In the past, I have not had a separate vitamin B12 recommendation for adults 65 years and older. In January, I reviewed a study from the UK suggesting that 500 µg per day might be necessary (see Cyanocobalamin in People 65+). Since then, I took some more time to research the subject and have concluded that I should be recommending 500 – 1,000 µg per day for adults 65 and older.
Note that I no longer have a twice daily or twice weekly recommendation for adults 65 years and older. I don’t believe there is enough information to determine either recommendation. Also note that these recommendations would hold for omnivores as well as vegans since all these studies were done on omnivores.
Adults Over 65 Years
Summary: Based on the studies below, it appears that 500 – 1,000 µg per day of cyanocobalamin is the ideal amount for people over 65 years of age to take in a daily dose.
There have been at least four relevant studies for how much vitamin B12 people over 65 years need, based on a once daily supplement. To my knowledge all of these supplements were cyanocobalamin.
A 2005 clinical trial from the Netherlands found that among people aged 70-94, who had vitamin B12 deficiency but were otherwise healthy, 16 weeks of 500 µg/day of cyanocobalamin was required to get MMA levels in the healthy range. Other doses tested were 2.5, 100, 250, and 1,000 µg (16).
A 2002 observational study from Canada of 242 people aged 70-94 without vitamin B12 deficiency found that those taking a daily supplement had significantly lower MMA levels (173 vs. 188 µmol/l; p = .042). However, there were many even in the daily supplement group who had elevated MMA levels. The range of supplements was from 2.6-37.5 µg/day with intakes being spread out about evenly over the range (17).
In a 2013 clinical trail from the UK in 100 people aged 65-86 with poor B12 status, 500 µg/day of cyanocobalamin was required to normalize MMA levels in 75-85% of the participants over 8 weeks. 500 µg was significantly better than 10 or 100 µg (18).
In a 2002 study from Seattle on 23 people 65 years and older with B12 deficiency but otherwise healthy, 1,000 µg of B12 was required to get the average MMA level into the normal range, as compared to 10 and 100 µg. This study was continuous in that first they put everyone on 10 µg for 6 weeks (moved average MMA from 581 to 400 nmol/l), then 100 µg for 6 weeks (moved average MMA from 400 to 380 nmol/l), and then 1,000 µg for 6 weeks (moved average MMA from 380 to 200 nmol/l). The final 6 weeks resulted in a big drop after the 2nd six weeks resulted in only a small drop (19).
16. Eussen SJ, de Groot LC, Clarke R, Schneede J, Ueland PM, Hoefnagels WH, van Staveren WA. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial. Arch Intern Med. 2005 May 23;165(10):1167-72. | link
17. Garcia A, Paris-Pombo A, Evans L, Day A, Freedman M. Is low-dose oral cobalamin enough to normalize cobalamin function in older people? J Am Geriatr Soc. 2002 Aug;50(8):1401-4. | link
18. Hill MH, Flatley JE, Barker ME, Garner CM, Manning NJ, Olpin SE, Moat SJ, Russell J, Powers HJ. A vitamin B-12 supplement of 500 μg/d for eight weeks does not normalize urinary methylmalonic acid or other biomarkers of vitamin B-12 status in elderly people with moderately poor vitamin B-12 status. J Nutr. 2013 Feb;143(2):142-7. | link
19. Rajan S, Wallace JI, Brodkin KI, Beresford SA, Allen RH, Stabler SP. Response of elevated methylmalonic acid to three dose levels of oral cobalamin in older adults. J Am Geriatr Soc. 2002 Nov;50(11):1789-95. | link