Nutrition status and brain function in aging

B Vitamins and Fatty Acids: What Do They Share with Small Vessel Disease-Related Dementia?

Many studies have been written on vitamin supplementation, fatty acid, and dementia, but results are still under debate, and no definite conclusion has yet been drawn. Nevertheless, a significant amount of lab evidence confirms that vitamins of the B group are tightly related to gene control for endothelium protection, act as antioxidants, play a co-enzymatic role in the most critical biochemical reactions inside the brain, and cooperate with many other elements, such as choline, for the synthesis of polyunsaturated phosphatidylcholine, through S-adenosyl-methionine (SAM) methyl donation. B-vitamins have anti-inflammatory properties and act in protective roles against neurodegenerative mechanisms, for example, through modulation of the glutamate currents and a reduction of the calcium currents. In addition, they also have extraordinary antioxidant properties. However, laboratory data are far from clinical practice. Many studies have tried to apply these results in everyday clinical activity, but results have been discouraging and far from a possible resolution of the associated mysteries, like those represented by Alzheimer's disease (AD) or small vessel disease dementia. Above all, two significant problems emerge from the research: No consensus exists on general diagnostic criteria-MCI or AD? Which diagnostic criteria should be applied for small vessel disease-related dementia? In addition, no general schema exists for determining a possible correct time of implementation to have effective results. Here we present an up-to-date review of the literature on such topics, shedding some light on the possible interaction of vitamins and phosphatidylcholine, and their role in brain metabolism and catabolism. Further studies should take into account all of these questions, with well-designed and world-homogeneous trials.

Altered brain structural topological properties in type 2 diabetes mellitus patients without complications

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a risk factor for cognitive dysfunction, and white matter (WM) microstructural impairments play a critical role in T2DM-related cognitive decline. Disruptions to the WM have been detected in T2DM patients before clinical diagnosis of cognitive dysfunction. Herein, we investigated changes in brain structural topological properties and their correlation with behavior in T2DM patients without complications.

METHODS

Diffusion tensor imaging (DTI) structural network topological analysis was performed on T2DM patients and healthy controls. Intergroup differences in global and nodal parameters were analyzed, and correlations between the network parameters and behavioral performance were tested.

RESULTS

Type 2 diabetes mellitus patients exhibited preserved small-world properties, but altered nodal properties, including decreased efficiency in the right hippocampus, right amygdala, left pallidum, left postcentral gyrus, and right pole of the superior temporal gyrus, and increased degree in the right inferior frontal gyrus. Correlations were also found between the altered global and nodal parameters and behavioral performance.

CONCLUSIONS

The results verified the existence of WM structural network changes and the association between structural properties and cognitive state in T2DM patients before the occurrence of complications. Research of structural properties may contribute to our understanding of the intrinsic links between T2DM and cognition.

The role of branched chain amino acid and tryptophan metabolism in rat's behavioral diversity: Intertwined peripheral and brain effects

Previously, we showed that a transient early-in-life interference with the expression of multiple genes by mithramycin (MTR) followed by later-in-life exposure to chronic stress, leads to a "daring" and novelty seeking behavior in rats. In this study we searched for molecular changes that contribute to this behavioral alteration. We applied a non-hypothesis driven strategy using whole genome cDNA array analysis (WGA) followed by Genome Scale Metabolic modeling analysis (GSMM). Gene expression validation was performed by qRT-PCR and immunoblotting. Brain and serum amino acids levels were measured by HPLC. WGA data directed us towards metabolic pathways and GSMM pointed at branched chain amino acids (BCAA) pathway. Out of 21 amino acids analyzed in the prefrontal cortex of MTR+Stress rats only tryptophan, whose brain levels depend on serum BCAA levels, showed a significant decrease. No change was observed in serotonin or kynurenine levels. However, a significant reduction in mRNA and protein levels of the large neutral amino acid transporter (LAT1), which transports BCAA and tryptophan into the brain, as well as in serum levels of tryptophan/BCAA ratio were observed. The latter may be attributed to the failure to increase serum insulin, following stress, in rats pre-exposed to mithramycin. Finally, significant correlations were observed between the anxiety index and tryptophan and between T-maze errors and LAT1. This study shows a specific behavioral pattern, which is linked to modulations in fluxes of amino acids both peripheral and central, which converge and reciprocally interact, and may thus be equally important targets for therapeutic intervention.

Electroencephalographic findings related with mild cognitive impairment in idiopathic rapid eye movement sleep behavior disorder

STUDY OBJECTIVES

Mild cognitive impairment (MCI) and electroencephalographic (EEG) slowing have been reported as common findings of idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) and α-synucleinopathies. The objective of this study is to clarify the relation between MCI and physiological markers in iRBD.

