Vitamins and natural products

Vitamin B9 (Folic Acid)

Vitamin B9, also called folic acid and folate, is water soluble. It cannot be stored in fat. Vitamin B9 must be supplied by food because the body cannot make it. Its synthetic form, folic acid, is used as a supplement, while folate occurs naturally in plant foods. 

Vitamin B9 enters into the synthesis of DNA and RNA, which are necessary for protein formation. It is therefore especially important during periods of rapid growth such as fetal development, childhood, and adolescence, due to its role in the production of new cells. 


What does vitamin B9 do? 

Vitamin B9 plays a major role in: 

  • Red blood cell formation;
  • Nervous and immune system functioning;
  • The healing of injuries and wounds;
  • Reducing the risks of neural tube malformations in fetuses;
  • Lowering the risk of cardiovascular diseases.


Recommended Dietary Allowances for Vitamin B9 (Folates): 

Amount (µg*)
Birth to 6 months
7 to 12 months
1 to 3 years
4 to 8 years
9 to 13 years
Age 14 and older
Pregnant women
Nursing mothers

Source: Food and Nutrition Board, Institute of Medicine, Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, 2000. The above data reflects a consensus between Canadian and U.S. health authorities.

*µg = microgram = millionth of a gram.

**Lacking sufficient scientific evidence, authorities have established adequate intake (AI) amounts rather than recommended dietary allowances (RDAs). Adequate folic acid intake is based on observed average intakes in North American babies in good health.

Note: The body absorbs vitamin B9 supplements better when they are taken with a meal.


Vitamin B9 is found in a number of foods, including legumes, dark green vegetables, liver, milk, and cheese, among others. Since vitamin B9 is sensitive to air, light, and heat, its content in some foods can be affected by canning, freezing, or cooking. 

Food Sources for Vitamin B9 (Folates): 

Portion Size
Poultry offal, roasted or braised
100g (3.5oz)
Lamb and calf liver, sautéed
100g (3.5oz)
Legumes, cooked
100g (3.5oz)
Pork liver, braised or sautéed
100g (3.5oz)
100g (3.5oz)
Spinach, boiled
125ml (0.5 cup)
Asparagus, boiled
125ml (0.5 cup)
Enriched pasta, cooked
125ml (0.5 cup)
60ml (0.25 cup)
Soybeans, boiled or sautéed
125ml (0.5 cup)
Broccoli, boiled
125ml (0.5 cup)
Romaine lettuce
250ml (1 cup)
Sunflower seeds, roasted
60ml (0.25 cup)
Sunflower seed butter
30ml (2 tbsp.)
Beets, cooked
125ml (0.5 cup)
Sprouted soybeans
125ml (0.5 cup)
Spinach, raw
250ml (1 cup)
Orange juice
125ml (0.5 cup)
Brussels sprouts, cooked
4 sprouts (80 g)
Okra (gumbo), boiled
125ml (0.5 cup)
Walnuts, hazelnuts and filberts, dehydrated, not blanched
60ml (0.25 cup)

Source:; Health Canada, Canadian Nutrient File, versions 2001b et 2005; U.S. Department of Agriculture (USDA), National Nutrient Database for Standard Reference.

*µg = microgram = millionth of a gram.


Vitamin B9 deficiency is common in our society, which tends to consume more high-fat, refined, manufactured food products at the expense of adequate fruit and vegetable intake. 

Deficiencies occur in some people in the following situations: 

  • Pregnancy and nursing;
  • Alcoholism;
  • Sustained diarrhea;
  • Persistent fever;
  • Anemia;
  • Intestinal illnesses;
  • Liver disease;
  • Renal function disorder (hemodialysis);
  • Constant stress;
  • Stomach surgery.

Note: Since oral contraceptives deplete folic acid reserves, it is a good idea to stop using contraception at least six months before conception to make sure that the fetus receives an adequate supply of folic acid during the first trimester of development. It is recommended that you take 0.4 mg of supplemental folic acid a day at least three months before conception and throughout the first trimester. 

If you already have a child with a neural tube anomaly or there is history of it in your family, talk to your doctor. Some women need up to 5 mg a day. 

Diabetics, epileptics, and the obese run a higher risk of bearing a child with a neural tube anomaly and should consult their doctor before planning a pregnancy. 

Signs of vitamin B9 (folic acid) deficiency: 

  • Diarrhea;
  • Appetite and weight loss;
  • Tongue inflammation (glossitis);
  • Headaches;
  • Heart palpitations;
  • Irritability and mood swings.

Severe deficiency can cause red blood cell depletion in the blood, altered mucous in the cervix, intestines, stomach, and vagina (cells become malignant), and growth delays. 

Adverse effects

None at normal doses. 

Signs of excess vitamin B9 (more than 5 mg a day): 

  • Onset or worsening of neurological complications (tingling or numbness of extremities, difficulty walking, loss of memory, dementia, mood disorder) in people suffering from vitamin B12 deficiency;
  • Digestive problems;
  • Irritability;
  • Confusion;
  • Disturbed sleep cycles;
  • Allergic reaction (rare).


Folic acid supplements can increase the risk of neurological disorders in people who: 

  • Suffer from vitamin B12 deficiency because excess folic acid could mask their vitamin B12 deficiency;
  • Are vegetarian;
  • Are elderly and suffer from atrophic gastritis;
  • Suffer from pernicious anemia;
  • Exhibit small bowel bacterial overgrowth.


Natural health products and vitamin supplements: 

  • none. 


  • Drug interactions are quite numerous. Several medications increase the elimination of folic acid or cause a deficiency with prolonged treatment. Conversely, some medications decrease its absorption or efficacy.
  • Folic acid can also reduce the blood level of certain drugs.

Examples of medications that can alter the nutritional status of folic acid: 

  • Anticonvulsants such as phenobarbital, phenytoin, primidone, carbamazepine, valproic acid, and divalproex;
  • Antibiotics such as tetracycline and trimethoprim;
  • Non-steroidal anti-inflammatory drugs or NSAIDs (aspirin, ibuprofen) in high doses and over a long period of time;
  • Antacids (proton pump inhibitors, histamine-2 inhibitors);
  • Oral contraceptives;
  • Anti-cholesterol drugs such as cholestyramine and cholestipol;
  • Medications to treat ulcerative colitis (sulfasalazine);
  • Drugs used to treat cancer, psoriasis, and rheumatoid arthritis such as methotrexate.

Note: Alcohol consumption can aggravate folate deficiency. Chronic smokers are also at risk of developing folic acid deficiency. 

Additional information

Speak with your pharmacist if you plan to take B9 supplements. Your pharmacist can help you choose the solution that’s best for you based on your health and any drugs you take. 

Other names

Vitamin B9, Folic acid, Folate, Folacin