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Human Reproduction Update May 2024The last decade has seen increased research on the relationship between diet and male fertility, but there are no clearly defined nutritional recommendations for men in...
BACKGROUND
The last decade has seen increased research on the relationship between diet and male fertility, but there are no clearly defined nutritional recommendations for men in the preconception period to support clinical fertility outcomes.
OBJECTIVE AND RATIONALE
The purpose of this scoping review is to examine the extent and range of research undertaken to evaluate the effect(s) of diet in the preconception period on male clinical fertility and reproductive outcomes.
SEARCH METHODS
Four electronic databases (MEDLINE and EMBASE via Ovid, CAB Direct, and CINAHL via EBSCO) were searched from inception to July 2023 for randomized controlled trials (RCTs) and observational studies (prospective/retrospective, case-control, and cross-sectional). Intervention studies in male participants or couples aiming to achieve dietary or nutritional change, or non-intervention studies examining dietary or nutritional components (whole diets, dietary patterns, food groups or individual foods) in the preconception period were included. Controls were defined as any comparison group for RCTs, and any/no comparison for observational studies. Primary outcomes of interest included the effect(s) of male preconception diet on clinical outcomes such as conception (natural or via ART), pregnancy rates and live birth rates. Secondary outcomes included time to conception and sperm parameters.
OUTCOMES
A total of 37 studies were eligible, including one RCT and 36 observational studies (prospective, cross-sectional, and case-control studies; four studies in non-ART populations) published between 2008 and 2023. Eight reported clinical outcomes, 26 reported on secondary outcomes, and three reported on both. The RCT did not assess clinical outcomes but found that tomato juice may benefit sperm motility. In observational studies, some evidence suggested that increasing fish or reducing sugar-sweetened beverages, processed meat or total fat may improve fecundability. Evidence for other clinical outcomes, such as pregnancy rates or live birth rates, showed no relationship with cereals, soy and dairy, and inconsistent relationships with consuming red meat or a 'healthy diet' pattern. For improved sperm parameters, limited evidence supported increasing fish, fats/fatty acids, carbohydrates and dairy, and reducing processed meat, while the evidence for fruits, vegetables, cereals, legumes, eggs, red meat and protein was inconsistent. Healthy diet patterns in general were shown to improve sperm health.
WIDER IMPLICATIONS
Specific dietary recommendations for improving male fertility are precluded by the lack of reporting on clinical pregnancy outcomes, heterogeneity of the available literature and the paucity of RCTs to determine causation or to rule out reverse causation. There may be some benefit from increasing fish, adopting a healthy dietary pattern, and reducing consumption of sugar-sweetened beverages and processed meat, but it is unclear whether these benefits extend beyond sperm parameters to improve clinical fertility. More studies exploring whole diets rather than singular foods or nutritional components in the context of male fertility are encouraged, particularly by means of RCTs where feasible. Further assessment of core fertility outcomes is warranted and requires careful planning in high-quality prospective studies and RCTs. These studies can lay the groundwork for targeted dietary guidelines and enhance the prospects of successful fertility outcomes for men in the preconception period. Systematic search of preconception diet suggests that increasing fish and reducing sugary drinks, processed meats and total fat may improve male fertility, while consuming healthy diets, fish, fats/fatty acids, carbohydrates and dairy and reducing processed meat can improve sperm health.
Topics: Humans; Male; Diet; Pregnancy; Female; Fertility; Preconception Care; Pregnancy Rate
PubMed: 38237150
DOI: 10.1093/humupd/dmad035 -
Molecular Autism Jan 2024Gastrointestinal symptoms and inflammatory gastrointestinal diseases exist at higher rates in the autistic population. It is not clear however whether autism is... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Gastrointestinal symptoms and inflammatory gastrointestinal diseases exist at higher rates in the autistic population. It is not clear however whether autism is associated with elevated gastrointestinal inflammation as studies examining non-invasive faecal biomarkers report conflicting findings. To understand the research landscape and identify gaps, we performed a systematic review and meta-analysis of studies measuring non-invasive markers of gastrointestinal inflammation in autistic and non-autistic samples. Our examination focused on faecal biomarkers as sampling is non-invasive and these markers are a direct reflection of inflammatory processes in the gastrointestinal tract.