DESIGN

Cross-sectional study.

SETTING

Yoyogi Sleep Disorder Center.

PATIENTS OR PARTICIPANTS

Thirty-one patients with iRBD including 17 younger patients with iRBD (younger than 70 y) and 17 control patients for the younger patients with iRBD.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Montreal Cognitive Assessment (MoCA) and n-polysomnogram (PSG) were conducted of all participants. In patients with iRBD, the factors associated with MCI were explored among parameters of REM sleep without atonia (RWA), score of Sniffin' Sticks Test (threshold-discrimination-identification [TDI] score), RBD morbidity, and RBD severity evaluated with the Japanese version of the RBD questionnaire (RBDQ-JP). The younger iRBD group showed significantly lower alpha power during wake and lower MoCA score than the age-matched control group. MCI was detected in 13 of 17 patients (76.5%) on MoCA in this group. Among patients wtih iRBD, the MoCA score negatively correlated with age, proportion of slow wave sleep, TDI score, and EEG spectral power. Multiple regression analysis provided the following equation: MoCA score = 50.871-0.116*age -5.307*log (δ power during REM sleep) + 0.086*TDI score (R² = 0.598, P < 0.01). The standardized partial regression coefficients were -0.558 for age, -0.491 for log (δ power during REM sleep), and 0.357 for TDI score (F = 9.900, P < 0.001).

CONCLUSIONS

Electroencephalographic slowing, especially during rapid eye movement sleep and olfactory dysfunction, was revealed to be associated with cognitive decline in idiopathic rapid eye movement sleep behavior disorder.

Topography of homeostatic sleep pressure dissipation across the night in young and middle-aged men and women

Decline in slow-wave activity (SWA) across the night is believed to reflect dissipation of the homeostatic sleep drive. This study evaluated the effects of age, sex and topography on SWA dissipation. The sleep electroencephalogram of 48 young [22 women, 26 men; mean = 23.3 years; standard deviation (SD) = 2.4] and 39 middle-aged (21 women, 18 men; mean = 51.9 years; SD = 4.6) healthy volunteers was analysed. Spectral analysis (0.5-22.0 Hz) was performed per non-rapid eye movement period for Fp1, F3, C3, P3 and O1. SWA (1.0-5.0 Hz) dissipation was modelled using linear and exponential decay functions applied to each age and sex subgroup data set for each derivation. The relative adequacy of both functions was compared using Akaike's information criterion. Results suggest that the exponential model provides a better data fit than the linear fit independently of age, gender and brain location. In women, age reduced the span (distance between the y intercept and the asymptote) of SWA decay in Fp1, F3, P3 and O1. In men, however, the effect of age on the span of SWA decay was limited to Fp1 and F3. In all age and sex subgroups, anterior regions showed a higher span than posterior regions. The asymptote was lower in anterior regions in young but not in middle-aged subjects. These results suggest that the homeostatic process operates on a larger scale in anterior regions. Importantly, ageing reduced the scale of homeostatic dissipation in both sexes, but this effect was more widespread across the brain in women.

Diabetes mellitus and gait dysfunction: possible explanatory factors

BACKGROUND AND OBJECTIVE

Gait characteristics differ in individuals with diabetes compared with those without diabetes. Limited information regarding potential explanatory factors for this association exists. This study examined the association between diabetes and gait characteristics in older adults and explored potential explanatory factors.

DESIGN

A cross-sectional, observational study design was used.

METHODS

At the 1998-1999 clinic visit, 558 ambulatory older adults (mean age=79 years) from the Pittsburgh site of the Cardiovascular Health Study had an assessment of their gait characteristics, diabetes, health status, cognition, mood, lower-extremity circulation and sensation, vision, lower-extremity strength (force-producing capacity), physical activity, and body mass index (BMI). A series of linear regression models were developed to examine the association between diabetes and gait characteristics and to examine potential explanatory factors for the associations.

RESULTS

Diabetes was related to gait speed (beta=-.06 m/s); however, the association was partially explained by health status variables, cognition, mood, lower-extremity circulation and sensation, visual impairment, lower-extremity strength, physical activity, and BMI. Health status and lower-extremity strength each explained the greatest proportion of the association (beta reduced 66% by each). Diabetes was related to step width (beta=.02 m), and the association could not be explained by the examined factors.

CONCLUSIONS

Diabetes was associated with gait alterations in older adults. Slowed gait speed appears to be secondary to the peripheral effect of the disease on other body systems. The effect of diabetes on step width was not explained in the analyses and may be related to peripheral motor nerve function or central influences of the disease, which could not be assessed in this study.

