Steam and liquid water are two different forms of the same chemical (pure) substance: water.

Substance used by an organism to survive, grow, and reproduce.

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Mineral (nutrient)

The chemical elements ordered in the periodic table

In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life.


A bottle of B-complex vitamin pills
Calcium combined with vitamin D (as calciferol) supplement tablets with fillers.
Jack Drummond's single-paragraph article in 1920 which provided structure and nomenclature used today for vitamins

A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism.

Vitamin C

Water-soluble vitamin found in citrus and other fruits and vegetables, and also sold as a dietary supplement.

Vitamin C supplements at a drug store.
The Nobel prizewinner Linus Pauling advocated taking vitamin C for the common cold in a 1970 book.
Vitamin C biosynthesis in plants
Citrus fruits were among the first sources of vitamin C available to ships' surgeons.
James Lind, a British Royal Navy surgeon who, in 1747, identified that a quality in fruit prevented scurvy in one of the first recorded controlled experiments.
Albert Szent-Györgyi wrote that he won a Nobel Prize after he found a way to mass-produce vitamin C for research purposes when he lived in Szeged, which had become the center of the paprika (red pepper) industry.
Albert Szent-Györgyi, pictured here in 1948, was awarded the 1937 Nobel Prize in Medicine "for his discoveries in connection with the biological combustion processes, with special reference to vitaminC and the catalysis of fumaric acid".

Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, and the enzymatic production of certain neurotransmitters.


Steam and liquid water are two different forms of the same chemical (pure) substance: water.

Micronutrients are essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health.


Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals.

Red, blue, and purple colors of berries derive mainly from polyphenol phytochemicals called anthocyanins
Cucurbita fruits, including squash and pumpkin, typically have high content of the phytochemical pigments called carotenoids
Berries of Atropa belladonna, also called deadly nightshade

As a term, phytochemicals is generally used to describe plant compounds that are under research with unestablished effects on health, and are not scientifically defined as essential nutrients.


In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.

Idealized representation of a molecule of a typical triglyceride, the main type of fat. Note the three fatty acid chains attached to the central glycerol portion of the molecule.
Composition of fats from various foods, as percentage of their total fat
The obese mouse on the left has large stores of adipose tissue. For comparison, a mouse with a normal amount of adipose tissue is shown on the right.
Amounts of fat types in selected foods
Schematic diagram of a triglyceride with a saturated fatty acid (top), a monounsaturated one (middle) and a polyunsaturated one (bottom).
Margarine, a common product that can contain trans fatty acids
Cover of original Crisco cookbook, 1912. Crisco was made by hydrogenating cottonseed oil. The formula was revised in the 2000s and now has only a small amount of trans fat.
Wilhelm Normann patented the hydrogenation of liquid oils in 1902
Conversion of cis to trans fatty acids in partial hydrogenation
Reference ranges for blood tests, showing usual ranges for triglycerides (increasing with age) in orange at right.

Fats are one of the three main macronutrient groups in human diet, along with carbohydrates and proteins, and the main components of common food products like milk, butter, tallow, lard, salt pork, and cooking oils.


Chemical element with the symbol S and atomic number 16.

As a solid, sulfur is a characteristic lemon yellow; when burned, sulfur melts into a blood-red liquid and emits a blue flame.
Sulfur vat from which railroad cars are loaded, Freeport Sulphur Co., Hoskins Mound, Texas (1943)
Most of the yellow and orange hues of Io are due to elemental sulfur and sulfur compounds deposited by active volcanoes.
Sulfur extraction, East Java
A man carrying sulfur blocks from Kawah Ijen, a volcano in East Java, Indonesia, 2009
The structure of the cyclooctasulfur molecule, S8
Lapis lazuli owes its blue color to a trisulfur radical anion
Two parallel sulfur chains grown inside a single-wall carbon nanotube (CNT, a). Zig-zag (b) and straight (c) S chains inside double-wall CNTs
Pharmaceutical container for sulfur from the first half of the 20th century. From the Museo del Objeto del Objeto collection
Traditional sulfur mining at Ijen Volcano, East Java, Indonesia. This image shows the dangerous and rugged conditions the miners face, including toxic smoke and high drops, as well as their lack of protective equipment. The pipes over which they are standing are for condensing sulfur vapors.
Sulfur recovered from hydrocarbons in Alberta, stockpiled for shipment in North Vancouver, British Columbia
Production and price (US market) of elemental sulfur
Sulfuric acid production in 2000
Sulfur candle originally sold for home fumigation
Schematic representation of disulfide bridges between two protein helices
Effect of acid rain on a forest, Jizera Mountains, Czech Republic
Allicin, a chemical compound in garlic
(R)-cysteine, an amino acid containing a thiol group
Methionine, an amino acid containing a thioether
Diphenyl disulfide, a representative disulfide
Perfluorooctanesulfonic acid, a surfactant
Dibenzothiophene, a component of crude oil
Penicillin, an antibiotic where "R" is the variable group

Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms.

Protein (nutrient)

Amino acids are the building blocks of protein.
Amino acids are necessary nutrients. Present in every cell, they are also precursors to nucleic acids, co-enzymes, hormones, immune response, repair and other molecules essential for life.
Protein milkshakes, made from protein powder (center) and milk (left), are a common bodybuilding supplement
An education campaign launched by the United States Department of Agriculture about 100 years ago, on cottage cheese as a lower-cost protein substitute for meat.
A child in Nigeria during the Biafra War suffering from kwashiorkor – one of the three protein energy malnutrition ailments afflicting over 10 million children in developing countries.

Proteins are essential nutrients for the human body.


Biosynthesis of choline in plants
Main pathways of choline (Chol) metabolism, synthesis and excretion. Click for details. Some of the abbreviations are used in this section.

Choline is an essential nutrient for humans and many other animals.

Cofactor (biochemistry)

Non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst .

The succinate dehydrogenase complex showing several cofactors, including flavin, iron–sulfur centers, and heme.
A simple [Fe2S2] cluster containing two iron atoms and two sulfur atoms, coordinated by four protein cysteine residues.
The redox reactions of nicotinamide adenine dinucleotide.

Coenzymes are mostly derived from vitamins and other organic essential nutrients in small amounts.