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Sleep disruption and activation of cellular inflammation mediate heightened pain sensitivity: a randomized clinical trial.
Irwin, MR, Olmstead, R, Bjurstrom, MF, Finan, PH, Smith, MT
Pain. 2023;164(5):1128-1137
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Sleep disturbance is associated with elevated levels of inflammation. Experimental studies have found that even a modest amount of sleep loss activates inflammatory processes. Experimental sleep disruption also induces alterations in sleep architecture including loss of slow wave or N3 sleep and loss of rapid eye movement sleep. The aim of this study was to clarify whether changes in the amount of N3 sleep and cellular inflammation mediate thermal pain sensitivity (i.e., heat pain threshold) in response to experimental sleep disruption. This study was a secondary analysis (assessor-blind) of a randomised controlled trial. The enrolled participants were randomised to 1 of 2 groups: 2 nights of undisturbed sleep (US) and 2 nights of sleep disruption or forced awakening (FA). Participants underwent 2 consecutive nights of US (or FA), followed by a 2-week washout interval in their home environment, and then completed 2 consecutive nights of the opposing sleep condition FA (or US). Results showed that in healthy adults, experimental disruption of sleep due to the administration of FA induced a significant decrease in heat pain threshold, as compared with responses after US. Experimental manipulation of sleep with FA also led to disturbance in sleep continuity and changes in sleep architecture, including loss of N3 sleep. Moreover, in the morning after FA, there was a robust activation of cellular inflammation Authors conclude that the differential loss of N3 sleep and increases in cellular inflammation may be important drivers of pain sensitivity in response to sleep disruption.
Abstract
Sleep loss heightens pain sensitivity, but the pathways underlying this association are not known. Given that experimental sleep disruption induces increases in cellular inflammation as well as selective loss of slow wave, N3 sleep, this study examined whether these mechanisms contribute to pain sensitivity following sleep loss in healthy adults. This assessor-blinded, cross-over sleep condition, single-site, randomized clinical trial enrolled 95 healthy adults (mean [SD] age, 27.8 [6.4]; female, 44 [53.7%]). The 2 sleep conditions were 2 nights of undisturbed sleep (US) and 2 nights of sleep disruption or forced awakening (FA, 8 pseudorandomly distributed awakenings and 200 minutes wake time during the 8-hour sleep opportunity), administered in a cross-over design after 2 weeks of washout and in a random order (FA-US; US-FA). Primary outcome was heat pain threshold (hPTH). Sleep architecture was assessed by polysomnography, and morning levels of cellular inflammation were evaluated by Toll-like receptor-4 stimulated monocyte intracellular proinflammatory cytokine production. As compared with US, FA was associated with decreases in the amount of slow wave or N3 sleep ( P < 0.001), increases in Toll-like receptor-4 stimulated production of interleukin-6 and tumor necrosis factor-α ( P = 0.03), and decreases in hPTH ( P = 0.02). A comprehensive causal mediation analysis found that FA had an indirect effect on hPTH by decreases in N3 sleep and subsequent increases in inflammation (estimate=-0.15; 95% confidence interval, -0.30 to -0.03; P < 0.05) with the proportion mediated 34.9%. Differential loss of slow wave, N3 sleep, and increases in cellular inflammation are important drivers of pain sensitivity after sleep disruption.Clinical Trials Registration: NCT01794689.
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Sleep-Opt-In: A Randomized Controlled Pilot Study to Improve Sleep and Glycemic Variability in Adults With Type 1 Diabetes.
Martyn-Nemeth, P, Duffecy, J, Quinn, L, Steffen, A, Baron, K, Chapagai, S, Burke, L, Reutrakul, S
The science of diabetes self-management and care. 2023;49(1):11-22
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Insufficient sleep (insufficient total sleep time) and irregular sleep timing (variability in the occurrence of sleep within a 24-hour period) are increasingly recognized as important contributors to glycaemic control and variability in type 1 diabetes (T1D). The aims of this study were to evaluate the feasibility and acceptability of a sleep intervention (Sleep-Opt-In) targeted for adults with type 1 diabetes with short or irregular sleep and to examine the effects of Sleep-Opt-In on sleep duration and regularity, glucose indices, and patient-reported outcomes. This study was a randomised controlled parallel trial design. Participants (n=14) were randomly assigned to either the Sleep-Opt-In intervention or a Healthy Living attention control group. Results showed that: - Sleep-Opt-In was feasible and acceptable to the target population. - participants with objectively confirmed short or irregular sleep, sleep irregularity improved by 25 minutes on average, whereas sleep duration improved only negligibly (8 minutes). - the control group experienced an increase in sleep duration but no change in sleep regularity. Authors conclude that Sleep-Opt-In is feasible, acceptable, and promising for further evaluation to improve sleep duration or regularity, glucose parameters and important patient reported outcomes of diabetes distress, daytime sleepiness, fatigue and depressive mood in the T1D population.
Abstract
PURPOSE The purpose of this study was to evaluate the feasibility and acceptability of a technology-assisted behavioral sleep intervention (Sleep-Opt-In) and to examine the effects of Sleep-Opt-In on sleep duration and regularity, glucose indices, and patient-reported outcomes. Short sleep duration and irregular sleep schedules are associated with reduced glycemic control and greater glycemic variability. METHODS A randomized controlled parallel-arm pilot study was employed. Adults with type 1 diabetes (n = 14) were recruited from the Midwest and randomized 3:2 to the sleep-optimization (Sleep-Opt-In) or Healthy Living attention control group. Sleep-Opt-In was an 8-week, remotely delivered intervention consisting of digital lessons, sleep tracker, and weekly coaching phone calls by a trained sleep coach. Assessments of sleep (actigraphy), glucose (A1C, continuous glucose monitoring), and patient-reported outcomes (questionnaires for daytime sleepiness, fatigue, diabetes distress, and depressive mood) were completed at baseline and at completion of the intervention. RESULTS Sleep-Opt-In was feasible and acceptable. Those in Sleep-Opt-In with objectively confirmed short or irregular sleep demonstrated an improvement in sleep regularity (25 minutes), reduced glycemic variability (3.2%), and improved time in range (6.9%) compared to the Healthy Living attention control group. Patient-reported outcomes improved only for the Sleep-Opt-In group. Fatigue and depressive mood improved compared to the control. CONCLUSIONS Sleep-Opt-In is feasible, acceptable, and promising for further evaluation as a means to improve sleep duration or regularity in the population of people with type 1 diabetes.
