Need for a nutrition-specific scientific paradigm for research quality improvement.

Nutrition science has been criticised for its methodology, apparently contradictory findings and generating controversy rather than consensus. However, while certain critiques of the field are valid and informative for developing a more cogent science, there are also unique considerations for the study of diet and nutrition that are either overlooked or omitted in these discourses. The ongoing critical discourse on the utility of nutrition sciences occurs at a time when the burden of non-communicable cardiometabolic disease continues to rise in the population. Nutrition science, along with other disciplinary fields, is tasked with producing a translational evidence-base fit for the purpose of improving population and individual health and reducing disease risk. Thus, an exploration of the unique methodological and epistemic considerations for nutrition research is important for nutrition researchers, students and practitioners, to further develop an improved scientific discipline for nutrition. This paper will expand on some of the challenges facing nutrition research, discussing methodological facets of nutritional epidemiology, randomised controlled trials and meta-analysis, and how these considerations may be applied to improve research methodology. A pragmatic research paradigm for nutrition science is also proposed, which places methodology at its centre, allowing for questions over both how we obtain knowledge and research design as the method to produce that knowledge to be connected, providing the field of nutrition research with a framework within which to capture the full complexity of nutrition and diet.

Avoidance of vitamin D deficiency to slow the COVID-19 pandemic.

Vitamin D deficiency, which impedes good immune function, is common during winter and spring in regions of high latitude. There is good evidence that vitamin D deficiency contributes to the seasonal increase of virus infections of the respiratory tract, from the common cold to influenza, and now possibly also COVID-19. This communication explores key factors that make it more likely, particularly in combination, that individuals are vitamin D deficient. These factors include old age, obesity, dark skin tone and common genetic variants that impede vitamin D status. Precision nutrition is an approach that aims to consider known personal risk factors and health circumstances to provide more effective nutrition guidance in health and disease. In regard to avoiding vitamin D deficiency, people with excess body fat, a dark skin tone or older age usually need to use a moderately dosed daily vitamin D supplement, particularly those living in a high-latitude region, getting little ultraviolet B exposure due to air pollution or staying mostly indoors. Carriers of the GC (group-specific component) rs4588 AA genotype also are more likely to become deficient. Very high-dosed supplements with more than 4000 IU vitamin D are rarely needed or justified. A state-by-state Mendelian randomisation analysis of excess COVID-19 mortality of African-Americans in the USA shows a greater disparity in northern states than in southern states. It is conceivable that vitamin D adequacy denies the virus easy footholds and thereby slows spreading of the contagion. This finding should drive home the message that vitamin D supplementation is particularly important for individuals with dark skin tones. Vitamin D deficiency, even for a few months during the winter and spring season, must be rigorously remedied because of its many adverse health impacts that include decreased life expectancy and increased mortality. Slowing the spread of COVID-19 would be an added bonus.

Dietary micronutrients in the wake of COVID-19: an appraisal of evidence with a focus on high-risk groups and preventative healthcare.

Existing micronutrient deficiencies, even if only a single micronutrient, can impair immune function and increase susceptibility to infectious disease. Certain population groups are more likely to have micronutrient deficiencies, while certain disease pathologies and treatment practices also exacerbate risk, meaning these groups tend to suffer increased morbidity and mortality from infectious diseases. Optimisation of overall nutritional status, including micronutrients, can be effective in reducing incidence of infectious disease. Micronutrient deficiencies are rarely recognised but are prevalent in the UK, as well as much more widely, particularly in high-risk groups susceptible to COVID-19. Practitioners should be aware of this fact and should make it a consideration for the screening process in COVID-19, or when screening may be difficult or impractical, to ensure blanket treatment as per the best practice guidelines. Correction of established micronutrient deficiencies, or in some cases assumed suboptimal status, has the potential to help support immune function and mitigate risk of infection. The effects of and immune response to COVID-19 share common characteristics with more well-characterised severe acute respiratory infections. Correction of micronutrient deficiencies has proven effective in several infectious diseases and has been shown to promote favourable clinical outcomes. Micronutrients appear to play key roles in mediating the inflammatory response and such effects may be enhanced through correction of deficiencies. Many of those at highest risk during the COVID-19 pandemic are also populations at highest risk of micronutrient deficiencies and poorer overall nutrition. Correction of micronutrient deficiencies in established COVID-19 infection may contribute to supporting immune response to infection in those at highest risk. There is a need for further research to establish optimal public health practice and clinical intervention regimens.

Dietary Choline Intake during Pregnancy and PEMT rs7946 Polymorphism on Risk of Preterm Birth: A Case-Control Study.

