From the Guidelines
The goal vitamin B12 level for older adults should be above 400 pg/mL (300 pmol/L) to prevent neurological symptoms and other complications, as evidenced by studies suggesting that higher intake levels are required to achieve optimal metabolic sufficiency 1. For older adults, maintaining levels in the mid to upper portion of the normal reference range (200-900 pg/mL) is ideal. If an older adult is deficient, treatment typically involves oral supplementation of 1,000 mcg daily for one month followed by 1,000 mcg weekly, or intramuscular injections of 1,000 mcg given weekly for 4-8 weeks, then monthly thereafter. Some key points to consider include:
- The prevalence of vitamin B12 deficiency in older adults is significant, with estimates ranging from 5.9% to 40% depending on the population and criteria used 1.
- Maintaining adequate B12 levels is crucial for older adults because deficiency can cause irreversible neurological damage, cognitive impairment, anemia, and increased cardiovascular risk.
- Regular monitoring every 6-12 months is recommended for those on supplementation or with risk factors for deficiency such as use of metformin, proton pump inhibitors, or following gastric surgery.
- The available evidence regarding vitamin B12 and its potential role in the development of sarcopenia presents an interesting mix of clinical observations and biophysiological mechanisms, highlighting the importance of considering and eliminating deficiencies of B vitamins in the investigation of sarcopenia 1.
From the Research
Vitamin B12 Levels in Older Adults
The goal vitamin B12 level for older adults is not explicitly stated in the provided studies. However, the recommended daily allowance for vitamin B12 is 2.4 micrograms, as mentioned in the study by 2.
Factors Affecting Vitamin B12 Levels
Several factors can affect vitamin B12 levels in older adults, including:
- Absorption of protein-bound vitamin B12, which is decreased in the elderly due to atrophic gastritis 2
- Ability to absorb crystalline vitamin B12, which remains intact in older people with atrophic gastritis 2
- Presence of single nucleotide polymorphisms (SNPs) in B12-related pathways, which may affect the efficiency of absorption, blood transport, cellular uptake, and intracellular transformations 3
Forms of Vitamin B12
There are several forms of vitamin B12, including:
- Methylcobalamin (MeCbl)
- Adenosylcobalamin (AdCbl)
- Hydroxocobalamin (OHCbl)
- Cyanocobalamin (CNCbl) All of these forms have been shown to improve vitamin B12 status, but their bioavailability may be influenced by factors such as gastrointestinal pathologies, age, and genetics 3.
Treatment and Supplementation
Treatment of vitamin B12 deficiency can be achieved through oral or intramuscular routes, with a combination of MeCbl and AdCbl or hydroxocobalamin or Cbl being recommended 4. Supplementation with any of the natural bioidentical forms of B12 (MeCbl, OHCbl, and/or AdCbl) is preferred over the use of CNCbl due to their superior bioavailability and safety 3.