What Are the Health Benefits?

Vitamin B12 is an essential vitamin, but it’s not one your body can produce. Instead, it is found naturally in many animal products.

Vitamin B12 is necessary for many processes in your body, including:

• maintaining your ability to think
• regulating and creating DNA
• producing energy
• keeping your brain and nervous system healthy

Your liver stores extra vitamin B12 for times when you consume less of it. But if those reserves run out, you may experience negative health effects.

Low vitamin B12 levels may cause symptoms such as:

• tingling in your hands and feet
• difficulty walking
• confusion and memory loss
• depression and irritability
• problems with smell, taste, or vision
• heart palpitations
• fatigue
• headaches
• pale skin
• weight loss
• glossitis (a painful, smooth, red tongue)

It’s important to treat low vitamin B12 levels to prevent anemia. Vitamin B12 is associated with a particular type of anemia known as megaloblastic anemia.

If you have anemia due to a lack of vitamin B12, your red blood cells may be larger and more oval-shaped than usual. This irregular shape can prevent the red blood cells from moving from your bone marrow to your bloodstream at a typical rate.

For most adults, the recommended daily intake of vitamin B12 is 2.4 micrograms (mcg).

However, the recommendation is slightly higher for people who are pregnant or nursing, at 2.6 mcg per day. And infants up to 6 months old need only 0.4 mcg daily.

Vitamin B12 is water-soluble. Your body can store it for 2–5 years and will release any extra B12 in your urine.

Many people can get enough vitamin B12 from the foods they eat each day. But because vitamin B12 is not present naturally in plant-based foods, vegans and vegetarians may need to consume foods that are fortified with it.

Oral supplements are also an option to help boost your vitamin B12 level. If your diet is low on foods that contain vitamin B12 or your body cannot appropriately digest those foods, a healthcare professional may recommend that you take an oral supplement each day.

Typically, your body absorbs vitamin B12 in a two-part process.

First, acid in your stomach separates B12 from the protein it’s attached to. Then, the B12 combines with a protein in your stomach called the intrinsic factor, and your body absorbs this pair in your ileum (the last part of your small intestine).

When you consume vitamin B12 as a supplement, your body may skip the first part of this process. That means injections may work better for you.

If you have a vitamin B12 deficiency, a healthcare professional may recommend that you receive injections to raise your B12 level. Vitamin B12 injections are also called hydroxycobalamin in the United States.

If you have anemia due to a low vitamin B12 level, you may need an injection every other day for 2 weeks or until your symptoms begin to improve.

B12 supplements and diet changes may not be effective in treating a deficiency caused by a medical condition, which is why doctors often recommend injections.

Foods high in vitamin B12 include:

• fish and seafood such as salmon, clams, and oysters
• lean red meat and chicken
• fortified breakfast cereals
• eggs
• dairy products such as milk, cheese, and yogurt

Vitamin B12 is not usually considered toxic, even at high levels. But vitamin B12 injections can cause some side effects, such as:

• pain, redness, and swelling at the injection site
• nausea and vomiting
• dizziness
• headaches

It’s important to let your doctor know if you experience serious side effects, such as heart palpitations, after a vitamin B12 injection.

Low vitamin B12 levels may cause diarrhea or constipation.

Additionally, a lack of vitamin B12 can prevent your red blood cells from providing enough oxygen to your digestive tract. This can lead to nausea, vomiting, gas, and bloating.

Vitamin B12 is important for the health of your cells and nervous system. Low vitamin B12 levels can cause tingling in your hands and feet, difficulties with mental function, and fatigue.

You can get more vitamin B12 by eating certain animal products and fortified foods. If you have a low vitamin B12 level, a healthcare professional may recommend injections or oral supplements.