METHODS
We extracted data from case-control studies examining faecal markers of gastrointestinal inflammation. We searched PubMed, Embase, Cochrane CENTRAL, CINAHL, PsycINFO, Web of Science Core Collection and Epistemonikos and forward and backwards citations of included studies published up to April 14, 2023 (PROSPERO CRD42022369279).
RESULTS
There were few studies examining faecal markers of gastrointestinal inflammation in the autistic population, and many established markers have not been studied. Meta-analyses of studies examining calprotectin (n = 9) and lactoferrin (n = 3) were carried out. A total of 508 autistic children and adolescents and 397 non-autistic children and adolescents were included in the meta-analysis of calprotectin studies which found no significant group differences (ROM: 1.30 [0.91, 1.86]). Estimated differences in calprotectin were lower in studies with siblings and studies which did not exclude non-autistic controls with gastrointestinal symptoms. A total of 139 autistic participants and 75 non-autistic controls were included in the meta-analysis of lactoferrin studies which found no significant group differences (ROM: 1.27 [0.79, 2.04]).
LIMITATIONS
All studies included in this systematic review and meta-analysis examined children and adolescents. Many studies included non-autistic controls with gastrointestinal symptoms which limit the validity of their findings. The majority of studies of gastrointestinal inflammation focused on children under 12 with few studies including adolescent participants. Most studies that included participants aged four or under did not account for the impact of age on calprotectin levels. Future studies should screen for relevant confounders, include larger samples and explore gastrointestinal inflammation in autistic adolescents and adults.
CONCLUSIONS
There is no evidence to suggest higher levels of gastrointestinal inflammation as measured by calprotectin and lactoferrin are present in autistic children and adolescents at the population level. Preliminary evidence suggests however that higher calprotectin levels may be present in a subset of autistic participants, who may be clinically characterised by more severe gastrointestinal symptoms and higher levels of autistic traits.
Topics: Adolescent; Child; Humans; Autistic Disorder; Biomarkers; Gastrointestinal Tract; Inflammation; Lactoferrin; Leukocyte L1 Antigen Complex
PubMed: 38233886
DOI: 10.1186/s13229-023-00575-0 -
Clinical Nutrition (Edinburgh, Scotland) Feb 2024Although previous studies investigated the relation of protein intake and gestational diabetes mellitus (GDM), their findings were controversial. Therefore, we aimed to... (Meta-Analysis)
Meta-Analysis
The relation of dietary protein intake before and during the pregnancy with gestational diabetes mellitus (GDM): A GRADE-assessed systematic review and dose-response meta-analysis of epidemiologic studies.
BACKGROUND
Although previous studies investigated the relation of protein intake and gestational diabetes mellitus (GDM), their findings were controversial. Therefore, we aimed to summarize this association, through a comprehensive systematic review and dose-response meta-analysis.
METHODS
Electronic databases including MEDLINE (PubMed), ISI Web of Science, Scopus and motor engineering of Google Scholar were systematically searched up to April 2023. Observational studies which investigated odds of GDM in relation to protein intake were included.
RESULTS
A total of 31,005 participants with 3451 cases of GDM from 13 eligible investigations were included in the systematic review and meta-analysis. Comparing the highest and lowest intakes of total, animal, and plant proteins revealed the summary RRs of 1.82 (95% CI: 1.42, 2.33), 1.79 (95% CI: 1.50, 2.14), and 0.98 (95% CI: 0.81, 1.20), respectively, indicating a significant positive association between total and animal protein intake and GDM. In the dose-response analyses, each 5% increment in energy intake from total protein during pregnancy was related to 20% increased odds of GDM (RR = 1.20; 95% CI: 1.09, 1.33). In the non-linear dose-response analyses, we found a non-linear association for animal protein intake during pregnancy (P for non-linearity <0.001); so that, a risk increase was seen from zero to 10% of energy intake from animal proteins, however, a risk reduction was seen after 10% of energy intake. However, there was not any significant non-linear trend between plant protein intake during pregnancy and risk of GDM. Based on the GRADE assessment, the quality of evidence for total, animal and plant protein was rated as "moderate", "moderate" and "very low", respectively.
CONCLUSION
We found a significant positive association between total protein intake and GDM; however, the associations of animal and plant protein intake with GDM were dose-dependent.
