A recent study published in Aging Medicine has provided valuable insights into the role of vitamin B12 in maintaining muscle function among the elderly, with a particular focus on effective dosage.¹ This research, conducted by Sowmya Sharma and colleagues, combines an extensive literature review with a pilot intervention study, offering practical guidance for vitamin B12 supplementation in older adults.

Key Findings with Focus on Dosage

1. Deficiency Threshold: The study defined vitamin B12 depletion as levels below 148 pmol/L in plasma. This is equivalent to approximately 200 pg/mL, a common threshold used in clinical practice.
2. Supplementation Dosage: The intervention group received a daily oral vitamin B12 supplement of 100 μg (micrograms). This is equivalent to 100 mcg, a dosage that falls within the range commonly available in over-the-counter supplements.
3. Duration: The supplementation period lasted for 3 months, suggesting that this timeframe is sufficient to observe significant improvements in muscle function.
4. Effectiveness: The 100 mcg daily dose was effective in improving muscle strength (Maximal Voluntary Contraction) and muscle quality (MVC/total muscle mass) in the B12-depleted group.
5. Comparison to Adequate Levels: After the 3-month supplementation period, the previously B12-depleted group's muscle function became comparable to that of the group with adequate B12 levels (≥148 pmol/L or ≥200 pg/mL).

Implications for Supplementation

This study provides evidence that a relatively modest daily supplement of 100 mcg of vitamin B12 can have significant benefits for muscle function in older adults with low B12 levels. This dosage is:

• Higher than the current Recommended Dietary Allowance (RDA) for adults, which is 2.4 mcg per day
• Lower than many high-dose B12 supplements on the market, which can range from 500 mcg to 5000 mcg or more
• Likely to be well-tolerated, as vitamin B12 is generally considered safe even at higher doses due to its water-soluble nature

Dr. Sucharita Sambashivaiah, one of the study's authors, commented, "Our research suggests that a daily 100 mcg vitamin B12 supplement could be an effective strategy for maintaining muscle function in older adults with low B12 levels. This dose appears to be sufficient to bring muscle function to levels comparable with those who have adequate B12 status."

Natural Sources of Vitamin B12

While the study focused on supplementation, it's worth noting the B12 content of some natural food sources for comparison:

• Beef liver (3 ounces): 70 mcg
• Clams (3 ounces): 17 mcg
• Fortified breakfast cereals (1 serving): 6 mcg
• Salmon (3 ounces): 4.8 mcg
• Milk (1 cup): 1.2 mcg

These figures highlight why supplementation may be necessary for some individuals, particularly those with decreased absorption or dietary restrictions.

Conclusion

This research provides evidence that a daily 100 mcg vitamin B12 supplement can effectively improve muscle function in older adults with low B12 levels. While this dosage proved beneficial in the study, it's important to note that individual needs may vary. Factors such as age, dietary intake, and certain medical conditions can affect B12 absorption and requirements.

As always, individuals should consult with their healthcare providers before starting any new supplementation regimen, especially those with pre-existing health conditions or those taking medications. Healthcare providers can determine appropriate dosages based on individual B12 levels and overall health status.

Owing to the water soluble nature of vitamin B12, a higher 1000 mcg dose would not be a concern for 'overdose' risk. You can learn more about the profound therapeutic properties of vitamin B12 here. And make sure to know the right form to take. Cyanocobalamin is NOT recommended for the following reasons described in our article here.

References

1: Sharma, Sowmya, Rohini Bhadra, Sumithra Selvam, and Sucharita Sambashivaiah. "Vitamin B12 Status and Skeletal Muscle Function among Elderly: A Literature Review and Pilot Study on the Effect of Oral Vitamin B12 Supplementation in Improving Muscle Function." Aging Medicine 7, no. 4 (2024): 480-489. https://doi.org/10.1002/agm2.12346.