Comparisons of plasma/serum micronutrients between Okinawan and Oregonian elders: a pilot study

Risk Factors Associated with Cortical Thickness and White Matter Hyperintensities in Dementia Free Okinawan Elderly

Background:

Cortical gray matter (GM) and white matter (WM) deterioration are signals of neurodegeneration and increased dementia risk; however, their specific etiologies in dementia-free aging is unclear.

Objective:

The objective of this study was to examine potentially modifiable risk factors of GM and WM degeneration in a well-characterized cohort of dementia-free elderly.

Methods:

96 Okinawan elderly participants (age 83.6) from the Keys to Optimal Cognitive Aging Project (KOCOA) underwent MRI and cognitive evaluation. Serum markers of inflammation (interleukin-6 (IL-6), high sensitivity C-reactive protein), cerebrovascular disease (systolic blood pressure (SBP) 140+, hemoglobin A1C (HgbA1C), total cholesterol), and essential minerals (copper (Cu), magnesium, and calcium) were examined in relation to mean cortical thickness (MCT) and white matter hyperintensities (WMH), adjusting for age and gender. Voxel-based morphometry (VBM) analyses identified relationships between regional GM density and the above markers.

Results:

Decreased MCT was associated with SBP 140 + (p = 0.029) and increased serum IL-6 (p = 0.036), HgbA1C (p = 0.002), and Cu (p = 0.025). In VBM analyses, increased IL-6, HgbA1C, and Cu were associated with decreased GM density in temporal lobe regions. HgbA1C (p = 0.004) was associated with greater WMH volume.

Conclusions:

Peripheral markers of Cu, CVD risk, and inflammation are associated with MRI-markers of decreased brain health in dementia-free Okinawan elderly, with regional cortical thinning in areas involved in early accumulation of Alzheimer’s disease pathology. Results identify potentially modifiable biomarkers as targets in the prevention of dementia in older individuals.

Associations between Serum Omega-3 Fatty Acid Levels and Cognitive Functions among Community-Dwelling Octogenarians in Okinawa, Japan: The KOCOA Study

BACKGROUND

Epidemiological studies have found frequent consumption of fatty fish is protective against cognitive decline. However, the association between circulating omega-3 polyunsaturated fatty acid (PUFA) levels and cognitive functions among the oldest old is not well known.

OBJECTIVE

To examine the association between serum PUFA levels and cognitive function among community-dwelling, non-demented elderly aged over 80 years old.

METHODS

The data came from the Keys to Optimal Cognitive Aging (KOCOA) study; an ongoing cohort of relatively healthy volunteers aged over 80 years old, living in Okinawa, Japan. One hundred eighty five participants (mean age 84.1±3.4 years) assessed in 2011 who were free from frank dementia (defined as Clinical Dementia Rating <1.0) were used for the current cross-sectional study. We examined whether serum omega-3 PUFAs (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]), arachidonic acid (AA), EPA/AA ratio, DHA/AA ratio, and DHA+EPA are associated with (1) age and (2) global cognitive function (Japanese MMSE) and executive function (Verbal Fluency Letter). Data was analyzed univariately by t-test and multivariately by cumulative logistic regression models controlling for age, gender, years of education, obesity, hypertension, diabetes, and dyslipidemia.

RESULTS

Serum DHA levels decreased with increasing age (p = 0.04). Higher global cognitive function was associated with higher levels of serum EPA (p = 0.03) and DHA + EPA (p = 0.03) after controlling for confounders.

CONCLUSIONS

Higher serum EPA and DHA + EPA levels were independently associated with better scores on global cognitive function among the oldest old, free from dementia. Longitudinal follow-up studies are warranted.

Demographic, phenotypic, and genetic characteristics of centenarians in Okinawa and Japan: Part 1-centenarians in Okinawa

A study of elderly Okinawans has been carried out by the Okinawa Centenarian Study (OCS) research group for over four decades. The OCS began in 1975 as a population-based study of centenarians (99-year-olds and older) and other selected elderly persons residing in the main island of the Japanese prefecture of Okinawa. As of 2015, over 1000 centenarians have been examined. By several measures of health and longevity the Okinawans can claim to be the world's healthiest and longest-lived people. In this paper we explore the demographic, phenotypic, and genetic characteristics of this fascinating population.

