Vitamin B12 deficiency could cause ‘memory issues’, numb hands-feet and muscle weakness
You need vitamin B12 to help make red blood cells, nerves, and DNA. The effects of deficiency can be varied and insidious—fatigue, a sore tongue, unsteadiness, muscle weakness, numbness in the hands and feet, depression, memory loss, and cognitive issues—and they’re often chalked up to other causes. “Symptoms may appear gradually over time and progress quickly in severe deficiencies,” says Raelene Brooks, PhD, dean at the University of Phoenix College of Nursing. In a 2025 study in the journal Annals of Neurology involving 231 older adults, all had normal blood levels of total B12 and the active form of B12,