Homocysteine & Cognition (2007)

This study evaluated the association between plasma homocysteine levels and cognition. The presence of mild cognitive impairment (MCI) in 1215 elderly subjects (aged 60-85years) from Korea was assessed. Individuals with MCI may be at an increased risk for developing dementia, including Alzheimer’s disease. Homocysteine levels, in addition to folate and vitamin B12 levels were measured in blood samples. The presence of MCI was assessed by an independent physician using Mayo clinic criteria which included: 1) memory complaint, preferably corroborated by an informant; 2) objective memory impairment for age; 3) largely preserved general cognition; 4) essentially normal activities of daily living; and 5) no dementia.

The results also showed that high homocysteine was associated with low blood folate or vitamin B12 levels suggesting that supplementation of these nutrients may be helpful in reducing elevated homocysteine levels.

The results found a strong association between increased plasma homocysteine levels and risk of MCI. The association appeared to be independent of other well-known risk factors for cognitive decline such as age, sex, education, smoking, marital status, and serum vitamin levels which suggests that hyperhomocysteinemia may be an independent risk factor for MCI in elderly Korean subjects.

Kim, J. et al., ‘Plasma Homocysteine Is Associated with the Risk of Mild Cognitive Impairment in an Elderly Korean Population’, The Journal of Nutrition, 137 (9), 2093-2098, September 2007

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Folate, B12 & cognitive impairment (2007)

This study investigated folate, B12 & cognitive impairment. A high folic acid and B12 intake in the elderly may be protective against age-related memory decline. However, those with a high folic acid intake, from fortified food or supplements, but a low B-12 status have more memory decline and hence a greater risk for dementia. They are also at greater risk of anaemia. This research found that 4% of the elderly in the USA have high folate and low B12 status.

In seniors with low vitamin B-12 status, high serum folate was associated with anemia and cognitive impairment. When vitamin B-12 status was normal, however, high serum folate was associated with protection against cognitive impairment.

Click here for the abstract

M S Morris, ‘Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification’, Am J Clin Nutr.85(1):193-200, 2007

B12 & Cognition (2011)

This study investigated B12 & cognition.  This study compared markers of vitamin B12 deficiency with various measures of brain shrinkage (MRI scans) and function (neuropsychological test results) over a 5 year period.  Results indicated that Methylmalonate, a specific marker of B12 deficiency, may affect cognition by reducing total brain volume. However, the effect of homocysteine (nonspecific to vitamin B12 deficiency) on cognitive performance may be mediated through increased white matter hyperintensity and cerebral infarcts.

Tangney CC, Aggarwal NT, Li H, Wilson RS, DeCarli C, Evans DA, Morris MC (2011) Vitamin B12, cognition, and brain MRI measures – A cross-sectional examination. Neurology 77:1276-1282

 Click here for abstract

Homocysteine & Brain Shrinkage (2011)

This study investigated homocysteine & brain shrinkage. UCLA School of Medicine researchers inlcuding a sample of 732 elderly people subjected to MRI brain scans, found that those with raised homocysteine levels have greater brain shrinkage regardless of age and diagnosis. Among those with cognitive impairment, the greater the homocysteine level the greater was the brain atrophy. The authors state ‘ Vitamin B supplements such as folate may help prevent homocysteine-related atrophy in Alzheimer’s disease by possibly reducing homocysteine levels.’

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Rajagopalan, P., Hua, X., Toga, A. W., Jack, C. R., Jr, Weiner, M. W., & Thompson, P. M. (2011). Homocysteine effects on brain volumes mapped in 732 elderly individuals. Neuroreport, 22(8), 391–395. https://doi.org/10.1097/WNR.0b013e328346bf85

Vitamin D & Cognition (2006)

This study examined vitamin D & cognition. Vitamin D status, cognitive performance, mood, and physical performance in older adults was assessed. 58% of the participants were found to have abnormally low vitamin D levels. Vitamin D deficiency was associated with presence of a mood disorder and with worse performance on 2 measures of mood and cognitive performance.

C H Wilkins et al., ‘Vitamin D deficiency is associated with low mood and worse cognitive performance in older adults’, J Geriatr Psychiatry, 14(12):1032-40, 2006

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Risk Factors for Alzheimer’s (2011)

This study investigated risk factors for Alzheimer’s. This study looked at the evidence regarding seven modifiable risk factors for Alzheimer’s. They calculated that about half of the 33 million cases worldwide could be prevented (that’s 17 million) and calculated that if these risk factors were to be modified to only a ‘relatively modest degree’, specifically by 10-25% as many as 1 – 3 million cases of the current 33 million worldwide could have been prevented.

