Vitamin B12 is an essential nutrient that plays a vital role in producing red blood cells, supporting healthy nerve function, and maintaining DNA. Since the body cannot make vitamin B12 on its own, it must be obtained through food or supplements. Rich sources include meat, fish, eggs, and dairy products, while people who avoid animal-based foods, such as some vegetarians and vegans, may need fortified foods or supplements to maintain healthy levels.

One of the earliest signs of vitamin B12 deficiency is persistent fatigue, which develops when the body cannot produce enough healthy red blood cells to transport oxygen efficiently. Other common symptoms include weakness, shortness of breath, dizziness, and difficulty concentrating. Because these symptoms are nonspecific, they are often mistaken for stress, poor sleep, or a busy lifestyle.

As the deficiency progresses, more noticeable physical symptoms may appear. These can include pale or yellowish skin, a sore or swollen tongue, mouth discomfort, and tingling or numbness in the hands and feet. Such symptoms may indicate that the body’s vitamin B12 stores have become significantly depleted.

Low vitamin B12 levels can also affect the nervous system and mental well-being, leading to forgetfulness, irritability, reduced focus, or slower thinking in some people. A simple blood test can confirm whether vitamin B12 levels are low. Depending on the underlying cause, treatment may involve dietary changes, oral supplements, or vitamin B12 injections recommended by a healthcare professional.