Can a B12 Deficiency Cause Swelling in My Legs?

A B12 deficiency isn't usually the cause of leg and ankle swelling.
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Swelling in your legs and ankles (aka edema) is a not-so-swell clue that you may need to see a doctor to find out the reason for it. A deficiency in vitamin B12, a key nutrient in meat and other animal-based foods, can be one reason for what causes edema to happen, although it's fairly uncommon.


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Read more:6 Early Signs of a Vitamin B12 Deficiency

Role of Vitamin B12

According to the Office of Dietary Supplements (ODS), vitamin B12 is necessary for your body to form healthy red blood cells and DNA. It also plays roles in brain and nerve function, along with several important biochemical reactions that help your body metabolize fat and protein.


The vitamin, the ODS explains, is naturally found in animal foods, like meat, eggs and dairy, but some grains are also fortified with it. It's also often added to nutritional yeast, which many vegans use as a cheese alternative.

Vitamin B12 Deficiency and Edema

According to Taylor Graber, MD, a resident physician and anesthesiologist at the University of California San Diego, swelling from a vitamin B12 deficiency is rare, but it can happen. "A significant B12 deficiency can lead to peripheral neuropathy and autonomic dysfunction, where the blood vessels dilate," he says. This causes fluid to leak out of the blood vessels, leading to swelling — or edema — in your tissues, mostly in your lower legs, ankles and feet.


While you may experience edema with a more severe vitamin B12 deficiency, according to ODS, the most common symptoms of B12 deficiency are:

  • Anemia.
  • Weakness.
  • Fatigue.
  • Weight loss.
  • Neurological changes.


If you suspect you may be deficient in vitamin B12, it's important to seek medical care as soon as possible because some of the complications can be severe.

Your doctor will diagnose a B12 deficiency based on the results of a blood test. "It can usually be reversed by oral, intramuscular or intravenous administration of B12 through its many different formulations," Dr. Graber says.

Preventing B12 Deficiency

Several populations are at an increased risk of developing a vitamin B12 deficiency, according to ODS. They include:

  • Older adults.
  • People with gastrointestinal disorders that limit their ability to absorb nutrients.
  • People who have had surgery to remove part of the stomach.
  • Strict vegans and vegetarians.
  • Infants who are breastfed by strict vegans or vegetarians.

To prevent a vitamin B12 deficiency from developing, it's recommended that those at high-risk take steps to ensure that they're getting enough of the vitamin from food sources or take a vitamin B12 supplement. In the case of strict vegetarians and vegans who don't consume eggs or dairy, the only food sources of vitamin B12 are fortified grains, like breakfast cereals and fortified nutritional yeast.

Managing Edema

Edema is one of the rarer side effects of a vitamin B12 deficiency, but you should see a doctor if you're experiencing any unexplained swelling. According to Dr. Graber, there are many other potential causes of edema, including heart or lung problems, digestive issues, kidney dysfunction and liver problems, all of which could require treatment that goes beyond reducing swelling.

Once you know why you have swelling, there are strategies to help you manage edema at home, according to the Mayo Clinic:

  • Move regularly to help pump fluid back toward your heart.
  • Elevate the swollen area above the level of your heart a few times every day.
  • Massage the swollen area to help push the fluid back toward your heart.
  • Wear compression hosiery to help prevent further swelling.
  • Keep the swollen area clean, moisturized and protected.
  • Reduce your salt intake (salt can worsen swelling).

While mild edema usually goes away on its own, the Mayo Clinic also cautions that more severe, ongoing edema may require diuretics (medications that help your body get rid of extra fluid).

Read more:6 Exercises for Swollen Feet and Ankles