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Micronutrients for Attention-Deficit/Hyperactivity Disorder in Youths: A Placebo-Controlled Randomized Clinical Trial.
Johnstone, JM, Hatsu, I, Tost, G, Srikanth, P, Eiterman, LP, Bruton, AM, Ast, HK, Robinette, LM, Stern, MM, Millington, EG, et al
Journal of the American Academy of Child and Adolescent Psychiatry. 2022;61(5):647-661
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Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition that affects about 5-7% of children. Characteristics of ADHD are age-inappropriate hyperactivity, impulsivity, and difficulties in focusing attention which arise from an impaired ability to regulate executive and emotional functions. The condition often persists into adulthood, where it presents an increased risk for poor educational achievements, substance abuse, incarceration, and mental health problems. In many cases, drug treatment can improve ADHD symptoms, yet concern remains about the side effects of these treatments. Some research has investigated the impact of nutrient supplementation on ADHD management, as many nutrients are essential for healthy brain function and are also involved in the production of neurotransmitters. In previous studies, supplementation with nutrients has shown some benefits but likewise also inconsistent results. This eight-week randomised placebo-controlled clinical trial evaluated the effects of a multi-nutrient supplement in 135 children with ADHD, aged 6-12 years. The study specifically focused on irritable mood symptoms. The multi-nutrient formula contained vitamins, minerals, amino acids, and antioxidants. Outcomes were measured by scores rated by clinicians (Clinical Global Impression-Improvement aka CGI-I) and scores rated by parents (Child and Adolescent Symptom Inventory-5 aka CASI-5). The multi-nutrient formula showed overall benefit in the blinded clinician rating but not by parental reports. According to the parents, overall improvement was reported, both in the placebo and intervention groups. The authors discussed how this absence of difference can be explained. Yet, on a subscale, the multi-nutrient group parents were more likely to report improvements. In addition, children with the additional micronutrients demonstrated greater height growth during the intervention. The supplement was well tolerated with good adherence and the monitored blood markers demonstrated safety of use.
Expert Review
Conflicts of interest:
None
Take Home Message:
This fully-blinded RCT of micronutrients addresses several concerns related to existing ADHD treatment, including the possibility of counteracting height suppression and treating associated irritable mood, emotional dysregulation, and aggression.
Although further research is needed, multinutrient supplementation should be considered for children with ADHD.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Attention-deficit hyperactivity disorder (ADHD) is a common psychiatric condition that can result in low educational performance and achievement. Around 5-7% of children are believed to be affected. Alongside inattention and hyperactivity, emotional dysregulation is a common feature of ADHD. Psychiatric problems can continue into adulthood and an increased risk of incarceration and substance abuse have been reported.
Treatment with prescription medications may improve symptoms of ADHD, however, potential side effects include mild growth suppression, and mood and emotional dysregulation. Non-pharmacological treatments are therefore being investigated.
Previous research on single nutrients have shown mixed results for emotional dysregulation and mood issues in ADHD. The aim of this study was to test whether supplementation with a multi-nutrient could be beneficial to children aged 6-12 years with ADHD and irritability.
Methods
126 unmedicated children from North America with ADHD (mean age 9.8 years) completed this 8-week study. All participants had at least 1 symptom of anger, irritability, peer conflict or Disruptive Mood Dysregulation Disorder (DMDD).
Randomisation was into an intervention (n=71) or placebo (N=55) group with a 3:2 ratio to promote enrolment. Participants were required to take 6-12 capsules daily, depending on age and tolerance, of micronutrients or a placebo. Micronutrient dosages were above the recommended dietary allowance (RDA). Outcomes were measured using clinician and parent rated assessments and by a further adult who knew the child well.
The trial was blinded to all participants, parents and study staff.
Results
The clinician-rated results found 54% of the micronutrient group and 18% of the placebo group had improvements in irritability symptoms (Risk ratio =2.97, 97.5% CI: 1.5, 5.90, p<0.001). This was not replicated in the parent/adult rated results. Children in the micronutrient group grew on average 6mm more than the placebo group (p=0.002). No serious adverse treatment effects were reported. Adherence to protocol was met by >74% of participants (n=93).
Conclusions
In this study, clinicians reported that micronutrients showed greater benefits than placebo for treating irritability and supporting growth in children with ADHD.
The study and authors received funding from several research and association bodies. However, no funder was involved in the study design or reporting. No conflicts of interest were declared.
Clinical practice applications:
- Multinutrient supplementation including vitamins, minerals, amino acids, and antioxidants may support height growth in children who take pharmacologic treatment
- Multi nutrient supplementation may also help with irritable mood, emotional dysregulation, and aggression in ADHD children
- Micronutrients given at doses between the Recommended Dietary Allowance and Upper Tolerable Intake Level appear safe and may be developed into an alternative or complementary treatment for ADHD.