Topics: Pregnancy; Female; Humans; Diabetes, Gestational; Dietary Proteins; Energy Intake; Glycemic Index; Plant Proteins; Risk Factors
PubMed: 38215681
DOI: 10.1016/j.clnu.2024.01.007 -
Nutrients Jan 2024Many epidemiological studies have evaluated the intake of macronutrients and the risk of mortality and cardiovascular disease (CVD). However, current evidence is... (Meta-Analysis)
Meta-Analysis Review
Many epidemiological studies have evaluated the intake of macronutrients and the risk of mortality and cardiovascular disease (CVD). However, current evidence is conflicting and warrants further investigation. Therefore, we carried out an umbrella review to examine and quantify the potential dose-response association of dietary macronutrient intake with CVD morbidity and mortality. Prospective cohort studies from PubMed, Embase, and CENTRAL were reviewed, which reported associations of macronutrients (protein, fat, and carbohydrate) with all-cause, CVD, cancer mortality, or CVD events. Multivariable relative risks (RR) were pooled, and heterogeneity was assessed. The results of 124 prospective cohort studies were included in the systematic review and 101 in the meta-analysis. During the follow-up period from 2.2 to 30 years, 506,086 deaths and 79,585 CVD events occurred among 5,107,821 participants. High total protein intake was associated with low CVD morbidity (RR 0.88, 95% confidence interval 0.82-0.94), while high total carbohydrate intake was associated with high CVD morbidity (1.08, 1.02-1.13). For fats, a high intake of total fat was associated with a decreased all-cause mortality risk (0.92, 0.85-0.99). Saturated fatty acid intake was only associated with cancer mortality (1.10, 1.06-1.14); Both monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) intake was associated with all-cause mortality (MUFA: 0.92, 0.86-0.98; PUFA: 0.91, 0.86-0.96). This meta-analysis supports that protein intake is associated with a decreased risk of CVD morbidity, while carbohydrate intake is associated with an increased risk of CVD morbidity. High total fat intake is associated with a low risk of all-cause mortality, and this effect was different in an analysis stratified by the type of fat.
Topics: Humans; Cardiovascular Diseases; Prospective Studies; Eating; Nutrients; Dietary Carbohydrates; Fatty Acids, Monounsaturated; Neoplasms
PubMed: 38201983
DOI: 10.3390/nu16010152 -
Animals : An Open Access Journal From... Dec 2023Soybean use has been low in pet foods, even though they are an excellent source of protein, polyunsaturated fatty acids, and gut fermentable fibers. The purpose of this... (Review)
Review
Soybean use has been low in pet foods, even though they are an excellent source of protein, polyunsaturated fatty acids, and gut fermentable fibers. The purpose of this evaluation was to conduct a systematic review of the public literature to explore how soybeans have been researched for pet food applications since 2000 and to provide strengths, weaknesses, opportunities, and threats for soybeans in the pet food industry. The review covered a total of 44 articles related to soybean ingredients and their potential value in the pet food arena. The articles were categorized by their research contents and narratively summarized to demonstrate useful information to both the pet and soybean industries. When soybean-based products have been adequately processed to reduce the antinutritive factors, they are comparable to processed animal proteins in nutritional value, palatability, and functionality in pet food processing. We conclude that various food processing technologies and the versatility of soybean ingredients allow soybean to have considerable inclusion potential in pet foods. More research on dietary soybean ingredients regarding pet food processing, fermentation benefits on health, and consumer acceptance will be needed to understand soybean's position in the future pet food industry.
PubMed: 38200747
DOI: 10.3390/ani14010016 -
Voprosy Pitaniia 2023Studies show that fruit juices are a source of macro- and micronutrients. Despite the fact that modern technologies for the industrial processing of fruits into juice...
