Vitamin B9 (Folate)#

Folate is a water-soluble vitamin needed to make new cells - especially red blood cells - and to copy DNA. It is critical in early pregnancy because a developing baby's brain and spinal cord form in the first 4 to 6 weeks, often before a person knows they are pregnant.

• Folate is the natural form found in food.
• Folic acid is the synthetic form used in vitamins and added to fortified foods.

Both are used in the body in the same way. In Canada, white flour, pasta, and cornmeal are fortified with folic acid, which is why folate deficiency is rare.

• Serum folate measures folate floating in the blood. It changes quickly with what you ate that day or whether you recently took a supplement.
• RBC folate measures the folate stored inside your red blood cells. It reflects your average folate status over the previous 2 to 3 months.

RBC folate is a better test of long-term folate status. Serum folate is more useful only if you suspect very recent deficiency. Most labs in Canada can offer either.

• Dark leafy greens (spinach, kale, romaine lettuce)
• Broccoli, Brussels sprouts, asparagus, beets
• Avocado
• Legumes (lentils, chickpeas, black beans, kidney beans)
• Citrus fruits, papaya, banana
• Eggs
• Nuts and seeds
• Fortified breads, pasta, and breakfast cereals

Folate testing is reasonable if you have:

• Macrocytic anemia (large red blood cells on a CBC) of unknown cause
• Heavy alcohol use
• Conditions that affect absorption (celiac disease, Crohn's disease, prior bowel surgery)
• Severely restricted diet for long periods
• Pregnancy with high-risk features (previous baby with a neural tube defect, family history)
• Medications that interfere with folate (see medication list below)

• Healthy adults with a varied diet
• People who already take a daily multivitamin or prenatal vitamin
• Pregnancy screening in a healthy person with no risk factors - prevention with daily folic acid is the recommended approach, not testing

Generally no. Canadian guidelines (SOGC and Health Canada) recommend that anyone who could become pregnant take 0.4 mg (400 mcg) of folic acid daily for at least 2 to 3 months before pregnancy and through the first trimester, without needing a blood test first. Higher doses (up to 5 mg daily) are recommended if there is a higher-risk situation (previous baby with a neural tube defect, certain medications, diabetes, or family history). Testing is not required to make this recommendation.

Yes - this is an important interaction. Folate and B12 deficiency can both cause the same type of anemia (large red blood cells). Taking high-dose folic acid can correct the anemia of B12 deficiency, but the nerve damage from B12 deficiency continues to progress. For this reason, B12 should be checked alongside folate whenever there is any concern about deficiency.

• RBC folate: no fasting needed (reflects 2 to 3 months of stores, not what you ate today)
• Serum folate: ideally fasting, because a recent meal or supplement can raise the level. If your clinician ordered serum folate specifically, fast for 6 to 8 hours.

For serum folate, hold the supplement for at least 24 hours so the result reflects your stored level rather than a recent dose. For RBC folate, this is less important because the test reflects long-term stores.

Symptoms develop slowly and often overlap with B12 deficiency. They include:

• Fatigue
• Pale skin
• Shortness of breath on exertion
• A sore, smooth, red tongue ("glossitis")
• Sores at the corners of the mouth
• Difficulty concentrating, low mood
• Mild numbness or tingling

Many of these symptoms have other common causes. A blood test is needed to confirm folate deficiency.

• Inadequate dietary intake (rare in Canada because of food fortification)
• Heavy alcohol use - alcohol interferes with folate absorption and metabolism
• Pregnancy and breastfeeding (higher needs)
• Conditions that affect absorption (celiac disease, Crohn's disease, prior bowel surgery)
• Certain medications:
  • Some anti-seizure medications
  • Sulfa-based antibiotics
  • Bile-binding cholesterol medications
  • Anti-inflammatory drugs for autoimmune disease (such as the type used for rheumatoid arthritis or some autoimmune skin conditions)
  • Some chemotherapy medications

Most folate deficiency is corrected with over-the-counter folic acid supplements (typically 1 mg or 5 mg daily) for 2 to 4 months, until stores are replenished. If there is an underlying cause (alcohol use, celiac disease, medication side effect), that also needs to be addressed.

Anyone diagnosed with folate deficiency should also have vitamin B12 tested at the same time, because the two deficiencies look similar and B12 must be replaced separately if it is low.

Very high doses of folic acid from supplements can mask a B12 deficiency on a complete blood count (CBC). For this reason, the Tolerable Upper Intake Level for synthetic folic acid is 1 mg per day in healthy adults. Higher doses (such as 5 mg for high-risk pregnancy) should be supervised by a clinician.

There is no concern about getting too much folate from food alone.

Yes, when recommended by your obstetric care provider for a higher-risk pregnancy. The 5 mg dose is used for at least 12 weeks before pregnancy and through the first trimester in people with a higher-risk situation (previous baby with a neural tube defect, certain medications such as anti-seizure medications, diabetes, obesity, or family history). After the first trimester, the dose is usually reduced to the 0.4 to 1 mg range found in prenatal vitamins.

In most provinces, folate testing is not insured unless there is a specific clinical reason (such as macrocytic anemia on a CBC, malabsorption disease, or evaluating known deficiency). TeleTest will only order folate as an insured test when there is a documented clinical reason. Otherwise, you can pay an uninsured fee at the lab.

Folic acid is an inexpensive over-the-counter supplement in Canada - usually less than $10 for several months' supply at 1 mg per day. Prenatal vitamins typically contain 0.4 to 1 mg of folic acid and cost slightly more.