Trans fatty acids
Home » Magazine » Good, issue 9 » Trans fatty acidsPartially hydrogenated vegetable oil doesn’t sound so yummy—and it becomes even less appetising once you learn about the trans fatty acids it contains
What are they?
Trans fatty acids, also known as trans fats, are formed when liquid vegetable oils are converted into semi-solid fats by adding hydrogen. The resulting ‘partially hydrogenated vegetable oil’ is used in commercial food production to make products such as crackers, biscuits, snack foods and baked goods, for deep-frying and to make margarine.
Low levels of trans fatty acids also occur naturally in meat and milk. Animal fats were once the only source of trans fats, but today most trans fat is consumed as partially hydrogenated vegetable oil, which contains up to 45 percent trans fat (of total fat content). Butter contains up to five percent trans fat.
Why are they used?
Partially hydrogenated vegetable oils are used in most commercially baked goods because they are cheaper than animal fats, have a longer shelf life and decrease refrigeration requirements. Partially hydrogenated fat is also popular commercially because of its ‘mouth feel’: it melts in the mouth. Because the fat is semi-solid, it keeps refrigerated margarine spreadable, unlike butter. It’s also vegetarian, vegan, kosher and halal.
What’s the problem?
Trans fat behaves like saturated fat in the body, although the US National Academy of Sciences says trans fatty acids are even more damaging to the heart.
Trans fats raise low-density lipoprotein (LDL, or ‘bad’ cholesterol), which increases your risk of coronary heart disease, heart attack and stroke. They also lower high-density lipoprotein (HDL, or ‘good’ cholesterol), which protects against cardiovascular disease. Trans fatty acids can also cause inflammation in the arteries, increasing the risk of diabetes, and have negative effects on foetal brain development.
Consuming trans fatty acids has no known benefit to human health.
How much am I eating?
Manufacturers aren’t required to label the trans fatty acid content of foods in New Zealand, unless they make a nutrition claim about cholesterol, saturated, polyunsaturated, monounsaturated or trans fatty acids, omega-3, omega-6 or omega-9 fatty acids.
The good news is that consumption of trans fatty acids is quite low in New Zealand, compared with many other countries. We get 0.7 percent of our daily kilojoules from trans fats, according to Food Standards Australia New Zealand (FSANZ), which is below the World Health Organization’s advice to consume no more than 1 percent of daily kilojoules from trans fats.
Health authorities worldwide recommend that people consume only trace amounts of trans fat.
What are the alternatives?
Food manufacturers are increasingly using palm oil as an alternative to partially hydrogenated fats—but since Malaysian and Indonesian rainforests are being cut down to produce palm oil, that’s not a great solution.
The other problem with reducing trans fatty acids in manufactured food is that it often leads to an increase in saturated fat content, which isn’t a healthy result. Butter contains less trans fat than margarine, but usually much more saturated fat and cholesterol. Soft margarines, which have less combined saturated and trans fats, may be a better option for those with cholesterol or heart-health concerns.
The easiest way to avoid trans fats is to avoid manufactured food that contains partially hydrogenated vegetable oil. At home, choose monounsaturated fats such as canola, rice bran and avocado oils (to cook with at high temperatures) and olive and hempseed oils (to use at lower temperatures and in dressings).
Thu November 26, 2009 @ 01:50 PM
via letters@good.net.nz