Vitamin B12 is an essential nutrient that helps produce red blood cells, supports nerve function, and maintains healthy DNA. Because the body cannot make it on its own, it must come from food or supplements.
B12 is found mainly in animal products such as meat, fish, eggs, and dairy. People who eat little or no animal-based foods may be at greater risk of deficiency unless they use fortified foods or supplements.
One of the earliest signs of low B12 is persistent fatigue. Other common symptoms include weakness, shortness of breath, dizziness, and difficulty concentrating.
As the deficiency worsens, symptoms may include pale or yellowish skin, a sore tongue, mouth ulcers, and tingling or numbness in the hands and feet. Low B12 can also affect the nervous system, leading to memory problems, irritability, poor focus, and mood changes.
A simple blood test can check vitamin B12 levels. Treatment may involve dietary changes, supplements, or injections, depending on the cause and severity of the deficiency.