The risk factors they considered were diabetes, midlife high blood pressure (hypertension), midlife obesity, smoking, depression, cognitive inactivity or low educational attainment, and physical inactivity. A major shortcoming of this report is that they didn’t consider dietary and lifestyle factors such as increasing B vitamins / reducing homocysteine, increasing essential fats and vitamin D, adopting a Mediterranean diet.

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Barnes, D. E., & Yaffe, K. (2011). The projected effect of risk factor reduction on Alzheimer’s disease prevalence. The Lancet. Neurology, 10(9), 819–828. https://doi.org/10.1016/S1474-4422(11)70072-2

Homocysteine & The Brain (2011)

A study conducted by UCLA School of Medicine researchers of 732 elderly people given MRI brain scans finds that those with raised homocysteine levels have greater brain shrinkage regardless of age and diagnosis. Among those with cognitive impairment, the greater the homocysteine level the greater was the brain atrophy. The authors state ‘ Vitamin B supplements may help prevent homocysteine-related atrophy in Alzheimer’s disease by possibly reducing homocysteine levels’.

Rajagopalan P, Hua X, Toga AW, Jack CR Jr, Weiner MW, Thompson PM.  Homocysteine effects on brain volumes mapped in 732 elderly individuals. Neuroreport, 22(8):391-5, 2011.

Clich here for abstract.

Folate & Alzheimer’s (2007)

This study investigated folate & Alzheimer’s. Folate helps the body to process homocysteine, which is associated with a higher risk of cardiovascular disease and stroke, and may also increase the risk of Alzheimer’s disease. Researchers studied the diets of 965 people age 65 and older who did not have dementia when the six-year study began.

Results demonstrated 192 cases of incident AD. The highest quartile of total folate intake was related to a lower risk of AD (hazard ratio, 0.5; 95% confidence interval, 0.3-0.9; P=.02 for trend) after adjustment for age, sex, education, ethnic group, the epsilon4 allele of apolipoprotein E, diabetes mellitus, hypertension, current smoking, heart disease, stroke, and vitamin B6 and B12 levels. Vitamin B6 and B12 levels were not related to the risk of AD.

Conclusions: Higher folate intake may decrease the risk of AD independent of other risk factors and levels of vitamins B6 and B12. These results require confirmation with clinical trials.

Luchsinger et al., ‘Relation of higher folate intake to lower risk of Alzheimer disease in the elderly’, Arch Neurol.;64(1):86-92, 2007

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Dementia & Alzheimer’s (2007)

This study investigated dementia & Alzheimer’s. Over 8000 over-65s were monitored for development of dementia and Alzheimer’s over a 4 year period and details of their dietary habits were analysed. Daily consumption of fruits and vegetables was found to be associated with a decreased risk of all types of dementia. Weekly consumption of fish was also associated with a decreased risk of all dementias and Alzheimer’s Disease but only amongst those people who do not have the genetic variation called ApoE4. The regular use of omega-3 supplements was associated with a slight decreased risk of all dementias. However, the regular use of omega-6 supplements, where it was not balanced with the use of omega-3 supplements or fish, actually doubled the risk developing dementia amongst those who do not have the ApoE4 gene. In summary, frequent consumption of fruits and vegetables, fish, and omega-3 rich oils may decrease the risk of dementia and Alzheimer disease, especially among ApoE4 non-carriers. In addition, balance of the omega 3:6 ratio may also be an integral risk factor, although further research is warranted.

Gateau P et al.,’Dietary patterns and risk of dementia: The Three-City cohort study, Barberger’.  Neurology. 2007 Nov 13;69(20):1921-30

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Vitamin D & Alzheimer’s (2011)

Scientists at Oxford University’s OPTIMA project* ran a study to look for a link between vitamin D & Alzheimer’s. Participants were comprised of 255 people with definite or probable Alzheimer’s and 260 healthy elderly people. The study looked at the gene for the vitamin D receptor, which manages the body’s response to vitamin D.

Findings were that there does appear to be a link. Two slight changes in the genetic code which makes up the gene for the vitamin D receptor were associated with risk of Alzheimer’s. These are preliminary findings, and more research is needed to understand their significance.

Lehmann DJ, Refsum H, Warden DR, Medway C, Wilcock GK, Smith AD (2011) The vitamin D receptor gene is associated with Alzheimer’s disease. Neurosci Lett. Oct 24;504(2):79-82.

*OPTIMA is led by Professor David Smith who is also on our Scientific Advisory Board

Click here for abstract.