Fats And Your Health
Fats and oils are found in foods of both plant and animal origin. Fats include oils which are liquid at room temperature – like olive oil or canola oil - and fats that are firm or solid at room temperature – like lard or butter. Fats and oils are made up of components called fatty acids. Some fatty acids can be made by the body but some cannot and these are known as “essential fatty acids” because we have to get them from the food we eat. These essential fatty acids are Omega-3 and Omega-6 fatty acids.What types of fat are found in food?
There are three different types of fat found in food: “saturated”, “polyunsaturated”, and “monounsaturated”. They differ in their chemical structure and vary in the way they affect the body.
Each of these fats can be found in animal and plant foods, although animal fat is usually saturated, while plant (or vegetable) fat is usually unsaturated. Palm and coconut oils are an exception to this rule, as they are mainly saturated fat. Foods often contain a mixture of polyunsaturated, monounsaturated and saturated fats. A fat or oil is referred to as saturated, monounsaturated or polyunsaturated depending on which type of fat is present in the largest amounts. For example, canola oil contains approximately 7% saturated fat, 30% polyunsaturated fat (a mixture of Omega-3 and Omega-6) and 63% monounsaturated fat. It is therefore referred to as monounsaturated oil.What do fats do?
- Omega-3 and Omega-6 fatty acids are needed for normal growth and development and for the normal functioning of the brain and nervous system. They are used in the production of hormones that help regulate blood pressure, blood clotting, blood fats, inflammation and the immune system
- All fats act as insulators for the body
- Fat helps to form protective padding around vital organs such as the heart, liver and kidneys
- Fat is a concentrated source of energy (kilojoules)
- Fats are the carriers of the fat-soluble vitamins A, D, E and K
Foods rich in Omega-3 fatty acids include: oily fish, walnuts, canola oil and eggs. Foods rich in Omega-6 fatty acids include: meat, safflower oil, sunflower oil and pumpkin seeds.How much fat do you need?
The amount of fat a person needs depends on their age, sex, body size and composition, activity levels, family history and health status. From the South African food based dietary guidelines, it is recommended that we should ideally eat a diet low in fat and particularly low in saturated fat.Tips for eating a balanced, low- fat diet
A balanced diet consists of fresh vegetables, fruit, cereals, legumes, grains, bread and pasta and moderate amounts of monounsaturated and polyunsaturated fats and oils. Eat lean meats and chicken, and try to include fish two to three times per week as they are a good source of Omega-3 fatty acids, as are eggs.Why do we need to eat less fat?
Fats are a very concentrated form of energy (37kJ/gram) having nearly twice the kilojoules content of protein or carbohydrate (17kJ/gram). Our bodies need fat but many South Africans consume foods that contain too much fat, especially too much saturated fat. This can lead directly or indirectly to a number of serious health problems including:
- Coronary heart disease, stroke, high blood pressure
- Weight gain leading to being overweight or obese. This is strongly associated with ill health especially when the fat is located around the waist
- Non-insulin dependent diabetes
- Some types of cancers
Fatty foods can be replaced with delicious and healthy alternatives, such as fruits, vegetables, wholegrain breads, legumes, seeds and wholegrain cereals and lean protein foods.
Understanding fat and cholesterol Heart Foundation (8 June 2010) includes other useful links
Heart Foundation 2008 Position statement “Dietary fats and dietary sterols for cardiovascular health”
Heart Foundation 2009 Summary of evidence “Dietary fats and dietary cholesterol for cardiovascular health”
Nutrient Reference Values for Australia and New Zealand: Recommendations to reduce chronic disease risk.
ISSFAL 2010 Dinner Debate: Healthy Fats for Healthy Hearts – Annotated Report of a Scientific Discussion Ann Nutr Metab 2011;58:59–65 Published online March 24 2011
Milk fat and health consequences. Gibson RA: Nestle Nutr Workshop Ser Pediatr Program. 2011;67:197-207. Epub 2011 Feb 16.
n-6 Fatty acids and cardiovascular health: a review of the evidence for dietary intake recommendations. Czernichow S, Thomas D, Bruckert E. Br J Nutr. 2010 Sep;104(6):788-96. Epub 2010 Jun 4.
n-6 fatty acid-specific and mixed polyunsaturate dietary interventions have different effects on CHD risk: a meta-analysis of randomised controlled trials. Ramsden CE, Hibbeln JR, Majchrzak SF, Davis JM. Br J Nutr. 2010 Dec;104(11):1586-600.
Dyerberg J. Eskesen DC. Andersen PW. Astrup A. Buemann B. Christensen JH. Clausen P. Rasmussen BF. Schmidt EB. Tholstrup T. Toft E. Toubro S. Stender S. Effects of trans- and n-3 unsaturated fatty acids on cardiovascular risk markers in healthy males. An 8 weeks dietary intervention study. European Journal of Clinical Nutrition 2004; 58:1062-70.