Research from Cornell University highlights the significant role of vitamin B12 in human biology, particularly its effects on metabolism, muscle function, and risk of age-related diseases. Published in the Journal of Nutrition, the study reveals new insights into how B12 supports cellular metabolism and identifies early signals of nutritional strain before classic deficiency symptoms arise.
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Martha Field, Ph.D., associate professor in the Division of Nutritional Sciences, stated, "This is the first study that shows B12 deficiency affects skeletal muscle mitochondrial energy production." Her co-author, Anna Thalacker-Mercer from the University of Alabama at Birmingham, found that B12 supplementation improved muscle mitochondrial function in aged mice.
Prior studies primarily focused on visible consequences of B12 deficiency, such as megaloblastic anemia and cognitive decline, rather than the underlying biological mechanisms. Field's research team, including first authors Luisa Castillo and Katarina Heyden, examined B12's interaction with lipid metabolism and epigenetic regulation, suggesting that even slight deficiencies could impact multiple biological systems.
Field noted, "B12 deficiency seemed to inhibit growth or maintenance of muscle mass," linking low B12 levels to reduced muscle mass and strength. Global B12 deficiency remains common, especially among older adults and those with limited access to animal-based foods, with estimates indicating that one in four older adults in developed nations may have suboptimal B12 levels.
The research aligns with findings that insufficient micronutrient intake can lead to chronic diseases. Despite severe B12 deficiency being rare in developed regions, marginal deficiencies are prevalent among older adults, vegans, vegetarians, and those with absorption disorders. Such lower levels may impair the body's response to metabolic stress and aging effects.
From a clinical perspective, the researchers propose using B12-related biomarkers for personalized nutrition approaches, moving away from generic supplement recommendations to tailor advice based on individual needs. This aligns with broader efforts to integrate nutrition science with systems-level biology.
These findings are based on cell models and will require validation in human studies. Field emphasized the importance of understanding the causal pathway to set the stage for future controlled human trials. The study was conducted by Castillo, Heyden, and several collaborators, and published on January 20, 2026.