0
selected
-
1.
Going with the grain: Fiber, cognition, and the microbiota-gut-brain-axis.
Berding, K, Carbia, C, Cryan, JF
Experimental biology and medicine (Maywood, N.J.). 2021;(7):796-811
-
-
Free full text
-
Abstract
Healthy dietary intake has been acknowledged for decades as one of the main contributors to health. More recently, the field of nutritional psychiatry has progressed our understanding regarding the importance of nutrition in supporting mental health and cognitive function. Thereby, individual nutrients, including omega-3 fatty acids and polyphenols, have been recognized to be key drivers in this relationship. With the progress in appreciating the influence of dietary fiber on health, increasingly research is focusing on deciphering its role in brain processes. However, while the importance of dietary fiber in gastrointestinal and metabolic health is well established, leading to the development of associated health claims, the evidence is not conclusive enough to support similar claims regarding cognitive function. Albeit the increasing knowledge of the impact of dietary fiber on mental health, only a few human studies have begun to shed light onto the underexplored connection between dietary fiber and cognition. Moreover, the microbiota-gut-brain axis has emerged as a key conduit for the effects of nutrition on the brain, especially fibers, that are acted on by specific bacteria to produce a variety of health-promoting metabolites. These metabolites (including short chain fatty acids) as well as the vagus nerve, the immune system, gut hormones, or the kynurenine pathway have been proposed as underlying mechanisms of the microbiota-brain crosstalk. In this minireview, we summarize the evidence available from human studies on the association between dietary fiber intake and cognitive function. We provide an overview of potential underlying mechanisms and discuss remaining questions that need to be answered in future studies. While this field is moving at a fast pace and holds promise for future important discoveries, especially data from human cohorts are required to further our understanding and drive the development of public health recommendations regarding dietary fiber in brain health.
-
2.
Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function.
Tan, BL, Norhaizan, ME
Nutrients. 2019;(11)
Abstract
Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a vitally important energy source; it affects brain function and provides direct energy. Several studies have indicated that high-fat consumption causes overproduction of circulating free fatty acids and systemic inflammation. Immune cells, free fatty acids, and circulating cytokines reach the hypothalamus and initiate local inflammation through processes such as microglial proliferation. Therefore, the role of high-fat diet (HFD) in promoting oxidative stress and neurodegeneration is worthy of further discussion. Of particular interest in this article, we highlight the associations and molecular mechanisms of HFD in the modulation of inflammation and cognitive deficits. Taken together, a better understanding of the role of oxidative stress in cognitive impairment following HFD consumption would provide a useful approach for the prevention of cognitive dysfunction.
-
3.
A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood.
Steenbergen, L, Sellaro, R, van Hemert, S, Bosch, JA, Colzato, LS
Brain, behavior, and immunity. 2015;:258-64
Abstract
BACKGROUND Recent insights into the role of the human microbiota in cognitive and affective functioning have led to the hypothesis that probiotic supplementation may act as an adjuvant strategy to ameliorate or prevent depression. OBJECTIVE Heightened cognitive reactivity to normal, transient changes in sad mood is an established marker of vulnerability to depression and is considered an important target for interventions. The present study aimed to test if a multispecies probiotic containing Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, and Lactococcus lactis (W19 and W58) may reduce cognitive reactivity in non-depressed individuals. DESIGN In a triple-blind, placebo-controlled, randomized, pre- and post-intervention assessment design, 20 healthy participants without current mood disorder received a 4-week probiotic food-supplement intervention with the multispecies probiotics, while 20 control participants received an inert placebo for the same period. In the pre- and post-intervention assessment, cognitive reactivity to sad mood was assessed using the revised Leiden index of depression sensitivity scale. RESULTS Compared to participants who received the placebo intervention, participants who received the 4-week multispecies probiotics intervention showed a significantly reduced overall cognitive reactivity to sad mood, which was largely accounted for by reduced rumination and aggressive thoughts. CONCLUSION These results provide the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood. Probiotics supplementation warrants further research as a potential preventive strategy for depression.
