Vitamin B12 (if over 50)
Only bacterial cells retain the capacity to synthesize B12, but almost all organisms, except plants and fungi, require B12. In humans, the absorption of B12 from food is a highly complicated process, and is frequently compromised with aging, such that about a quarter of community-living elderly are B12-deficient. For nursing home residents, the proportion is 46%1.
In the wild, the consequences of B12 deficiency, which include anemia, lower extremity weakness, loss of postural balance, and dementia2, would quickly result in death. This suggests that the high likelihood for B12 deficiency in elderly has been “built in” by evolution as a mechanism to kill off the eldest generation.
What is the connection between vitamin B12 and inflammation? A B12 deficiency leads to high levels of homocysteine; this compound causes inflammation leading to osteoporosis3, vascular disease4, and retinal and brain disease5, just to mention a few.
In 1998, Health Canada together with the U.S. Institute of Medicine, recommended “Because 10 to 30 percent of older people may malabsorb food-bound vitamin B12, it is advisable for those older than 50 years to meet the RDA mainly by consuming foods fortified with vitamin B12 or a supplement containing vitamin B12”(see Table 3, Footnote d). In Canada, as no B12 fortified foods are available, supplements are the only avenue to get synthetic B12. Unfortunately, it appears the vast majority of Canadians, including physicians and other health care providers, are unaware of this recommendation.
As animal-based foods are the only sources of food B12, a vegan or quasi-vegan diet such as the methionine and protein restricted diets suggested above is already likely to result in B12 deficiency, including in younger people and in children, unless supplements are taken.
How much B12 should be taken? It depends on whether someone has symptoms that are likely to be due to B12 deficiency. In such cases, I would prescribe intramuscular or subcutaneous injections of 1000 micrograms (mcg) daily for a week, then once weekly for 4 weeks, and then monthly, for life.
Unfortunately, in individuals who have pernicious anemia, even this large dose may be insufficient. In these cases, weekly injections of 1000 mcg B12 may be necessary, again for life. In Canada, a doctor’s prescription is not necessary to obtain B12 for injection from a pharmacy.
For individuals over 50 without symptoms, I recommend sublingual methylcobalamin, eg 1000 mcg every other day. This preparation has been shown to be well absorbed (at least in children)8.
At the beginning of the COVID-19 pandemic, residents of nursing homes were most likely to have severe illness and to die from infection. Near the end of 2020, I wrote an article suggesting that B12 deficiency could be a cause of this excess severity and mortality, and might also impair vaccine effectiveness in vulnerable nursing home residents. Unfortunately, I was unable to get my medical colleagues, regional health administrators, or the provincial government to take this seriously. Click here to access the article.
I’m going to end instalment 7 here, with a couple of additional comments. These days, in western societies, pretty well all of the classic vitamin deficiencies such as scurvy (vitamin C deficiency), rickets (vitamin D deficiency), pellagra (niacin deficiency) or beriberi (thiamine deficiency) are essentially non-existent. Even neural tube defects caused by folate deficiency have diminished greatly. The exception is vitamin B12 deficiency, extremely common in seniors, and likely a very important cause of people being admitted to nursing homes when they suffer from falls, incontinence, or dementia caused by a lack of B12.
This would be simple to fix, but governments and doctors seem uninterested in doing so. Is this because the geriatric industry is so important to our economy?
I admit that I’m quite fixated on vitamin B12. My mother suffered from pernicious anemia (PA), and it is likely I do also, as PA is at least partially hereditary. I first looked at PA in detail in my second year in medical school – click here to download my essay. My website has a number of other articles; type B12 (followed by Enter or Return) into the search box in the upper right-hand corner.
Instalment 8 will look at some other dietary supplements which might be part of your approach to reduce inflammation.
- Cuskelly GJ, Mooney KM, Young IS. Folate and vitamin B12: friendly or enemy nutrients for the elderly. Proc Nutr Soc. 2007;66:548-558. PMID 17961276 ↩
- Oberlin BS, Tangney CC, Gustashaw KA, Rasmussen HE. Vitamin B12 deficiency in relation to functional disabilities. Nutrients. 2013;5:4462-4475. PMID 24225845 ↩
- De Martinis M, Sirufo MM, Nocelli C, Fontanella L, Ginaldi L. Hyperhomocysteinemia is Associated with Inflammation, Bone Resorption, Vitamin B12 and Folate Deficiency and MTHFR C677T Polymorphism in Postmenopausal Women with Decreased Bone Mineral Density. Int J Environ Res Public Health. 2020;17:E4260. PMID 32549258 ↩
- Balint B, Jepchumba VK, Guéant JL, Guéant-Rodriguez RM. Mechanisms of homocysteine-induced damage to the endothelial, medial and adventitial layers of the arterial wall. Biochimie. 2020;173:100-106. PMID 32105811 ↩
- Elsherbiny NM, Sharma I, Kira D et al. Homocysteine Induces Inflammation in Retina and Brain. Biomolecules. 2020;10:E393. PMID 32138265 ↩
- Carmel R. Efficacy and safety of fortification and supplementation with vitamin B12: biochemical and physiological effects. Food Nutr Bull. 2008;29:S177-87. PMID 18709891 ↩
- Ambrosone CB, Zirpoli GR, Hutson AD et al. Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221). J Clin Oncol. 2020;38:804-814. PMID 31855498 ↩
- Tuğba-Kartal A, Çağla-Mutlu Z. Comparison of Sublingual and Intramuscular Administration of Vitamin B12 for the Treatment of Vitamin B12 Deficiency in Children. Rev Invest Clin. 2020;73PMID 33053572 ↩
- instalment 6: behaviours that increase inflammation, and therefore should be avoided
- instalment 8: more useful dietary supplements