HEALTHWATCH
Bad fats
DR. G SENGOTTUVELU
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Transfat is not essential and provides no known benefit but is used in a range of products for human consumption.
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TRANSFAT (also known as transfatty acids) is a specific type of fat formed when liquid oils are converted into solid fats by adding hydrogen through hydrogenation. This increases stability of flavour and palatability and shelf life of food. The food is unable to break down transfat, so it accumulates in the body causing harmful effects.
Role of fat
Fat is a major source of energy for the body and aids in vitamin absorption. Both animal and plant-derived products contain fat. Unsaturated fats are beneficial when consumed in moderation, saturated and transfat are harmful. Therefore choose foods low in both saturated and transfats for a healthy diet.
A small amount of transfat is found naturally, primarily in some animal-based foods such as butter, milk products, cheese, beef and lamb. Transfat is also found in some foods that also contain saturated fat such as vegetable shortenings, some margarines, crackers, candies, cookies, snack foods, fried foods, baked foods and other processed foods made with partially hydrogenated vegetable oils.
Today, transfat consumed is used notably in the fast food, snack food, fried food and baked good industries. This cheap and harmful oil is used as an ingredient in a range of products from biscuits to noodles, samosas to French fries. Transfat are also found in restaurants as shortenings used for deep-frying because of its cheap value, rancidity and taste.
Food labelling
In India, the processed food industry lists transfat as `partially hydrogenated vegetable oil', `hydrogenated vegetable oil or `vegetable shortening' in their Nutrition fact levels. The list of ingredients may mention transfat under one of these terms.
To reduce consumption of transfat, food labelling should be clear, partially hydrogenated oils should be replaced with a healthy oil, transfat in commercial cooking should be banned, companies or food manufacturers should be encouraged to use transfat-free oil in packaged foods and restaurants should use healthy oils.
With the addition of transfat to the Nutrition Facts Panel, consumers can review food choices. Do not assume similar products are the same. Check Nutrition Facts Panel because even similar food items can vary in calories, ingredients, nutrients and the size and number of servings in a package. Even if you buy the same brand, should check the Nutrition Facts Panel frequently because ingredients can change.
Some dietary supplements also contain transfat from partially hydrogenated vegetable oil or saturated fat or cholesterol. If a dietary supplement contains a reportable amount of trans or saturated fat (0.5 gm or more), dietary supplement manufacturers must list the amounts on the Supplements Facts Panel.
Aim for a total fat intake of not more than 30 per cent of calories, as recommended by the nutritional guidelines. If you need to reduce fat intake, do so primarily by cutting back on saturated and transfats. The major sources of transfat in our diet are the readymade and fried foods. These are not labelled, so the consumer does not know how much transfat he consumes.
The World Health Organisation (WHO) recommends that transfat should not be consumed at all. From September 1, 2007, the use of transfats will have to be listed on food labels of all products manufactured in India.
Cardiovascular risk
It is estimated that three years after the effective date, transfat labelling will prevent between 600 and 1200 cases of Coronary Heart Disease (CHD) and 250 to 500 deaths a year. It takes about three years for lower Low Density Lipoprotein to result in lower CHD risk.
According to nutritional guidelines, transfat is not essential and provide no known benefit to human health. The primary health risk from transfat consumption is an elevated risk of cardiovascular disease.
The consumption of transfatty acids raises levels of LDL, reduces levels of High Density Lipoprotein (HDL) i.e. increases bad cholesterol and decreases good cholesterol and increases the ratio of total cholesterol to HDL cholesterol. It causes the artery to become clogged and develop heart disease and stroke.
A comprehensive review of studies indicates that there is a strong and reliable connection between transfat consumption and cardiovascular diseases. Health authorities worldwide recommend that consumption of transfat be reduced to trace amounts. Transfat from partially hydrogenated oils are generally considered to be more of a health risk than those occurring naturally.
There are suggestions that the negative consequences of transfat consumption go beyond the cardiovascular risk. In general, that consuming transfat specifically increases the risk of other chronic health problems. One recent study has found connections between transfat and prostate cancer.
There is a growing concern that the risk of Type-2 diabetes increases with transfat consumption. Research indicates that transfat may increase weight gain and abdominal fat, despite a similar caloric intake.
Transfat is metabolised differently by the liver compared to the other fats and this may cause liver dysfunction. Each two per cent increase in transfat intake is associated with a 73 per cent greater risk of ovulatory infertility.
Transfatty acids adversely affect immune response by lowering efficiency of B-cell response and increasing proliferation of T-cells. Transfatty acids lower the amount of cream in milk from lactating females thus lowering the over all quality available to the infant.
Transfatty acids cause alterations to numerous physiological functions of biological membranes that are critical for cell homeostasis. For example, appropriate membrane transport and membrane fluidity and these fatty acids isomers produce alterations in adipose cell size, cell number, lipid class and fatty acid composition.
Check the oil
Most commercially available oils are highly processed and should not be consumed. The best oil would be extra virgin olive oil stored in glass. All corn and soy oils should be avoided.
For certain individuals, sesame oil is excellent as it can inhibit the formation of arachidonic acid, a fat that is a major precursor of inflammation.
Other cold pressed oils that might be useful are safflower, sunflower, almond and organic peanut oil. Organic coconut oil would be the best oil to cook with, as it is completely saturated and no transfats can be made from it.
The writer is an Interventional Cardiologist, based in Chennai.
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