Fats and Other Lipids
Fat takes many forms.
You know about the good (monounsaturated fats) and the bad (trans fats), but what exactly are triglycerides or lipoproteins? Understanding the terms used by your doctor and the ones you see on nutrition labels is a crucial part of maintaining your health.
A waxy substance found in animal foods and produced by your liver, cholesterol is a part of every cell in your body, serving a variety of functions. In addition to building and maintaining the outer layers of our cells, it also aids in the production of bile (fluid stored in the gallbladder that helps with digestion), vitamin D, the hormone aldosterone (which helps the body regulate blood pressure) and certain sex hormones. While cholesterol is crucial for proper organ function, high levels of a certain type can be unhealthy (see LDL below).
Fat found in the foods we eat is called dietary fat. Along with protein and carbohydrates, dietary fat supplies energy to the body. Monounsaturated and polyunsaturated fats are examples of healthier dietary fats, while saturated and trans fats are considered less healthy as they can increase your risk of heart disease.
Essential Fatty Acids
As their name suggests, essential fatty acids are fats that the body needs but cannot create itself; they must be obtained from food or by taking supplements. The two basic types of essential fatty acids are omega-3 and omega-6.
Omega-3 fatty acids are found in picks like fatty fish, flaxseed oil, dark leafy greens and walnuts. They can decrease inflammation and regulate blood pressure, blood sugar and immune function, as well as reduce the risk of developing type 2 diabetes. Omega-6 fatty acids are found in animal fats and in certain types of oil. Gamma-linolenic acid (GLA) is a type of omega-6 that is found in primrose oil, borage oil and black currant seed oil and has been shown to help with allergies, arthritis and some cancers. Both omega-3 and omega-6 fatty acids are types of polyunsaturated fat (see below).
Often called “good cholesterol,” HDL stands for high-density lipoprotein. HDL works by carrying excess cholesterol that it finds in the bloodstream to your liver, where it is broken down to be excreted.
Found in certain margarines and vegetable shortenings, hydrogenated fat is the end result of a chemical process that converts liquid fat into a semi-solid state so that a product can have a long shelf life.
Hydrogenated fat is not considered part of a healthy diet, as it can raise the levels of LDL or “bad cholesterol” in your diet while lowering the levels of HDL. Partially hydrogenated fat may sound better for you than fully hydrogenated fat, but the opposite is true: Partially hydrogenated fat is just another name for trans fat (see below) and should be consumed as infrequently as possible
Often called “bad cholesterol,” LDL stands for low-density lipoprotein. LDL may collect in the walls of your blood vessels and can, over time, cause damage that puts you at a greater risk for heart attack.
The scientific term for liquid and solid fats, lipids store energy, aid in cell and hormone development and help the body to absorb, transport and store certain fat-soluble vitamins.
A combination of proteins and fat, lipoproteins are water soluble, which allows them to transport fat—most often in the form of cholesterol and triglycerides—through the bloodstream.
Found in a variety of foods and oils, monosmonounsaturated fats remain liquid at room temperature and can decrease your risk of heart disease. Canola and olive oils, avocados and almonds are a few foods that contain them.
Polyunsaturated fats are most often found in plant-based foods and oils, and, like monounsaturated fats, they also remain liquid at room temperature. Omega-3s and omega-6s are two important types of polyunsaturated fats. Good sources include fatty fish, peanuts, sunflower seeds, flax seeds and sesame, safflower, soybean and corn oil.
Found mostly in animal products such as meats, butter, cream cheese and milk, saturated fats remain solid or semi-solid at room temperature. Certain saturated fats raise LDL cholesterol levels, which can increase your risk of heart disease and type 2 diabetes. However, it’s important to point out that not all saturated fats contribute to increased cholesterol.
Stearic acid is a form of saturated fat (found in foods like coconut oil and dark chocolate) that has not been shown to raise LDL levels; it also increases plaque buildup in arteries less than other types of saturated fat.
The sum of polyunsaturated, monounsaturated, saturated and trans fat grams in a food represents its total fat content.
A byproduct of the hydrogenation process, which makes a polyunsaturated fat more stable for increased shelf life, trans fats are associated with elevation in LDL cholesterol, and may be linked to reproductive cancers, inflammation and osteoporosis.
When reading nutrition labels, pay attention to anything marked “partially hydrogenated vegetable oil,” which is another name for trans fat. The good news is that the FDA has given companies until 2018 to remove trans fats from their processed food products. Trans fats will still exist in meat and dairy products, where they naturally occur, and at low levels in oils (due to the manufacturing process).
A very common form of fat, triglycerides are stored in the body and released as energy. Diets high in fat, carbohydrates or alcohol can contribute to elevated triglyceride levels, which increase your risk of heart disease.