By Balu Muthaiyah, Musthafa M. Essa, Moon Lee, Ved Chauhan, Kulbir Kaur and Abha Chauhan
Previous in vitro studies have shown that walnut extract can inhibit amyloid- (A) fibrillization, can solubilize its fibrils, and has a protective effect against A-induced oxidative stress and cellular death.
In this study, we analyzed the effect of dietary supplementation with walnuts on learning skills, memory, anxiety, locomotor activity, and motor coordination in the Tg2576 transgenic (tg) mouse model of AD (AD-tg).
These experimental and control mice were examined at the ages of 13–14 months by Morris water maze (for spatial memory and learning ability), T maze (for position discrimination learning ability), rotarod (for psychomotor coordination), and elevated plus maze (for anxiety-related behavior).
AD-tg mice on the control diet (T0) showed memory deficit, anxiety-related behavior, and severe impairment in spatial learning ability, position discrimination learning ability, and motor coordination compared to the Wt mice on the same diet. The AD-tg mice receiving the diets with 6% or 9% walnuts (T6 and T9) showed a significant improvement in memory, learning ability, anxiety, and motor development compared to the AD-tg mice on the control diet (T0). There was no statistically significant difference in behavioral performance between the T6/T9 mice on walnuts-enriched diets and the Wt group on the control diet.
These findings suggest that dietary supplementation with walnuts may have a beneficial effect in reducing the risk, delaying the onset, or slowing the progression of, or preventing AD.
*Preliminary animal research has been investigating the potential benefit walnuts may have on fighting cognitive diseases, such as Alzheimer’s and Dementia. Please note, that these animal studies are provided as background and used to formulate hypotheses for additional research needed to determine the effects on humans.
PUBLISHED : MAY 14, 2014
STUDY TYPE : ANIMAL FEEDING STUDY
TOPICS : HEALTH & WALNUTS, COGNITIVE AND AGING
SOURCE : http://iospress.metapress.com/content/n644184610325684/fulltext.pdf
By Derek R. Fisher, Shibu M. Poulose, Donna F. Bielinski, Barbara Shukitt-Hale
The shift in equilibrium towards excess reactive oxygen or nitrogen species production from innate antioxidant defenses in brain is a critical factor in the declining neural function and cognitive deficit accompanying age. Previous studies from our laboratory have reported that walnuts, rich in polyphenols, antioxidants, and omega fatty acids such as alpha-linolenic acid and linoleic acid, improve the age-associated declines in cognition and neural function in rats. Possible mechanisms of action of these effects include enhancing protective signaling, altering membrane microstructures, decreasing inflammation, and preventing accumulation of polyubiquitinated protein aggregates in critical regions of the brain.
Walnut diet serum (6 and 9%) significantly attenuated lipopolysaccharide-induced nitrite release compared to untreated control cells and those treated with serum from rats fed 0% walnut diets. The results also indicated a significant reduction in pro-inflammatory tumor necrosis factor-alpha, cyclooxygenase-2, and inducible nitric oxide synthase.
These results suggest antioxidant and anti-inflammatory protection or enhancement of membrane-associated functions in brain cells by walnut serum metabolites.
*Preliminary animal research has been investigating the potential benefit walnuts may have on fighting cognitive diseases, such as Alzheimer’s and Dementia. Please note that these animal studies are provided as background and used to formulate hypotheses for additional research needed to determine the effects on humans.
PUBLISHED : AUGUST 25, 2014
STUDY TYPE : IN VITRO STUDY
TOPIC : COGNITIVE AND AGING
SOURCE : http://www.maneyonline.com/doi/abs/10.1179/1476830514Y.0000000150
By Sonia García-Calzón, Miguel A. Martínez-González, Cristina Razquin, Dolores Corella, Jordi Salas-Salvadó, J. Alfredo Martínez, Guillermo Zalba and Amelia Marti
The gene variant Pro/Ala (rs1801282) in the PPARγ2 has been associated with lower cardiovascular risk and greater benefit from lifestyle interventions. This polymorphism also seems to be associated with longer lifespan, but no information on telomere length (TL) is available. Our aim was to study the association between the Ala allele and changes in TL in high cardiovascular risk subjects and the potential interaction with a Mediterranean dietary pattern.
A total of 521 subjects (55-80 years) participating in the Prevención con Dieta Mediterránea randomized trial were genotyped. Changes in TL, measured by quantitative real-time polymerase chain reaction (PCR), were assessed over 5 years of a nutritional intervention, which promoted adherence to the Mediterranean diet (MeDiet).
Interestingly, Ala carriers showed lower telomere shortening after 5 years compared with the Pro/Pro genotype (P=0.031). This association was modulated by MeDiet because those Ala carriers who reported better conformity to the MeDiet exhibited increased TL (P < 0.001). Moreover, a reduction in carbohydrate intake (≤9.5 g/d) resulted in increased TL among Ala carriers. Notably, an apparent gene-diet interaction was found through the observed changes in the MUFA+PUFA/carbohydrates ratio: as this ratio increased, TL lengthening was detected to a greater extent in the Ala carriers compared with the Pro/Pro subjects (P for interaction < 0.001).
