From the Guidelines
The optimal vitamin B6 intake for elderly individuals is likely higher than the current recommended dietary allowance, with a suggested minimum requirement of 1.96 and 1.90 mg/d for men and women, respectively, as indicated by recent depletion/repletion studies 1. To determine the optimal vitamin B6 level, it is essential to consider the latest research findings. A study published in 2018 in the Nutrition Research Reviews journal suggests that the current UK dietary recommendations for vitamin B6 intake may be outdated, particularly for elderly individuals 1. The study highlights that the existing guidelines are based on small sample groups of young men and do not take into account the increased protein requirements of elderly individuals.
Key Findings
- The current RDA for vitamin B6 intake in the UK is 1.4 and 1.2 mg/d for men and women aged ≥50 years, respectively 1.
- Recent investigations do not support an association between protein intake and vitamin B6 status in elderly men and women 1.
- Depletion/repletion studies in healthy elderly individuals indicate an extended physiological range of function for vitamin B6 in response to increased levels of intake 1.
- The minimum requirement for vitamin B6 in the elderly is suggested to be 1.96 and 1.90 mg/d for men and women, respectively, based on studies examining multiple associated physiological outcomes 1.
Implications for Practice
- Elderly individuals may require higher intakes of vitamin B6 to maintain optimal levels, particularly if they have increased protein requirements 1.
- Vitamin B6 supplementation may be necessary for some individuals, particularly if they are not meeting their dietary needs through food sources alone.
- Healthcare professionals should consider the latest research findings when providing guidance on vitamin B6 intake for elderly individuals.
From the FDA Drug Label
The average adult minimum daily requirement is about 1.25 mg. The ‘‘Recommended Dietary Allowance’’ of the National Academy of Sciences is estimated to be as much as 2.2 mg for adults and 2. 5 mg for pregnant and lactating women. The optimal vitamin B6 level is not directly stated in terms of a specific blood or plasma concentration, but the Recommended Dietary Allowance is estimated to be:
- 2.2 mg for adults
- 2.5 mg for pregnant and lactating women 2 Key points:
- The average adult minimum daily requirement is about 1.25 mg
- Requirements may be higher in certain individuals, such as those with genetic defects or taking certain medications.
From the Research
Optimal Vitamin B6 Level
The optimal vitamin B6 level can be determined by considering the recommended dietary allowance (RDA) and the average requirement (AR) for different populations.
- The RDA for vitamin B6 is generally considered to be 15 micrograms/g dietary protein, which translates to 1.5-2.2 mg/d for adults 3.
- However, the average requirement (AR) for vitamin B6 has been estimated to be 1.2 mg/day for adult females and 1.3 mg/day for adult males, with corresponding recommended intakes (RI) of 1.4 mg/day and 1.6 mg/day, respectively 4.
- For infants, the estimated value is 0.1 mg/day and 0.3 mg/day, depending on age, while for children and adolescents, the AR ranges between 0.5 and 1.5 mg/day, and the RI is between 0.6 mg/day and 1.6 mg/day 4.
- During pregnancy, the AR is 1.3 mg/day in the first trimester and 1.5 mg/day in the second and third trimesters, with corresponding RI of 1.5 mg/day and 1.8 mg/day 4.
- For lactating women, the AR is 1.3 mg/day and the RI is 1.6 mg/day 4.
- It is also important to note that certain populations, such as those with chronic renal failure, may require different levels of vitamin B6, with recommended doses ranging from 5-20 mg/day 5.
Biochemical Indicators of Vitamin B6 Status
Biochemical indicators of vitamin B6 status, such as plasma pyridoxal-5'-phosphate (PLP) concentrations, can be used to assess vitamin B6 adequacy.
- A PLP concentration of ≥30 nmol/L is considered indicative of adequate vitamin B6 status 4.
- Studies have shown that plasma B-6 vitamer concentrations, including PLP, 4-pyridoxic acid, pyridoxine, pyridoxamine, and pyridoxamine-5'-phosphate, are similar across different gender and age groups, with males 25-50 years having significantly higher plasma pyridoxal concentrations than females 6.
Health Implications of Vitamin B6 Deficiency
Vitamin B6 deficiency can have significant health implications, including neurological damage and impaired immune function.
- High intakes of vitamin B6 (in excess of 500 mg/d) have been associated with neurological damage, while more modest doses (50-100 mg/d) may also pose health risks 3.
- Vitamin B6 deficiency has been linked to various diseases, including those involving defects in vitamin B6 metabolism or utilization 7.