Lifestyle-related factors in predementia and dementia syndromes

Cognitive decline and dementia have a deep impact on the health and quality of life of older subjects and their caregivers. Since the therapeutic options currently available have demonstrated limited efficacy, the search for preventive strategies for cognitive decline and dementia are mandatory. A possible role of lifestyle-related factors was recently proposed for age-related changes of cognitive function, predementia syndromes and the cognitive decline of degenerative (Alzheimer's disease [AD]) or vascular origin. At present, cumulative evidence suggests that vascular risk factors may be important in the development of mild cognitive impairment (MCI), dementia and AD. Moderate alcohol drinking has been proposed as a protective factor against MCI and dementia in several longitudinal studies, but contrasting findings also exist. The Mediterranean diet could therefore be an interesting model with which to further study the association between dietary patterns and cognitive functioning, given the suggested role of many components of this diet (monounsaturated fatty acids, polyunsaturated fatty acids, cereals and red wine) in contrasting cognitive impairment and dementia. The association between low education and predementia and dementia syndromes is supported by the majority of studies, but very few studies have investigated whether this association may be attributed with lifestyle factors that covary with education. Studies in the literature seem to identify in physical exercise one promising strategy in decreasing cognitive decline, but some of the limitations of these studies do not allow us to draw definite conclusions. At present, in older subjects, healthy diets, antioxidant supplements, the prevention of nutritional deficiencies, and moderate physical activity could be considered the first line of defense against the development and progression of predementia and dementia syndromes. However, in most cases, these were only observational studies, and results are awaited from large multicenter randomized clinical trials in older persons that may clarify the possible synergy, for example, between moderate exercise, physical activity and healthy Mediterranean diet on cognition in the elderly.

Safety and Efficacy of a Ginkgo Biloba–Containing Dietary Supplement on Cognitive Function, Quality of Life, and Platelet Function in Healthy, Cognitively Intact Older Adults

OBJECTIVE

To determine if a ginkgo biloba-containing supplement improves cognitive function and quality of life, alters primary hemostasis, and is safe in healthy, cognitively intact older adults.

DESIGN

Four-month, randomized, double-blind, placebo-controlled parallel design.

SUBJECTS/SETTING

Ninety men and women (age range 65 to 84 years) were recruited to a university clinic. Eligibility included those without dementia or depression, not taking psychoactive medications or medications or supplements that alter hemostasis.

INTERVENTION

Ninety subjects were randomly assigned to placebo or a ginkgo biloba-based supplement containing 160 mg ginkgo biloba, 68 mg gotu kola, and 180 mg decosahexaenoic acid per day for 4 months.

MAIN OUTCOME MEASURES

Assessments included: six standardized cognitive function tests, the SF-36 Quality of Life questionnaire, the Platelet Function Analyzer-100 (Dade Behring, Eschbom, Germany), and the monitoring of adverse events.

STATISTICAL ANALYSES

Baseline characteristics and study hypotheses were tested using analysis of covariance. Tests were two-tailed with a 0.05 significance level.

RESULTS

Seventy-eight subjects (87%) completed both baseline and 4-month testing (n=36 in placebo group, n=42 in ginkgo biloba group). At baseline, the participants' cognitive function was above average. One of six cognitive tests indicated significant protocol differences at 4 months (P=0.03), favoring the placebo. There were no significant differences in quality of life, platelet function, or adverse events.

CONCLUSIONS

These finding do not support the use of a ginkgo biloba-containing supplement for improving cognitive function or quality of life in cognitively intact, older, healthy adults. However, high baseline scores may have contributed to the null findings. The ginkgo biloba product seems safe and did not alter platelet function, though additional studies are needed to evaluate the interaction of varying doses of ginkgo biloba and ginkgo biloba-containing supplements with medications and supplements that alter hemostasis.

Is B vitamins deficiency associated with prevalence of Alzheimer's disease in Cuban elderly?

Alzheimer's disease (AD), is a major public health problem among the elderly in industrialized countries and a growing problem in developing countries. In Cuba, 14,6% of the population is older than 60 years. The AD prevalence in Cuba lies between 5,13-7,14%. Several studies have shown the relationship between the low nutritional status of B vitamins, hyperhomocysteinaemia with loss of neuro-cognitive function and AD. In studies during the epidemic neuropathy that affected Cuba between 1992-1993, B vitamins deficiency and smoking habits were strongly associated with the epidemic. Some studies in healthy adults and elderly after this epidemic have shown a sub-clinical deficiency of some B vitamins and a high prevalence of infection by Helicobacter pylori. The possibility that B vitamin deficiencies could be an additional risk factor for the high prevalence of the AD in Cuba is discussed.

