Many people associate vitamin B12 with their energy levels. If you’re living with systemic lupus erythematosus (SLE), you may be curious whether symptoms such as tiredness and fatigue could be connected to levels of vitamin B12.

One MyLupusTeam member asked, “I found out my vitamin B12 was a little low. Has anyone else had this with lupus?”

While researchers don’t know if lupus can directly cause low vitamin B12 — also known as a vitamin B12 deficiency — some medications and conditions associated with lupus may make it more likely.

What Is Vitamin B12?

Vitamin B12 — also called cobalamin — is an essential nutrient that helps your body function properly. It plays an important role in keeping your nerve cells healthy and making red blood cells (RBCs).

Your body doesn’t make any vitamin B12 by itself, so you have to get all of it that you need from food or supplements. For most Americans, getting enough vitamin B12 in their diet isn’t a problem. The recommended dietary allowance of vitamin B12 is 2.4 micrograms daily.

Vitamin B12 is naturally found in foods of animal origin, such as meat, fish, eggs, and dairy products. This vitamin is often added to foods like breakfast cereal, bread, or nutritional yeast — known as fortified foods. These fortified foods are essential for people with plant-based diets to maintain adequate B12 levels without additional supplementation.

What Is Vitamin B12 Deficiency?

If you have a vitamin B12 deficiency, it means you don’t have enough B12 in your blood. Low B12 can be diagnosed with a blood test, typically classified as levels below 150 nanograms per liter.

You may have a vitamin B12 deficiency if you don’t get enough vitamin B12 from food or supplements or if your body has trouble absorbing it from your digestive system.

Risk Factors for Vitamin B12 Deficiency

Some people may be more likely to have low vitamin B12. Risk factors for a vitamin B12 deficiency include:

• Age — People over 60 may have more problems absorbing vitamin B12.
• Diet — Individuals who follow a plant-based diet may not eat enough foods with vitamin B12.
• Alcohol — Digestive system damage from long-term, heavy drinking can make it harder to absorb vitamin B12.
• Medical conditions — Some medical conditions can make it harder to absorb vitamin B12 from your digestive system, such as Sjögren’s syndrome, celiac disease, or Crohn’s disease.
• Pernicious anemia — People with this rare medical condition can’t make a protein called intrinsic factor, which helps absorb vitamin B12.
• Medications — Some medications associated with low vitamin B12 include metformin (Glucophage), oral contraceptives (birth control pills), and heartburn medications.

What Does Vitamin B12 Deficiency Feel Like?

The symptoms of low vitamin B12 can differ from person to person. Some people don’t have any signs of a vitamin deficiency, while others have more severe symptoms.

“I’ve been diagnosed with a vitamin B12 and vitamin D deficiency. So, I’m feeling more drained than usual,” explained a MyLupusTeam member.

Symptoms of low vitamin B12 may include:

• Tiredness or weakness
• Nausea, vomiting, or diarrhea
• Loss of appetite
• Weight loss
• Mouth or tongue soreness
• Yellowing of the skin
• Numbness or tingling in the hands and feet
• Confusion
• Vision problems
• Depression
• Mood changes

Vitamin B12 and Your Health

Low vitamin B12 can affect your risk of developing some medical conditions. Vitamin B12 is extremely important for making RBCs and keeping the nervous system healthy. To stay healthy, it’s important to get enough vitamin B12 from your diet or with the help of supplements.

Anemia

Vitamin B12 deficiency can cause anemia — a condition when you don’t have enough healthy RBCs. About half of people with lupus are already affected by anemia.

Vitamin B12 and another B vitamin, folate, are needed to make RBCs that can efficiently carry oxygen to your body’s tissues. Without these vitamins, your body makes RBCs that are too big and can’t carry enough oxygen to meet your body’s needs.

Cardiovascular Disease

Vitamin B12 deficiency may affect your risk of cardiovascular (heart) disease. People with lupus have about double the risk of developing heart disease as the general population.

Vitamin B12 is involved in breaking down a protein called homocysteine. People with low vitamin B12 can have higher homocysteine levels. Researchers have found links between high levels of homocysteine and increased risk of heart disease and stroke.

Although research shows that taking vitamin B12 supplements can decrease homocysteine levels, researchers haven’t found that it reduces the risk of heart disease.

Can Lupus Cause Vitamin B12 Deficiency?

Researchers have found that vitamin B12 levels are lower in people with lupus. The reason for this isn’t clear, but some of the medical conditions that increase the risk of vitamin B12 deficiency are associated with lupus.

Sjögren’s Syndrome

Sjögren’s syndrome is an autoimmune disease that causes dry eyes and dry mouth. It happens when the immune system mistakenly attacks the glands that make tears and saliva. Between 14 percent and 18 percent of people with SLE also have Sjögren’s syndrome. Decreased saliva production could make it harder to absorb vitamin B12 from the digestive tract.

Digestive System Problems

Between 8 percent and 40 percent of people with active SLE have complications with their digestive system — including the mouth, esophagus, intestines, liver, pancreas, and gallbladder. Inflammation in your digestive system can decrease vitamin B12 absorption.

People with lupus often experience gastrointestinal reflux disease (GERD) — also known as heartburn. GERD can be treated with medications that block stomach acid production, like proton pump inhibitors and histamine blockers. These medications can make it harder for you to absorb vitamin B12. This is because your stomach acid helps separate vitamin B12 from food.

Diabetes

People with lupus may have an increased risk of developing diabetes — a disease that causes your glucose (blood sugar) levels to be too high. Using metformin, a widely prescribed medication for diabetes, can lead to lower levels of vitamin B12 as a possible side effect. In a study of 1,111 people living with type 2 diabetes, 22.2 percent developed a vitamin B12 deficiency after taking metformin for at least six months.

Can Lupus Cause High Vitamin B12 Levels?

There isn’t any evidence that lupus can cause high vitamin B12 levels. High vitamin B12 levels are very rare. Your body doesn’t store extra vitamin B12, so even high doses of vitamin B12 are considered safe.

Treating and Preventing Vitamin B12 Deficiency

Talk to your doctor if you’re concerned about a vitamin B12 deficiency. They can use a blood test to check your vitamin B12 levels. Your doctor might also check for signs of anemia with a complete blood count.

If your vitamin B12 is low, your doctor may prescribe B12 or a laboratory-made type of vitamin B12 called cyanocobalamin. Vitamin B12 comes in different forms, such as:

• Tablets you take by mouth
• Nasal sprays or gel
• An injection into your muscle

You can prevent low B12 by eating animal products (like meat and dairy) and/or fortified foods (like bread and cereal). Drinking alcohol in moderation or avoiding it completely may help prevent damage to your digestive tract and absorption issues of vitamin B12.

Never start taking vitamin supplements, including vitamin B12, without checking with your doctor. They will consider any possible interactions with your current medications or existing health conditions to provide you with the best guidance.

Talk With Others Who Understand

MyLupusTeam is the social network for people with lupus and their loved ones. On MyLupusTeam, more than 223,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus.

Do you have low vitamin B12? Share your experience in the comments below, or start a conversation by posting on your Activities page.