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Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.
Barnes, LL, Dhana, K, Liu, X, Carey, VJ, Ventrelle, J, Johnson, K, Hollings, CS, Bishop, L, Laranjo, N, Stubbs, BJ, et al
The New England journal of medicine. 2023;389(7):602-611
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Lifestyle interventions targeting diet are a possible approach that could affect public health. Most clinical trials have investigated comprehensive diets, in contrast to dietary manipulation of single foods or nutrients. The aim of this study was to evaluate the effects of a 3-year dietary intervention on cognitive decline and brain-imaging markers of dementia and Alzheimer’s disease in older, cognitively unimpaired adults at risk for dementia because of family history. This study was a 3-year, two-site, randomised, controlled trial. The participants were randomly assigned to follow the MIND diet with mild caloric restriction for weight loss or their usual diet with the same mild caloric restriction for weight loss (control diet). Participants were randomly assigned in a 1:1 ratio. Results showed that the participants who followed the MIND diet had small improvements in a global measure of cognition that were similar to those who followed a control diet with mild caloric restriction. Authors concluded that brain health, cognitive function and brain imaging outcomes (after 3 years) did not differ significantly between participants who followed the MIND diet and those who followed a control diet with a mild caloric restriction.
Abstract
BACKGROUND Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia. METHODS We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants. RESULTS A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups. CONCLUSIONS Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).
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Effects of Diet on 10-Year Atherosclerotic Cardiovascular Disease Risk (from the DASH Trial).
Jeong, SY, Wee, CC, Kovell, LC, Plante, TB, Miller, ER, Appel, LJ, Mukamal, KJ, Juraschek, SP
The American journal of cardiology. 2023;187:10-17
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Determining the 10-year risk of heart disease can be used as tool to determine appropriate treatment plans. This study of 459 adults aged 22-75 years with obesity aimed to compare the effects on the 10-year risk for the development heart disease of an 8-week dietary approaches to stop hypertension (DASH) diet, with the standard American diet (AD) and a diet high in fruits and vegetables (F/V). The results showed that the DASH diet significantly improved risk factors such as systolic blood pressure and total cholesterol. However, the F/V diet had an improvement in good cholesterol, which the DASH diet did not. This equated to a similar 10% reduction in the 10-year heart disease risk compared to the AD. It was concluded that compared to a typical AD, DASH and F/V diets reduced the risk for heart disease over a 10-year period. However, the actual risk reduction was only small and individuals with obesity may need to reduce their risk further with other therapies. This study could be used by healthcare professionals to recommend a DASH diet or a diet high in fruits and vegetables to reduce the long-term risk for heart disease alongside other proven therapies or methods to reduce risk.
Expert Review
Conflicts of interest:
None
Take Home Message:
- DASH and F/V diets may be of benefit to obese individuals to decrease their risk for ASCVD
- The DASH diet did reduce HDL cholesterol and recommendations should be made to limit this effect (e.g. exercise and more fruit and vegetables in the diet).
Evidence Category:
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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
This study aimed to determine the effect of the Dietary Approaches to Stop Hypertension (DASH) diet compared to a standard American diet (AD) and a diet emphasising fruits and vegetables (F/V) on the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) and how adopting these diets affect specific risk factors (e.g systolic blood pressure (SBP), diastolic blood pressure (DBP) and blood lipids).
Methods
- Secondary analysis from the DASH trial which ran for 8 weeks in 459 adults aged 22-75 years with obesity
- All meals were provided and dietary intake was adjusted to prevent weight loss
- The primary outcome was an absolute and relative difference in 10-year ASCVD risk from baseline.
Participants were randomised to one of three diets:
1) DASH diet
2) F/V diet, similar to AD but with more fruits and vegetables and higher potassium and magnesium
3) Standard AD.