Very old adults with better memory function have higher low-density lipoprotein cholesterol levels and lower triglyceride to high-density lipoprotein cholesterol ratios: KOCOA Project

We cross-sectionally examined which lipid profiles are associated with better cognitive function among those aged 80 and older, free of dementia (Clinical Dementia Rating ≤0.5), functionally independent, and community-dwelling. Our cohort consisted of 193 participants from the "Keys to Optimal Cognitive Aging (KOCOA) Project", a prospective cohort study in Okinawa, Japan. Higher low-density lipoprotein cholesterol levels and lower triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratios were associated with higher scores in memory performance after controlling for confounders. Further research is required to clarify the associations among LDL-C levels, TG/HDL-C ratios, and healthy cognitive aging.

Extending healthy ageing: nutrient sensitive pathway and centenarian population

Ageing is a challenge for any living organism and human longevity is a complex phenotype. With increasing life expectancy, maintaining long-term health, functionality and well-being during ageing has become an essential goal. To increase our understanding of how ageing works, it may be advantageous to analyze the phenotype of centenarians, perhaps one of the best examples of successful ageing. Healthy ageing involves the interaction between genes, the environment, and lifestyle factors, particularly diet. Besides evaluating specific gene-environment interactions in relation to exceptional longevity, it is important to focus attention on modifiable lifestyle factors such as diet and nutrition to achieve extension of health span. Furthermore, a better understanding of human longevity may assist in the design of strategies to extend the duration of optimal human health. In this article we briefly discuss relevant topics on ageing and longevity with particular focus on dietary patterns of centenarians and nutrient-sensing pathways that have a pivotal role in the regulation of life span. Finally, we also discuss the potential role of Nrf2 system in the pro-ageing signaling emphasizing its phytohormetic activation.

Metabolic syndrome and cognitive decline among the oldest old in Okinawa: in search of a mechanism. The KOCOA Project

The study aim was to test whether the metabolic syndrome or its components predicted cognitive decline among persons aged 80 years and older (mean 85.0 years). Participants were members of the "Keys to Optimal Cognitive Aging Project," a prospective cohort study in Okinawa, Japan. Metabolic syndrome was assessed at baseline. Cognitive functions were assessed annually for up to 3 years. One hundred and forty-eight participants completed at least one follow-up with 101 participating in all three assessments and 47 participating in two of the three assessments. The mean and median duration of follow-up were 1.8 and 2 years, respectively. Metabolic syndrome and four components were not associated with decline in global and executive cognitive functions. However, high glycosylated hemoglobin was associated with decline in memory function at the second follow-up. Our study supports accumulating evidence that the positive association between metabolic syndrome and cognitive function might not hold for the oldest old.

Oxidative stress and longevity in okinawa: an investigation of blood lipid peroxidation and tocopherol in okinawan centenarians

Background. The Free Radical Theory of Aging mechanistically links oxidative stress to aging. Okinawa has among the world's longest-lived populations but oxidative stress in this population has not been well characterized. Methods. We compared plasma lipid peroxide (LPO) and vitamin E—plasma and intracellular tocopherol levels (total α, β, and γ), in centenarians with younger controls. Results. Both LPO and vitamin E tocopherols were lower in centenarians, with the exception of intracellular β-tocopherol, which was significantly higher in centenarians versus younger controls. There were no significant differences between age groups for tocopherol: cholesterol and tocopherol: LPO ratios. Correlations were found between α-Tocopherol and LPO in septuagenarians but not in centenarians. Conclusions. The low plasma level of LPO in Okinawan centenarians, compared to younger controls, argues for protection against oxidative stress in the centenarian population and is consistent with the predictions of the Free Radical Theory of Aging. However, the present work does not strongly support a role for vitamin E in this phenomenon. The role of intracellular β-tocopherol deserves additional study. More research is needed on the contribution of oxidative stress and antioxidants to human longevity.

Discovery of novel sources of vitamin b(12) in traditional korean foods from nutritional surveys of centenarians

Human longevity can be explained by a variety of factors, among them, nutritional factor would play an important role. In our study of Korean centenarians for their longevity, the apparent nutritional imbalance in the traditional semi-vegetarian diet raised a special attention, especially on vitamin B₁₂ status, supplied by animal foods. Interestingly, we found that the prevalence of vitamin B₁₂ deficient Korean centenarians was not higher compared with those from Western nations with animal-oriented traditional foods. We assumed that there might be some unveiled sources for vitamin B₁₂ in the Korean traditional foods. Screening of vitamin B₁₂ contents has revealed that some traditional soybean-fermented foods, such as Doenjang and Chunggukjang, and seaweeds contain considerable amounts of vitamin B₁₂. Taken together, it can be summarized that the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B₁₂, resulting in maintenance of health status.