Abstract
The Centre for Food Safety (CFS) and the Consumer Council (CC) have conducted a joint study on trans fats in locally available foods. The study aimed to assess the levels of trans fats in foods available in the local market and to increase consumer understanding of trans fats and their health implications.
Background
2. Trans fats (trans fatty acids) are formed during a process called hydrogenation, which turns oil from liquid form into semi-solid or solid form. Hydrogenated vegetable oils are used in food production for extending shelf-life and improving the texture of food.
3. Trans fats are mostly found in hydrogenated vegetable oils such as shortening and margarines. Fried food and bakery products (e.g., crackers, cookies, cakes, pastries, chips, etc.) with hydrogenated vegetable oil used as ingredients or in cooking process are the main sources of trans fats in our diet. A low level of trans fats is also found naturally in the milk and the fat of sheep and cattle.
4. Trans fats and saturated fats both raise low-density lipoprotein (LDL) cholesterol (so-called bad cholesterol) level. Besides, trans fats may also lower the level of high-density lipoprotein (HDL) cholesterol (so-called good cholesterol). Studies have found that excessive intake of trans fats increases the risk of coronary heart disease.
5. The World Health Organization and the Food and Agriculture Organization of the United Nations suggest that diets should provide a very low intake of trans fats, i.e. an intake of less than 1% of daily energy intake. For example, an individual with a daily energy intake of 2000 kilocalories should limit the intake of trans fats to less than 2.2 grams per day. At present, there is no international consensus on the regulatory control on trans fats. The Centre for Food Safety will closely monitor the latest international developments regarding regulation of trans fats.
The study
6. A total of 80 products, including (i) bakery products (including breads, cakes, egg tarts, chicken pies and batter-made food such as egg rolls, waffles and egg puffs); (ii) deep fried foods (including French fries, fried chicken, pork chop, fritters and pastries); and (iii) butter and margarine/margarine-like spreads were collected for testing. The study covered both prepackaged and non-prepackaged foods. Laboratory analyses of total fats, trans fats, saturated fats, cholesterol, and energy were conducted by the Food Research Laboratory of CFS.
7. The study found that trans fats levels varied a lot among same kind of food. For example, trans fats levels in 23 bread samples ranged from zero to 1.8 grams per 100 grams. Trans fats levels in 11 batter-made products ranged from zero to 1.0 gram per 100 grams. For the 14 fried products, there was also a wide range of trans fats levels from 0.034 to 2.4 grams per 100 grams. Seven margarine/margarine like spreads contained trans fats levels from 0.12 to 4.2 grams per 100 grams. Such results indicated that it is practically possible to reduce trans fats levels in food.
8. Some of the products tested contained relatively high levels of trans fats. For example, two cream-filled breads with shredded coconut, with weight of 95 grams and 83 grams, contained about 1.3 and 1.5 grams of trans fats respectively. Consumption of one piece already comprises a significant percentage (some 60-70%) of daily recommended intake.
9. Besides trans fats, saturated fats and cholesterol are also risk factors for coronary heart disease. Some bakery and deep fried food samples were found high in saturated fats; some cake samples were high in cholesterol. The butter sample had saturated fats level higher than that of all margarine /margarine-like spreads samples.
Advice
10. The public is advised to maintain a balanced diet, avoid using hydrogenated oils/fats and animal fats in preparing food and reduce the intake of foods that are high in trans fats and/or saturated fats.
11. The trade is advised to avoid using hydrogenated vegetable oil and research on the reduction of trans fats and saturated fats in foods. The ingredients, vegetable shortening and margarine, if used, should be clearly declared for prepackaged food.
October 2007
Risk Assessment Section
Centre for Food Safety
Food and Environmental Hygiene Department
For the study report (only available in Chinese), please click the following website:
" Trans Fats in Locally Available Foods (Part I) (Chinese version)"