-
4.
A double-blind, randomized clinical trial of dietary supplementation on cognitive and immune functioning in healthy older adults.
Lewis, JE, Melillo, AB, Tiozzo, E, Chen, L, Leonard, S, Howell, M, Diaz, J, Gonzalez, K, Woolger, JM, Konefal, J, et al
BMC complementary and alternative medicine. 2014;:43
Abstract
BACKGROUND Declining cognitive function is relatively common and increasingly prevalent. Studies have shown that different nutrients (e.g., Ginkgo biloba and vitamin E) appear to be effective at improving memory and concentration, while less is known about their effect on immunity. METHODS This study investigated the effect of Ginkgo Synergy(®) plus Choline (n = 33) and OPC Synergy(®) plus Catalyn(®) (n = 31) versus placebo (n = 33) in a 6-month, randomized, double-blind trial on cognitive and immune functioning among English-speaking, non-smoking, healthy older adults. The Stroop Color and Word Test, Trail Making Test A and B, Controlled Oral Word Association, Hopkins Verbal Learning, Mini-Mental State Exam, and Digit Symbol were administered at baseline and 3 and 6 months follow-up to assess cognitive functioning. Cytokines and growth factors were measured at baseline and 6 months to assess inflammation and immune functioning. Data were analyzed with linear mixed modeling. RESULTS No serious adverse events were noted in this study. According to time on the Trail Making Test-B, the Ginkgo Synergy(®) plus Choline arm showed improvement from baseline to 3 months follow-up (mean difference = 24.2; SE = 6.4; 95% CI: 8.6, 39.7; p = 0.01). On the Controlled Oral Word Association Trial-S, the scores significantly increased for the Ginkgo Synergy(®) plus Choline arm from baseline to 6 months follow-up (mean difference = 2.1; SE = 0.8; 95% CI: 0.2, 3.9; p < 0.05) and for the OPC Synergy(®) plus Catalyn(®) arm from baseline to 3 months follow-up (mean difference = 2.1; SE = 0.8; 95% CI: 0.2, 4.0; p < 0.05). Epidermal growth factor significantly decreased from baseline to 6 months follow-up for the Ginkgo Synergy(®) plus Choline arm (mean difference = 120.7; SE = 28.4; 95% CI: 62.6, 178.8; p < 0.001). CONCLUSIONS Our study showed isolated and modest effects of a Ginkgo biloba plus choline-based formula on cognitive and immune functioning among healthy older adults with no history of significant cognitive deficits. Our trial was registered with clinicaltrials.gov (ID: NCT01672359). This study was supported by a grant from Standard Process, Inc.
-
5.
The role of extended-release niacin on immune activation and neurocognition in HIV-infected patients treated with antiretroviral therapy - CTN PT006: study protocol for a randomized controlled trial.
Lebouché, B, Jenabian, MA, Singer, J, Graziani, GM, Engler, K, Trottier, B, Thomas, R, Brouillette, MJ, Routy, JP
Trials. 2014;:390
Abstract
BACKGROUND Approximately 30% of HIV-1-infected patients receiving antiretroviral therapy who achieve virologic control have unsatisfactory immune reconstitution, with CD4+ T-cell counts persistently below 350 cells/μL. These patients are at elevated risk for clinical progression to AIDS and non-AIDS events. CD4+ T-cell depletion following infection and persistent immune activation can partially explain this low CD4+ T-cell recovery. Recent data suggest a link between the tryptophan oxidation pathway, immune activation and HIV disease progression based on overstimulation of the tryptophan oxidation pathway by HIV antigens and by interferon-gamma. This overstimulation reduces levels of circulating tryptophan, resulting in inflammation which has been implicated in the development of neurocognitive dysfunction. Niacin (vitamin B3) is able to control the excess tryptophan oxidation, correcting tryptophan depletion, and therefore represents an interesting strategy to improve CD4 recovery.We aim to design a crossover proof-of-concept study to assess supplementation with an extended-release form of niacin (Niaspan FCT™) in combination with antiretroviral therapy, compared to antiretroviral therapy alone, on T-cell immune activation as defined by changes in the percentage of CD8+ CD38+ HLA-DR+ T-cells. METHODS/DESIGN This randomized, open-label, interventional crossover study with an immediate versus deferred use of Niaspan FCT for 24 weeks will assess its ability to reduce immune activation and thus increase CD4 recovery in 20 HIV-infected individuals with suboptimal immune responses despite sustained virologic suppression. A substudy evaluating neurocognitive function will also be conducted. DISCUSSION This randomized trial will provide an opportunity to evaluate the potential benefit of oral extended-release niacin, a drug that can indirectly increase tryptophan, to reduce immune activation and in turn increase CD4+ T-cell recovery. The study will also allow for the evaluation of the impact of Niaspan FCT on neurocognitive function in HIV-infected individuals with suboptimal immune responses despite sustained virologic suppression. TRIAL REGISTRATION This study was registered with ClinicalTrials.gov on 17 December 2013 (registration number: NCT02018965).
