Low levels of vitamin B12 could affect far more than bone health, according to new research. The nutrient, often called the “energy vitamin,” works at the cellular level to help mitochondria produce the energy muscles need to function.
New research shows that when B12 levels are low, muscle cells may struggle to generate energy efficiently, and damage can start at the level of DNA. B12 plays a key role in helping cells build and repair DNA. When B12 is low, this process stalls, and mitochondrial DNA becomes more prone to errors.
Mitochondrial DNA contains the blueprints for proteins that mitochondria need to produce energy. When this DNA is damaged, cells cannot generate energy as effectively.
Researchers at Cornell University and the University of Alabama at Birmingham studied how B12 deficiency affects energy production in muscles. They looked at two groups of mice: young-adult males that were either genetically prone to impaired B12 use or fed a B12-deficient diet for seven weeks, and older mice that received weekly B12 injections for eight weeks.
The study found that in mice with low B12, the mitochondria in their muscles could not work at full capacity. Energy output from key parts of the mitochondria dropped by about 25% in muscle tissue rich in mitochondria. Mice on the B12-deficient diet had roughly 10 times more DNA errors in their mitochondria, a sign of instability that can further impair energy production.
In older mice, B12 injections doubled the activity of a key energy-producing component in their leg muscles, suggesting supplementation may help restore mitochondrial function with age.
B12 deficiency is more common in certain groups. Adults over 50 become less efficient at absorbing B12 from food because they produce less stomach acid. Vegans and vegetarians often need to supplement because B12 is found almost exclusively in animal products. People with digestive conditions like Crohn’s disease, celiac disease, or a history of stomach surgery can also have trouble absorbing B12.
The study notes that B12 deficiency has been linked to muscle weakness, mitochondrial problems, and increased risk of frailty in older adults.
To maintain healthy B12 levels, eating B12-rich foods such as clams, beef liver, fish like salmon, trout, and tuna, eggs, and fortified nutritional yeast can help. People over 50, those on plant-based diets, or individuals with digestive issues should consider asking their doctor about checking B12 levels. A test for methylmalonic acid can give a more sensitive reading on B12 status.
Combining adequate B12 with strength training and enough protein may help maintain muscle function as people age. For those who are deficient or at risk, a quality B12 supplement can help, and a doctor can recommend the right form and dose.
This research adds to growing evidence that B12 plays a key role in how muscles produce energy. For anyone focused on healthy aging, keeping B12 levels in check through diet, testing, and supplementation when needed is a simple way to support mitochondria and muscles over the long term.