The Pro12Ala polymorphism is associated with TL homeostasis after 5 years follow-up in subjects at high cardiovascular risk. In addition, a higher adherence to the MeDiet pattern strengthens the prevention of telomere shortening among Ala carriers.
PUBLISHED : NOVEMBER 18, 2014
STUDY TYPE : EPIDEMIOLOGY STUDY
TOPIC : COGNITIVE AND AGING, MEDITERRANEAN DIET, PREDIMED
SOURCE : http://circgenetics.ahajournals.org/content/early/2014/11/18/CIRCGENETICS.114.000635
By Lenore Arab, Alfonso Ang
To examine the association between walnut consumption and measures of cognitive function in the US population.
Nationally representative cross sectional study using 24 hour dietary recalls of intakes to assess walnut and other nut consumption as compared to the group reporting no nut consumption.
Setting: 1988-1994 and 1999-2002 rounds of the National Health and Nutrition Examination Survey (NHANES). Population: Representative weighted sample of US adults 20 to 90 years of age. Main Outcome Measure: The Neurobehavioral Evaluation System 2 (NES2), consisting of simple reaction time (SRTT), symbol digit substitution (SDST), the single digit learning (SDLT), Story Recall (SRT) and digit-symbol substitution (DSST) tests.
Adults 20-59 years old reporting walnut consumption of an average of 10.3 g/d required 16.4ms less time to respond on the SRTT, P=0.03, and 0.39s less for the SDST, P=0.01. SDLT scores were also significantly lower by 2.38s (P=0.05). Similar results were obtained when tertiles of walnut consumption were examined in trend analyses. Significantly better outcomes were noted in all cognitive test scores among those with higher walnut consumption (P < 0.01). Among adults 60 years and older, walnut consumers averaged 13.1 g/d, scored 7.1 percentile points higher, P=0.03 on the SRT and 7.3 percentile points higher on the DSST, P=0.05. Here also trend analyses indicate significant improvements in all cognitive test scores (P < 0.01) except for SRTT (P = 0.06) in the fully adjusted models.
These significant, positive associations between walnut consumption and cognitive functions among all adults, regardless of age, gender or ethnicity suggest that daily walnut intake may be a simple beneficial dietary behavior.
PUBLISHED : DECEMBER 16, 2014
STUDY TYPE : META-ANALYSIS AND/OR SYSTEMATIC REVIEW
TOPIC : COGNITIVE AND AGING
SOURCE : http://link.springer.com/article/10.1007/s12603-014-0569-2
By Cinta Valls-Pedret; Aleix Sala-Vila, DPharm; Mercè Serra-Mir; Dolores Corella; Rafael de la Torre; Miguel Ángel; Martínez-González; Elena H. Martínez-Lapiscina; Montserrat Fitó; Ana Pérez-Heras; Jordi Salas-Salvadó, MD; Ramon; Estruch; Emilio Ros
Oxidative stress and vascular impairment are believed to mediate in part age-related cognitive decline, a strong risk factor for development of dementia. Epidemiological studies suggest that a Mediterranean Diet, an antioxidant-rich cardioprotective dietary pattern, delays cognitive decline, but clinical trial evidence is lacking.
To investigate whether a Mediterranean diet supplemented with antioxidant rich foods influences cognitive function compared to a control diet.
Randomized, parallel-group, controlled trial. Barcelona, Spain. Cognitively healthy volunteers (n=447, 52% women, mean age 66.9 years) at high cardiovascular risk enrolled into the PREDIMED nutrition intervention trial underwent neuropsychological assessment at inclusion and were offered retest at the end of the study.
Participants were randomly assigned to a Mediterranean diet supplemented with extra-virgin olive oil (olive oil) (1 liter/week), a Mediterranean diet supplemented with mixed nuts (30 g/day), or control diet (advice to reduce dietary fat).
Rates of cognitive change over time based on a neuropsychological test battery: Mini-Mental State Examination, Rey Auditory Verbal Learning Test (RAVLT), Animals Semantic Fluency, Digit span from Wechsler Adult Intelligence Scale, Verbal Paired Associates from Wechsler Memory Scale, and Color Trail Test. We used mean z scores of change in each individual test to construct three cognitive composites: memory, frontal (attention and executive function), and global cognition. Follow-up cognitive tests were available in 334 participants after intervention (median of 4.1years). In multivariate analyses adjusted for confounders, participants allocated to a Mediterranean diet +olive oil scored better in RAVLT (P=.049) and Color Trail part 2 (P=.044) compared with controls. Similarly adjusted cognitive composites showed that, compared to the control group, the Mediterranean diet+nuts group improved performance above baseline in memory tests (P=.041), while the Mediterranean diet+olive oil group performed better in tests of frontal (P=.003) and global cognition (P=.005). All cognitive composites significantly (P < .05) decreased from baseline in controls.
In an older population a Mediterranean diet supplemented with olive oil or nuts was associated with improved cognitive function.
PUBLISHED : MAY 11, 2015
STUDY TYPE : RANDOMIZED CONTROLLED CLINICAL TRIAL
TOPIC : HEALTH & WALNUTS, COGNITIVE AND AGING, MEDITERRANEAN DIET
SOURCE : http://archinte.jamanetwork.com/article.aspx?articleid=2293082