Fats and lipids have been given a bad rap in the media as the culprit for obesity and its related diseases such as heart attack and high cholesterol. However, your body needs them for survival and proper cellular function like carbohydrates, protein and other essential nutrients. By understanding their basic functions and properties of their role in your body, you may appreciate the work fats and lipids are doing.
Definition
Lipid is a broad term for energy-storing compounds, which includes fats, waxes, sterols, fat-soluble vitamins and phospholipids. Molecules in this group have a hydrophobic or amphiphilic (liking both water and fat), side, separating the fluids inside cells from their aqueous environment.
Fats are a subgroup of lipids called triglycerides, which are made up of glycerol and a long fatty acid chain. This chain is made up of hydrocarbons (hydrogen and carbon atoms) and is the major energy-yield compound in your body.
Types of Fats
There are three main types of fats: saturated, monounsaturated, and polyunsaturated. Saturated fats are solid at room temperature, and their fatty acid chains are made up of single carbon bonds. Common sources of saturated fats are animal products such as butter and lard. Plant sources include coconut oil and palm oil.
Monounsaturated fats contain only one double carbon bond while polyunsaturated fats have two or more double bonds. Both are liquid at room temperature. Sources of monounsaturated and polyunsaturated fats include avocados and fish oils (omega-3, omega-6), respectively.
Functions
Fat is vital to many functions in your body, including providing cellular membrane structure, maintaining healthy hair and skin, transporting fat-soluble vitamins (A, D, E, K), insulating your organs and protecting your body from shock. It also provides stored energy (9 calories per gram of fat) in the adipose tissues and skeletal muscles.
Nutrition Considerations
According to the American Heart Association, you should consume 20 to 25 percent of your diet from fat, with no more than 10 percent of total fat consumption from saturated fat. Ideally, get your daily fat intake from fish and plant sources, such as trout, bass, canola oil, corn oil, seeds, nuts and beans.
If you have heart disease, total fat should not exceed more than 20 percent of the daily intake. You can reduce fat intake by consuming whole grain foods, low-fat or nonfat products, fruits and vegetables.
Trans Fats
This type of artificial fat is made from healthy unsaturated fats that have their molecular structures altered by transferring some hydrogens in the fatty acid chain to the opposite sides of the carbon-to-carbon double bond. This process, known as hydrogenation, causes the fat to behave more like saturated fat, thereby becoming more solid at room temperature. Therefore, consuming trans fats can cause heart disease and other diseases that saturated fats can cause. These fats are often found in fried foods in restaurants, packaged cookies and cakes, breaded meats, chicken pot pies and hamburgers.
References
- "Nutrition From Science to Life"; Mary Grosvenor, Lori Smolin; 2002
- "What's the Skinny About Fatty Acids? Omega 3 Fats"; John Mamana; 2004
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