Importance of B vitamins intake for better cognitive health in an aging society
The world population is growing older due to lower fertility and increased longevity. Population ages 65 and above is projected to more than double its size by 2050. According to United Nations 2019, the most recent data suggests that people aged 65 and above comprises 9% of the total population, and 7% of the Southeast Asian population1.
Although advancing age brings wisdom, it is also associated with cognitive decline that ranges from mild cognitive impairment to dementia. A meta-analysis study has estimated that the rate of people with mild cognitive impairment progress to dementia is approximately 39%2. Globally, around 50 million people have dementia, and the numbers will be more than triple by 20503.
The association of B vitamins and cognitive health has long been studied. In 1983, Goodwin et al.4 reported an association between poor scoring in Halstead-Reitan Categories Tests (a nonverbal test of abstract thinking ability) in healthy elderly people with low blood levels of vitamin C, riboflavin (vitamin B2), folate (vitamin B9) and cobalamin (vitamin B12). Moreover, subjects with lower levels of plasma vitamin C and B12 also scored worse in the Wechsler Memory Test.
Studies have highlighted the significant association of higher intake of B vitamins, such as B2, niacin (vitamin B3), pyridoxine (vitamin B6), B9, and B12, with better cognitive function4,5,6,7. Although there are large numbers of studies defining the role of B vitamins on cognitive health in the Western population, only few studies have been done in the Asian population.
A 2019 study by Sheng LT et al.8 done in the Chinese population living in Singapore evaluated the effect of dietary intakes of six B vitamins (i.e. thiamin (vitamin B1), B2,B3, B6, B9, B12) on cognitive function. This study included 16,948 participants aged 45-74 years in 1993-1998, who were then followed-up for an average of 20 years. The cohort taking diet with higher vitamin B2 and B9 during this period had statistically significant lower risk of developing cognitive impairment in old age. Furthermore, they found that the dietary intake of vitamin B2 and B9 was not excessively high in this population, i.e. 0.9 mg/ day and 154 mg/day, respectively, compared to the Western population. Thus, it is suggested that vitamin B9 may help reduce the risk of cognitive impairment in populations with relatively lower intake levels8.
An association of plasma and dietary folate with cognitive function, particularly, the protective effect of folate against decrease in spatial copying and language fluency score has been demonstrated by Tucker et al.9. Furthermore, a study on older adults in a Chinese population also demonstrated the association of folate with language and episodic memory ability10.
By the year 2008, 77 cross-sectional studies and 33 prospective studies have shown associations between homocysteine and/or B vitamins and cognitive deficit or dementia11. VITACOG study found a beneficial effect of a two-year supplementation of combined B-vitamins (i.e. daily dose of 0.8 mg folic acid, 0.5 mg vitamin B12 and 20 mg vitamin B6) on the cognitive performance of individuals with mild cognitive impairment and elevated plasma homocysteine levels12. Furthermore, the same study also demonstrated that supplementation with B-vitamins reduced the yearly rate of brain atrophy by 29.6%, as measured by MRI scans13.
These findings suggest a relationship between B-vitamins status and cognitive decline in elderly people. Recommendations on adopting of healthy lifestyle, food fortification and B-vitamins supplementation may have a positive impact on public health as well as cognitive health in an aging society.
- United Nations, Department of Economic and Social Affairs, Population Division (2019). World Population Prospects 2019: Data Booklet (ST/ESA/SER.A/424).
- Mitchell AJ, Shiri-Feshki M. Rate of progression of mild cognitive impairment to dementia: Meta-analysis of 41 robust inception cohort studies. Acta Psychiatrica Scandinavica. 2009;119(4):252-65.
- Dementia [Internet]. Who.int. 2019 [cited 9 July 2019]. Available from: https://www.who.int/news-room/fact-sheets/detail/dementia
- Goodwin JS, Goodwin JM, Garry PJ. Association between nutritional status and cognitive functioning in a healthy elderly population. JAMA. 1983;249(21):2917–21.
- McCaddon A, Kelly CL. Alzheimer’s disease: A ‘cobalaminergic’ hypothesis. Med Hypotheses. 1992;37(3):161–165.
- Regland B, Gottfries CG. Slowed synthesis of DNA and methionine is a pathogenetic mechanism common to dementia in Down’s syndrome, AIDS and Alzheimer’s disease? Med Hypotheses. 1992;38(1):11–19.
- Qin B, Xun P, Jacobs DR Jr, Zhu N, Daviglus ML, Reis JP, Steffen LM, Van Horn L, Sidney S, He K. Intake of niacin, folate, vitamin B-6, and vitamin B-12 through young adulthood and cognitive function in midlife: the Coronary Artery Risk Development in Young Adults (CARDIA) study. The American Journal of Clinical Nutrition. 2017;106(4):1032-1040.
- Sheng LT, Jiang YW, Pan XF, Feng L, Yuan JM, Pan A, Koh WP. Association between Dietary Intakes of B Vitamins in Midlife and Cognitive Impairment in Late-Life: the Singapore Chinese Health Study. The Journals of Gerontology: Series A, Biological Sciences and Medical Sciences. 2019;pii:glz125.
- Tucker KL, Qiao N, Scott T, Rosenberg I, Spiro A., III High homocysteine and low B vitamins predict cognitive decline in aging men: the Veterans Affairs Normative Aging Study. The American Journal of Clinical Nutrition.2005;82(3):627–635.
- Feng L, Ng TP, Chuah L, Niti M, Kua EH. Homocysteine, folate, and vitamin B-12 and cognitive performance in older Chinese adults: findings from the Singapore Longitudinal Ageing study.The American Journal of Clinical Nutrition. 2006;84(6):1506–1512.
- Smith AD. The worldwide challenge of the dementias: a role for B vitamins and homocysteine?Food and Nutrition Bulletin. 2008;29(2 Suppl):S143–72.
- De Jager CA, Oulhaj A, Jacoby R, Refsum H, Smith AD. Cognitive and clinical outcomes of homocysteine-lowering B-vitamin treatment in mild cognitive impairment: A randomized controlled trial. International Journal of Geriatric Psychiatry. 2012;27(6):592–600.
- Smith AD, Smith SM, de Jager CA, Whitbread P, Johnston C, Agacinski G, Oulhaj A, Bradley KM, Jacoby R, Refsum H. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: A randomized controlled trial. PLoS One.2010;5(9);e12244.