Considerations for future research:
- Further large scale research is needed into the potential benefits of micronutrients for children with ADHD and irritability
Abstract
OBJECTIVE To evaluate whether micronutrients (vitamins/minerals) benefit attention-deficit/hyperactivity disorder (ADHD) and irritability in a North American pediatric sample. METHOD A 3-site, 8-week, placebo-controlled, randomized clinical trial of micronutrients was conducted in nonmedicated children aged 6 to 12 years with ADHD and at least 1 impairing irritability symptom by parent report on the Child and Adolescent Symptom Inventory-5 (CASI-5). A priori-defined primary outcomes were Clinical Global Impression-Improvement (CGI-I) (CGI-I of 1 or 2 = treatment responder) and parent-rated CASI-5 composite score of ADHD, oppositional defiant, disruptive mood dysregulation, and peer conflict symptoms, including impairment scores. RESULTS Of 135 randomized (mean age 9.8 years), 126 youths (93%) comprised the modified intention-to-treat population. Blinding was maintained. For the CGI-I, 54% of the micronutrient and 18% of the placebo group were responders (risk ratio = 2.97, 97.5% CI = 1.50, 5.90, p < .001). CASI-5 composite scores improved significantly for both groups (p < .01), with a mean change of -0.31 (95% CI = -0.39, -0.23) in the micronutrient group and a mean change of -0.28 (95% CI = -0.38, -0.19) in the placebo group. However, the between-group difference was not significant (mean change = -0.02; 97.5% CI = -0.16, 0.12, effect size = 0.07, p = .70). The micronutrient group grew 6 mm more than the placebo group (p = .002). No serious adverse events or clinically significant changes from baseline in blood and urine tests occurred. CONCLUSION Micronutrients showed global benefit over placebo by blinded clinician rating, but not by parent-report CASI-5 composite rating in a population with ADHD and irritability. Micronutrients showed greater height growth. Micronutrients were well tolerated, and the majority of participants adhered to the number of capsules prescribed. This randomized controlled trial replicates safety and efficacy reported for ADHD in 2 smaller trials of a similar formula containing all vitamins and known essential minerals in amounts between the Recommended Dietary Allowance and Upper Tolerable Intake Level. CLINICAL TRIAL REGISTRATION INFORMATION Micronutrients for ADHD in Youth (MADDY) Study; https://clinicaltrials.gov; NCT03252522.
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Circulating levels of maternal vitamin D and risk of ADHD in offspring: results from the Vitamin D Antenatal Asthma Reduction Trial.
Chu, SH, Huang, M, Kelly, RS, Kachroo, P, Litonjua, AA, Weiss, ST, Lasky-Su, J
International journal of epidemiology. 2022;51(3):910-918
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Acting as both a nutrient and a hormone, vitamin D has been found to play a critical role in neurodevelopment across sensitive periods in utero, infancy and early childhood. Among neurodevelopmental and behavioural disorders in early life, attention-deficit/hyperactivity disorder (ADHD) is the most common among children worldwide. Low levels of circulating 25-hydroxy-vitamin D [25(OH)D] have been shown to associate with prevalent ADHD. The aims of this study were to (i) determine the association between maternal vitamin D levels in the first and third trimesters of pregnancy and the risk of offspring ADHD by age 6 years or later; and (ii) to identify potential sensitive periods in utero during which vitamin D levels might be most important for reducing risk of ADHD. This is an ancillary study of the Vitamin D Antenatal Asthma Reduction Trial (VDAART). The VDAART was a randomised, double-blinded, multicentre, clinical trial in which 876 participating mothers were recruited between 10–18 weeks of gestation and assigned to receive either 4400 or 400 IU/day of vitamin D throughout pregnancy. Results show protective associations between maternal 25(OH)D sufficiency in the third trimester and child ADHD, but not at baseline. Furthermore, both at baseline and in the third trimester, there were higher odds of ADHD in male offspring as compared with female offspring with 25(OH)D insufficient mothers (analyses limited by small sample sizes) Authors conclude that higher levels of maternal vitamin D during pregnancy may play a protective role against risk of ADHD in offspring, but further studies are needed to confirm this association and any therapeutic potential therein.
Expert Review
Conflicts of interest:
None
Take Home Message:
Ensure that women in pregnancy, and possibly also those seeking to conceive, have adequate vitamin D status in order to reduce the risk of ADHD in offspring.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
This paper describes a secondary data analysis from an RCT that looked at the effect of prenatal vitamin D supplementation on risk of childhood asthma in offspring. Enrolled women aged 18–39 years with a history of asthma, eczema or allergic rhinitis, or whose partner (biological father of child) had a history of the aforementioned condition, received either 400 IU or 4400 IU vitamin D daily for the duration of their pregnancy. Offspring follow-up is still ongoing.
Aims
The current study aims were twofold: (i) to determine the association between maternal vitamin D levels in trimesters 1 and 3 and the risk of attention deficit/hyperactivity disorder (ADHD) in offspring diagnosed by age 6 years or later; and (ii) to identify potentially sensitive periods during gestation in which vitamin D levels may be especially important for reducing risk of ADHD.
Methods
The analytical sample included 679 mother-child pairs, from the original sample of 876 participating mothers. No sample size calculation was reported, though the sample was considered representative of the overall RCT study population.
Maternal vitamin D (serum 25(OH)D) was classified as follows
- Highly deficient <12 ng/mL
- Deficient 12 ng/mL to 19.9 ng/mL
- Insufficient 20 ng/mL to 29.9 ng/mL
- Sufficient ≥30 ng/mL
ADHD status was assessed through parental reporting between ages 6 and 9 years.
Results
No baseline associations between a vitamin D sufficient status and offspring ADHD in maternal samples collected during trimester 1 were observed (OR 1.06, 95% CI 0.51–2.19; P.0.871), though this association became statistically significant at trimester 3 (OR 0.47, 95% CI 0.26–0.84; P.0.011). This translated to a 53% less chance of having a child with ADHD at age 6 or later among mothers with vitamin D sufficiency compared with children of mothers with vitamin D deficiency. There was also a linear trend in the protective association of vitamin D sufficiency (≥30 ng/mL) on reduced risk of offspring ADHD at age 6 years or later in data from trimester 3. Stratified analyses revealed a protective association for sufficient maternal vitamin D status and offspring ADHD among males (OR 0.47, 95% CI 0.23–0.94).
Conclusions
The authors concluded that vitamin D sufficiency (≥30 ng/mL) in the 3rd trimester of gestation may decrease the risk of ADHD development in offspring.
Notes: The authors reported no relevant conflicts of interest.
Clinical practice applications:
Ensuring a sufficient vitamin D status by the 3rd trimester of pregnancy may help to lessen the risk of ADHD in offspring. Nutritional therapists and other clinicians working with pregnant women or women looking to conceive should consider checking vitamin D status and providing corrective supplementation and lifestyle advice to augment vitamin D levels where indicated.