Results
- DASH significantly lowered SBP, total cholesterol, and HDL cholesterol compared to F/V (absolute difference SBP: -2.8, (95% confidence interval [CI]-4.5, -1.2), total cholesterol: 9.3 (-14.7, 3.9), and HDL cholesterol: -3.5 (-5.0, -2.1) P=<0.05 for all)
- DASH significantly lowered SBP, total cholesterol, and HDL cholesterol compared to AD (absolute difference SBP: -5.3 (-7.0, -3.7), total cholesterol: -13.1 (-18.5, -7.7), and HDL cholesterol: -3.8 (-5.2, -2.4) P=<0.05 for all)
- Compared to AD, DASH and F/V diets reduced 10-year ASCVD relative risk by -10.3%
( −14.4 to −5.9) and −9.9% ( −14.0 to −5.5) respectively
- This translated into low actual risk reductions of -0.21% for the F/V diet and -0.17% for the DASH diet
- Although DASH improved SBP, and total cholesterol compared to F/V, no differences in ASCVD risk between DASH and F/V were apparent. This was attributable to the detrimental effect of the DASH diet on HDL cholesterol, which was not seen in the F/V diet
- The effects of the DASH diet were more pronounced in black participants and in women.
Conclusion
Compared to the AD, DASH and F/V reduced 10-year ASCVD risk by approximately 10% over 8-weeks. The DASH diet was more effective for women and black adults.
Clinical practice applications:
- DASH and F/V diets decrease risk factors and an individual’s risk of ASCVD, and should be encouraged in individuals with obesity, especially women and black adults
- However, these diets do still leave obese individuals at risk for ASCVD.
Considerations for future research:
- Research on these diets in combination with weight loss regimes may give more pronounced results
- It may also be interesting to understand the mechanisms behind why the DASH diet reduces HDL cholesterol.
Abstract
Although modern risk estimators, such as the American College of Cardiology/American Heart Association Pooled Cohort Equation, play a central role in the decisions of patients to start pharmacologic therapy to prevent atherosclerotic cardiovascular disease (ASCVD), there is limited evidence to inform expectations for 10-year ASCVD risk reduction from established lifestyle interventions. Using data from the original DASH (Dietary Approaches to Stop Hypertension) trial, we determined the effects of adopting the DASH diet on 10-year ASCVD risk compared with adopting a control or a fruits and vegetables (F/V) diet. The DASH trial included 459 adults aged 22 to 75 years without CVD and not taking antihypertensive or diabetes mellitus medications, who were randomized to controlled feeding of a control diet, an F/V diet, or the DASH diet for 8 weeks. We determined 10-year ASCVD risk with the American College of Cardiology/American Heart Association Pooled Cohort Equation based on blood pressure and lipids measured before and after the 8-week intervention. Compared with the control diet, the DASH and F/V diets changed 10-year ASCVD risk by -10.3% (95% confidence interval [CI] -14.4 to -5.9) and -9.9% (95% CI -14.0 to -5.5) respectively; these effects were more pronounced in women and Black adults. There was no difference between the DASH and F/V diets (-0.4%, 95% CI -6.9 to 6.5). ASCVD reductions attributable to the difference in systolic blood pressure alone were -14.6% (-17.3 to -11.7) with the DASH diet and -7.9% (-10.9 to -4.8) with the F/V diet, a net relative advantage of 7.2% greater relative reduction from DASH compared with F/V. This was offset by the effects on high-density lipoprotein of the DASH diet, which increased 10-year ASCVD by 8.8% (5.5 to 12.3) compared with the more neutral effect of the F/V diet of -1.9% (-5.0 to 1.2). In conclusion, compared with a typical American diet, the DASH and F/V diets reduced 10-year ASCVD risk scores by about 10% over 8 weeks. These findings are informative for counseling patients on both choices of diet and expectations for 10-year ASCVD risk reduction.
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The effects of dietary patterns and food groups on symptomatic osteoarthritis: A systematic review.
Zeng, J, Franklin, DK, Das, A, Hirani, V
Nutrition & dietetics: the journal of the Dietitians Association of Australia. 2023;80(1):21-43
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Osteoarthritis is a chronic joint disease that can lead to disability, characterised by the deterioration and loss of joint cartilage, inflammation, pain, aches, and stiffness. Research has shown a positive association between osteoarthritis progression and pro-inflammatory diets, such as Western diets, and a negative association with anti-inflammatory diets, such as the DASH and Mediterranean diets. This systematic review evaluated the evidence from the literature to show the positive and negative associations between osteoarthritis and diet. The Prudent diet, Mediterranean diet, and increased fibre intake were effective in reducing the progression of osteoarthritis and alleviating its symptoms, while the Western diet increased the progression of symptomatic osteoarthritis. The Prudent diet was found to be particularly effective in alleviating symptomatic osteoarthritis. The beneficial effects of anti-inflammatory diets and increased fibre intake are thought to be due to the reduction and suppression of inflammatory cytokines, while inflammatory diets have the opposite effect. Although there is high heterogeneity between the studies, healthcare professionals can use the results of this systematic review to understand the therapeutic clinical utility of anti-inflammatory diets and high-fibre intake in reducing the progression of symptomatic osteoarthritis in people above the age of 45 years. Further robust studies are needed to evaluate the effectiveness of other therapeutic dietary strategies.