-
6.
Two strategies for response to 14 °C cold-water immersion: is there a difference in the response of motor, cognitive, immune and stress markers?
Brazaitis, M, Eimantas, N, Daniuseviciute, L, Mickeviciene, D, Steponaviciute, R, Skurvydas, A
PloS one. 2014;(9):e109020
Abstract
Here, we address the question of why some people have a greater chance of surviving and/or better resistance to cold-related-injuries in prolonged exposure to acute cold environments than do others, despite similar physical characteristics. The main aim of this study was to compare physiological and psychological reactions between people who exhibited fast cooling (FC; n = 20) or slow cooling (SC; n = 20) responses to cold water immersion. Individuals in whom the T(re) decreased to a set point of 35.5 °C before the end of the 170-min cooling time were indicated as the FC group; individuals in whom the T(re) did not decrease to the set point of 35.5 °C before the end of the 170-min cooling time were classified as the SC group. Cold stress was induced using intermittent immersion in bath water at 14 °C. Motor (spinal and supraspinal reflexes, voluntary and electrically induced skeletal muscle contraction force) and cognitive (executive function, short term memory, short term spatial recognition) performance, immune variables (neutrophils, leucocytes, lymphocytes, monocytes, IL-6, TNF-α), markers of hypothalamic-pituitary-adrenal axis activity (cortisol, corticosterone) and autonomic nervous system activity (epinephrine, norepinephrine) were monitored. The data obtained in this study suggest that the response of the FC group to cooling vs the SC group response was more likely an insulative-hypothermic response and that the SC vs the FC group displayed a metabolic-insulative response. The observations that an exposure time to 14 °C cold water--which was nearly twice as short (96-min vs 170-min) with a greater rectal temperature decrease (35.5 °C vs 36.2 °C) in the FC group compared with the SC group--induces similar responses of motor, cognitive, and blood stress markers were novel. The most important finding is that subjects with a lower cold-strain-index (SC group) showed stimulation of some markers of innate immunity and suppression of markers of specific immunity.
-
7.
The impact of inflammation on cognitive function in older adults: implications for healthcare practice and research.
Sartori, AC, Vance, DE, Slater, LZ, Crowe, M
The Journal of neuroscience nursing : journal of the American Association of Neuroscience Nurses. 2012;(4):206-17
-
-
Free full text
-
Abstract
Accumulating evidence suggests that levels of inflammation, an immune response, increase with age throughout the body and the brain. The effects of inflammation on the brain, both acute and chronic, have been associated with cognitive decline and risk of dementia in older adults. Factors believed to increase inflammation include certain health-related behaviors, such as smoking, poor diet, and inactivity as well as health conditions like diabetes, hypertension, and chronic obstructive pulmonary disease, most of which require medical intervention and monitoring. As such, nurses and healthcare professionals are likely to encounter patients who are at a high risk for future development of inflammation-related cognitive decline. A review of inflammatory processes and their relation to cognitive function in older adults is provided, along with factors that may increase or reduce inflammation. Implications for practice and research are discussed.