B Vitamins and Cognitive Performance Among Older Adults

7/28/2019 B Vitamins and Cognitive Performance Among Older Adults

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B Vitamins and CognitivePerformance Among Older

Adults

Nurdiyana Abd Halim


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CROSS SECTIONAL STUDIES (outline)

Multiple nutrients and cognitive performance

Folate and B12 and cognitive performance

Folate, B12, B6, homocysteine and cognitive

performance


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Multiple nutrients and cognitive

performance

Goodwin, Goodwin and Garry (1983)

No significant relationship between nutrientintakes and cognitive function, and a significant,

though weak, relationship between plasma levelsof vitamin B12 and C and the memory test.

Low plasma folate; performed significantly morepoorly on abstract thinking and problem solving

test.

Changes in cognitive performance in older adultsmight be secondary to nutrition rather than duesolely to inevitable age-related decline.


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Multiple nutrients and cognitive

performance

Ortega and colleagues (1996,1997)

Folate, but not B12 or B6, deficiency was

common and that those with adequate MMSE

(Mini Mental Status Examination) had

significantly higher serum and erythrocyte

levels of folate concentration than those with

less adequate scores.


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Folate and B12 and cognitive

performance

Bell and colleagues (1990)

Those with below median values for both

folate and B12 had significantly lower scores

on the MMSE than those who were higher in

folate and B12.

Lower levels of folate and B12, even within

normal range, may interact to produce CNS

metabolic abnormalities affecting cognitive

function.


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performance

Wahlin, Hill, Winblad and Backman (1996)

Those with low levels of folate or low levels of bothfolate and B12 performed significantly worse than

those with normal levels of folate and B12. Low levels of B12 alone had no impact on memory

performance.

It may be critical to alter folate levels to enhanceperformance.

Later in 1999, they found that there were no combinedeffects for folate and B12, and conclude that folate maybe more critical than B12 to memory performance inold age.


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performance

Lindeman et al. (2000)

No significant relationship between low serum

B12 and cognitive performance.

Low serum folate concentrations is associated

with poorer function in cognitive performance

on learning, memory and psychomotor speed.


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Folate, B12, B6, homocysteine and

cognitive performance

Riggs et al. (1996)

Homocysteine negatively associated with

plasma folate and B12.

Significant correlation between high plasma

homocysteine, low plasma folate, low B12(poor spatial copying performance) and lowB6 (poor backward digit span).


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CONCLUSION FROM CROSS SECTIONAL

STUDIES

Low folate intake and status emerges as the most

reliable associate of cognitive performance,

either alone or in combination with low B12.

The relationship between the B vitamins and

cognition may be mediated by homocysteine

levels because homocysteine uniquely predictedcognitive performance after controlling for B

vitamin status.


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LONGITUDINAL STUDIES

Multiple nutrients and cognitive performance

La Rue et al. (1997)

Concurrent plasma, erythrocyte, and dietary intakelevels of folate status were correlated significantly onlywith abstract reasoning.

Past serum transferrin status and past intakes ofvitamins B12, B6, A, and E were correlated with currentcognitive performance.

Modest association was found between nutritionalmeasures and cognitive performance


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Folate and cognitive performance

Ebly et al. (1998)

Individuals with the lowest serum folate quartile

were more likely to have cognitive loss, to bedemented, institutionalized, and depressed, andto have a higher mortality rate at a 2-year followup.

Low score on the MMSE and on short termmemory.


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CONCLUSION FROM LONGITUDINAL

STUDIES

Prior intake of B vitamins is a predictor of

cognitive change at a later date.

Low folate status may be a predictor of

cognitive change among older adults.


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EXPERIMENTAL STUDIES

Dror et al. (1996) Supplementation with folate, B12, and B6 had no

effect on MMSE scores, but positive effect onGeriatric Depression Scale (GDS) scores. (no

control group)Tolonen et al. (1988)

Significant positive effects of B6 supplementation

on visual reproduction (clock drawing). No significant effect of supplementation on

memory or Digit spans performance.