Considerations for future research:
The authors of this study postulated that the statistically significant protective association between vitamin D at trimester 3 and ADHD in offspring was not significant in trimester 1 due to a low observed variability in vitamin D status (>75% of women were vitamin D insufficient), and thus the statistical test being underpowered to see difference between groups with sufficient or insufficient status.
Further research could expand upon this hypothesis to test whether vitamin D status in trimester 1, or preconceptually, may offer a protective association for ADHD and other related neurological conditions that may manifest in early life.
Abstract
BACKGROUND Low levels of circulating 25-hydroxy-vitamin D [25(OH)D] have been shown to associate with prevalent attention-deficit/hyperactivity disorder (ADHD), but few studies have examined the association between 25(OH)D during fetal development and risk of childhood ADHD. METHODS Maternal plasma 25(OH)D was measured at 10-18 and 32-38 weeks of gestation, with sufficiency defined as 25(OH)D ≥ 30 ng/ml. Offspring ADHD status between ages 6-9 years was measured by parent report of clinical ADHD diagnosis among 680 mother-child pairs from the Vitamin D Antenatal Asthma Reduction Trial. Association between maternal 25(OH)D and child ADHD was assessed using logistic regression, adjusting for maternal age, race and ethnicity. Effect modification by offspring sex was also assessed. RESULTS No associations between maternal 25(OH)D at 10-18 weeks of gestation and offspring ADHD were observed. In the third trimester, we observed associations between maternal vitamin D sufficiency and offspring ADHD [odds ratio (OR) 0.47, 95% confidence interval (CI) 0.26-0.84], in addition to maternal 25(OH)D sufficiency category, comparing the deficient (OR 0.34, 95% CI 0.12-0.94), insufficient (OR 0.41, 95% CI 0.15-1.10) and sufficient (OR 0.20, 95% CI 0.08-0.54) categories against highly deficient 25(OH)D, respectively. Stratified analyses revealed a protective association for sufficient maternal 25(OH)D and child ADHD among males (OR 0.47, 95% CI 0.23-0.94); the synergy index for additive effect modification of risk was 1.78 (95% CI 0.62-5.08). CONCLUSIONS Higher levels of maternal vitamin D in the third trimester are associated with lower risk of ADHD in offspring, with modest evidence for a stronger effect among male offspring. However, larger studies will be necessary to confirm these findings.
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Mediterranean and Western diet effects on Alzheimer's disease biomarkers, cerebral perfusion, and cognition in mid-life: A randomized trial.
Hoscheidt, S, Sanderlin, AH, Baker, LD, Jung, Y, Lockhart, S, Kellar, D, Whitlow, CT, Hanson, AJ, Friedman, S, Register, T, et al
Alzheimer's & dementia : the journal of the Alzheimer's Association. 2022;18(3):457-468
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There is a current understanding that Alzheimer’s disease (AD) development is related to a high intake of saturated fat and simple carbohydrates, which are found in abundance in the so-called Western Diet (WD). In contrast the consumption of low saturated fat and simple carbohydrates characteristic of the Mediterranean Diet (MD), has been associated with a reduced risk for the development of AD. This study aimed to look at the association of the MD and WD with AD in a more robust way using the randomised control method in 84 individuals both with and without mild memory impairment. The results showed that depending on whether an individual has mild brain impairment determines their response to the MD or WD after 4 weeks. In those without brain impairment the adoption of the WD resulted in a shift towards increasing the risk for AD development and the reverse following the MD. Whereas in those with brain impairment, the adoption of the WD was protective against the development of AD and the MD moved individuals towards worse disease outcomes. It was concluded that diet can be of importance in the prevention or progression of AD and that further studies are required to determine the possible mechanisms through which these two diets can act differentially. This study could be used by health care professionals to understand that diet can have a large impact on AD.
Expert Review
Conflicts of interest:
None
Take Home Message:
- A Med-diet may be beneficial for supporting brain health, cognitive function. metabolic health and reduce the risk of an AD pathology in middle-aged adults with normal cognitive function
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Epidemiological studies have associated a Western diet (West-diet) with an increased risk of Alzheimer’s disease (AD) and other dementias. This study aimed to examine the impact of a Mediterranean-diet (Med-diet) versus a West-diet on AD pathology, cognition, vascular function and metabolic markers in middle aged adults with normal cognitive (NC) function compared to adults with mild cognitive impairment (MCI).
Methods
N=41 NC adult females completed the Med-diet and N=43 adult females with MCI completed the West-diet arm of this study. The average age of the participants was 56y. All participants received isocaloric diets which were either high or low in saturated fat, sodium and glycaemic index (GI) for 4 weeks. Statistical analyses were conducted per dietary arm as well as per cognitive function (NC vs MCI).
Results
- NC Participants were found to have decreased cerebro-spinal fluid (CSF) biomarkers (p=.026) following the Med-diet and increased levels following the West-diet. Whereas, cerebral perfusion increased following the med-diet and decreased after the West-diet (p=.003). These results indicate a reduced AD risk. The MCI group showed no changes to CSF or cerebral perfusion for either dietary group.
- Cognition tended to improve for the NC Med-diet and remain the same for the NC West-diet group. No changes were found for the MCI groups.
- Total cholesterol levels were increased following the West-diet and decreased following the Med-diet for both groups (p=0.0001).
- Glucose and HbA1C were unchanged in the NC group following the Med-diet, increased for the West-diet (p=.049) and decreased for the MCI group (p=<.001). whereas fasting insulin was increased in the NC Med-diet group and decreased in the MCI Med-diet (p=.0.12) and West diet groups.
Conclusion
The results of this study found that diet may modulate AD pathology, cognitive and metabolic function in middle-aged adults. A West-like diet may increase risk of AD through its effects on impairing cognitive function, reducing cerebral infusion and negatively influencing metabolic health in NC adults. Conversely, A Med-diet may promote brain function and metabolic health. However, surprisingly, in this study the results were reversed for MCI middle aged adults, the results showed improvement in metabolic and cerebrospinal fluid biomarkers for the West-diet. These results require further confirmation.
