Could Low Vitamin B12 Be Affecting Your Brain and Energy?

Dr. Thomas Bailey, MD
Sep 7
2 min read

Vitamin B12 is a powerhouse nutrient that plays a vital role in keeping your brain and nerves healthy. It helps your body make DNA and red blood cells, while also supporting memory, mood, and overall nerve function.

Foods rich in Vitamin B12, including salmon, eggs, shrimp, and cheese, surround a board reading "vitamin B12" on a white surface.

By the age of 75-80, 40% of people have a diminished ability to absorb food-bound B12. Low vitamin B12 can lead to a decline in nerve health, particularly in the spine and brain, which can contribute to the risk of developing dementia in older adults.

When the body doesn’t get enough vitamin B12, you may also notice:

· Fatigue or low energy

· Trouble with balance

· Numbness or tingling in the hands and feet

· Changes in mood or memory

Why testing can be tricky

A standard blood test for vitamin B12 doesn’t always tell the whole story. That’s because it measures total B12, not the amount your body can actually use. If symptoms or concerns are present, additional testing may be needed:

· Methylmalonic acid (MMA): Elevated levels can signal an early vitamin B12 deficiency—even before symptoms appear.

· Homocysteine: High levels can also indicate B12 deficiency (sometimes along with other vitamin issues).

These tests are especially useful when B12 levels look “low-normal” on standard labs, but symptoms suggest otherwise.

The good news

Vial of Cyanocobalamin Injection, USP 30,000 mcg/30 mL. Label in red, black text. Multiple dose vial, Rx Only, on a blue surface.

If a deficiency is found, treatment is typically simple and effective. High-dose oral supplements or B12 injections can restore levels. Many people start feeling better within a few months, and early treatment can prevent long-term nerve damage.

Takeaway

If you’ve been experiencing unexplained fatigue, nerve symptoms, or memory changes, it may be worth talking about vitamin B12 testing. Early detection and treatment can make a big difference for your health and quality of life.

Doctor in a white coat with a stethoscope, standing in a medical office. The coat reads "T. Bailey, M.D. Internal Medicine." Blue cabinets behind.

If you’d like to discuss B12 testing or have questions about your neurological health, feel free to reach out to Mahoning Valley Direct Primary Care—Dr Tom Bailey is here to help.