Studies show that fruit juices are a source of macro- and micronutrients. Despite the fact that modern technologies for the industrial processing of fruits into juice are aimed at preserving the bioactive compounds of the original raw materials, juices are the subject of controversy due to the presence of free sugars and less dietary fiber than in fresh fruits. of the work was to systematize the available studies on the effect of 100% juices on nutrition quality, obesity and type 2 diabetes mellitus. . Systematic search in PubMed, Google Scholar, eLIBRARY databases in accordance with the inclusion criteria: the study examined 100% fruit or vegetable juices, the article was in Russian or English in a peer-reviewed journal, the subjects (in the case of clinical studies) were people aged 1 to 18 years and older. 98 sources were analyzed based on the title of the article, of which 35 did not relate to juices. 63 sources were analyzed based on their abstracts, of which 28 were included in the main study. . According to the results of the literature analysis, it follows that moderate consumption of 100% juices not only does not have negative effects on human health, but, on the contrary improve the health of the organism. In particular, its intake helps lower blood pressure and the content of highly sensitive C-reactive protein, thereby reducing the risk of cardiovascular diseases. Juices enrich the daily diet due to the macro- and micronutrients they contain, which improves the quality of nutrition in general. Researches prove that there is no correlation between moderate juice consumption and type 2 diabetes onset. The glycemic index of the juices is low or medium, which distinguishes them from standard soft drinks containing sugar. The consumption of juices (100-500 ml/day) does not increase the risk of obesity in adults and children. . Negative effects, such as weight gain and an increased risk of diabetic diseases, can only be observed with excessive consumption of juices.
Topics: Adult; Child; Humans; Diabetes Mellitus, Type 2; Fruit; Micronutrients; Nutritive Value; Obesity
PubMed: 38198403
DOI: 10.33029/0042-8833-2023-92-5-28-38 -
BMC Oral Health Jan 2024White spot lesions represent the first stage of caries and their prevalence has been increasing in recent years, particularly in patients undergoing orthodontic...
BACKGROUND
White spot lesions represent the first stage of caries and their prevalence has been increasing in recent years, particularly in patients undergoing orthodontic treatment. DIferential diagnosis and lesion activity are essential to decide on the clinical approaches to treatment. The aim of this study is to understand if the new diagnostic tools such as fluorescence, microradiography and computed microtomography have the potential to change the conventional treatment of white spots".
METHODS
A systematic search of available studies in the literature was carried out, using PRISMA guidelines, in Pubmed and Scopus electronic databases and manually to identify relevant articles to answer the PICO question: "Do the new diagnostic tools have the potential to change the conventional treatment of white spots?". This systematic review included randomized controlled trials (RCT), cross-sectional and longitudinal studies complying with the following inclusion criteria: (i) studies in humans, (ii) studies about white spot lesions, (iii) studies published between 2012 and 2023, (iv) studies having both diagnosis and treatment and (v) studies with full text available. In this review we excluded other systematic reviews of clinical trials and in vitro studies. The RoB tool was used to assess the risk of bias.
RESULTS
The systematic literature search identified 143 potentially relevant references, which after applying the exclusion criteria, resulted in 20 articles. Regarding diagnostic methods, most articles found were based on conventional methods of visual examination (n:10) or fluorescence (n:7). The least referenced diagnostic techniques were based on the use of clinical photographs (n:2), cross-sectional microradiography (n:1) and computed microtomography (n:1). The use of DIAGNOdent was reported by 3 in vitro studies. With regard to therapies, most studies reported the use of infiltrating resin (n:7) and fluoride-based products (n:5). Other studies have reported the use of self-assembling peptide P11-4 (n:1), home care (n:1), casein phosphopeptide-amorphous calcium phosphate (n:2) and hydrochloric acid (n:1). Combination therapies were also considered.
CONCLUSION
Diagnostic tool does not have the potential to change the form of treatment, whether it is a conventional method or a more differentiated one.
