Nutrition is about eating a healthy and balanced diet. Food and drink provide the energy and nutrients you need to be healthy. Understanding these nutrition terms may make it easier for you to make better food choices.

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Amino Acids

Amino acids are the building blocks of proteins. The body produces many amino acids and others come from food. The body absorbs amino acids through the small intestine into the blood. Then the blood carries them throughout the body.
Source: NIH MedlinePlus

Blood Glucose

Glucose — also called blood sugar — is the main sugar found in the blood and the main source of energy for your body.
Source: NIH MedlinePlus

Calories

A unit of energy in food. Carbohydrates, fats, protein, and alcohol in the foods and drinks we eat provide food energy or "calories."
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Carbohydrates

Carbohydrates are one of the main types of nutrients. Your digestive system changes carbohydrates into glucose (blood sugar). Your body uses this sugar for energy for your cells, tissues and organs. It stores any extra sugar in your liver and muscles for when it is needed. There are two types of carbohydrates: simple and complex. Simple carbohydrates include natural and added sugars. Complex carbohydrates include whole grain breads and cereals, starchy vegetables and legumes.
Source: NIH MedlinePlus

Cholesterol

Cholesterol is a waxy, fat-like substance that’s found in all cells of the body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. However, cholesterol also is found in some of the foods you eat. High levels of cholesterol in the blood can increase your risk of heart disease.
Source: National Heart, Lung, and Blood Institute

Dehydration

Dehydration is a condition that happens when you do not take in enough liquids to replace those that you lose. You can lose liquids through frequent urinating, sweating, diarrhea, or vomiting. When you are dehydrated, your body does not have enough fluid and electrolytes to work properly.
Source: NIH MedlinePlus

Diet

Your diet is made up of what you eat and drink. There are many different types of diets, such as vegetarian diets, weight loss diets, and diets for people with certain health problems.
Source: NIH MedlinePlus

Dietary Supplements

A dietary supplement is a product you take to supplement your diet. It contains one or more dietary ingredients (including vitamins; minerals; herbs or other botanicals; amino acids; and other substances). Supplements do not have to go through the testing that drugs do for effectiveness and safety.
Source: National Institutes of Health, Office of Dietary Supplements

Digestion

Digestion is the process the body uses to break down food into nutrients. The body uses the nutrients for energy, growth, and cell repair.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Electrolytes

Electrolytes are minerals in body fluids. They include sodium, potassium, magnesium, and chloride. When you are dehydrated, your body does not have enough fluid and electrolytes.
Source: NIH MedlinePlus

Enzymes

Enzymes are substances that speed up chemical reactions in the body.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Fatty Acid

Fatty acid is a major component of fats that is used by the body for energy and tissue development.
Source: National Cancer Institute

Fiber

Fiber is a substance in plants. Dietary fiber is the kind you eat. It's a type of carbohydrate. You may also see it listed on a food label as soluble fiber or insoluble fiber. Both types have important health benefits. Fiber makes you feel full faster, and stay full for a longer time. That can help you control your weight. It helps digestion and helps prevent constipation.
Source: NIH MedlinePlus

Gluten

Gluten is a protein found in wheat, rye, and barley. It can also be in products such as vitamin and nutrient supplements, lip balms, and certain medicines.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Glycemic Index

The glycemic index (GI) measures how a carbohydrate-containing food raises blood sugar.
Source: NIH MedlinePlus

HDL

HDL stands for high-density lipoproteins. It is also known as “good” cholesterol. HDL is one of the two types of lipoproteins that carry cholesterol throughout your body. It carries the cholesterol from other parts of your body back to your liver. Your liver removes the cholesterol from your body.
Source: National Heart, Lung, and Blood Institute

LDL

LDL stands for low-density lipoproteins. It is also known as “bad” cholesterol. LDL is one of the two types of lipoproteins that carry cholesterol throughout your body. A high LDL level leads to a buildup of cholesterol in your arteries.
Source: National Heart, Lung, and Blood Institute

Metabolism

Metabolism is the process your body uses to get or make energy from the food you eat.
Source: NIH MedlinePlus