No conflicts of interest were declared.
Clinical practice applications:
- A Med-diet may be beneficial for supporting brain health, cognitive function, metabolic health and reducing the risk of an AD pathology in middle-aged adults with normal cognitive function but not for those with MCI.
Considerations for future research:
The authors acknowledged several limitations to this study.
- These results require further confirmation through longer and larger studies, particularly the surprising finding that a West-diet may confer beneficial effects on metabolic and brain health for middle-aged adults with MCI.
Abstract
INTRODUCTION Mid-life dietary patterns are associated with Alzheimer's disease (AD) risk, although few controlled trials have been conducted. METHODS Eighty-seven participants (age range: 45 to 65) with normal cognition (NC, n = 56) or mild cognitive impairment (MCI, n = 31) received isocaloric diets high or low in saturated fat, glycemic index, and sodium (Western-like/West-diet vs. Mediterranean-like/Med-diet) for 4 weeks. Diet effects on cerebrospinal fluid (CSF) biomarkers, cognition, and cerebral perfusion were assessed to determine whether responses differed by cognitive status. RESULTS CSF amyloid beta (Aβ)42/40 ratios increased following the Med-diet, and decreased after West-diet for NC adults, whereas the MCI group showed the reverse pattern. For the MCI group, the West-diet reduced and the Med-diet increased total tau (t-tau), whereas CSF Aβ42 /t-tau ratios increased following the West-diet and decreased following the Med-diet. For NC participants, the Med-diet increased and the West-diet decreased cerebral perfusion. DISCUSSION Diet response during middle age may highlight early pathophysiological processes that increase AD risk.
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Higher circulating α-carotene was associated with better cognitive function: an evaluation among the MIND trial participants.
Liu, X, Dhana, K, Furtado, JD, Agarwal, P, Aggarwal, NT, Tangney, C, Laranjo, N, Carey, V, Barnes, LL, Sacks, FM
Journal of nutritional science. 2021;10:e64
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Diet has been identified as one of the important modifiable lifestyle factors in preventing Alzheimer’s disease. Carotenoids are potent antioxidants, naturally occurring pigments found in red, yellow, orange and dark green fruits and vegetables. Literature from epidemiological studies links fruit and vegetable consumption, and higher levels of carotenoids, with a lower risk of cognitive decline among older adults from different regions. The aim of this study was to examine (1) the association between dietary intakes of carotenoids and global/domain-specific cognition, and (2) how participants’ dietary patterns corresponded to their plasma levels of carotenoids. This study is an evaluation of baseline blood nutrients and cognition among the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) participants. Participants are predominantly Caucasian females with a mean age of 69⋅8 years. Results show that high levels of plasma α-carotene were associated with higher scores for global cognition, and episodic and semantic memory. The carotenoids lutein and zeaxanthin (combined) were positively associated with better scores for semantic memory. A dietary pattern that featured greater consumption of vegetables other than green leafy vegetables and fruits, corresponded to high α-carotene in blood which was associated with higher cognition scores. Authors conclude that blood nutrient levels as objective markers could characterise individuals’ dietary patterns, which could facilitate a targeted dietary intervention to prevent cognitive decline.
Abstract
There is emerging evidence linking fruit and vegetable consumption and cognitive function. However, studies focusing on the nutrients underlying this relationship are lacking. We aim to examine the association between plasma nutrients and cognition in a population at risk for cognitive decline with a suboptimal diet. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) trial is a randomized controlled intervention that examines the effects of the MIND diet to prevent cognitive decline. The primary outcome is global cognition. A multivariate linear model was used to investigate the association between blood nutrients and global and/or domain-specific cognition. The model was adjusted for age, sex, education, study site, smoking status, cognitive activities and physical activities. High plasma α-carotene was associated with better global cognition. Participants in the highest tertile of plasma α-carotene had a higher global cognition z score of 0⋅17 when compared with individuals in the lowest tertile (P 0⋅002). Circulating α-carotene levels were also associated with higher semantic memory scores (P for trend 0⋅007). Lutein and zeaxanthin (combined) was positively associated with higher semantic memory scores (P for trend 0⋅009). Our study demonstrated that higher α-carotene levels in blood were associated with higher global cognition scores in a US population at risk for cognitive decline. The higher α-carotene levels in blood reflected greater intakes of fruits, other types of vegetables and lesser intakes of butter and margarine and meat. The higher circulating levels of lutein plus zeaxanthin reflected a dietary pattern with high intakes of fruits, green leafy, other vegetables and cheese, and low consumption of fried foods. Objective nutrient markers in the blood can better characterize dietary intake, which may facilitate the implementation of a tailored dietary intervention for the prevention of cognitive decline.
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Dietary alteration of n-3 and n-6 fatty acids for headache reduction in adults with migraine: randomized controlled trial.
Ramsden, CE, Zamora, D, Faurot, KR, MacIntosh, B, Horowitz, M, Keyes, GS, Yuan, ZX, Miller, V, Lynch, C, Honvoh, G, et al
BMJ (Clinical research ed.). 2021;374:n1448
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This study could be of interest to practitioners who are interested in dietary interventions that may decrease the incidence or severity of headaches in women. Omega 3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are believed to be precursors for molecules that may have pain reducing properties. Whereas omega 6 fatty acids such as linoleic acid are believed to be precursors for molecules that may have pain promoting effects. The objective of this 3 armed randomised, double blinded controlled trial was to determine whether increasing dietary intake of omega 3 EPA and DHA, whilst either maintaining or decreasing omega 6 linoleic acid, may lead to a decrease in headache frequency and severity. 182 participants were assigned into one of 3 treatment groups, the first, H3 diet, increasing EPA and DHA to 1.5g/day and maintaining linoleic acid, the second, H3-L6 diet, increasing EPA and DHA to 1.5g/day whilst decreasing linoleic acid and the control group maintaining EPA, DHA and linoleic acid. Both the H3 and H3-L6 diets increased the levels of the molecule believed to be involved in reducing pain to a statistically significant level. This was found to be consistent with the results reported by the patients both in headache hours per day and days with headache in the month. The authors conclude that increasing levels of omega 3 fatty acids in the diet whilst decreasing levels of omega 6 fatty acids in the diet may decrease the frequency and severity of headaches. This study was for 16 weeks and predominantly women with a mean age of 38, further studies for longer and on other populations such as men, children and older populations, would be required to see if the same results could be obtained.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Important from a public health perspective
- Increasing n-3 levels and decreasing n-6 levels could be modified by dietary change and appear to reduce the frequency and duration of headaches in migraine sufferers
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
Circulating lipid mediators have been implicated in headache pathogenesis.
