Lipids are a type of macronutrient that provides you with energy. Lipids exist in almost all kinds of foods, especially in avocados, meats, fish, dairy products, grains, nuts and seeds. Despite the negative reputation that the media portray lipids, lipids, or fats, provide many different vital functions in your body, such as providing structures for cell membranes and transporting nutrients in your bloodstream.
Each type of lipid performs different tasks and interact with each other. Triglycerides provide structure to your adipose tissues and energy for your cells. Cholesterol provides structure for your cell membranes, steroid hormones and bile acids. Lipoproteins transport fats and other nutrients throughout your body in your bloodstream. Phospholipids are another component of your cell membranes and regulate the amount of fluid inside a cell.
Your adipose tissues contain a storage of fat-soluble vitamins -- A, D, E, K -- that your body releases into your bloodstream when your vitamin intake is low. These types of vitamins dissolve in fat and provide many vital functions to maintain your health. Cholesterol, a type of lipid, emulsifies fat-soluble vitamins and transports them through your intestines during absorption. Once in the bloodstream, cholesterol carries the vitamins to your adipose tissues for storage or delivers it to areas in your body where it is needed.
High-density lipoproteins, or HDL, are a type of lipid that carries cholesterol away from your artieries, while low-density lipoproteins, or LDL, carry cholesterol to your arteries. Dietitian Mary Grosvenor recommends that 85 percent of your daily fat intake come from unsaturated fats that raise HDL levels. This prevents accumulation of cholesterol in your blood vessels that can cause heart disease, high blood pressure and cancer.
Energy and Insulation
Lipids in the form of triglycerides are stored in your adipose tissues beneath your skin and around your organs. This forms a natural, protective layer of insulation that prevents excessive heat loss and minimizes damage from blunt trauma and shock. Your muscles use triglycerides for energy by breaking them down to their basic carbon and hydrogen components during and after exercise. Because each gram of fat has 9 calories, it is an excellent source of energy. According to sports dietitian Ellen Coleman, to use triglycerides for energy, you must have enough glucose to help initiate the fat-burning process. Otherwise, your body converts protein from your muscles to glucose, which can lower your metabolism.
Excellent sources of healthy, unsaturated fats include vegetable oils, nuts, seeds, legumes, avocados and cold-water fish. The American Heart Association recommends that you eat more of these foods to help you prevent cardiovascular diseases, inflammation and reduce your risks of getting cancer. Minimize foods containing high levels of saturated fats and cholesterol, such as fatty cuts of meat and organ meats.
- Nutrition From Science to Life; Mary Grosvenor
- American Heart Association; Triglycerides
- Ultimate Sports Nutrition; Ellen Coleman