Although it's always best to get your nutrients from food, you may require a vitamin B12 supplement as a complement to meet your nutrient needs due to a reason that makes you prone to a deficiency. It's important to know how much you should take and if there is a best time to take B12 to get the optimal health benefits from your supplement.
What Is Vitamin B12?
Known as cobalamin, vitamin B12 is one of a group of eight vitamins that make up the B-complex group. Vitamin B12 benefits many metabolic functions in your body, including keeping your nervous and neurological systems healthy. Vitamin B12 is needed for the production of red blood cells and the synthesis of proteins, such as hormones and enzymes that are required for digestion.
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Read more: Vitamin B12 Benefits & Side Effects
How Much Do You Need?
As with most vitamins, your body cannot make vitamin B12. Although you don't need a lot of it, you must get enough from food or supplements to meet your needs to take advantage of vitamin B12 benefits to keeping you healthy. According to the National Institutes of Health, your average daily recommended intake depends on your age and gender and is as follows:
- Children: ages 1 to 3 years — 0.9 micrograms; ages 4 to 8 years — 1.2 micrograms; ages 9 to 13 — 1.8 micrograms
- Teens: ages 14 to 18 years — 2.4 micrograms
- Adults: 2.4 micrograms
- Pregnant women: 2.6 micrograms
- Breastfeeding women: 2.8 micrograms
Reasons to Take B12 Supplements
You may find you are one of the 1.5 to 15 percent of the population deficient in vitamin B12, no matter how much vitamin-rich food you eat. If your body is not absorbing vitamin B12 properly, or if your demands for the vitamin are higher, it may be due to a condition that requires you to take supplements. Some of these conditions include:
- A vegetarian or vegan diet
- Recovery from gastrointestinal or weight-loss surgery
- Pregnancy or breastfeeding
- Drug or alcohol abuse
- Medications that reduce stomach acid, such as heartburn drugs
- Medical conditions that interfere with vitamin absorption, such as Crohn's or celiac disease
- Pancreatic cancer or gastrointestinal disorders
- Elderly people with low levels of stomach acid
- Pernicious anemia, an autoimmune condition that affects your stomach
Vitamin B12 Deficiency
A deficiency in vitamin B12 can develop slowly with gradual symptoms intensifying over time. Usually, a blood test is needed to confirm a vitamin B12 deficiency and your need for a supplement. Symptoms may include:
- Sensations of numbness and tingling in the hands, legs or feet
- Difficulty walking and problems with balance
- Swelling or inflammation of the tongue
- Impaired cognitive difficulties or memory loss
- Weakness and fatigue
Early detection of a deficiency and treatment is important as low vitamin B12 can cause severe neurological problems and blood diseases.
Food Sources of Vitamin B12
Vitamin B12 is produced by bacteria in the bodies of certain animals, so foods containing B12 are only animal-based foods. Beef liver and clams contain the most vitamin B12 per serving. Plant-based foods are often fortified with B12, useful if you don't eat meat or fish. Examples of foods containing vitamin B12 include:
- Meat: beef, pork, lamb, venison, organ meats
- Fish and seafood
- Poultry: chicken, duck, turkey
- Dairy products: milk, cheese, yogurt, cream, eggs
- Fortified foods: such as grains, cereals and health bars, plant milks, nutritional yeast and some soy products
Vitamin B12 Supplements
If you are at risk of being deficient in vitamin B12, especially if you are a vegetarian or have a medical condition, you should take preventative measures to ensure an adequate intake with the use of supplements, advises a study in the February 2013 Nutritional Reviews.
As a supplement, vitamin B12 is usually cyanocobalamin, which is a form that is readily converted into active methylcobalamin and 5-deoxyadenosylcobalamin by your body. Dietary supplements can also contain other forms of B12. All forms have similar absorption and bioavailability. Dietary supplements use crystalline vitamin B12, which are efficiently absorbed even in the absence of stomach acid.
You have a number of choices when it comes to taking vitamin B12. Supplements are available in individual B12 forms, included in multivitamins or B-complex vitamins, or combined with added nutrients, such as folic acid. You can take vitamin B12 in various ways, including:
- Oral capsule or tablet
- Sublingual (dissolved under tongue)
- Chewable pill
- Nasal gel
- Injected intramuscularly by your health care practitioner
Best Time to Take B12
There are several factors to consider when deciding when is the best time to take B12.
B vitamins are water-soluble and excess amounts are generally excreted with your urine. Many multivitamins contain a high B12 dosage, as much as 25 micrograms, which is more than 400 percent of the recommended daily value, according to Harvard Health Publishing.
Although vitamin B12 can be stored in your liver, if you are taking supplements to treat a deficiency, not all of the vitamin B12 can be used by your body at once. For example, about 20 micrograms from a 1,000 microgram oral B12 dosage supplement are absorbed by your body. Therefore, instead of taking a high B12 dosage in a supplement all at once, splitting the amount can ensure steady blood levels.
If the vitamin B12 is in the form of a time-release capsule, it will dissolve much slower and over an extended period of time. With the vitamin released incrementally into your blood, you eliminate the chance of excreting too much excess from your body.
Morning or Night?
Since B vitamins, including B12, are used by your body to boost energy and to stimulate your metabolism and nervous system, taking your supplement in the morning and early afternoon may make more sense than taking it when you are getting ready for bed. Taking B12 at night may affect your ability to fall asleep.
In addition, vitamin B12 supplements should be taken with food to avoid digestive upsets, and you may not feel like eating right before bedtime. Since your digestion slows down while you are sleeping, taking your supplement at night might not be associated with the most efficient use of all vitamin B12 benefits.
However, if you are taking vitamin B12 as part of your prenatal supplement, and it increases your feeling of nausea or morning sickness, consider taking the vitamin at bedtime with a small amount of food.
Keep a Schedule
Whether you take your B12 supplement in the morning or later in the day, it's important that you maintain a regular schedule and pick a time you'll remember.
Perhaps you could keep your supplement on your kitchen counter next to your coffee pot, so it jogs your memory when you reach for your morning cup. When taking supplements, it's really all about you assessing your own lifestyle and needs.
Read more: The Side Effects of Too Much Vitamin B12
Side Effects and Interactions
If you take high-dose vitamin B12 supplements to treat a deficiency, you may experience some side effects, including:
Vitamin B12 has a low potential for toxicity, but high amounts may interact with certain medications. Some possible interactions include:
- Aminosalicylic acid, used to treat digestive problems
- Colchicine, an anti-inflammatory drug used to treat gout
- Metformin, a diabetes drug
- Proton pump inhibitors or other stomach acid-reducing drugs
- Vitamin C supplements — take vitamin C at least two hours after taking a vitamin B12 supplement.
Always consult with your health care provider before taking any supplements, especially if you are on other supplements or medications.
- National Institutes of Health: "Vitamin B12"
- Harvard Health Publishing: "Vitamin B12 Deficiency Can be Sneaky, Harmful"
- Nutritional Reviews: "How Prevalent Is Vitamin B(12) Deficiency Among Vegetarians?"
- Nutrients: "Intakes of Folate and Vitamin B12 and Biomarkers of Status in the Very Old: The Newcastle 85+ Study"
- Harvard Health Publishing: "The A List for Vitamin B-12 Sources"
- MedlinePlus: "Vitamin B12"
- Drugs.com: "Cyanocobalamin (B12) Chewable Tablets"
- MayoClinic: "Vitamin B-12"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.