Monounsaturated Fat

Monounsaturated fat is a type of fat is found in avocados, canola oil, nuts, olives and olive oil, and seeds. Eating food that has more monounsaturated fat (or "healthy fat") instead of saturated fat (like butter) may help lower cholesterol and reduce heart disease risk. However, monounsaturated fat has the same number of calories as other types of fat and may contribute to weight gain if you eat too much of it.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Nutrient

Nutrients are chemical compounds in food that are used by the body to function properly and maintain health. Examples include proteins, fats, carbohydrates, vitamins, and minerals.
Source: National Institutes of Health, Office of Dietary Supplements

Nutrition

This field of study focuses on foods and substances in foods that help animals (and plants) to grow and stay healthy. Nutrition science also includes behaviors and social factors related to food choices. The foods we eat provide energy (calories) and nutrients such as protein, fat, carbohydrate, vitamins, minerals, and water. Eating healthy foods in the right amounts gives your body energy to perform daily activities, helps you to maintain a healthy body weight, and can lower your risk for certain diseases such as diabetes and heart disease. 
Source: National Institutes of Health, Office of Dietary Supplements

Polyunsaturated Fat

Polyunsaturated fat is a type of fat that is liquid at room temperature. There are two types of polyunsaturated fatty acids (PUFAs): omega-6 and omega-3. Omega-6 fatty acids are found in liquid vegetable oils, such as corn oil, safflower oil, and soybean oil. Omega-3 fatty acids come from plant sources—including canola oil, flaxseed, soybean oil, and walnuts—and from fish and shellfish.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Protein

Protein is in every living cell in the body. Your body needs protein from the foods you eat to build and maintain bones, muscles, and skin. You get proteins in your diet from meat, dairy products, nuts, and certain grains and beans. Proteins from meat and other animal products are complete proteins. This means they supply all of the amino acids the body can't make on its own. Plant proteins are incomplete. You must combine different types of plant proteins to get all of the amino acids your body needs. You need to eat protein every day, because your body doesn't store it the way it stores fats or carbohydrates.
Source: NIH MedlinePlus

Saturated Fat

Saturated fat is a type of fat that is solid at room temperature. Saturated fat is found in full-fat dairy products (like butter, cheese, cream, regular ice cream, and whole milk), coconut oil, lard, palm oil, ready-to-eat meats, and the skin and fat of chicken and turkey, among other foods. Saturated fats have the same number of calories as other types of fat, and may contribute to weight gain if eaten in excess. Eating a diet high in saturated fat also raises blood cholesterol and risk of heart disease.
Source: National Institute of Diabetes and Digestive and Kidney Diseases

Sodium

Table salt is made up of the elements sodium and chlorine - the technical name for salt is sodium chloride. Your body needs some sodium to work properly. It helps with the function of nerves and muscles. It also helps to keep the right balance of fluids in your body.
Source: NIH MedlinePlus

Sugar

Sugars are a type of simple carbohydrate. They have a sweet taste. Sugars can be found naturally in fruits, vegetables, milk, and milk products. They are also added to many foods and drinks during preparation or processing. Types of sugar include glucose, fructose, and sucrose. Your digestive system breaks down sugar into glucose. Your cells use the glucose for energy.
Source: NIH MedlinePlus

Total Fat

Fat is a type of nutrient. You need a certain amount of fat in your diet to stay healthy, but not too much. Fats give you energy and help your body absorb vitamins. Dietary fat also plays a major role in your cholesterol levels. Not all fats are the same. You should try to avoid saturated fats and trans fats.
Source: NIH MedlinePlus

Trans Fat

Trans fat is a type of fat that is created when liquid oils are changed into solid fats, like shortening and some margarines. It makes them last longer without going bad. It may also be found in crackers, cookies, and snack foods. Trans fat raises your LDL (bad) cholesterol and lowers your HDL (good) cholesterol.
Source: NIH MedlinePlus

Triglycerides

Triglycerides are a type of fat found in your blood. Too much of this type of fat may raise the risk of coronary artery heart disease, especially in women.
Source: National Heart, Lung, and Blood Institute

Water Intake

We all need to drink water. How much you need depends on your size, activity level, and the weather where you live. Keeping track of your water intake helps make sure that you get enough. Your intake includes fluids that you drink, and fluids you get from food.
Source: NIH MedlinePlus