Objective
To determine whether dietary interventions that increase n-3 fatty acids with and without reduction in n-6 linoleic acid can alter circulating lipid mediators implicated in headache pathogenesis, and decrease headache in adults with migraine.
Study Design
Three arm, parallel group, randomized, modified double blind, controlled trial.
Participants
182 participants (88% women, mean age 38 years) with migraines on 5-20 days per month (67% met criteria for chronic migraine).
Interventions
Three diets designed with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid altered as controlled variables:
- H3 diet (n=61)—increase EPA+DHA to 1.5 g/day and maintain linoleic acid at around 7% of total energy intake
- H3-L6 diet (n=61)—increase n-3 EPA+DHA to 1.5 g/day and decrease linoleic acid to ≤1.8% of total energy intake
- Control diet (n=60)—maintain EPA+DHA at <150 mg/day and linoleic acid at around 7% of total energy intake
All participants received foods accounting for two thirds of daily food energy and 1/3rd from foods not provided by the Research Kitchen. For these foods participants rely on their training by the dietitian and website diet guides for shopping and choosing foods in restaurants. Participants were encouraged to continue seeing their headache physician and continue usual care.
Results
In intention-to-treat analyses (n=182) at 16 weeks
- The H3-L6 and H3 diets increased circulating 17-HDHA compared with the control diet (baseline-adjusted mean difference 0.6, 95% confidence interval 0.2 to 0.9; 0.7, 0.4 to 1.1, respectively).
- The observed improvement in HIT-6 scores (quality of life) in the H3-L6 and H3 groups was not statistically significant (−1.6, −4.2 to 1.0, and −1.5, −4.2 to 1.2, respectively).
- Compared with the control diet, the H3-L6 and H3 diets decreased total headache hours per day (−1.7, −2.5 to −0.9, and −1.3, −2.1 to −0.5, respectively), moderate to severe headache hours per day, (−0.8, −1.2 to −0.4, and −0.7, −1.1 to −0.3, respectively) and headache days per month (−4.0, −5.2 to −2.7, and −2.0, −3.3 to −0.7, respectively).
- The H3-L6 diet decreased headache days per month more than the H3 diet, suggesting additional benefit from lowering dietary linoleic acid (−2.0, −3.2 to −0.8).
- The H3-L6 and H3 diets altered n-3 and n-6 fatty acids and several of their nociceptive oxylipin derivatives in plasma, serum, erythrocytes or immune cells, but did not alter classic headache mediators calcitonin gene related peptide and prostaglandin E2.
Conclusions
The H3-L6 and H3 interventions altered bioactive mediators implicated in headache pathogenesis and decreased frequency and severity of headaches, but did not significantly improve quality of life.
Clinical practice applications:
These findings might be useful for Nutritional Therapists and Clinical Practitioners:
- To inform practitioners of the benefits of assessing n-3 and n-6 fatty acids in migraine patients.
- Inform practitioners of the potential benefits to reducing n-6 as well as increasing n-3 levels in migraine patients
- Inform practitioners of the potential lack of correlation between headache duration and frequency and quality of life measures
Considerations for future research:
- Trialing larger doses of n-3
- Longer term follow up whilst maintaining these diets
- Attempting to validate an optimal serum level of 17-HDHA for these patients that could be used in clinical practice
Abstract
OBJECTIVE To determine whether dietary interventions that increase n-3 fatty acids with and without reduction in n-6 linoleic acid can alter circulating lipid mediators implicated in headache pathogenesis, and decrease headache in adults with migraine. DESIGN Three arm, parallel group, randomized, modified double blind, controlled trial. SETTING Ambulatory, academic medical center in the United States over 16 weeks. PARTICIPANTS 182 participants (88% women, mean age 38 years) with migraines on 5-20 days per month (67% met criteria for chronic migraine). INTERVENTIONS Three diets designed with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid altered as controlled variables: H3 diet (n=61)-increase EPA+DHA to 1.5 g/day and maintain linoleic acid at around 7% of energy; H3-L6 diet (n=61)-increase n-3 EPA+DHA to 1.5 g/day and decrease linoleic acid to ≤1.8% of energy; control diet (n=60)-maintain EPA+DHA at <150 mg/day and linoleic acid at around 7% of energy. All participants received foods accounting for two thirds of daily food energy and continued usual care. MAIN OUTCOME MEASURES The primary endpoints (week 16) were the antinociceptive mediator 17-hydroxydocosahexaenoic acid (17-HDHA) in blood and the headache impact test (HIT-6), a six item questionnaire assessing headache impact on quality of life. Headache frequency was assessed daily with an electronic diary. RESULTS In intention-to-treat analyses (n=182), the H3-L6 and H3 diets increased circulating 17-HDHA (log ng/mL) compared with the control diet (baseline-adjusted mean difference 0.6, 95% confidence interval 0.2 to 0.9; 0.7, 0.4 to 1.1, respectively). The observed improvement in HIT-6 scores in the H3-L6 and H3 groups was not statistically significant (-1.6, -4.2 to 1.0, and -1.5, -4.2 to 1.2, respectively). Compared with the control diet, the H3-L6 and H3 diets decreased total headache hours per day (-1.7, -2.5 to -0.9, and -1.3, -2.1 to -0.5, respectively), moderate to severe headache hours per day (-0.8, -1.2 to -0.4, and -0.7, -1.1 to -0.3, respectively), and headache days per month (-4.0, -5.2 to -2.7, and -2.0, -3.3 to -0.7, respectively). The H3-L6 diet decreased headache days per month more than the H3 diet (-2.0, -3.2 to -0.8), suggesting additional benefit from lowering dietary linoleic acid. The H3-L6 and H3 diets altered n-3 and n-6 fatty acids and several of their nociceptive oxylipin derivatives in plasma, serum, erythrocytes or immune cells, but did not alter classic headache mediators calcitonin gene related peptide and prostaglandin E2. CONCLUSIONS The H3-L6 and H3 interventions altered bioactive mediators implicated in headache pathogenesis and decreased frequency and severity of headaches, but did not significantly improve quality of life. TRIAL REGISTRATION ClinicalTrials.gov NCT02012790.