Abstract
AIM: To systematically review current literature to determine the association between symptomatic osteoarthritis and dietary patterns, diet quality and food groups in adults aged ≥45 years. METHODS The review was registered on PROSPERO (CRD42021270891). Cochrane Central Library, Cumulative Index of Nursing and Allied Health Literature, Embase, Medline and Web of Science databases were searched. A total of 3816 records were identified. Eligible articles involved populations aged ≥45 years with symptomatic osteoarthritis, assessing dietary patterns, diet quality or food groups, with pain in joints as outcomes. The Joanna Briggs Institute Critical Appraisal Checklists were used for quality assessment. Grading of Recommendations, Assessment, Development and Evaluation was used to assess the certainty of evidence. RESULTS Six cohort studies were included. The Prudent dietary pattern and the Mediterranean dietary pattern reduced the progression of osteoarthritis symptoms. The Western dietary pattern increased symptomatic osteoarthritis progression. Increased total fibre consumption reduced symptomatic osteoarthritis progression and pain worsening, but the effects of fibre from each food group were inconclusive. Diet with high inflammatory potential increased risk of new onset symptomatic osteoarthritis, but the effects of overall diet quality were inconclusive. CONCLUSIONS The Prudent dietary pattern showed the highest protection on symptomatic osteoarthritis in adults aged 45 years and over. The body of evidence is limited, suggesting that further research is needed to corroborate the estimated effect at a high certainty of evidence, and to incorporate previously unstudied dietary patterns and food groups. Identifying the most beneficial dietary pattern may inform future guidelines for reducing symptomatic osteoarthritis in middle aged and older adults.
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Effects of the Dietary Approaches to Stop Hypertension Diet on Change in Cardiac Biomarkers Over Time: Results From the DASH-Sodium Trial.
Belanger, MJ, Kovell, LC, Turkson-Ocran, RA, Mukamal, KJ, Liu, X, Appel, LJ, Miller, ER, Sacks, FM, Christenson, RH, Rebuck, H, et al
Journal of the American Heart Association. 2023;12(2):e026684
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Most deaths from cardiovascular disease (CVD) can be attributed to specific modifiable risk factors. The Dietary Approaches to Stop Hypertension (DASH) diet, rich in fruits, vegetables, low-fat dairy and reduced in saturated fat and cholesterol, is associated with a lower risk of CVD events over time. The aim of this study was to examine the time course of change in biomarkers of cardiac injury, strain, and inflammation from consuming the DASH diet in comparison with a typical American diet. This study is a secondary analysis of the DASH-Sodium randomised clinical trial which recruited adult men and women, aged ≥22years. The participants were randomly assigned in a parallel-arm design to the DASH diet or a typical American diet (control) in a 1:1 ratio. Results show that in comparison with a typical American diet, the DASH diet reduced two of the investigated biomarkers progressively over a 12-week period. Authors conclude that their findings highlight the need for public health policies and interventions that support sustained adherence to a healthy eating pattern for cardiovascular health.
