Vitamin B9

Vitamin B9, also known as folate or folic acid (the synthetic form), is a water-soluble vitamin that is part of the B-complex family. It plays a critical role in various biological processes, including DNA synthesis and repair, cell division, and the production of red blood cells. Folate is especially important during periods of rapid growth and development, such as pregnancy and infancy.


The discovery of vitamin B9 dates back to the 1930s. Folic acid was first identified by the American biochemist and nutritionist, Dr. Lucy Wills, in 1931. Dr. Wills discovered folic acid while conducting research on anaemia in pregnant women in India. She found that a certain yeast extract, later identified as folic acid, could be used to treat the anaemia. Her work laid the foundation for understanding the importance of folic acid in human health, particularly during pregnancy to prevent neural tube defects in developing foetuses.

Functions of Vitamin B9

Vitamin B9, also known as folate (or folic acid in its synthetic form), is essential for numerous biological processes within the body. Some of the primary functions of vitamin B9 include:

  • DNA synthesis and repair: Folate plays a crucial role in the synthesis and repair of DNA, the genetic material that carries instructions for the development, functioning, and reproduction of all living organisms.
  • Cell division and growth: Vitamin B9 is necessary for proper cell division and growth, as it helps in the formation of new cells and tissues, making it especially important during periods of rapid growth, such as pregnancy, infancy, and adolescence.
  • Red blood cell production: Folate is involved in the production of red blood cells, which are responsible for carrying oxygen throughout the body. A deficiency in vitamin B9 can lead to megaloblastic anaemia, a condition characterised by abnormally large and immature red blood cells.
  • Amino acid metabolism: Vitamin B9 is essential for the metabolism of certain amino acids, including the conversion of homocysteine to methionine. Elevated homocysteine levels have been linked to an increased risk of cardiovascular disease.
  • Neurotransmitter synthesis: Folate is involved in the synthesis of neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are critical for proper brain function and mood regulation.
  • Foetal development: Adequate folate intake is crucial during pregnancy, as it helps prevent neural tube defects, such as spina bifida and anencephaly, in developing foetuses.
  • Cognitive function: Vitamin B9 has been linked to cognitive function and memory, with some studies suggesting that adequate folate intake may help protect against age-related cognitive decline and dementia.

Good Sources Of Vitamin B9

Vitamin B9, or folate, is naturally found in a variety of foods. Consuming these foods can help ensure you get adequate amounts of this essential nutrient. Some good sources of vitamin B9 include:

  • Leafy green vegetables: Spinach, kale, collard greens, and other dark leafy greens are rich sources of folate.
  • Legumes: Beans, lentils, and peas are excellent sources of folate and provide additional nutritional benefits like protein and fibre.
  • Fruits: Citrus fruits like oranges, grapefruits, and lemons, as well as other fruits such as papaya, strawberries, and avocados, contain folate.
  • Nuts and seeds: Almonds, walnuts, sunflower seeds, and flaxseeds are good sources of folate.
  • Whole grains: Brown rice, barley, quinoa, and whole wheat products contain folate and other essential nutrients.
  • Vegetables: Asparagus, Brussels sprouts, broccoli, and cauliflower are good sources of folate.
  • Fortified foods: Some breakfast cereals, breads, and pastas are fortified with folic acid, the synthetic form of folate. Check the labels to find products with added folic acid.

Folic acid, the synthetic form of folate, is also available in supplements and is often recommended for women of childbearing age and pregnant women to prevent neural tube defects during foetal development. To maximise folate intake, consume a balanced and varied diet that includes a wide range of these food sources. Keep in mind that folate is sensitive to heat and light, so proper storage and minimal cooking time can help preserve the folate content in foods.

How Much Vitamin B9 Do We Need?

The recommended daily intake of vitamin B9 (folate) varies depending on age, sex, and life stage. The National Institutes of Health (NIH) provides the following Dietary Reference Intakes (DRIs) for folate:

  • Infants (0-6 months)*: 65 mcg (micrograms) DFE (Dietary Folate Equivalents) per day
  • Infants (7-12 months)*: 80 mcg DFE per day
  • Children (1-3 years): 150 mcg DFE per day
  • Children (4-8 years): 200 mcg DFE per day
  • Children (9-13 years): 300 mcg DFE per day
  • Teens (14-18 years): 400 mcg DFE per day
  • Adults (19 years and older): 400 mcg DFE per day
  • Pregnant women: 600 mcg DFE per day
  • Breastfeeding women: 500 mcg DFE per day

*For infants, the values provided are Adequate Intakes (AI) rather than DRIs, as there is not enough data to establish DRIs for this age group.

