Nutrients in foods
- Topic in Gardening courses
This page is about nutrients that plants provide. This topic is to be distinguished from the nutrients that plants themselves need for their growth, or plant nutrients.
Nutrients in foods do not only come from plants as humans also consume animal products. For the Gardening courses, however, the focus is on nutrients in food that come from plants.
Besides nutrients, plants can also give us active ingredients, substances in plants that have medicinal effects.
Macronutrients are those that are needed in larger quantities.
- Main article: Protein
Proteins form a class of nitrogenous (containing nitrogen) compounds that consist of large molecules of chains of amino acids. Proteins are an essential part of all living organisms, esp. structural components of body tissues such as muscles, hair, skin. They also exist in living bodies as enzymes and antibodies. Proteins are needed for cells to grow. Protein in food gives us calories, four calories in one gram.
Our bodies can make most amino acids. A few amino acids we must get from the food we eat. These are known as 'essential amino acids.'
- Main article: Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents (ether, chloroform, benzene) and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids .
Fats may be either solid or liquid at room temperature, depending on their structure and composition. Although the words "oils", "fats", and "lipids" are all used to refer to fats, "oils" is usually used to refer to fats that are liquids at normal room temperature, while "fats" is usually used to refer to fats that are solids at normal room temperature. "Lipids" is used to refer to both liquid and solid fats.
Fat is a nutrient that is an important source of calories. One gram of fat supplies 9 calories - more than twice the amount we get from carbohydrates or protein.
Fat also is needed to carry and store essential fat-soluble vitamins, like vitamins A and D.
- Main article: Carbohydrate
A carbohydrate is an organic compound consisting of carbon, hydrogen, and oxygen, with, in most cases, a hydrogen:oxygen atom ratio of 2:1 (as in water). In biochemistry the term is a synonym of saccharide. The word saccharide comes from the Greek word σάκχαρον (sákkharon), meaning "sugar".
In food science the term carbohydrate often means food that that is particularly rich in the complex carbohydrate starch (such as cereals, bread, and pasta) or simple carbohydrates, such as sugar (found in candy, jams, and desserts).
Carbohydrates are the body's main source of energy. Plant foods like cereals, bread, rice, pasta, potatoes, plantains and corn are good sources of starch. They give us the energy we need to do daily activities. These starchy foods also give us important vitamins and minerals.
Micronutrients are nutrients needed in very small amounts.
- Main article: Vitamin
Vitamins are natural substances found in plants and animals that are essential nutrients for human beings. Deficiencies of vitamins produce specific disorders. An organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet.
There are two types of vitamins: water-soluble and fat-soluble. There are 13 essential vitamins and each one has a special role to play within the body.
- Main article: Minerals in food
Dietary minerals (also known as mineral nutrients) are the chemical elements required by living organisms, other than the four elements Carbon, Hydrogen, Nitrogen, and Oxygen present in common organic molecules.
Minerals in food are sometimes divided in two categories.
- Main article: Organic acid
An organic acid is an organic compound with acidic properties. In general, organic acids are weak acids and do not dissociate completely in water. On the other hand, most organic acids are very soluble in organic solvents. Organic acids are used in food preservation because of their effects on bacteria.
A few common examples include: Lactic acid, Acetic acid, Formic acid, Citric acid, Oxalic acid, Uric acid.