Abstract
Background The Dietary Approaches to Stop Hypertension (DASH) diet has been shown to reduce biomarkers of cardiovascular disease. We aimed to characterize the time course of change in biomarkers of cardiac injury (high-sensitivity cardiac troponin I), cardiac strain (NT-proBNP [N-terminal pro-B-type natriuretic peptide]), and inflammation (hs-CRP [high-sensitivity C-reactive protein]) while consuming the DASH diet. Methods and Results The DASH-Sodium trial was a randomized controlled trial of 412 adults with elevated blood pressure or hypertension. Participants were randomly assigned to 12 weeks of the DASH diet or a typical American diet. Energy intake was adjusted to maintain body weight. Measurements of high-sensitivity cardiac troponin I, NT-proBNP, and hs-CRP were performed in stored serum specimens, collected at baseline and ≈4, 8, and 12 weeks after randomization. In both the control diet and DASH diet, levels of NT-proBNP decreased; however, there was no difference between diets (P-trend compared with control=0.22). On the DASH diet versus control, levels of high-sensitivity cardiac troponin I decreased progressively during follow-up (P-trend compared with control=0.025), but a statistically significant between-diet difference in change from baseline levels was not observed until week 12 (% difference, 17.78% [95% CI, -29.51% to -4.09%]). A similar pattern was evident for hs-CRP (P-trend compared with control=0.01; % difference at week 12, 19.97% [95% CI, -31.94% to -5.89%]). Conclusions In comparison with a typical American diet, the DASH diet reduced high-sensitivity cardiac troponin I and hs-CRP progressively over 12 weeks. These results suggest that the DASH diet has cumulative benefits over time on biomarkers of subclinical cardiac injury and inflammation. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00000608.
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Metabolomic Profiles Associated With Blood Pressure Reduction in Response to the DASH and DASH-Sodium Dietary Interventions.
Kim, H, Appel, LJ, Lichtenstein, AH, Wong, KE, Chatterjee, N, Rhee, EP, Rebholz, CM
Hypertension (Dallas, Tex. : 1979). 2023;80(7):1494-1506
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DASH (Dietary Approaches to Stop Hypertension) diet is recommended for reducing blood pressure (BP) and the risk of cardiovascular disease (CVD). The DASH diet emphasises the intake of fruits, vegetables, and low-fat dairy, includes a variety of protein sources and it is low in red and processed meats and sugar-sweetened beverages. The aim of this study was to identify metabolites associated with differences in systolic blood pressure (SBP) or diastolic blood pressure (DBP) in response to the diet interventions. This study used data from 2 randomised controlled feeding trials (DASH trial and DASH-Sodium trial). Results show the identification of 42 unique metabolites (9 serum and 33 urine) which were significantly associated with changes in SBP or DBP DASH diet versus control diet interventions. Furthermore, pathway overrepresentation analysis revealed metabolite pathways that were relevant for the association between DASH diet and BP. Authors conclude that their findings provide insights on formulating intervention strategies to reduce BP.
Abstract
BACKGROUND The DASH (Dietary Approaches to Stop Hypertension) diets reduced blood pressure (BP) in the DASH and DASH-Sodium trials, but the underlying mechanisms are unclear. We identified metabolites associated with systolic BP or diastolic BP (DBP) changes induced by dietary interventions (DASH versus control arms) in 2 randomized controlled feeding studies-the DASH and DASH-Sodium trials. METHODS Metabolomic profiling was conducted in serum and urine samples collected at the end of diet interventions: DASH (n=219) and DASH-Sodium (n=395). Using multivariable linear regression models, associations were examined between metabolites and change in systolic BP and DBP. Tested for interactions between diet interventions and metabolites were the following comparisons: (1) DASH versus control diets in the DASH trial (serum), (2) DASH high-sodium versus control high-sodium diets in the DASH-Sodium trial (urine), and (3) DASH low-sodium versus control high-sodium diets in the DASH-Sodium trial (urine). RESULTS Sixty-five significant interactions were identified (DASH trial [serum], 12; DASH high sodium [urine], 35; DASH low sodium [urine], 18) between metabolites and systolic BP or DBP. In the DASH trial, serum tryptophan betaine was associated with reductions in DBP in participants consuming the DASH diets but not control diets (P interaction, 0.023). In the DASH-Sodium trial, urine levels of N-methylglutamate and proline derivatives (eg, stachydrine, 3-hydroxystachydrine, N-methylproline, and N-methylhydroxyproline) were associated with reductions in systolic BP or DBP in participants consuming the DASH diets but not control diets (P interaction, <0.05 for all tests). CONCLUSIONS We identified metabolites that were associated with BP lowering in response to dietary interventions. REGISTRATION URL: https://www. CLINICALTRIALS gov/ct2/show/NCT03403166; Unique identifier: NCT03403166 (DASH trial). URL: https://www. CLINICALTRIALS gov/ct2/show/NCT00000608; Unique identifier: NCT00000608 (DASH-Sodium trial).
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Nutritional intervention for diabetes mellitus with Alzheimer's disease.
