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 function^4,5,6,7. 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.