DFE (Dietary Folate Equivalents) is used to account for the differences in absorption between naturally occurring folate in foods and the synthetic form, folic acid. One mcg DFE is equal to 1 mcg of food folate or 0.6 mcg of folic acid from supplements and fortified foods.

These values are general guidelines, and individual needs may vary depending on factors such as overall health, lifestyle, and dietary choices. Most people can obtain adequate amounts of folate through.

What Are The Signs Of Vitamin B9 Deficiency?

Vitamin B9 (folate) deficiency can lead to various symptoms and health issues. Some common signs and symptoms of vitamin B9 deficiency include:

  • Fatigue and weakness: Folate is involved in the production of red blood cells, which carry oxygen throughout the body. A deficiency can lead to a reduced number of red blood cells (anaemia), causing fatigue and weakness.
  • Megaloblastic anaemia: A specific type of anaemia characterised by large, immature red blood cells that are unable to carry oxygen effectively. This condition can cause symptoms like fatigue, weakness, shortness of breath, rapid heartbeat, and pale skin.
  • Glossitis: Inflammation and soreness of the tongue, sometimes accompanied by changes in the colour and texture of the tongue.
  • Mouth sores and ulcers: Painful sores or ulcers can develop in the mouth as a result of a folate deficiency.
  • Gastrointestinal symptoms: Symptoms such as diarrhoea, loss of appetite, and weight loss may be present in some cases of vitamin B9 deficiency.
  • Cognitive symptoms: Folate deficiency can cause cognitive issues, such as difficulty concentrating, irritability, and forgetfulness. In severe cases, it may lead to depression or other mood disorders.
  • Neurological symptoms: A deficiency in vitamin B9 can result in peripheral neuropathy, which is characterised by tingling, numbness, or pain in the hands and feet.
  • Compromised immune function: A folate deficiency can weaken the immune system, making the body more susceptible to infections.
  • Birth defects: In pregnant women, a deficiency of vitamin B9 can lead to neural tube defects, such as spina bifida and anencephaly, in the developing foetus.

If you suspect you have a vitamin B9 deficiency, it is essential to consult with a healthcare professional for proper diagnosis and treatment.

What Happens If I Take Too Much Vitamin B9?

Vitamin B9, or folate, is a water-soluble vitamin, which means that excess amounts are generally excreted through urine, reducing the risk of toxicity. However, taking excessive amounts of the synthetic form, folic acid, in supplements or from fortified foods can have some potential side effects and risks:

  • Masking vitamin B12 deficiency: High levels of folic acid can mask the symptoms of a vitamin B12 deficiency, which can lead to nerve damage if left untreated. Both vitamin B12 and folate deficiency can cause megaloblastic anaemia, but only vitamin B12 deficiency can cause neurological problems. By alleviating the anaemia symptoms, excessive folic acid intake can delay the diagnosis and treatment of a vitamin B12 deficiency.
  • Increased risk of certain cancers: Some studies have suggested that high levels of folic acid may be associated with an increased risk of certain types of cancer, such as colorectal and prostate cancer. However, more research is needed to establish a clear link between excessive folic acid intake and cancer risk.
  • Cognitive effects in older adults: In some cases, high doses of folic acid have been linked to cognitive impairment and a decline in cognitive function in older adults, particularly when vitamin B12 levels are insufficient.
  • Potential drug interactions: Folic acid may interact with certain medications, such as anticonvulsants and chemotherapy drugs, which could reduce the effectiveness of the medications or affect the levels of folic acid in your body.

It is generally best to obtain nutrients, including folate, from a well-balanced and varied diet rather than relying on high-dose supplements. If you are considering taking folic acid supplements, consult with a healthcare professional to determine the appropriate dosage based on your specific needs. Pregnant women and women trying to conceive are often advised to take folic acid supplements to reduce the risk of neural tube defects, but it’s important to follow the recommended dosages and to consult with a medical doctor or other healthcare provider before starting any supplement regimen or adjusting dosages.