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Deijen et al. (1992)

Significant positive effects of B6 supplementation onmeasures of the amount of information retained in longterm memory, but there were no effects for iconic or shortterm memory.

B6 supplementation might have a modest but significant

effect in improving the storage of information, therebyreducing age-related memory loss.

Fioravanti et al. (1997)

Significant positive effects of folate supplementation onattention and memory.


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CONCLUSION FROM EXPERIMENTAL

STUDIES

B6 and folate supplementation have positive

effects on the memory performance of older

adults.


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LOW-NORMALVITAMIN B-12

STATUS ANDCOGNITIVE

IMPAIRMENT


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Discrepancies in review:

The evidence from longitudinal cohort and case-controlstudies suggests that there is no significant associationbetween blood concentrations or the dietary intake ofvitamin B-12 and cognitive test performance orAlzheimers disease.

6 prospective studies; an inverse relation betweencognitive deficit or dementia and vitamin B-12 intakeor blood concentrations.

Another 10 studies found no association with vitaminB-12 status.


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Summary of the Review

The association of low vitamin B-12 status

with cognitive deficit may depend on the

context.

Low vitamin B-12 status within the normal

range is a significant risk factor for cognitive

decline in the elderly.


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POSSIBLE BIOLOGICAL MECHANISM

Progressive loss of brain tissues is a factor associated with cognitive decline and

dementia. Low-normal vitamin B-12 status at baseline is a predictor of wholebrain atrophy in community-dwelling elderly.

Progressive atrophy of the brain was associated with plasma vitamin B-12

concentrations ranging from 800 to 160 pmol/L and with holotranscobalamin

concentrations from 250 to 25 pmol/L.

Atrophy of the brain


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POSSIBLE BIOLOGICAL MECHANISM

Damage to the white matter

In spinal cord and the brain

Damage to myelin as a result of deficient methylationof myelin basic protein.

Damage to white matter was related to vitamin B-12status over the normal range, as assessed by plasmatotal vitamin B-12, holotranscobalamin,

transcobalamin saturation and MMA. Changes in the white matter are reversible with

treatment with vitamin B-12.


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COGNITIVE ENHANCING EFFECT OF B

VITAMINS


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B vitamins may slow cognitive decline-

Oxford University study

Daily supplements of B vitamins may slow thedecline in mental function in people with mildcognitive impairment.

A daily combination of folic acid, and vitaminB6 and b12 was associated with a 30%reduction in levels of the amino acidhomocysteine, and improvements in a rangeof mental tests, including global cognition andepisodic memory.


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VITACOG StudiesC.A. de Jager, A. Oulhaj, R. Jacoby, H. Refsum, A.D. Smith

Executive function was stabilized in B vitamin group,compared with placebo.

People with high homocysteine levels, they found that B

supplementation was associated with significantimprovements in global cognition, episodic memory, andsemantic memory.

B vitamin treatment did stabilize performance on the CLOX

test of executive and planning function, this effect wasindependent of baseline homocysteine, perhaps indicatinga direct effect of one or more of the B vitamins.


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VITACOG Studies

B vitamin treatmentactually improved the

clinical outcome, but only

in participants with

baseline tHcy>

13.1mol/L. particularlystriking was the effect of B-

vitamin treatment on the

proportion of participants

with a CDR score of zero,

which doubled after 2 year

of treatment.


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EAT RIGHT TO PREVENT YOUR BRAIN FROM SHRINKING


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REFERENCES

De Jager C.A., Oulhaj A., Jacoby R., Refsu, H. &

Smith A.D. (2012) Cognitive and clinical

outcomes of homocysteine-lowering B-

vitamin treatment in mild cognitiveimpairment: a randomized controlled trial. Int

J Geriatr Psychiatry2012; 27: 592600.

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B Vitamins and Cognitive Performance Among Older Adults