Nutritional factors, cognitive decline, and dementia

Nutritional factors and nutritional deficiencies have been repeatedly associated with cognitive impairment. Most of the evidence is based on cross-sectional studies, which cannot prove whether a nutritional deficit is the cause or the consequence of an impaired cognitive status. In fact, cognitive impairment, in turn, can determine changes in dietary habits and consequent nutritional deficiencies. We reviewed clinical and epidemiological studies from January 1983 to June 2004. Several cross-sectional and fewer prospective studies reported an association between dietary or supplemental intake of antioxidants and protection from cognitive decline and dementia. There are negative reports as well and some methodological biases might have affected the consistencies across studies. Deficiencies of several B vitamins have been associated with cognitive dysfunction in many observational studies. More recently, deficiencies of folate (B9) and cobalamine (B12) have been studied in relation to hyperhomocysteinemia as potential determinants of cognitive impairment, dementia, and Alzheimer's disease (AD). A small number of studies assessed the association between intake of macronutrients and cognitive function or dementia. Among the others, the intake of fatty acids and cholesterol has received particular attention. Although the results are not always consistent, most studies have reported a protective role of dietary intakes of poly- and mono-unsaturated fatty acids against cognitive decline and AD. We point out that well designed intervention studies are warranted in order to establish specific levels of micro- and macronutrient deficiencies and to set general recommendations for the population.

Similarities and differences between Alzheimer's disease and vascular dementia from the viewpoint of nutrition

Dietary habits were compared in patients with Alzheimer's disease (AD) and those with vascular dementia (VaD). Twenty-seven patients with AD, 15 patients with VaD, and 49 age-matched controls were enrolled. Nutritional status was assessed using a semiquantified food-frequency questionnaire. Dietary habits were very similar in male patients with AD and VaD. Both groups had significantly higher energy intake than their energy demands: +25% for AD and +35% for VaD, respectively. However, major sources of energy were different: grains and animal fats for AD versus only grains for VaD. Calculation of nutrients revealed excess intake of n-6 polyunsaturated fatty acids (PUFA) and relative deficiencies of multiple vitamins including antioxidants, vitamin C and carotene, and the vitamin B group. In contrast, dietary habits in female patients with AD differed significantly from those of male patients. Female patients consumed significantly lower amounts of fish and green vegetables. Calculation of nutrients showed absolute deficiencies of n-3 PUFA, multiple vitamins, and minerals. Our results show that AD and VaD are similar from the viewpoint of nutrition, except for the higher consumption of animal fats for AD patients, probably reflecting Westernization of dietary habits in recent years. Nutrition may be relevant to the pathogenesis of dementia through many processes. Higher intake of energy and lower intake of antioxidants may exaggerate the process of dementia through oxidative stress. Excessive amounts of n-6 PUFA or deficiency of n-3 PUFA may cause chronic inflammation, platelet aggregation, or endothelial dysfunction of microvasculature. Nutrition may be useful for preventing dementia, although gender-specific differences must be taken into account.

Prevention of brain aging and dementia

The brain is subjected to multiple factors that result in damage to its cellular constituents, the neuron and supporting cells, and the neural networks that form the bases of cognitive ability. Like other systems, the brain has remarkable capacity to repair that damage and to adapt or compensate for the loss of neurons and the disruption of the neural architecture. Brain aging and dementia can be conceptualized as a balance between neuronal injury and repair. This balance can be affected not only by genetic and age-related factors but also by multiple environmental factors. The latter includes many factors, including education, nutrition, exercise, socialization, and stress. As individuals, we have the potential to modify these factors through lifestyle choices. Advances in neuroscience have led to the development of pharmacologic agents that can ameliorate the effects of even genetic (e.g., statins and antihypertensive agents) and age-related (e.g., antioxidants and estrogen replacement) factors. By altering the balance between neuronal injury and repair, we can delay the expression and progression of the neurodegenerative processes of brain aging, AD, and related dementias.

Folate, homocysteine, and neurological function

The study of different neurological problems, including stroke, Alzheimer's disease (AD), and depression, has propelled a greater interest in interrelationships among folate, homocysteine, and neurological function. Specifically, low folate status is a suspected risk factor for depression that also results in an increase in circulating levels of the sulfur amino acid homocysteine. Homocysteine has emerged as an independent risk factor for stroke, and recent studies suggest that vascular disease affecting the brain and Alzheimer's disease may result together in senile dementia. The relationship between stroke and AD was at first interpreted as coincidence, given the pathologic distinctions between the two diseases. However, the connection is now hypothesized to reflect some common pathogenic factors involving folate, homocysteine, or both. It remains unclear whether there is a causal relationship between neurological dysfunction in either condition with folate or homocysteine. Nevertheless, since improvement of folate status lowers homocysteine levels, the hypothesis that folate supplementation may lower the risk of several important health consequences of aging, including various forms of neuropsychiatric dysfunction, is worthy of current intensive exploration.