Li, Z, Li, S, Xiao, Y, Zhong, T, Yu, X, Wang, L
Frontiers in nutrition. 2022;9:1046726
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Diabetes Mellitus (DM) affects more than 463 million people worldwide. Similarly, the number of deaths related to Alzheimer’s disease (AD) has increased by 145%. There are several common risk factors for Type 2 Diabetes and AD, including obesity, insulin resistance, and ageing, as well as common pathological mechanisms, including altered insulin signalling, oxidative stress, neuroinflammation, mitochondrial dysfunction, formation of glycated proteins and metabolic syndrome. This review aims to summarize the therapeutic effects of different nutritional therapy strategies on the reduction of DM and AD risk. Controlling blood sugar levels and reducing calorie intake is crucial to preventing diabetes and Alzheimer's disease. The low-carbohydrate, ketogenic, and Mediterranean diets have been found to improve glucose control in people with Type 2 diabetes (T2D). In addition, MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) and a ketogenic diet may improve cognition in AD patients. Lactobacillus, Bifidobacterium probiotics, and prebiotics, such as inulin, may inhibit the progression of T2D and AD diseases by suppressing inflammation and modulating gut microbes. In addition, vitamins A, C, D, E, B6, B12, folate, long-chain polyunsaturated fatty acids, zinc, magnesium, and polyphenols may improve cognitive decline, homocysteine levels, and insulin resistance in AD and T2D patients. Healthcare professionals can use the results of this review to understand the beneficial effects of dietary strategies and multi-nutrient supplementation on DM and AD. However, further robust studies are required to investigate the risk factors and underlying mechanisms behind DM-combined AD progression.
Abstract
The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.
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The Potential Role of Gut Microbiota in Alzheimer's Disease: From Diagnosis to Treatment.
Varesi, A, Pierella, E, Romeo, M, Piccini, GB, Alfano, C, Bjørklund, G, Oppong, A, Ricevuti, G, Esposito, C, Chirumbolo, S, et al
Nutrients. 2022;14(3)
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Alzheimer’s Disease (AD) affects 50,000,000 people world-wide. The disease is characterized by the deposition of beta amyloid (Aβ) plaques and tangles of hyperphosphorylated tau neurofibrils, leading to neuroinflammation and progressive cognitive decline. It is not completely clear what causes AD or how it evolves. Different therapeutic options have been proposed but many have not produced significant benefits. Recent studies have liked changes in the gut microbiome to neurodegeneration via the gut microbiota brain axis (GMBA). This review summarises the role of the gut microbiota in brain health and disease and it shows evidence for its dysregulation in AD patients. The review discusses how certain markers of dysbiosis might be used as a diagnostic tool for AD. Therapeutic interventions such as prebiotics, specific probiotics, fecal microbiota transplantation and diets are discussed. Although promising results have been published, more research is needed before considering a clinical application.
Abstract
Gut microbiota is emerging as a key regulator of many disease conditions and its dysregulation is implicated in the pathogenesis of several gastrointestinal and extraintestinal disorders. More recently, gut microbiome alterations have been linked to neurodegeneration through the increasingly defined gut microbiota brain axis, opening the possibility for new microbiota-based therapeutic options. Although several studies have been conducted to unravel the possible relationship between Alzheimer's Disease (AD) pathogenesis and progression, the diagnostic and therapeutic potential of approaches aiming at restoring gut microbiota eubiosis remain to be fully addressed. In this narrative review, we briefly summarize the role of gut microbiota homeostasis in brain health and disease, and we present evidence for its dysregulation in AD patients. Based on these observations, we then discuss how dysbiosis might be exploited as a new diagnostic tool in early and advanced disease stages, and we examine the potential of prebiotics, probiotics, fecal microbiota transplantation, and diets as complementary therapeutic interventions on disease pathogenesis and progression, thus offering new insights into the diagnosis and treatment of this devastating and progressive disease.
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The effect of healthy dietary patterns on male semen quality: a systematic review and meta-analysis.
