Vitamin B₉

Vitamin B9 is also known as folic acid and as folate. It is one of the group of B vitamins.

See also an overview of the main vitamins.

*Active Form of Vitamin B9:

The active form of vitamin B₉ is 5,6,7,8-tetrahydrofolate (THF), a chemical that is involved in the transfer of one-carbon units which are involved in the synthesis and elongation of many organic compounds.

*This information is useful to people who also need to understand the chemical reactions within the body, i.e. details about metabolism.

Functions of Vitamin B9:

The main functions of vitamin B₉ are :

• Synthesis of nucleic acids and other important biochemicals, including:
  • purines - which are important for the formation of nucleic acids because 2 of the 4 deoxyribonucleotides and 2 of the 4 ribonucleotides, the chemical "building-blocks" of DNA and RNA respectively, are purines.
  • adenosine monophosphate (AMP), also known as 5'-adenylic acid - a nucleotide used as a monomer in RNA.
  • guanosine monophosphate (GMP), also known as 5'-guanidylic acid or guanylic acid - a nucleotide used as a monomer in RNA.
  • thymidine, which is more precisely called pyrimidine deoxynucleoside and is also known as deoxythymidine, deoxyribosylthymine, and thymine deoxyriboside - the DNA nucleoside T, which pairs with deoxyadenosine in double-stranded DNA.
  • amino acids, e.g. glycine and methionine
• Cell division due to its role in synthesis of nucleic acids
• Production of healthy red blood cells, hence deficiency can lead to anaemia.
• In pre-conception & in early pregnancy folic acid is thought to help prevent neural tube defects and other congenital foetal malformations.
• Contribution to healthy heart functioning because vitamin B9 can help to reduce levels of the amino acid homocysteine, which it is thought may damage arteries if present in excessive amounts.
• Contribution to maintenance of strong bones, hence useful for protection against brittle bones, as in osteoporosis.
• Supports mental and emotional health.

Sources of Vitamin B9:

Examples of sources of vitamin B₉ (also called folic acid and folate) include:

• Green leafy vegetables (such as spinach, broccoli and brussel sprouts). Also peas.
• Some meats, e.g. liver, kidney
• Nuts e.g. peanuts
• Whole grains e.g. wholegrain cereals
• Breakfast cereals fortified with vitamin B9 (which may be listed as 'folic acid' or 'folate')
• Wheatgerm
• Yeast extract
• Bananas
• Avocados

Vitamin B9 is absorbed in the duodenum and the jejunum and can be stored in the body in small quantities, mainly in the liver. Humans are only able to store a small proportion of their daily requirement of vitamin B9 so a state of deficiency can develop in a fairly short time, e.g. over just a few months, if dietary intake is insufficient and especially if that occurs during a period of growth i.e. in children or teenagers.

Although vitamin B9 is present in many foods it is easily destroyed by food processing at high temperatures e.g. when cooking foods.

Problems due to insufficient or too much Vitamin B9:

See also vitamins, minerals, amino acids, what is a balanced diet? and the health benefits of drinking water.