Rosalee Brown DIETITIAN'S DESK
Fat is a very important ingredient in food preparation as it adds aroma, flavour, colour and texture to dishes. Fat also has an impact on our overall health.
Fatty acids
Of the two main types of fatty acids, one is normally solid at room temperature and is mainly from animals. This fat is called saturated fat and evidence shows that it raises cholesterol levels in the blood and increases the risk of heart diseases.
The other main type of fatty acid is unsaturated which is usually liquid at room temperature but solidifies when chilled, it is mainly from plant sources such as nuts, seeds and avocado pear. This fat is beneficial to health, in moderation, and can help to reduce cholesterol when it replaces saturated and trans fat in the diet.
Another type of unsaturated fat is polyunsaturated fat which includes omega 6 and 3 and is found in oily fish, nuts, seeds and plants such as soy and oil.
Hydrogenation
Liquid fats changed to solid offer many benefits to manufacturing such as increasing the shelf life of food products and offers greater options for creating a wider variety of food items. Hydrogenation involves adding hydrogen atoms to the unsaturated fat which chemically has room to accommodate these atoms. The liquid fat can be transformed to a solid where all the vacant bonds are filled or semi solid where only some are filled.
Trans fat
During the process of making partially hydrogenated fats the hydrogen gets attached in two main fashions. One of these is called the trans fashion, when the hydrogen atom is on either side of the structure, making it easier to become hard. The fully hydrogenated fat has little or no trans fat, only saturated fat.
Dangers
Saturated fat increases the bad cholesterol, low density lipoproteins (LDL) in our blood. Trans fat is worse as it does the same thing, in addition to reducing the good cholesterol, high density lipoprotein (HDL). Trans fat also increases another type of fat in the blood called triglycerides, which has been shown to increase the hardening of the arteries and the risk for stroke and heart diseases.
Trans fat can damage the lining of cells of the blood vessels leading to increased inflammation and fatty blockage in blood vessels and also interfere with the correct workings of essential fatty acids.
Daily fat calories should be less than 30 per cent of total caloric intake and it takes approximately three per cent of daily calories from trans fat to increase LDL and six per cent to reduce HDL.
Where are trans fats
Trans fat can be found in some of the same foods which contain saturated fat such as vegetable shortenings, some margarines, crackers, candies, cookies, snack foods, fried foods, baked goods and other processed foods made with partially hydrogenated vegetable oils. Fully hydrogenated oils do not contain trans fat only saturated fats. The largest portion of the trans fat in the diet comes from baked products.
Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.
What actions can I take?
Read labels - Strive for one per cent or less of daily caloric intake from trans fat.
Use naturally occurring unhydrogenated oils.
Use processed foods made with unhydrogenated oils.
Use soft liquid margarines with no more than 2g saturated fats as a substitute for butter and hard margarine.
Use other heart-healthy fats such as nuts, avocado and peanut butter.
Consume foods which are low in saturated fats and trans fat combined.
Reduce total fat intake; this will help to also reduce trans fat. It is difficult to eliminate all trans fat from the diet but strive to reduce its intake to safe levels.