The effect of nutritional intervention in elderly subjects residing in group-living for the demented

OBJECTIVES

We studied the nutritional status and the effects of nutritional intervention on body weight, cognition and activities of daily life (ADL)-function in demented individuals.

DESIGN

Controlled non-randomised study.

SETTING

Group-living for demented elderly (GLD), ie community assisted housing.

SUBJECTS AND INTERVENTIONS

Twenty-two residents living in one of two units (GLD-I), received oral liquid supplements (1720 kJ/410 kcal/day) and the personnel of the GLD-I were given nutritional education. Fourteen residents in the other unit (GLD-C) served as controls. After 6 months 21 (83 (4) y, 81% women) and 12 (85 (4) y, 100% women) of the participants, respectively, were re-examined according to body mass index (BMI, kg/m2), cognitive function (Mini Mental State Examination (MMSE, 0-30 p) and Clinical Dementia Rating Scale (CDR) and the Katz' ADL index.

RESULTS

Body mass index (BMI) < or =20 was found in 19% of the participants and 44% had BMI< or =23. BMI correlated with MMSE (r=0.43, P<0.01). The weight of the residents in the intervention group increased by 3.4 (3) kg (P=0.001) at follow-up, whereas the weight remained unchanged in the control group. The cognitive function was low at the start in both groups, ie MMSE approximately 9 and no apparent positive effect of the nutritional intervention was seen. In addition, the ADL functions appeared to deteriorate in both groups.

CONCLUSIONS

Being underweight was common among demented elderly in group-living and was related to low cognitive capacity. Five months of oral supplementation, along with education of personnel, was followed by a weight gain. In this study the nutritional treatment did not affect the rate of decline in cognitive function or Katz' ADL index.

SPONSORSHIP

Supported by grants from the Swedish National Board of Health and Social Welfare. Semper Foods AB provided the liquid supplements.

The influence of serum vitamin B12 and folate status on cognitive functioning in very old age

This study examined the relationship between low levels of serum vitamin B12 and folic acid (FA) and cognitive functioning in very old age. The four subsamples of non-demented persons aged 75-96 years - normal B12/normal FA; low B12/normal FA; normal B12/low FA; and low B12/low FA, were matched for age and education. A battery of cognitive tests was administered including Clock Tests, Block Design, Trail Making Tests (TMT), Digit Span, and tests of verbal fluency. Subjects with low levels of vitamins showed deficits in Block Design, TMT-B, Digit Span Backward, and letter fluency, but not in the remaining tests. In general, the effects of FA exceeded those of B12. This pattern of results was interpreted to mean that elderly persons with low vitamin levels have difficulty when fast and accurate processing of novel information is required, but are quite efficient in utilizing pre-existing knowledge structures.

Cognitive decline is associated with systemic oxidative stress: the EVA study. Etude du Vieillissement Artériel

OBJECTIVE

To determine whether systemic oxidative stress status is associated with cognitive decline.

DESIGN

A longitudinal population-based study.

SETTING

A cohort study of older subjects in Nantes, France.

PARTICIPANTS

A total of 1166 high cognitive functioning subjects aged 60 to 70 in the Etude du Vieillissement Arteriel (EVA) cohort with a 4 year follow-up.

MEASUREMENTS

Subjects completed a baseline interview and a global cognitive test (Mini-Mental Status Examination (MMSE)). Blood samples were obtained at baseline to determine plasma levels of selenium, carotenoids, thiobarbituric acid reactant substances (TBARS), an indicator of lipoperoxidation, and red blood cell vitamin E. Risk of cognitive decline, defined as a loss of 3 points in MMSE score between baseline and the 4 year follow-up, was assessed by oxidative stress level.

RESULTS

Subjects with the highest levels of TBARS show an increased risk of cognitive decline (adjusted odds ratio (OR) = 2.25; confidence interval (CI) 95% = 1.26-4.02). This result is reinforced in the lower antioxidant status subgroup. Subjects with low levels of selenium have an increased risk of cognitive decline (OR = 1.58; CI 95% = 1.08-2.31) after adjustment for various confounding factors.

CONCLUSIONS

These results suggest that increased levels of oxidative stress and/or antioxidant deficiencies may pose risk factors for cognitive decline. The direct implication of oxidative stress in vascular and neurodegenerative mechanisms that lead to cognitive impairment should be further explored.