Cao, LL, Chang, JJ, Wang, SJ, Li, YH, Yuan, MY, Wang, GF, Su, PY
Asian journal of andrology. 2022;24(5):549-557
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Infertility has been identified by the World Health Organization as a worldwide problem. The analysis of semen quality is key in assessing male fertility. The aim of this study was to explore the effect of healthy dietary patterns on male semen quality. This study is a systematic review and meta-analysis of six articles. The six articles were cross-sectional studies involving 1244 subjects, however, 708 subjects with the lowest and highest adherence to a healthy dietary pattern were included in the meta-analysis. Results show that the sperm concentration, progressive sperm motility, and total sperm count were significantly higher in the group with high consumption of a healthy dietary pattern than those in the group with low consumption; however, there wasn’t a clear relationship between normal sperm morphology, total sperm motility, and semen volume. Authors conclude that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This Systematic Review and Meta Analysis showed that healthy dietary patterns had beneficial effects on sperm concentration, total sperm count, and progressive sperm motility in males, which affect male fertility.
- Authors concluded that healthy dietary patterns may promote male reproductive health and thus improve semen quality in the population.
- Healthy dietary patterns meant the Mediterranean diet for 4 out of 6 studies. All healthy diet patterns were determined by the authors to be rich in plant-based foods, where saturated fats provide only a small percentage of the total energy intake.
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
- This study aimed to determine the effects of healthy dietary patterns on semen quality.
Methodology
- This meta-analysis was performed following PRISMA guidelines and included 6 cross-sectional studies with 1244 participants
- The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters.
- In 4 of the studies participants were divided into groups based on their scores for the Mediterranean diet from low to high adherence.
- 2 studies examined the DASH diet and the prudent diet and used food frequency questionnaires to compare high consumption with low consumption of healthy dietary patterns.
- The PICOS (Participants, Intervention, Comparison, Outcomes, and Study design) criteria that were used to structure the research question.
- 11 Checklists were used to assess the quality of included studies.
Results:
By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed:
- significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml−1, 95% confidence interval [CI]: 1.26 × 106 ml−1–12.49 × 106 ml−1; P < 0.05)
- significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106–31.03 × 106; P < 0.05)
- significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%–9.12%; P < 0.01) but there was no significant correlation between healthy dietary patterns and total sperm motility (MD: 6.86%, 95% CI: −0.25%–13.96%; P > 0.05).
- there was no significant association between a healthy dietary pattern and normal sperm morphology (MD: 0.28%, 95% CI: −0.33%–0.90%; P > 0.05)
- there was no significant association between a healthy dietary pattern and semen volume (MD: 0.04 ml, 95% CI: −0.20 ml–0.28 ml; P > 0.05).
Limitations:
- Included studies were all cross-sectional studies, and it is impossible to determine the causal relationship between the high intake of healthy dietary patterns and semen quality.
- The number of studies included was small, and there was not enough literature to support authors in drawing reliable conclusions.
- No comparison was made between specific diets such as dash vs Mediterranean.
Clinical practice applications:
- The authors concluded that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
- Dietary interventions for men should be included as part of preconceptional clinical management,
- Dietary interventions for men should also be considered in infertility clinical management.
Considerations for future research:
- Randomised Clinical Trials should be conducted to build on these findings.
Abstract
The incidence of infertility has recently risen. Semen quality is an important male fertility indicator, and dietary factors can affect semen quality. We conducted this systematic review and meta-analysis to determine the effects of healthy dietary patterns on semen quality. A literature search was conducted in 3 databases (Embase, Web of Science and PubMed) on August 21, 2021. The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters; six studies (1244 subjects) were included. By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml-1, 95% confidence interval [CI]: 1.26 × 106 ml-1-12.49 × 106 ml-1; P < 0.05), a significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106-31.03 × 106; P < 0.05), and a significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%-9.12%; P < 0.01). The sperm concentration, progressive sperm motility, and total sperm count were significantly higher in men with higher versus lower consumption of healthy dietary patterns. However, the results must be interpreted with caution.
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The Role of Diet Quality in Mediating the Association between Ultra-Processed Food Intake, Obesity and Health-Related Outcomes: A Review of Prospective Cohort Studies.
