- Avocados
- Olives
Polyunsaturated fat
- Soya bean, corn and safflower oil
- Walnuts
- Seeds such as sunflower, sesame, pumpkin and flax seeds
- Soya bean milk and soya bean curd
- Fatty fish such as herring, mackerel, salmon, sardine, trout and tuna
BAD FAT
Saturated fat
- Palm and coconut oil and lard
- High-fat cuts of beef, lamb and pork and chicken with the skin
- Whole-fat dairy products such as milk, butter, cream, cheese and ice cream
Trans fat
- Stick margarine and vegetable shortening
- Commercially baked pastries, cookies, doughnuts, muffins, cakes and pizza dough
- Packaged snacks such as crackers, popcorn, chips and candy bars
- Deep-fried food such as french fries, fried chicken, chicken nuggets and breaded fish
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