There are five primary functions of carbohydrates in the human body. They are energy production, energy storage, building macromolecules, sparing protein, and assisting in lipid metabolism.
The primary role of carbohydrates is to supply energy to all cells in the body. Many cells prefer glucose as a source of energy versus other compounds like fatty acids. Some cells, such as red blood cells, are only able to produce cellular energy from glucose. The brain is also highly sensitive to low blood-glucose levels because it uses only glucose to produce energy and function unless under extreme starvation conditions.
About 70 percent of the glucose entering the body from digestion is redistributed by the liver back into the blood for use by other tissues. Cells that require energy remove the glucose from the blood with a transport protein in their membranes. The energy from glucose comes from the chemical bonds between the carbon atoms. Sunlight energy was required to produce these high-energy bonds in the process of photosynthesis.
Cells in our bodies break these bonds and capture the energy to perform cellular respiration. Cellular respiration is basically a controlled burning of glucose versus an uncontrolled burning. A cell uses many chemical reactions in multiple enzymatic steps to slow the release of energy no explosion and more efficiently capture the energy held within the chemical bonds in glucose. The first stage in the breakdown of glucose is called glycolysis. Glycolysis, or the splitting of glucose, occurs in an intricate series of ten enzymatic-reaction steps.
The second stage of glucose breakdown occurs in the energy factory organelles, called mitochondria. One carbon atom and two oxygen atoms are removed, yielding more energy. The energy from these carbon bonds is carried to another area of the mitochondria, making the cellular energy available in a form cells can use. Add or change institution. Save Preferences. Privacy Policy Terms of Use. Access your subscriptions. Free access to newly published articles. Purchase access.
Rent article Rent this article from DeepDyve. Access to free article PDF downloads. Save your search. Fats deliver 9 calories per gram of fat, compared to 4 calories in each gram of carbohydrates and proteins. You need dietary fats, not just for energy, but also because they help build cells, make hormones and digest fat-soluble nutrients.
The Institute of Medicine recommends getting 20 percent to 35 percent of your daily calories from fats. The best way to fill your daily requirement is with unsaturated fats because they help lower cholesterol.
You'll get these healthy fats from fish such as salmon, tuna and trout, canola oil, flaxseeds, walnuts and other nuts. As you create a diet that balances macronutrients, plan on filling 10 to 35 percent of your daily calories with protein. If your protein does not exceed 35 percent of your calories, then the rest of your diet should supply enough carbs and fats to support the protein-sparing effect. Lean meat, poultry, fish and soybeans have 20 to 25 grams of protein in a 3-ounce serving.
Beans are the next best source, with each cup supplying about 15 grams of protein. One cup of cooked quinoa has 8 grams of protein, while you'll get roughly 6 grams from 1 cup of cooked oatmeal, low-fat milk or yogurt and 1 ounce of cheese.
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