Topics: Humans; Combined Modality Therapy; Dental Care; Caseins; Databases, Factual; Dental Caries; Fluorides
PubMed: 38195439
DOI: 10.1186/s12903-023-03720-6 -
Journal of Sleep Research Jan 2024Insufficient sleep is a growing global problem, with poor sleep associated with many negative health and performance outcomes. Previous reviews investigating the effect... (Review)
Review
Insufficient sleep is a growing global problem, with poor sleep associated with many negative health and performance outcomes. Previous reviews investigating the effect of diet on sleep have highlighted the amino acid tryptophan as a promising sleep-promoting nutrient, with the richest food source of tryptophan, ⍺-lactalbumin, requiring further investigation. Therefore, this systematic review aimed to review the existing evidence of association between ⍺-lactalbumin and sleep. Four electronic databases (CINAHL Complete, Embase, MEDLINE Complete, and SPORTDiscus with Full Text) were searched from database inception to March 2023, with primary research articles included if they contained α-lactalbumin as an independent variable, an outcome measure of sleep or sleepiness, and participants were ≥ 18 years old. Eight studies were reviewed, with four studies recruiting athletic populations (50%) and four recruiting healthy participants (50%). Sleep or sleepiness was measured objectively in six studies (75%), with two studies employing polysomnography and four utilizing actigraphy to assess sleep. Across the studies, 20-60 g of ⍺-lactalbumin was supplemented, with five studies (63%) observing a positive association between α-lactalbumin and sleep. Sleep-onset latency was the primary sleep metric improved following evening supplementation of α-lactalbumin (≤ 3.5 hr pre-sleep), with no studies observing any negative associations with sleep. Data from this review suggest that individuals that have difficulty initiating sleep may benefit most from pre-sleep α-lactalbumin supplementation. Further research is required to establish the effect that α-lactalbumin has on sleep architecture, through the use of more comprehensive sleep analysis tools such as portable electroencephalography or polysomnography, in combination with stringent dietary controls.
PubMed: 38185736
DOI: 10.1111/jsr.14141 -
Nature Food Jan 2024The protein transition, aiming to rebalance protein intake between animal and alternative proteins, is gaining momentum in scientific and policy discussions on food...
The protein transition, aiming to rebalance protein intake between animal and alternative proteins, is gaining momentum in scientific and policy discussions on food system transformation. Here, using a systematic review approach, we identified 33 articles that address challenges in reducing the environmental impacts of protein production and consumption, providing healthy diets for a growing population and preventing adverse effects of industrial livestock production systems. We found unclear definitions of the protein transition, conflicting views on reduction or replacement of dietary protein and a lack of attention to systemic change by reducing protein to its macronutrient function. Three narratives were identified, namely, the consumer narrative focusing on consumption-based solutions targeting dietary changes; the techno-centred narrative developing new, more resource-efficient protein production systems; and the socio-technological narrative that intends to transition the agri-food system from an animal-dominated regime to an alternative protein regime. We conclude that solutions should consider factors such as scale, initiating actors and expected impact to support complementary protein transition approaches.
Topics: Animals; Developed Countries; Diet, Healthy; Environment; Nutrients; Dietary Proteins; Humans
PubMed: 38172295
DOI: 10.1038/s43016-023-00906-7 -
Food & Function Jan 2024Exercise-induced muscle damage is common in athletes and recreational exercisers and can lead to muscle soreness, weakness, and impaired muscle function. The precise...
Exercise-induced muscle damage is common in athletes and recreational exercisers and can lead to muscle soreness, weakness, and impaired muscle function. The precise mechanisms are unclear but oxidative stress and inflammation are thought to play a role. (Poly)phenols are substances abundant in berries that have been suggested to possess antioxidant and anti-inflammatory effects that could help improve exercise performance and/or recovery from exercise. The objective of this systematic review was to evaluate the benefits of berry supplementation on exercise performance and recovery, as well as on exercise-induced oxidative and inflammatory biomarkers in healthy individuals. A comprehensive search was conducted in PubMed, ProQuest Medline, Web of Science, Cochrane Library, and Scopus. Studies were included if the participants were healthy individuals who were supplemented with any berry or berry-based products in comparison to a control group. Of the 13 articles included in this review, no significant differences in the exercise performance were found and only one study reported benefits for markers of recovery. Interleukins and c-reactive protein were the most frequently reported biomarkers, but there was limited evidence that berry supplementation impacted them post-exercise. Most studies were of high quality and showed a low risk of bias. berry supplementation is not effective in modulating markers of exercise-induced inflammation and oxidative distress in healthy individuals; nevertheless, more studies are required to evaluate their effects on exercise performance and recovery in this population.
Topics: Humans; Antioxidants; Biomarkers; Blueberry Plants; Dietary Supplements; Fruit; Inflammation; Oxidative Stress; Vaccinium; Vaccinium macrocarpon; Vaccinium myrtillus
PubMed: 38165220
DOI: 10.1039/d3fo04435a