Vitamin B Levels Have a Direct Impact on Cognitive Functioning in Elderly Adults

Cognitive Skills Go For a Toss as a Person Grows Old without Proper Nutrition & Lifestyle Interventions

​If you are someone who loves to solve puzzles and can’t settle for anything lesser than solving it 100% good for you! But if you have taken up math or problem solving with the sole intention to escape from the clutches of dementia without a flair for it then you might struggle through the entire solving time trying to have fun but ending without any. Yes, puzzle solving is a tactic way to stay clear of dementia as your mind is being put into good use day in and day out. Dementia-what was considered a rare occurrence some decades back has now started showing its face in all corners of the Earth growing to be a public health concern increasing financial burden and affecting quality of life. Age is one important factor that can speed up the dementia process which is irreversible and so are the genetic causes behind it. So, apart from these the only way in which risk of dementia could be minimized is by figuring out the non-genetic factors that could be modified in order to prevent cognitive decline as there is no cure available for dementia until now.

Ageing has been associated with increased cognitive impairment that can be anything from mild cognitive impairment (MCI) to dementia with MCI having the ability to progress into dementia within 5 years of diagnosis. The world has more than 50 million people who are victims of dementia and the numbers are said to triple by 2050. Hence, it has become absolutely necessary to focus on those factors that can be modified to delay the onset of dementia as much as possible. We have numerous lifestyle and nutritional factors that exist as modifiable risk factors for cognitive decline and one such is the decreased levels of folate, vitamin B6 and vitamin B12 and increased homocysteine levels that contribute to cognitive dysfunction in ageing population. Homocysteine is the result of methylation cycle and cannot be produced from any dietary source. Folate and Vitamin B12 are essential in the methylation of homocysteine to methionine and in the re-methylation and synthesis of S-adenosylmethionine. Hyperhomocysteinemia due to disturbed monocarbon metabolism is a risk factor for cognitive impairment and Alzheimer’s disease. Increased plasma homocysteine (Hcy) levels indicate folate deficiency. Hence, increased plasma homocysteine levels in association with low levels of folate, vitamin B6 and B12 show decreased cognitive performance and supplementing the body with B vitamins helps in reversing or preventing cognitive decline.

We have numerous studies showing that increased Hcy levels is an independent risk factor for impaired cognitive function or Alzheimer’s disease (AD). We have several studies showing increased deficiency of folate, vitamin B6 and B12 in Western countries. Also, there are evidences of a relationship between levels of B vitamins in blood and cognitive function in these countries and South Korea also shows such relationships. We have an elderly Korean population study that shows that hyperhomocysteinemia might be a risk factor for mild cognitive impairment (MCI) and that plasma folate, vitamin B12 and Hcy are associated with cognitive function in cognitively impaired elderly population. Another study in Australia that looked into the relationship between serum B vitamin levels and cognitive function according to the degree of cognitive damage in AD, MCI and normal individuals did not possess any dietary information. We do know that B vitamin levels, especially folate levels, is affected by dietary intake and that low dietary intake of B vitamins is associated with cognitive decline or an increased risk of AD but there is little information on the relationship between B vitamins and cognitive function among elderly population in Korea-a country where folic acid fortification has not yet been made mandatory.
South Korea is one of the countries that has the highest growing ageing population in the world where almost 10% of the elderly above 65 years of age suffer from dementia and around 28% have MCI. This definitely calls for further research in understanding the relationship between B vitamins intake and cognitive function in normal, MCI and AD groups in Korean elderly over 60 years of age in South Korea.

South Korean Study
The study consisted of a total of 321 subjects of whom 121 were normal participants, 100 were MCI patients and 100 were AD patients. All the participants were given a Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-K) that assessed for both neuropsychological and clinical symptoms. Information on age, gender, marital status, education, smoking, alcohol use; disease existence including diabetes mellitus, hypertension, stroke, dyslipidaemia, cardiovascular disease and thyroid disease and height, weight and BMI measurements were taken.

All the participants went through a 24-hour recall for information on dietary intake, their consumption of dietary supplements and nutrient content available in these supplements.

Results
The average age of the participants was 74.8 ± 7.2 years and patients with AD were older than those without AD, were less educated, less often lived with a spouse and comprised majorly of females. Energy intake of participants was 1490.4 ± 445.5 kcal and this was almost 75% lesser than the estimated energy requirement (EER) for KDRI. Energy, protein and folic acid intake was lower in both MCI and AD group compared to the normal group. Results showed that:

1. Folate intake was positively associated with total intake of protein, vitamin B2, vitamin B6 and folic acid and vitamin B12 intake was positively associated with total vitamin B2 intake.
2. Plasma Hcy was negatively correlated with total intake of vitamin B2, vitamin B6, B12 and folic acid
3. In those with AD, plasma folate was positively associated with total folic acid intake and Hcy was negatively associated with total vitamin B6 intake. No association was found between plasma vitamin B12 and intake of other B vitamins.
4. In those with MCI, plasma folate was positively associated with total intake of protein, vitamin B2, B6 and folic acid. Plasma vitamin B12 was positively correlated with total folic acid intake and Hcy was negatively corelated with total vitamin B2 intake.
5. In those individuals belonging to the normal group, plasma folate and vitamin B12 was positively associated with total protein intake, vitamin B2, B6 and folic acid but there was no association between plasma Hcy and B vitamins intake.
6. There was no association found between cognitive function scores and dietary parameters in AD subjects. In MCI subjects, dietary vitamin B2 intake was associated with World List Memory, World List Recognition and Constructional Recall Test scores. In normal individuals, vitamin B6 intake was positively associated with World List Memory Test scores.
7. Total vitamin B2 intake was positively linked with MMSE-KC and Boston Naming Test scores and total vitamin B6 intake was linked with Boston Naming Test scores. Folic acid consumption was linked to MMSE-KC, World List Memory Test and Constructional Recall Test scores. Vitamin B6 intake was linked to MMSE-KC, Boston Naming Test, World Fluency, World List Memory, World List Recognition Test, Constructional Recall Test and Constructional Praxis Test score.

The study showed that there was a strong association shown between B vitamins intake and those individuals with AD and MCI compared to normal individuals.

Northern Ireland Study
Another study focused on individuals aged >60 years not suffering from vitamin B12 deficiency. Each of their cognitive skills were assessed with a maximum score of 30 possible, a score <25 indicated possible cognitive impairment and <20 indicated dementia. All the participants reported of their dietary intake using a food frequency questionnaire. The study included a total of 155 participants with a mean age of 70 years, well-educated, most of whom were females with low rates of depression. Results showed that individuals with a lower vitamin B6 biomarker status or lower dietary B6 intake were at a 3.5-4-fold greater risk of cognitive decline. Lower dietary intake and vitamin B6 levels was linked to a greater rate of cognitive decline over a 4-year follow-up period. Participants with lower vitamin B6 status at baseline were at a 3.5 times greater rate of cognitive decline over a 4-year follow-up period and those with a lower dietary intake of vitamin B6 at baseline were 4 times likelier to experience greater cognitive decline over the 4-year period.

References
Association between Intake of B Vitamins and Cognitive Function in Elderly Koreans with Cognitive Impairment: https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-13-118
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B-vitamin Intake & Biomarker Status in Relation to Cognitive Decline in Healthy Older Adults in a 4-Year Follow-up Study: https://www.mdpi.com/2072-6643/9/1/53/htm
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Vitamin B12 Deficiency & Cognitive Impairment in Elderly Population: https://www.mdpi.com/2072-6643/9/1/53/htm