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8.
Obesity and Sex-Related Associations With Differential Effects of Sucralose vs Sucrose on Appetite and Reward Processing: A Randomized Crossover Trial.
Yunker, AG, Alves, JM, Luo, S, Angelo, B, DeFendis, A, Pickering, TA, Monterosso, JR, Page, KA
JAMA network open. 2021;4(9):e2126313
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Added sweeteners are increasingly being used in foods to maintain the sweet taste without the added calories, however the health consequences of this are still unclear. Most of the research that exists is in men of normal weight, however women and individuals with obesity have shown to have differing appetite responses. This randomised crossover trial of 74 adults aimed to determine the effect of consuming sweetener compared to sugar on brain, hormone, and appetite responses and whether these differed by sex and obesity status. The results showed that women had increased food related brain responses and consumed greater calories following ingestion of an artificially sweetened drink. In those with obesity food related brain response was also increased following sweetener consumption. Blood glucose hormone response was decreased following sweetener consumption compared to sugar consumption. It was concluded that females and individuals with obesity have differing brain activity following consumption of sweetener. This study could be used by healthcare professionals to understand that the recommendation of artificial sweeteners for weight loss in women and those who are already suffering from obesity may lead to greater calorie consumption. However further research is needed to confirm this.
Abstract
Importance: Nonnutritive sweeteners (NNSs) are used as an alternative to nutritive sweeteners to quench desire for sweets while reducing caloric intake. However, studies have shown mixed results concerning the effects of NNSs on appetite, and the associations between sex and obesity with reward and appetitive responses to NNS compared with nutritive sugar are unknown. Objective: To examine neural reactivity to different types of high-calorie food cues (ie, sweet and savory), metabolic responses, and eating behavior following consumption of sucralose (NNS) vs sucrose (nutritive sugar) among healthy young adults. Design, Setting, and Participants: In a randomized, within-participant, crossover trial including 3 separate visits, participants underwent a functional magnetic resonance imaging task measuring blood oxygen level-dependent signal in response to visual cues. For each study visit, participants arrived at the Dornsife Cognitive Neuroimaging Center of University of Southern California at approximately 8:00 am after a 12-hour overnight fast. Blood was sampled at baseline and 10, 35, and 120 minutes after participants received a drink containing sucrose, sucralose, or water to measure plasma glucose, insulin, glucagon-like peptide(7-36), acyl-ghrelin, total peptide YY, and leptin. Participants were then presented with an ad libitum meal. Participants were right-handed, nonsmokers, weight-stable for at least 3 months before the study visits, nondieters, not taking medication, and with no history of eating disorders, illicit drug use, or medical diagnoses. Data analysis was performed from March 2020 to March 2021. Interventions: Participants ingested 300-mL drinks containing either sucrose (75 g), sucralose (individually sweetness matched), or water (as a control). Main Outcomes and Measures: Primary outcomes of interest were the effects of body mass index (BMI) status and sex on blood oxygen level-dependent signal to high-calorie food cues, endocrine, and feeding responses following sucralose vs sucrose consumption. Secondary outcomes included neural, endocrine, and feeding responses following sucrose vs water and sucralose vs water (control) consumption, and cue-induced appetite ratings following sucralose vs sucrose (and vs water). Results: A total of 76 participants were randomized, but 2 dropped out, leaving 74 adults (43 women [58%]; mean [SD] age, 23.40 [3.96] years; BMI range, 19.18-40.27) who completed the study. In this crossover design, 73 participants each received water (drink 1) and sucrose (drink 2), and 72 participants received water (drink 1), sucrose (drink 2), and sucralose (drink 3). Sucrose vs sucralose was associated with greater production of circulating glucose, insulin, and glucagon-like peptide-1 and suppression of acyl-ghrelin, but no differences were found for peptide YY or leptin. BMI status by drink interactions were observed in the medial frontal cortex (MFC; P for interaction < .001) and orbitofrontal cortex (OFC; P for interaction = .002). Individuals with obesity (MFC, β, 0.60; 95% CI, 0.38 to 0.83; P < .001; OFC, β, 0.27; 95% CI, 0.11 to 0.43; P = .002), but not those with overweight (MFC, β, 0.02; 95% CI, -0.19 to 0.23; P = .87; OFC, β, -0.06; 95% CI, -0.21 to 0.09; P = .41) or healthy weight (MFC, β, -0.13; 95% CI, -0.34 to 0.07; P = .21; OFC, β, -0.08; 95% CI, -0.23 to 0.06; P = .16), exhibited greater responsivity in the MFC and OFC to savory food cues after sucralose vs sucrose. Sex by drink interactions were observed in the MFC (P for interaction = .03) and OFC (P for interaction = .03) after consumption of sucralose vs sucrose. Female participants had greater MFC and OFC responses to food cues (MFC high-calorie vs low-calorie cues, β, 0.21; 95% CI, 0.05 to 0.37; P = .01; MFC sweet vs nonfood cues, β, 0.22; 95% CI, 0.02 to 0.42; P = .03; OFC food vs nonfood cues, β, 0.12; 95% CI, 0.02 to 0.22; P = .03; and OFC sweet vs nonfood cues, β, 0.15; 95% CI, 0.03 to 0.27; P = .01), but male participants' responses did not differ (MFC high-calorie vs low-calorie cues, β, 0.01; 95% CI, -0.19 to 0.21; P = .90; MFC sweet vs nonfood cues, β, -0.04; 95% CI, -0.26 to 0.18; P = .69; OFC food vs nonfood cues, β, -0.08; 95% CI, -0.24 to 0.08; P = .32; OFC sweet vs nonfood cues, β, -0.11; 95% CI, -0.31 to 0.09; P = .31). A sex by drink interaction on total calories consumed during the buffet meal was observed (P for interaction = .03). Female participants consumed greater total calories (β, 1.73; 95% CI, 0.38 to 3.08; P = .01), whereas caloric intake did not differ in male participants (β, 0.68; 95% CI, -0.99 to 2.35; P = .42) after sucralose vs sucrose ingestion. Conclusions and Relevance: These findings suggest that female individuals and those with obesity may be particularly sensitive to disparate neural responsivity elicited by sucralose compared with sucrose consumption. Trial Registration: ClinicalTrials.gov Identifier: NCT02945475.
