A substance made or used when the body breaks down food, drugs or chemicals, or its own tissue names metabolite. The metabolites can be grouped into two major types: primary and secondary.
- Lipids, short peptides, nucleic acids, sugars, amino acids, alcohols, and organic acids generated naturally through metabolic processes like catabolism or anabolism are known as primary metabolites.
A primary metabolite is directly involved in normal growth, development, and reproduction. Some metabolites must be obtained from the diet or synthesized by genes found in the gut microflora which are referred to essential metabolites.
Essential metabolites include vitamins (such as vitamin K and biotin) and essential amino acids (valine, phenylalanine, leucine, isoleucine, histidine, methionine, lysine, threonine, and tryptophan).
Nutritional deficiency of these metabolites leads to diseases such as pellagra (lack of vitamin B3), rickets (lack of vitamin D) and kwashiorkor (lack of protein or essential amino acids).
- Secondary metabolites, also called natural products, are organic compounds of low molecular mass that are produced by bacteria (e.g., Bacillus spp., Pseudomonas spp., and Streptomyces spp.), fungi (e.g., Penicillium spp., Aspergillus spp., Trichoderma spp.), and plants of certain taxonomic groups.
Xenobiotic compounds, such as phytoestrogens, alkaloids, and polyphenols derived from dietary sources or the environment, as well as microbial byproducts, pollutants, chemical contaminants, and pesticides, are also considered metabolites.
However, unlike endogenous compounds known as primary metabolites, essential for an organism’s growth and development, these compounds are referred to as secondary metabolites and are not necessarily required for these processes.
