By Donna Hayek, RDN
Vitamin B12 is often called the “energy vitamin,” but it also helps support healthy muscle function. While protein helps build and maintain muscles, it cannot do the job alone. Vitamin B12 is needed for DNA synthesis, nerve function, and red blood cell production—all important for keeping the body functioning well as we age.
People at greater risk of vitamin B12 deficiency include vegans, older adults, and those with conditions that affect nutrient absorption, such as Crohn’s disease and celiac disease. Long-term use of certain medications, including acid-reducing medications for GERD, can also increase the risk.
Vitamin B12 deficiency can cause anemia, fatigue, muscle weakness, nerve problems such as numbness or tingling, and difficulties with memory or thinking. Correcting a deficiency may help improve related symptoms. However, taking extra B12 has not been shown to boost energy or performance in people who already get enough.
Food sources of vitamin B12 include clams, beef liver, salmon, tuna, poultry, milk, yogurt, cheese, and eggs. Vegan sources include fortified nutritional yeast, fortified breakfast cereals, and fortified plant milks. Check labels, as not all products contain added B12.
How Much Vitamin B12 Do You Need?
- Most adults: 2.4 mcg daily.
- During pregnancy: 2.6 mcg daily.
- While breastfeeding: 2.8 mcg daily.
Supplement needs depend on your diet, ability to absorb B12, and blood test results. A confirmed deficiency may require high-dose oral supplements or injections under your healthcare provider’s guidance.