Dicken, SJ, Batterham, RL
Nutrients. 2021;14(1)
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Diet has long been a cornerstone of weight management, with dietary policies being a core feature of government and health organisation strategies to reduce obesity worldwide. Indeed, poor diets are a leading cause of preventable obesity-related death and non-communicable diseases, including cancer, cardiovascular disease and type 2 diabetes. The aim of this study was to provide novel insights into the relative impact of nutrient content and dietary patterns vs. ultra-processing on obesity and adverse health-related outcomes. This study is a review of prospective cohort studies. Findings show that adjustment for fat, sugar and sodium intake, or adjustment for adherence to a range of healthy or unhealthy dietary patterns has a minimal impact on the adverse associations between UPF intake and a diverse range of health-related outcomes. Authors conclude that their findings raise important questions regarding current policy and future research needs, suggesting that the nature and extent of processing is an important dietary dimension.
Abstract
Prospective cohort studies show that higher intakes of ultra-processed food (UPF) increase the risk of obesity and obesity-related outcomes, including cardiovascular disease, cancer and type 2 diabetes. Whether ultra-processing itself is detrimental, or whether UPFs just have a lower nutritional quality, is debated. Higher UPF intakes are inversely associated with fruit, vegetables, legumes and seafood consumption. Therefore, the association between UPFs and poor health could simply be from excess nutrient intake or from a less healthful dietary pattern. If so, adjustment for dietary quality or pattern should explain or greatly reduce the size of the significant associations between UPFs and health-related outcomes. Here, we provide an overview of the literature and by using a novel approach, review the relative impact of adjusting for diet quality/patterns on the reported associations between UPF intake and health-related outcomes in prospective cohort studies. We find that the majority of the associations between UPFs, obesity and health-related outcomes remain significant and unchanged in magnitude after adjustment for diet quality or pattern. Our findings suggest that the adverse consequences of UPFs are independent of dietary quality or pattern, questioning the utility of reformulation to mitigate against the obesity pandemic and wider negative health outcomes of UPFs.
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Associations of Dietary Intake on Biological Markers of Inflammation in Children and Adolescents: A Systematic Review.
Bujtor, M, Turner, AI, Torres, SJ, Esteban-Gonzalo, L, Pariante, CM, Borsini, A
Nutrients. 2021;13(2)
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Plain language summary
Inflammation is the normal physiological response to injury in the body and is designed to protect the host. However, in children and adolescents, chronic low-grade inflammation has been linked to a wide range of conditions. Certain markers in the blood can be measured and used to determine levels of inflammation in the body. This review of 53 studies provides the first evidence for the association between dietary intake and biological markers of inflammation in children and adolescents. Results show that adhering to a healthy way of eating such as the Mediterranean diet, are associated with decreased levels of pro-inflammatory biomarkers. The Western Dietary pattern, as well as intake of ultra-processed foods is associated with higher levels of the same pro-inflammatory markers. A good quality diet, high in fruit and vegetables, wholegrains, fibre and healthy fats ameliorates low-grade inflammation, and therefore represents a potential therapeutic approach. It is also an important element for disease prevention in both children and adolescents.
Abstract
BACKGROUND In children and adolescents, chronic low-grade inflammation has been implicated in the pathogenesis of co- and multi-morbid conditions to mental health disorders. Diet quality is a potential mechanism of action that can exacerbate or ameliorate low-grade inflammation; however, the exact way dietary intake can regulate the immune response in children and adolescents is still to be fully understood. METHODS Studies that measured dietary intake (patterns of diet, indices, food groups, nutrients) and any inflammatory biomarkers in children and adolescents aged 2 to19 years and published until November 2020 were included in this systematic review, and were selected in line with PRISMA guidelines through the following databases: Academic Search Complete, CINAHL, Global Health, Medline COMPLETE and Web of Science-Core Collection. A total of 53 articles were identified. RESULTS Results show that adequate adherence to healthful dietary patterns such as the Mediterranean diet, or food groups such as vegetables and fruit, or macro/micro nutrients such as fibre or vitamin C and E, are associated with decreased levels of pro-inflammatory biomarkers, mainly c-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), whereas adherence to a Western dietary pattern, as well as intake of food groups such as added sugars, macro-nutrients such as saturated fatty acids or ultra-processed foods, is associated with higher levels of the same pro-inflammatory biomarkers. CONCLUSIONS This is the first systematic review examining dietary intake and biological markers of inflammation in both children and adolescents. A good quality diet, high in vegetable and fruit intake, wholegrains, fibre and healthy fats ameliorates low-grade inflammation, and therefore represents a promising therapeutic approach, as well as an important element for disease prevention in both children and adolescents.