Phytanic acid is a branched chain fatty acid that humans can obtain through the consumption of dairy products, ruminant animal fats, and certain fish. Western diets are estimated to provide 50-100 mg of phytanic acid per day. In a study conducted in Oxford, individuals who consumed meat had, on average, a 6.7-fold higher geometric mean plasma phytanic acid concentration than did vegans.

Human pathology

Unlike most fatty acids, phytanic acid cannot be metabolized by β-oxidation

Beta oxidation

Beta oxidation is the process by which fatty acids, in the form of Acyl-CoA molecules, are broken down in mitochondria and/or in peroxisomes to generate Acetyl-CoA, the entry molecule for the Citric Acid cycle....

. Instead, it undergoes α-oxidation

Alpha oxidation

Enzymatic steps of alpha oxidation|right|thumb|250pxAlpha oxidation is a process by which certain fatty acids are broken down by removal of a single carbon from the carboxyl end...

 in the peroxisome

Peroxisome

Peroxisomes are organelles found in virtually all eukaryotic cells. They are involved in the catabolism of very long chain fatty acids, branched chain fatty acids, D-amino acids, polyamines, and biosynthesis of plasmalogens, etherphospholipids critical for the normal function of mammalian brains...

, where it is converted into pristanic acid

Pristanic acid

Pristanic acid is a terpenoid acid present at micromolar concentrations in the blood plasma of healthy individuals. It is also found in the lipids from many sources such as freshwater sponges, krill, earthworms, whales, human milk fat, bovine depot fat, butterfat or Californian petroleum. It is...

 by the removal of one carbon. Pristanic acid can undergo several rounds of β-oxidation

Beta oxidation

Beta oxidation is the process by which fatty acids, in the form of Acyl-CoA molecules, are broken down in mitochondria and/or in peroxisomes to generate Acetyl-CoA, the entry molecule for the Citric Acid cycle....

 in the peroxisome to form medium chain fatty acids that can be converted to carbon dioxide and water in mitochondria.

Individuals with adult Refsum disease, an autosomal recessive neurological disorder

Neurological disorder

A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...

 caused by mutations in the PHYH gene, have impaired α-oxidation activity and accumulate large stores of phytanic acid in their blood and tissues. This frequently leads to peripheral polyneuropathy, cerebellar ataxia

Cerebellar ataxia

Cerebellar ataxia is a form of ataxia originating in the cerebellum.-References:...

, retinitis pigmentosa

Retinitis pigmentosa

Retinitis pigmentosa is a group of genetic eye conditions that leads to incurable blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some...

, anosmia

Anosmia

Anosmia is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be either temporary or permanent. A related term, hyposmia, refers to a decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one...

, and hearing loss.

Presence in other organisms

In ruminant

Ruminant

A ruminant is a mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first compartment of the stomach, principally through bacterial actions, then regurgitating the semi-digested mass, now known as cud, and chewing it again...

 animals, the gut fermentation of ingested plant materials liberates phytol

Phytol

Phytol is an acyclic diterpene alcohol that can be used as a precursor for the manufacture of synthetic forms of vitamin E and vitamin K1. In ruminants, the gut fermentation of ingested plant materials liberates phytol, a constituent of chlorophyll, which is then converted to phytanic acid and...

, a constituent of chlorophyll

Chlorophyll

Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...

, which is then converted to phytanic acid and stored in fats. Recently, indirect evidence has been provided that the great apes

Great Apes

Great Apes may refer to*Great apes, species in the biological family Hominidae, including humans, chimpanzees, gorillas, and orangutans*Great Apes , a 1997 novel by Will Self...

 (bonobos

Bonobos

Bonobos is a dub band from Osaka, Japan. They formed in August of 2001. Their current lineup includes; Chunho Sai , Yasuyuki Sasaki , Natsuko Morimoto , Bondo Tsuji and Izumi Matsui...

, chimpanzees, gorillas, and orangutans), in contrast to humans, derive significant amounts of phytanic acid from the hindgut fermentation

Hindgut fermentation

Hindgut fermentation is a digestive process seen in monogastric herbivores, animals with a simple, single-chambered stomach. Cellulose is digested with the aid of symbiotic bacteria. The microbial fermentation occurs in the digestive organs that follow the small intestine, namely the large...

 of plant materials.

Freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 sponge

Sea sponge

Sponges are animals of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells, but can also have...

s contain terpenoid

Terpenoid

The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...

 acids such as 4,8,12-trimethyltridecanoic, phytanic and pristanic acid

Pristanic acid

Pristanic acid is a terpenoid acid present at micromolar concentrations in the blood plasma of healthy individuals. It is also found in the lipids from many sources such as freshwater sponges, krill, earthworms, whales, human milk fat, bovine depot fat, butterfat or Californian petroleum. It is...

s, which indicates that these acids may have chemotaxonomical

Chemotaxonomy

Chemotaxonomy , also called chemosystematics, is the attempt to classify and identify organisms , according to demonstrable differences and similarities in their biochemical compositions. The compounds studied in most of the cases are mostly proteins, amino acids and peptides...

 significance for both marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 and freshwater sponges.

Insects, such as the sumac flea beetle, are reported to use phytol

Phytol

Phytol is an acyclic diterpene alcohol that can be used as a precursor for the manufacture of synthetic forms of vitamin E and vitamin K1. In ruminants, the gut fermentation of ingested plant materials liberates phytol, a constituent of chlorophyll, which is then converted to phytanic acid and...

 and its metabolites (e.g. phytanic acid) as chemical deterrents against predation. These compounds originate from host plants.

Modulator of transcription

Phytanic acid and its metabolites have been reported to bind to and/or activate the transcription factors PPAR-alpha  and retinoid X receptor

Retinoid X receptor

The retinoid X receptor is a type of nuclear receptor that is activated by 9-cis retinoic acid. There are three retinoic X receptors : RXR-alpha, RXR-beta, and RXR-gamma, encoded by the , , genes, respectively....

(RXR).