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9.
Reductions in anti-inflammatory gut bacteria are associated with depression in a sample of young adults.
Liu, RT, Rowan-Nash, AD, Sheehan, AE, Walsh, RFL, Sanzari, CM, Korry, BJ, Belenky, P
Brain, behavior, and immunity. 2020;88:308-324
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Alterations to the gut microbiota may be associated with depression and anxiety disorders through a pathway known as the gut-brain axis. Inflammation may be the mediator between the two, as individuals with major depressive disorder (MDD) have reported high levels of inflammation, which the gut microbiota may have the capacity to protect against. This observational study of the gut microbiota of 90 young adults with MDD and 47 healthy controls aimed to determine the relationship between inflammatory gut microbiota and symptoms of depression. The results showed changes to several species of gut microbiota in those with MDD and that the level of change was related to MDD symptom severity. These changes were observed even in those taking psychotropic medications. Changes at the taxonomic level indicated that those with higher symptoms of depression had more pronounced differences compared with healthy controls. Although the observed differences were indicative of an inflammatory microbiome, no changes were observed in blood markers of inflammation between those individuals with MDD and healthy controls. It was concluded that the gut microbiome of individuals with MDD was different from healthy individuals in favour of an inflammatory environment. This study could be used by healthcare professionals to understand that the status of the gut microbiota may be an important measure in individuals with MDD and that a treatment plan to ensure gut health is considered may help with symptoms of depression.
Abstract
We assessed the gut microbiota of 90 American young adults, comparing 43 participants with major depressive disorder (MDD) and 47 healthy controls, and found that the MDD subjects had significantly different gut microbiota compared to the healthy controls at multiple taxonomic levels. At the phylum level, participants with MDD had lower levels of Firmicutes and higher levels of Bacteroidetes, with similar trends in the at the class (Clostridia and Bacteroidia) and order (Clostridiales and Bacteroidales) levels. At the genus level, the MDD group had lower levels of Faecalibacterium and other related members of the family Ruminococcaceae, which was also reduced relative to healthy controls. Additionally, the class Gammaproteobacteria and genus Flavonifractor were enriched in participants with MDD. Accordingly, predicted functional differences between the two groups include a reduced abundance of short-chain fatty acid production pathways in the MDD group. We also demonstrated that the magnitude of taxonomic changes was associated with the severity of depressive symptoms in many cases, and that most changes were present regardless of whether depressed participants were taking psychotropic medications. Overall, our results support a link between MDD and lower levels of anti-inflammatory, butyrate-producing bacteria, and may support a connection between the gut microbiota and the chronic, low-grade inflammation often observed in MDD patients.
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Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults.
Gratton, G, Weaver, SR, Burley, CV, Low, KA, Maclin, EL, Johns, PW, Pham, QS, Lucas, SJE, Fabiani, M, Rendeiro, C
Scientific reports. 2020;10(1):19409
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Fruits and vegetables contain flavonoids that can protect against vascular diseases and cognitive ageing. Studies have shown that cocoa flavonoids can enhance the function of endothelial cells and blood vessels in peripheral arteries. This randomised, double-blinded, placebo-controlled crossover study assessed the effects of cocoa flavanols on cerebral and peripheral vascular and cognitive function. The healthy young subjects showed greater tissue oxygenation and cerebrovascular reactivity in the frontal parts of the brain during the carbon dioxide challenge after high cocoa flavonoid intervention. Furthermore, the cocoa flavonoid intervention improved cognitive and peripheral endothelial functions in healthy young subjects. Even though the mechanistic link behind the beneficial effects of flavonoids is not understood completely, the positive effects could be due to the ability of flavanols to enhance the bioavailability of circulation Nitric Oxide (NO). The study also found that flavonoids improved cognitive function in healthy individuals only when there was a high cognitive demand. Further robust studies are required to evaluate the mechanisms behind the benefits associated with acute flavonoid intake. Healthcare professionals can utilise the findings from this study to gain insight into the advantages of consuming a flavonoid-rich diet. Additionally, they can learn about the differing responses to flavanol intake between individuals.
Abstract
Cocoa flavanols protect humans against vascular disease, as evidenced by improvements in peripheral endothelial function, likely through nitric oxide signalling. Emerging evidence also suggests that flavanol-rich diets protect against cognitive aging, but mechanisms remain elusive. In a randomized double-blind within-subject acute study in healthy young adults, we link these two lines of research by showing, for the first time, that flavanol intake leads to faster and greater brain oxygenation responses to hypercapnia, as well as higher performance only when cognitive demand is high. Individual difference analyses further show that participants who benefit from flavanols intake during hypercapnia are also those who do so in the cognitive challenge. These data support the hypothesis that similar vascular mechanisms underlie both the peripheral and cerebral effects of flavanols. They further show the importance of studies combining physiological and graded cognitive challenges in young adults to investigate the actions of dietary flavanols on brain function.