Lack of vitamin B9: Symptoms & treatments

[Article updated on 19/09/2023]

Vitamin B9, also called folic acid or folate, is a water-soluble component. This means that it is soluble in water. It is found in large quantities in green vegetables, such as broccoli or spinach. A vitamin B9 deficiency prevents the proper functioning of different mechanisms in the human body. It is important to know the symptoms linked to this anomaly, but also the possible treatments. I tell you about it in this article.

Before reading on

I’m not an expert in this field, but I am passionate about nutrition and health.

The articles you’ll find on my site are the result of in-depth research that I’d like to share with you. However, I would like to stress that I am not a health professional and that my advice should in no way replace that of a qualified physician. I’m here to guide you, but it’s important that you consult a professional for specific questions or medical concerns. Your well-being is important. So be sure to consult the appropriate experts and take the best possible care of yourself.

Vitamin B9

His role

Vitamin B9, folic acid and folate refer to the same nutrient. The difference ? Folates are found naturally in foods. Vitamin B9 and folic acid, on the other hand, are a synthesized form used as a supplement. The body is unable to synthesize vitamin B9, hence the need to seek it out in foods and supplements. A daily intake of the nutrient is important given its many functions, particularly in:

  • The design of genetic material, such as DNA or RNA;
  • Cell growth by synthesizing amino acids;
  • The production of red blood cells;
  • The course of wound healing and the immune system;
Everything you need to know about vitamin B9 deficiency
Vitamin B9, folic acid and folate refer to the same nutrient.

Regulation of homocysteine ​​production. It is a molecule that should not be in excess to avoid cardiovascular diseases.

Recommended daily intake

Here is the recommended daily intake of vitamin B9 according to your age:

  • Infant: 70µg/d
  • Child aged 1 to 3 years: 100 mcg/d
  • Child aged 4 to 6 years: 150µg/d
  • Child aged 7 to 9 years: 200µg/d
  • Child aged 10 to 12 years: 250µg/day
  • Adolescent aged 13 to 15: 300µg/day
  • Women from 16 years old: 330µg/d
  • Men from 16 years old: 330µg/day
  • Pregnant and breastfeeding women: 400µg/d

The National Agency for Food, Environmental and Occupational Health Safety recommends that pregnant women take a folic acid supplement of 400 mcg/day. It is recommended to administer it at least 2 months before pregnancy and 1 month after the start date of pregnancy.

Food sources of vitamin B9

Vitamin B9 is strongly present in legumes, green vegetables and organ meats, including:

  • Cooked legumes: 100 g = 300 µg
  • Boiled spinach: ½ cup = 140 mcg
  • Poultry offal: 100 g = 350 µg
  • Boiled broccoli: ½ cup = 90 mcg
  • Rich pasta: ½ cup = 120 µg
  • Cooked beets: ½ cup = 70µg
  • Sautéed veal or lamb liver: 100 g = 350 µg
  • Dehydrated hazelnuts, walnuts, filberts: ¼ cup = 40µg
  • Boiled asparagus: ½ cup = 135µg

Orange juice: ½ cup = 59µg

Good to know

Regarding vitamin B9, here is what you need to know:

  • Store foods containing it in the refrigerator: the nutrient is sensitive to heat, UV light and oxygen;
  • Favor steaming and/or stewing: the water-soluble nature of vitamin B9 is not suitable for cooking in open water;

Vitamin B9 deficiency


Consider taking a test to assess the level of vitamin B9 in your body if you have the following symptoms:

  • Tiredness ;
  • Irritability;
  • Headaches ;
  • Significant and prolonged stress;
  • Shortness of breath;
  • Heart palpitations;
  • Anemia;
  • Diarrhea;
Everything you need to know about vitamin B9 deficiency.
Symptoms such as irritability may appear in cases of vitamin B9 deficiency
  • Loss of appetite;
  • Weight loss;
  • Mood changes;
  • Difficulty staying focused;
  • Prolonged fever;
  • Renal function disorders;
  • Intestinal diseases;
  • Liver problems;
  • A problem with the renal system.

