How a Vitamin B Deficiency Affects Blood Pressure

There's a reason that B vitamins are considered "essential" nutrients: Your body needs them to function. Because it can't make them on its own, you need to get them from food, and sometimes supplements, every day. Shortages can turn into serious health problems, like blood pressure that's too low.

Read more: The 6 Big Health Risks of Low Blood Pressure — and What to Do About It

The B vitamins play a number of important roles in the body. Two of particular importance, according to the Mayo Clinic, are vitamin B12 (cobalamin) and B9, better known as folate. B12, found in meat, fish and dairy, helps with cell metabolism, red blood cell formation, nerve function and DNA production. Folate, found in a number of fruits, vegetables, peas and nuts, is essential to the growth and development of babies early in pregnancy, among other functions, Mayo explains.

If you become deficient in these vitamins, not only will you not derive their benefits, but you can also develop health issues. One of the most common of these medical conditions, notes the American Heart Association (AHA), is low blood pressure.

A deficiency in vitamin B12 or folate puts you at risk for developing anemia, a condition in which your body doesn't produce enough red blood cells, according to the AHA. Having fewer red blood cells means less volume in the bloodstream, which in turn causes low blood pressure.

Ami Beniaminovitz, MD, a board-certified cardiologist with Manhattan Cardiology in New York City, notes an even more direct way in which vitamin B12 deficiency can negatively impact your blood pressure. "Vitamin B12 deficiency can damage the autonomic nervous system," he says, noting neurological symptoms that can result from a B12 deficiency.

"This system helps regulate blood pressure, especially when going from lying down or sitting to standing. If this system is damaged, or is not as responsive, it can cause a dangerous drop in blood pressure when standing, a phenomenon known as orthostatic hypotension," Dr. Beniaminovitz says.

Low blood pressure can lead to other concerning symptoms, according to the Mayo Clinic, such as nausea, trouble concentrating, fatigue, blurred vision and even dizziness or fainting. In the case of extreme low blood pressure, people can become confused, get cold, clammy skin, develop a weak or rapid heartbeat or have shallow breathing.

Low blood pressure is generally considered to be a systolic (top number) of 90 milligrams of mercury or lower over a diastolic (bottom number) of 60 or lower, says the National Heart, Lung, and Blood Institute.

If you have low blood pressure as a result of a folate or vitamin B deficiency, your best bet may be to increase your intake of these nutrients in your daily diet, notes Mayo Clinic. However, because the main source of vitamin B12 is primarily animal proteins, vegans or vegetarians may require a supplement in order to get their daily value of this nutrient, according to the American College of Cardiology (ACC).

Read more: The Best Method to Increase Vitamin B12 Levels

It's possible to eat plenty of vitamin B12 foods yet still develop a deficiency. This can happen when your digestive system fails to absorb the vitamin, ACC explains. This can occur due to another medical condition, such as celiac or Crohn's disease, a surgery that removed a portion of the stomach or a condition known as pernicious anemia, in which the body can no longer absorb vitamin B12 from food.

"Resolving the B12 deficiency depends on the cause," says Dr. Beniaminovitz. "If you are a vegan or vegetarian, it could be as simple as taking a B12 supplement. If you are not a vegan or vegetarian, then incorporating food sources that contain vitamin B12 — such as poultry, meat, fish and dairy products — is sufficient. Other patients need injections or nasal sprays as they have issues with the absorption of B12. It is best to talk with your doctor if you have or suspect B12 deficiency."

Foods that should help resolve a folate deficiency include spinach, avocados, oranges and beans. However, supplemental folate, usually in a prenatal vitamin combination, is recommended for women who are pregnant or may become pregnant due to its importance in a baby's development.