What are trans-fats?
Trans fat is a fat found in foods. Trans fat is made when a liquid vegetable oil is changed into a solid fat. Trans fat is often added to processed foods because it can improve taste and texture and helps the food stay fresh longer.
Fats in foods are made up of 4 different types of fats - polyunsaturated, monounsaturated, saturated and trans. Trans fats are found naturally in some animal-based foods, but are also formed when liquid oils are made into semi-solid fats like shortening and hard margarine. Scientific evidence has shown that dietary saturated and trans fats can increase your risk of developing heart disease. You can reduce this risk by choosing healthier foods that contain little or no trans-fat.
Type of trans-fats?
1. Industrial trans-fats
Trans fats are fats - triglycerides of fatty acids - which contain trans fatty acids. These are unsaturated fatty acids that contain at least one double bond in the trans configuration, as opposed to the cis configuration ordinarily found in nature.
The main source of these synthetic trans fatty acids is hydrogenation - an industrial process in which oil is heated to a high temperature (typically 260-270ºC) under pressure and in the presence of a metal catalyst such as nickel, Rayner's nickel (a nickel / aluminium alloy) platinum, palladium or cobalt, then hydrogen is introduced. The catalyst is normally present in the form of a fine powder and one health concern is that a small quantity of it must remain in the oil. The hydrogen is absorbed into the fat molecules, changing its molecular structure and its chemical composition as it converts the unsaturated oil to a more saturated form.
2. Natural Trans Fats
Some trans fatty acids are also found in the meat and milk of ruminant animals. However there is little evidence that these naturally-occurring trans fatty acids are harmful in their native state,
Some trans fatty acids occur naturally in the digestive system of ruminant animals such as cows, sheep and goats. Some trans fatty acids are therefore present in meat, milk and other dairy produce. These are mostly C18 monounsaturated trans fatty acids, principally (almost half) vaccenic acid
Why is trans-fat bad for your health?
Trans fat increases your risk of heart disease. This is because:
•Trans fat raises your LDL (bad) cholesterol AND
•Trans fat lowers your HDL (good) cholesterol
How much trans-fat can I eat?
Trans fat is not needed for a healthy diet. You should aim to eat as little trans-fat as possible.
What foods have trans-fat?
These foods often have trans-fat. You will need to read the Nutrition Facts table to know for sure:
•Deep fried foods (spring rolls, chicken nuggets, frozen hash browns, French fries)
•Ready to eat frozen foods (quiche, burritos, pizza, pizza pockets, French fries, egg rolls, veggie and beef patties)
•Hard (stick) margarine and shortening
•Commercially baked goods (donuts, Danishes, cakes, pies)
•Convenience foods (icing, puff pastry, taco shells, pie crusts, cake mixes)
•Toaster pastries (waffles, pancakes, breakfast sandwiches)
•Oriental noodles
•Snack puddings
•Liquid coffee whiteners
•Packaged salty snacks (microwave popcorn, chips, crackers)
•Packaged sweet snacks (cookies, granola bars)
Trans fat can also be found naturally in some foods. Meat, milk, and butter naturally contain small amounts of trans fat. The trans-fat found naturally in foods is different than manufactured trans-fat and does not increase your risk of heart disease.
New Research-Industrial And Natural Trans Fats Impact On Health
Researchers in Canada have gained new insights into the how different types of trans fats impact health. Their findings add to new knowledge on a special 'family' of natural trans fats that are produced by animals, such as sheep, goats, and cattle, and found in the milk and meat from these animals.According to the researchers, these natural ruminant trans fats are different to industrial trans fats as they are not harmful and may potentially improve health. Dr. Spencer Proctor, Director of the Metabolic and Cardiovascular Disease Laboratory at the University of Alberta in Canada, explained.We are learning there is a very important public health message to convey about ruminant natural trans fats and how these are different from the industrial trans fats that have been targeted as harmful to health. The research indicates that consuming these natural trans fats as part of a balanced diet is not a health concern. On the contrary, there is increasing evidence these are 'good fats' and could be fundamentally health-enhancing. They should not be an unintended target of the bid to rid the diet of trans fats.To date, the research on natural trans fats has been based on a strong foundation of animal model studies and an increasing number of clinical trials. Dr. Jean-Michel Chardigny, National Institute for Agricultural Research (INRA) in France said:, Our knowledge of natural trans fats is relatively recent and will we continue to learn more about the human health implications. But clearly we know they are different from industrial trans fats and should not be painted with the same brush.Chardigny examined data from 13 clinical trials that analyzed the effect of natural trans fats on cardiovascular health risk factors. According to Chardigny, several studies confirmed the harmful effects of industrial trans fats, but research to date on natural trans fats has revealed no such effects.
Chardigny explained:, “There is no association between natural trans fats intake and cholesterol-dependent cardiovascular risk factors. According to Dr. Marianne Uhre Jakobsen, Associate Professor, Public Health, Aarhus University, Denmark "The findings indicate that intake of natural trans fats is not associated with coronary heart disease within the range of intake in the general population."The researchers state that health recommendations and food labels need to clearly differentiate between industrial and natural trans fats. These scientists and their colleagues are exploring approaches for further international collaboration among researchers as well as health and food regulatory authorities in order to make progress on this front.
Proctor explained, We want to help the public better understand the very different health implications of the two different categories of trans fats, including through the nutrition information they get on food labels. We're confident we can achieve that be continuing to work together.Findings from the study were presented at the 10th Congress for the International Society for the Study of Fatty Acids & Lipids (ISSFAL).
(Source- Congress for the International Society for the Study of Fatty Acids & Lipids (ISSFAL).)