The causes

I present to you a list of reasons that could be the cause of vitamin B9 deficiency:

  • Genetics: it is impossible for the body of certain categories of people to convert vitamin B9 into a usable element, notably methylfolate.
  • Diet: a diet low in fruits and vegetables, but also in enriched cereals can be the cause of a lack of vitamin B9. Don’t hesitate to vary your diet. Also, it is important to favor cooking that retains as much folate as possible.
Everything you need to know about vitamin B9 deficiency.
A kidney problem can cause a vitamin B9 deficiency
  • Diseases: folate deficiency can be caused by diseases impacting the absorption mechanism in the gastrointestinal tract. Examples include celiac disease, Crohn’s disease, cancers and significant kidney disorders.
  • Alcohol: alcoholic beverages hinder the absorption of vitamin B9. They also promote significant excretion of folate through urine.
  • Medications: it is rather the side effects of medications that can cause folate deficiency. Trimethoprim-sulfamethoxazole, phenytoin, sulfasalazine and methotrexate may cause the problem. Freeze foods: frozen foods preserve vitamin B9 better.

Risk factors

Risk factors for lack of vitamin B9 may include:

  • Pregnancy ;
  • Difficulty in absorption;
  • Malnutrition or a poorly varied diet;
  • Childbearing age;
  • A genetic variation.

Possible complications

A severe folate deficiency worsens, to the point of causing:

  • Heart disease: vitamin B9 participates in the regulation of homocysteine, an element causing heart disease;
  • Anemia: a low amount of folate hinders the synthesis of red blood cells. This situation can cause megaloblastic anemia preventing the transport of oxygen in the body.
  • A neural tube defect or NTD: folic acid contributes to the development of the fetal spinal cord and brain. A deficiency at this level can lead to NTD, namely anencephaly and spina bifida.

Diagnosis of vitamin B9 deficiency

Blood testing is a way to determine the level of folate in the body. This operation is insufficient to determine the origin of anemia due to folate deficiency. Anemia due to folate deficiency can be caused by a lack of vitamin B12 or iron. The doctor can then ask the patient to carry out in-depth analyses.

Treatment of vitamin B9 deficiency

Choose foods that are sources of vitamin B9

Include foods rich in folate in your diet, especially those I mentioned above. Also, you can take a folic acid supplement. Although you take a folic acid supplement, it is important to eat a balanced diet. This allows you to meet other nutritional needs.

Everything you need to know about vitamin B9 deficiency.
Choose foods that are sources of vitamin B9

Invest, for example, in cereals that claim to be rich in folic acid on their label. Prefer to get advice from a doctor, whether you decide to take a folate supplement or not. If he recommends this option, the treatment can last around 4 months, or even more depending on the result. Regarding dosage, I recommend following your doctor’s instructions.

Precautions to take

Precautions should be taken when administering vitamin B9. The risks of overdose are low given that it is a water-soluble vitamin.

However, patients who have taken a quantity of folate greater than 5 mg/day have faced problems such as:

  • Gastrointestinal disorders;
  • An allergy ;
  • Sleep disorders.

Folic acid may interfere with the effectiveness of antiepileptic medications. It can also deprive microbes or cancer cells of folate. In any case, check with a doctor before taking a food supplement containing the nutrient.

Prevention of vitamin B9 deficiency

One of the best ways to prevent a folate deficiency is to eat a healthy, balanced diet. I have made a list of foods rich in vitamin B9 for you. Incorporate them regularly into your recipes. This will allow you to avoid cases of anemia due to folate deficiency. Fortunately, the FDA or Food and Drug Administration requires manufacturers to add folic acid to their products. This initiative aims to reduce the number of individuals suffering from deficiency. Flour and cereal products are among the foods affected by the new law.