Vitamin B9

Figure 1. The chemical structure of Folic Acid (precursor to Vitamin B9 or Folate).

Vitamin B9 or Folate is a micronutrient and one of eight essential B vitamins. Vitamin B9 is required for the body to make DNA and RNA and metabolise amino acids necessary for cell division. Vitamin B9 cannot be synthesised in the human body and must therefore be obtained via one's diet or supplementation. A popular supplement is Folic Acid, which is converted to Vitamin B9 in the human body. Folic Acid is commonly used as a supplement by women during pregnancy to reduce the risk of neural tube defects in the baby. Vitamin B9 also plays a key role in breaking down homocysteine, an amino acid that can exert harmful effects in the body (e.g. the heart) when present in high amounts. Vitamin B9 is needed to produce healthy red blood cells, thus is especially critical during periods of rapid growth, such as during pregnancy and fetal development.

Food Sources

A wide variety of foods naturally contain Vitamin B9, but the form that is added to foods and supplements, folic acid, is better absorbed. Examples of food sources include:

• Dark green leafy vegetables (turnip greens, spinach, romaine lettuce, asparagus, Brussels sprouts, broccoli)
• Beans
• Peanuts
• Sunflower seeds
  
• Whole grains
• Liver
• Seafood
• Eggs

Taken as a Dietary Supplement

As a dietary supplement, Vitamin B9 is used to treat Vitamin B9 deficiency. While rare, certain conditions may induce Vitamin B9 deficiency, including alcoholism, pregnancy, digestive disorders, or genetic mutations (which inhibit absorption of Vitamin B9). Symptoms of Vitamin B9 deficiency include:

• Megaloblastic anaemia (a condition arising from a lack of folate in the diet or poor absorption that produces less red blood cells, and larger in size than normal)
• Weakness, fatigue
• Irregular heartbeat
• Shortness of breath
• Difficulty concentrating
• Hair loss
• Pale skin
• Mouth sores.

The Recommended Dietary Allowance for Vitamin B9 for men and women ages 19+ years is 400 mcg. Pregnant and lactating women require 600mcg and 500mcg, respectively. The Tolerable Upper Intake Level for adults for Folic Acid is set at 1000 mcg daily. While Vitamin B9 toxicity is very unlikely, the upper intake limit is set because studies have shown that taking higher amounts can mask a Vitamin B12 deficiency (needed to make red blood cells), which can result in anaemia.

Background

Vitamin B9 (indirectly, Folic Acid) is listed in the World Health Organization's List of Essential Medicines.