[Alzheimer's disease: from pathology to preventive methods?]

INTRODUCTION

Sporadic Alzheimer's disease is the most frequent form of dementia and appears to be associated with increasing age and certain genetic and environmental factors. Some studies have recently been published on potential protective factors.

CURRENT KNOWLEDGE AND KEY POINTS

Several genes appear to be involved; one of the most common is the ApoE4 allele on chromosome 19. The physiopathology is not elucidated, but recent studies have shown a protective effect for NSAIDs, estrogen, nutritional factors (vitamins E, B6 and B12) as well as some biochemical amino acids (homocysteine).

FUTURE PROSPECTS AND PROJECTS

Interventional studies are now in progress and some preventive approaches will soon be available.

Alzheimer disease: protective factors

Approximately 6-8% of all persons aged >65 y have Alzheimer disease and the prevalence of the disease is increasing. Any intervention strategy aimed at decreasing risks or delaying the onset of the disease will therefore have a substantial effect on health care costs. Nutrition seems to be one of the factors that may play a protective role in Alzheimer disease. Many studies suggest that oxidative stress and the accumulation of free radicals are involved in the pathophysiology of the disease. Several studies have shown the existence of a correlation between cognitive skills and the serum concentrations of folate, vitamin B-12, vitamin B-6, and, more recently, homocysteine. However, nutritional factors have to be studied not alone but with the other factors related to Alzheimer disease: genetics, estrogen, antiinflammatory drug use, and socioeconomic variables. The objective of this article was to review recent studies in this field.

B vitamins, homocysteine, and neurocognitive function in the elderly

Evidence of the importance of the B vitamins folic acid, vitamin B-12, and vitamin B-6 for the well-being and normal function of the brain derives from data showing neurologic and psychologic dysfunction in vitamin deficiency states and in cases of congenital defects of one-carbon metabolism. The status of these vitamins is frequently inadequate in the elderly and recent studies have shown associations between loss of cognitive function or Alzheimer disease and inadequate B vitamin status. The question that arises is whether these B vitamin inadequacies contribute to such brain malfunctions or result from aging and disease. From a theoretical standpoint, these inadequacies could give rise to impairment of methylation reactions that are crucial to the health of brain tissue. In addition or perhaps instead, these inadequacies could result in hyperhomocysteinemia, a recently identified risk factor for occlusive vascular disease, stroke, and thrombosis, any of which may result in brain ischemia. Advances in the understanding of this putative relation between inadequate vitamin status and loss of cognitive function in the elderly are likely to be slow and may depend on the outcomes of both prospective studies and longitudinal studies in which nutritional intervention is provided before cognitive decline occurs.

Causes of iron and zinc deficiencies and their effects on brain

Low consumption of foods rich in bioavailable iron (Fe) and zinc (Zn) such as meat, particularly red meat, and high consumption of foods rich in inhibitors of Fe and Zn absorption, such as phytate, certain dietary fibers and calcium, cause Fe and Zn deficiencies. Neuropsychologic impairment is one of several potential outcomes of these deficiencies.

Cognitive impairment and oxidative stress in the elderly: results of epidemiological studies

Cognitive impairment is a major component of age-related dementing diseases and it has been suggested that it could share the same pathological pathways with neurodegenerative processes and cerebrovascular lesions. The free radical theory of ageing could be one of these pathways. Implication of free radical damage in processes related to cerebral ageing is a good argument in favour of the hypothesis that antioxidants may protect against cognitive impairment. Observational studies (mostly cross-sectional) of relationships between cognitive impairment and antioxidant status are based on the evaluation of dietary intake or on the levels of carotenoids, selenium and vitamins A, C and E in plasma or red blood cells. More convincing results were obtained on vitamin C and carotenoids. Despite some limitations, the comparison between results obtained in various populations is becoming increasingly informative and these studies argue for a protective effect of antioxidants on cognitive performance.

Further evidence on the effects of vitamin B12 and folate levels on episodic memory functioning: a population-based study of healthy very old adults

BACKGROUND

The relationship between vitamin status and cognitive functioning has been addressed in several recent studies with inconclusive results. The purpose of this study was to examine separate and combined effects of serum vitamin B12 and folic acid on episodic memory functioning in very old age.

METHODS

Four study groups were selected from a population-based sample of healthy very old adults (90-101 years of age): normal B12/normal folic acid, low B12/normal folic acid, normal B12/low folic acid, and low B12/low folic acid. Cutoff levels were set at 180 pmol/L for vitamin B12 and at 13 nmol/L for folic acid. Subjects completed two episodic recall tasks (objects and words) and two episodic recognition tasks (faces and words).

