Nutrients: Definition, Types

What are nutrients?

By definition, a nutrient is any substance that is absorbed and either provides you with energy or enables growth, repair or proper functioning of your body.

Examples of nutrients and their functions:

• Starch and its breakdown product glucose provide you with energy.
• Proteins build muscles and form enzymes.
• Lipids form the cell membranes and certain hormones.
• Potassium and sodium enable the proper functioning of the nerves.
• Vitamin C is necessary for the wound healing.

Nutrient Functions

Nutrients are substances intended primarily to nourish your body and not to treat diseases. Nutrients can be, of course, used to treat diseases caused by nutrient deficiencies–for example, vitamin C is used to treat scorbut–and, in rare cases, some other diseases, for example, magnesium sulfate injections are used to treat seizures during pregnancy.

Nutrients Sources

You usually get nutrients from foods and beverages. You can also get them from the dietary supplements in the form of pills or liquids, by intravenous or intramuscular injections or transdermal patches applied on the skin.

Nutrients Types

Macronutrients or Mayor Nutrients, and Micronutrients

Macronutrients include carbohydrates, proteins, lipids (fats) and also alcohol (ethanol). You consume them in great, that is “gram,” amounts. They provide you with energy and building blocks for your body growth and repair.

Micronutrients include vitamins and minerals. You usually consume them in small, that is “milligram,” amounts. They, for example, help to build your bones, enable muscle contractions, transport oxygen via the blood; they have many other functions in your body.

Trace minerals include chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium and zinc. You usually consume them in very small, that is “microgram,” amounts, but they are all essential for your health.

Water, Dietary Fiber and Alcohol

You often do not find water, dietary fiber and alcohol on the nutrients lists, but they are proper nutrients because they are absorbed and have beneficial effects in your body.

Organic and Inorganic Nutrients

Organic nutrients are typically found in living beings: in humans, animals and plants. They include carbohydrates, proteins, lipids and vitamins. Organic nutrients posses carbohydrate-hydrogen (C-H) bonds ^[3].

Inorganic nutrients are typically found in non living things, but, in smaller amounts, also in living beings. They include minerals. Water can be also considered an inorganic nutrient. Inorganic nutrients do not posses carbon-hydrogen (C-H) bonds ^[3].

Both organic and inorganic nutrients are equally important. Organic nutrients are not “better” or “healthier.”

Fat and Water Soluble Nutrients

Lipids (fats and cholesterol), vitamins A, D, E and K are fat soluble ^[2]. When consumed in excess, they can be stored in your body fat for more than few months. All other vitamins, minerals, proteins and digestible carbohydrates are water soluble; only some of them can be stored in your body for a prolonged time, for example, calcium and phosphorus in the bones, proteins in muscles and glucose (in the form of glycogen) in the liver. Other water soluble nutrients are regularly excreted from the body so you need to replace them frequently.

Essential Nutrients

Essential nutrients are necessary for health, but cannot be produced in your body in sufficient amounts or at all, so you need to obtain them from foods or dietary supplements. They include all vitamins, certain minerals, 9 amino acids, 2 fatty acids and water.

What are not nutrients?

• Substances found in foods but not absorbed into your body, for example, a synthetic sugar lactulose, which passes the gut and is completely removed with the stool.
• Substances found in foods, absorbed but not used in your body and therefore excreted unchanged, such as a sweetener saccharin.
• Food contaminants, absorbed in your body that stay in your body but have harmful rather than beneficial effect, for example, mercury.
• Probiotics, which are live or dead microorganisms (bacteria or yeasts) that do not pass from the gut into the blood but can have beneficial effects on the intestine.
• Drugs that are not necessary for the functioning of the healthy human body, for example, aspirin.