Are You Getting Enough Vitamin B12?

09 December 2024

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Essential for everything from energy production to neurological function, vitamin B12 serves as a cornerstone for maintaining vitality and wellness. However, many people may not realize they're falling short of this crucial vitamin, leading to potential health issues.

In this blog, we’ll delve into the pivotal roles that vitamin B12 plays in your body, highlight foods high in vitamin B12 and explain why some people have issues absorbing this vitamin.

What is vitamin B12?

At a glance: Vitamin B12, or cobalamin, is a vital water-soluble vitamin crucial for red blood cell formation, DNA synthesis, nerve health and energy production. There are eight B vitamins, including vitamin B12.

Vitamin B12 is typically the most commonly discussed B vitamin due to its crucial roles in energy production, red blood cell formation and neurological function.

Essential for producing healthy red blood cells.
Aids in DNA synthesis.
Maintains the health of nerve cells and supports proper neurological function.
Helps convert food into energy by helping metabolize fats and carbohydrates.
Supports cognitive function.
Lowers homocysteine levels in the blood to promote heart health.

The body processes vitamin B12 through digestion and absorption.

In the stomach, hydrochloric acid and digestive enzymes help release vitamin B12 from proteins.
It then binds to a protein called intrinsic factor, which is produced by the stomach's parietal cells.
The B12-intrinsic factor complex travels to the small intestine where it’s absorbed into the bloodstream.
After absorption, vitamin B12 binds to transport proteins called transcobalamin, which carry it through the bloodstream.
The liver stores a significant amount of vitamin B12, which can last for several years.

Foods high in vitamin B12

Key points: Vitamin B12 is found in animal-based foods like fish, meat, poultry, eggs and dairy. While plant foods lack natural B12, fortified cereals and nutritional yeasts offer highly bioavailable sources. Here are some of the foods highest in vitamin B12, along with their approximate daily value (DV) percentages based on a standard daily requirement of 2.4 micrograms (μg).

Sources of vitamin B12 primarily come from animal products, although fortified foods also have vitamins added during the manufacturing process.

Clams: A 3-ounce serving provides about 84 micrograms (3,500% of the DV).
Beef liver: A 3-ounce serving contains about 70 micrograms (2,900% of the DV).
Trout: A 3-ounce serving provides about 5.4 micrograms (225% of the DV).
Salmon: A 3-ounce serving of salmon contains approximately 4.8 micrograms (200% of the DV).
Canned tuna: A 3-ounce serving offers about 2.5 micrograms (104% of the DV).
Fortified cereals: A typical serving of breakfast has about 2.4 micrograms (100% of the DV).
Milk: A cup of milk provides about 1.2 micrograms (50% of the DV).
Yogurt: A cup of yogurt offers around 1.1 micrograms (46% of the DV).
Eggs: Two large eggs contain about 1.1 micrograms (46% of the DV).

What happens if you don’t get enough vitamin B12?

Why it matters: A deficiency in vitamin B12 can lead to anemia, fatigue and neurological issues. Some people have medical conditions that prevent the stomach and small intestine from absorbing vitamin B12. Others, such as people who follow a plant-based diet or older adults may not receive enough vitamin B12 through the foods they eat.

Anemia can occur if your body can't produce sufficient healthy red blood cells.

When B12 levels are insufficient, red blood cells can't divide normally and larger-than-normal red blood cells called megaloblasts begin to develop.
These cells are often immature and dysfunctional, leading to a reduced ability to carry oxygen throughout the body.

Nerve damage can occur if the body doesn’t have enough vitamin B12 to maintain the protective covering that surrounds nerve fibers called the myelin sheath.

Without sufficient B12, the myelin sheath can become damaged or deteriorate, leading to disrupted nerve signal transmission.
This can cause symptoms like numbness, tingling and a feeling of pins and needles, particularly in the hands and feet.

Cognitive impairment can be present in people with low levels of B12.

Prolonged vitamin B12 deficiency can result in more severe neurological issues, such as balance problems, difficulty walking, memory loss and cognitive disturbances.

Mood changes may develop due to inadequate vitamin B12 levels.

Vitamin B12 aids in producing neurotransmitters like serotonin and dopamine, crucial for mood regulation.
A deficiency can disrupt these chemicals, potentially leading to depression and anxiety.

Glossitis and mouth ulcers are more common in people with vitamin B12 deficiency due to its essential role in maintaining healthy cells and tissues.

A deficiency can impair the rapid turnover of cells in the mouth, leading to inflammation and soreness of the mouth and tongue.

Vision problems can develop in more severe cases of prolonged vitamin B12 deficiency.

Nerves, such as the optic nerve that processes visual information from the eyes to the brain, need vitamin B12 to maintain its health.
Low B12 levels can also affect the blood supply to the retina (light-sensitive layer at the back of the eye) and disrupt vision.

Why do some people have issues with vitamin B12 absorption?

What to know: Other than older adults who experience absorption issues, some medical conditions, dietary habits, medications and surgical procedures can interfere with the body's ability to properly take in and use vitamin B12.

Medical conditions can impact different parts of the digestive system and hinder its capacity to process and absorb nutrients effectively.

Pernicious anemia is an autoimmune condition that reduces the production of intrinsic factor, a protein necessary for B12 absorption.
Gastrointestinal disorders such as Crohn's disease, celiac disease and inflammatory bowel disease can damage the intestines and impair B12 absorption.
Chronic atrophic gastritis thins the stomach lining and reduces stomach acid production, which is needed to release B12 from food.
Some medical conditions (immune system disorders and chronic pancreatitis) can cause small intestinal bacterial overgrowth, and the excessive bacteria will consume vitamin B12.

Surgery to remove parts of the stomach or intestines can impact absorption.

Gastric bypass or partial gastrectomy can reduce the stomach's ability to produce intrinsic factor.
Bowel resections can directly impact the area where B12 is absorbed.

Certain medications can impact absorption by interfering with the digestive processes necessary for vitamin B12 uptake.

Proton pump inhibitors (PPIs) and H2 receptor antagonists treat acid reflux by reducing stomach acid production, but long-term use can lead to decreased B12 absorption.
Metformin, a treatment for type 2 diabetes, can impact gut motility and change the intestinal environment.

Dietary habits lacking in vitamin B12-rich foods can lead to deficiency if not supplemented.

Vegans and vegetarians who do not consume fortified foods or supplements may have a higher risk of B12 deficiency.
Diets high in processed foods lack essential nutrients, including B12, leading to deficiencies over time.
Excessive alcohol intake can damage the stomach lining and intestines.
Diets that lead to reduced stomach acid production, whether through food choices or lifestyle, can hinder the release of B12 from food.
Extremely high-fiber diets can sometimes interfere with nutrient absorption.