RESULTS

Neither vitamin affected recognition or primary memory. Most interesting, although B12 was unrelated to recall performance, subjects with low folic acid levels showed impairment in both word recall and object recall.

CONCLUSIONS

These results replicate and extend previous findings that folic acid may be more critical than B12 to memory functioning in late life. The selective effects of folic acid on episodic recall were discussed in terms of encoding and retrieval mechanisms, as well as in relation to brain protein synthesis.

Characterization of seizures in the flathead rat: a new genetic model of epilepsy in early postnatal development

PURPOSE

Disorders in normal central nervous system (CNS) development are often associated with epilepsy. This report characterizes seizures in a novel genetic model of developmental epilepsy, the Flathead (FH) rat.

METHODS

Animals (n = 76) ages P0-22 were monitored for clinical and electrographic seizure activity. The effects of various AEDs on seizure frequency and duration also were assessed: phenobarbital (PB; 40 mg/kg), valproate (VPA; 400 mg/kg), or ethosuximide (ESM; 600 mg/kg).

RESULTS

FHs display episodes of behavior characterized by whole-body tremor, strub tail, alternating forelimb clonus, and complete tonus. EEG recordings from neocortex reveal that FH seizures are bilateral and begin around P7. Seizures occur at a frequency of approximately six per hour from P7 to P18 and the average duration of seizures increases through development. PB, VPA, and ESM failed to prevent seizures; however, PB significantly increased the interval of seizures but had no effects on the duration of seizures, whereas VPA decreased the duration of seizures and not the interval.

CONCLUSIONS

Seizures in FH rats occur at a constant and high frequency through a defined period in early postnatal development, and these seizures are not completely blocked by high doses of PB, VPA, or ESM. Because FH is a single-locus mutant displaying a highly regular pattern of seizure activity, it is an ideal model for examining the process of epileptogenesis in the developing brain, evaluating new AED therapies, and determining the identity of a gene essential to the normal development of cortical excitability.

Altered plasma antioxidant status in subjects with Alzheimer's disease and vascular dementia

OBJECTIVES

Oxygen-free radicals and lipid hydroperoxides may have an aetiological role in the development of lesions in the central nervous system in patients with Alzheimer's disease and in those with vascular dementia. This study aimed to make a cross-sectional comparison of blood markers of oxidative stress in two groups of patients with these disorders and a control group.

DESIGN

Cross-sectional comparative study.

SETTING

Established memory clinics in Cardiff organized by a University Department of Geriatric Medicine within an acute care NHS Trust.

METHODS

Following a dietary assessment, postprandial venous blood samples were obtained from the following: 25 subjects with probable Alzheimer's disease (AD) (mean age 74.3; 10 F, 15 M); 17 subjects with probable vascular dementia (VD) (mean age 75.5; 5 F, 12 M); and 41 controls (mean age 73.4; 24 F, 17 M) for measurement of circulating lipid peroxides (LP), total antioxidant capacity (TAC), vitamin C (VitC), vitamin E (VitE) and beta-carotene (BC).

RESULTS

Plasma levels of VitC were significantly lower in subjects with vascular dementia compared with controls (VD, 6.5 (4.8, 8.2); controls, 10.0 (8.38, 11.6); VD vs controls, p = 0.015), but no significant difference was seen between controls and patients with Alzheimer's disease (AD, mean 8.3 (6.2, 10.4)). VitE levels were significantly lower in subjects with AD compared with controls (31.1 (28.2, 34.0) vs 36.0 (32.8, 39.2), p = 0.035). BC levels were similar in subjects with AD and controls, but significantly elevated in those with VD (AD, 0.28 (0.2, 0.34); VD, 0.40, (0.27, 0.53); controls, 0.28 (0.22, 0.34); VD vs controls, p = 0.046). There were no significant differences in LP or TAC between the three groups.

CONCLUSIONS

Subjects with dementia attributed to Alzheimer's disease or to vascular disease have a degree of disturbance in antioxidant balance which may predispose to increased oxidative stress. This may be a potential therapeutic area for antioxidant supplementation.

The relation between antioxidants and memory performance in the old and very old

OBJECTIVES

Aging processes, and among them brain aging, are thought to be associated with free radical action. It is hypothesized that plasma antioxidant vitamin levels correlate with cognitive performance in healthy older subjects.

DESIGN

Longitudinal and cross-sectional comparisons.

SETTING

The city of Basle, considered representative of the older urban population in Switzerland.

