As a result, high-fat foods are a convenient source of energy. For example, 1 gram of fat or oil provides 9 calories compared with 4 calories found in 1 gram of carbohydrate or protein. Depending on the level of physical activity and on nutritional needs, fat requirements vary greatly from person to person.
When energy needs are high, the body welcomes the high-caloric density of fats. For instance, infants and growing children require higher amounts of fat to support normal growth and development.
If an infant or child is given a low-fat diet for an extended period, growth and development will not progress normally. Other individuals with high-energy needs are athletes, people who have physically demanding jobs, and those recuperating from illness. When the body has used all of its calories from carbohydrates which can occur after just twenty minutes of exercise , it initiates fat usage.
A professional swimmer must consume large amounts of food energy to meet the demands of swimming long distances, so eating fat-rich foods makes sense. In contrast, if a person who leads a sedentary lifestyle eats the same fat-rich foods, they will likely get more fat calories than their body requires. Fat contains dissolved compounds that contribute to mouth-watering aromas and flavors. Fat also adds texture to food and helps keep baked foods moist. Fats contribute to smooth, creamy, moist, tender, and crispy textures of various foods.
Frying foods locks in flavor and lessens cooking time. Fat plays another valuable role in nutrition. Fat contributes to satiety, or the sensation of fullness. In search of insight, Oklahoma State University biochemist Estela Arrese studies triglyceride metabolism in unexpected places: silkworms, fruit flies and mosquitoes.
The main type of fat we consume, triglycerides are especially suited for energy storage because they pack more than twice as much energy as carbohydrates or proteins. Once triglycerides have been broken down during digestion, they are shipped out to cells through the bloodstream. Some of the fat gets used for energy right away. The rest is stored inside cells in blobs called lipid droplets. When we need extra energy-for instance, when we run a marathon-our bodies use enzymes called lipases to break down the stored triglycerides.
The cell's power plants, mitochondria, can then create more of the body's main energy source: adenosine triphosphate, or ATP. Arrese works to identify, purify and determine the roles of individual proteins involved in triglyceride metabolism. Her lab was the first to purify the main fat regulation protein in insects, TGL, and now she is trying to learn what it does.
She also discovered the function of a key lipid droplet protein called Lsd1, and she is investigating its sister, Lsd2. Let us take this as an opportunity to learn more about lipids and how important they are for human health. Lipids include oils, fats and some steroids. They are a group of molecules built from fatty acids and are bonded to a variety of other compounds. They are of immense importance to the biological world.
They have important cell roles in human body. They are one of the four molecules of life but they have far more variations in their structure than nucleic acids, carbohydrates and proteins. All lipids are insoluble in water. Since they are repelled by water, they are known as hydrophobic molecules.
They create a protective layer around the cells to help maintain them. Most people never need to think much about phospholipids. However, there is a rare autoimmune disorder called antiphospholipid syndrome APS , in which proteins on these lipids are attacked.
The protective cell layers are damaged as a result. This disorder is seen more often in people with lupus , especially women.
As APS attacks blood cells and vessels, it poses a risk of blood clots that can lead to heart attacks and strokes. APS also may lead to pregnancy complications. Its common name, "sticky blood," is an apt description for what happens inside the body when things go awry with these key lipids.
Sterols are a subset of steroids, a type of hormone. You may be familiar with plant sterols phytosterols found in foods that offer health benefits. They are very similar to the primary sterol in humans— cholesterol. Cholesterol is processed in the liver and contributes to many critical body functions.
They include the making of hormones and vitamin D, as well as bile salts that work on fats so they can be absorbed by the cells. There are two types of proteins that carry cholesterol through the bloodstream: high-density lipoprotein HDL and low-density lipoprotein LDL.
Triglycerides are the fats and oils that you are familiar with in foods. This type of lipid can be saturated or unsaturated , which is part of what makes them solid or liquid, respectively, at room temperature.
Omega fatty acids are essential nutrients that come from certain foods you eat. Tuna and salmon are excellent sources, as are some nuts, seeds, and leafy vegetables. These fats reduce inflammation, blood pressure, and triglyceride levels.
They reduce the risk of sudden death by a heart attack and prevent blood clots from forming. Trans fats are fats that have been artificially hydrogenated so that they have a texture desired for processed foods. Eating foods that contain trans fats can lead to high levels of LDL cholesterol. Phospholipids help compose the protective layer that surrounds your cells.
Sterols are hormones. Triglycerides are fats and oils. Lipids are synthesized or stored to support the cells and assist in essential processes. Lipids also have many external uses. In addition to the phospholipid role in protecting cells, lipids are at work in many ways in your body.
Lipids are integral to the nervous system and found in its myelin sheaths. These are the fatty tissue sleeves that protect your nerve cells and increase the conduction of their impulses. Lipids make it possible for the body to use vitamins. Lipids help the body to absorb the fat-soluble vitamins A, D, E, and K:. These are only some of the vital benefits and functions of these important vitamins. Lipids are part of the production of certain hormones including estrogen , testosterone , and cortisol.
These play a role in the development of sexual characteristics and are needed to control your immune system and metabolism. They also help to balance your water and sodium levels, control inflammation, and help with your body's resilience and ability to heal. The main types of lipids include sterols, like cholesterol, and triglycerides.
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