PARTICIPANTS

A total of 442 subjects aged 65 to 94 years (mean: 75 years; 312 male, 132 female) was selected from a random sample.

MEASUREMENTS

In 1993, participants were tested for memory, and plasma vitamin levels were measured for the three antioxidants alpha-tocopherol, ascorbic acid, and beta-carotene. These vitamin parameters, measured previously in 1971 in the same sample, were integrated in our analyses. In addition, plasma cholesterol, ferritin, and systolic blood pressure were taken into account. Memory variables were priming, working-memory, free recall, recognition and the WAIS-R vocabulary test (semantic memory).

RESULTS

Correlations showed significant stability of the plasma antioxidants over the time lag of 22 years (alpha-tocopherol: r = .47, P < or = .001; beta-carotene: r = .43, P < .001; ascorbic acid: r = .22, P < .001). Free recall, recognition, and vocabulary (but not priming and working-memory) correlated significantly with ascorbic acid and beta-carotene in the cross-sectional 1993 data as well as in the longitudinal 1971-1993 analysis. These two antioxidants remained significant predictors, especially of semantic memory, after controlling for possible confounding variables like age, education, and gender using multiple regression analyses and ANOVAs.

CONCLUSION

Among people aged 65 and older, higher ascorbic acid and beta-carotene plasma level are associated with better memory performance. These results indicate the important role played by antioxidants in brain aging and may have implications for prevention of progressive cognitive impairments.

Vitamin status of eating disorder patients: relationship to clinical indices and effect of treatment

Vitamin abnormalities in eating disorder patients may contribute to altered neuropsychological status and the development of sequelae such as cognitive dysfunction. We examined the relationship between vitamin status and clinical indices in 13 low-weight patients with anorexia or bulimia nervosa at admission to a treatment program. Vitamin status was evaluated again at discharge (2-6 weeks later) in nine of these patients. Four patients (31%) initially had erythrocyte enzyme activity indices suggesting deficiency for riboflavin and for vitamin B-6. Patients with biochemical evidence for riboflavin deficiency had lower relative body weight than those with normal riboflavin status (p < .02). Three patients (23%) had elevated plasma cholesterol concentrations (> 5.69 mmol/L). Plasma retinol concentrations were within the normal range. Plasma alpha-tocopherol concentrations were positively associated with serum albumin (p < .04), cholesterol (p < .0003), and total lipids (p < .0003), and were inversely associated with body mass index (p < .04). At discharge, thiamin, riboflavin and vitamin B-6 status indicators were normal in all cases examined. Suboptimal vitamin status is common in eating disorder patients but is normalized with dietary intervention and nutritional rehabilitation.

Relationships between macronutrient intake, handicaps, and cognitive impairments in free living elderly people

It is still unknown what if any relationships exist between intake of macronutrients by the elderly, and their functional or cognitive handicaps, particularly for free living elderly people. We investigated 226 men and 215 women, aged 65 or more, free living and in good health. They were randomly selected in the département of Bas-Rhin, after stratification for age, sex and residence (rural or urban). Handicaps and cognitive functions of each subject were assessed with the Géronte scale and the Mini-Mental State Examination (MMSE), respectively. Food intake was measured by a three-day record. A multiple correspondence analysis concluded that functional parameters and macronutrient intakes were rather independent. The relationships found were detailed by a backward stepwise logistic regression. In men, alcohol intake was associated with an improvement in functional and cognitive parameters, and polyunsaturated fatty acids with the capacity to move outside the home. In women, lipid intake increased the MMSE score. Overweight in women was linked with better functional and cognitive performances, and in men with the capacity to move outside the home. In both sexes, age worsened the score of functional and cognitive parameters. In conclusion, macronutrient intakes and functional or cognitive parameters were found to be mutually independent; this suggests that macronutrient deficiencies are of little importance in the worsening functional or mental autonomy of the elderly. The relationships found between functional variables and alcohol or polyunsaturated fatty acid intakes in men, and lipid intakes in women, and overweight in both sexes might evidence a better state of health.

Effect of advanced brain atrophy and vitamin deficiency on cognitive functions in non-demented subjects

The relationship between the cognitive functions, structural changes of the brain and vitamin levels was evaluated in 36 non-demented subjects with advanced brain atrophy, and 57 age- and sex-matched healthy controls. In the control subjects ageing was associated with mild decline of cognitive skills, but the cognitive changes were not linked to the structural changes of the brain. In contrast, advanced brain atrophy and vitamin deficiency was related to the decline of complex cognitive functions in the atrophy group. Our results indicate that there are limits of normal age-related changes of the brain structure, and advanced brain atrophy on CT scans increase the probability of mild deficits of the cognitive skills.