INTRODUCTION AND AIMS: Choline-metabolizing genetic variation may interact with choline intake on fetal programming and pregnancy outcome. This case-control study aims to explore the association of maternal choline consumption and phosphatidylethanolamine N-methyltransferase (PEMT) gene polymorphism rs7946 with preterm birth risk. METHODS: 145 Han Chinese women with preterm delivery and 157 Han Chinese women with term delivery were recruited in Shanghai. Dietary choline intake during pregnancy was assessed using a validated food frequency questionnaire. Additionally, DNA samples were genotyped for PEMT rs7946 (G5465A) with plasma homocysteine (Hcy) levels measured. RESULTS: Compared with the lowest quartile of choline intake, women within the highest consumption quartile had adjusted odds ratio (aOR) for preterm birth of 0.48 (95% confidence interval, CI [0.24, 0.95]). There was a significant interaction between maternal choline intake and PEMT rs7946 (p for interaction = 0.04), where the AA genotype carriers who consumed the energy-adjusted choline <255.01 mg/day had aOR for preterm birth of 3.75 (95% CI [1.24, 11.35]), compared to those with GG genotype and choline intake >255.01 mg/day during pregnancy. Additionally, the greatest elevated plasma Hcy was found in the cases with AA genotype and choline consumption <255.01 mg/day (p < 0.001). CONCLUSION: The AA genotype of PEMT rs7946 may be associated with increased preterm birth in these Han Chinese women with low choline intake during pregnancy.

Muscle cross-sectional area and motor unit properties of the medial gastrocnemius and vastus lateralis in normal weight and overfat children.

NEW FINDINGS: What is the central question of this study? Are differences in muscle size and motor unit properties between normal weight and overfat children muscle specific? What is the main finding and its importance? Muscle cross-sectional area and motor unit action potential amplitudes and firing rates were similar between overfat and normal weight children for both the medial gastrocnemius and vastus lateralis muscles. There was no evidence that the chronic mechanical overload provided by the greater body mass resulted in significant hypertrophy of contractile tissue or motor units that would be used during lower-to-moderate intensity activities. ABSTRACT: This study examined the possible differences in muscle cross-sectional area (mCSA), motor unit action potential amplitudes (MUAPAMPS ) and interspike intervals (ISIs) of the firing instances of the medial gastrocnemius (MG) and vastus lateralis (VL) between normal weight (NW) and overfat (OF) children aged 7-10 years. Fourteen NW (age = 8.6 ± 1.1 years, BMI = 15.8 ± 1.4 kg m-2 ) and 12 OF (age = 8.8 ± 0.9 years, BMI = 21.8 ± 2.4 kg m-2 ) children performed isometric trapezoidal muscle actions at 40% of maximal voluntary contraction of the plantar flexors and knee extensors. Surface electromyography was recorded from the MG and VL and decomposed into the firing events of motor units (MUs). Statistical procedures were performed on the composite recruitment thresholds (RTs), ISIs and MUAPAMPS of recorded MUs collapsed across subjects and the y-intercepts and slopes calculated from each subject's ISI and MUAPAMP vs. RT relationships. Ultrasound was used to assess mCSA, echo intensity (mEI), and subcutaneous fat (sFAT) of the MG and VL. The OF had greater mCSAs, mEI and sFAT (P = 0.004-0.024), but there were no differences in mCSA when accounting for mEI for the MG (P = 0.506) and VL (P = 0.326). The NW children had significantly greater composite MUAPAMPS for the VL and MG (P < 0.001), but only significantly larger MUAPAMPS of the VL remained for the NW (P < 0.001) when subjects were matched for sFAT. There were no differences between groups for the ISI or MUAPAMP vs. RT relationships (P > 0.05). These findings suggest that the OF children did not undergo significant muscle or MU hypertrophy that would be routinely activated during activities of daily living.

Advancing Nutrition Education, Training, and Research for Medical Students, Residents, Fellows, Attending Physicians, and Other Clinicians: Building Competencies and Interdisciplinary Coordination.

Nutrition plays an important role in health promotion and disease prevention and treatment across the lifespan. Physicians and other healthcare professionals are expected to counsel patients about nutrition, but recent surveys report minimal to no improvements in medical nutrition education in US medical schools. A workshop sponsored by the National Heart, Lung, and Blood Institute addressed this gap in knowledge by convening experts in clinical and academic health professional schools. Representatives from the National Board of Medical Examiners, the Accreditation Council for Graduate Medical Education, the Liaison Committee on Medical Education, and the American Society for Nutrition provided relevant presentations. Reported is an overview of lessons learned from nutrition education efforts in medical schools and health professional schools including interprofessional domains and competency-based nutrition education. Proposed is a framework for coordinating activities of various entities using a public-private partnership platform. Recommendations for nutrition research and accreditation are provided.

Acute Ingestion of a Mixed Flavonoid and Caffeine Supplement Increases Energy Expenditure and Fat Oxidation in Adult Women: A Randomized, Crossover Clinical Trial.

This randomized, double-blinded, crossover study measured the acute effect of ingesting a mixed flavonoid-caffeine (MFC) supplement compared to placebo (PL) on energy expenditure (EE) and fat oxidation (FATox) in a metabolic chamber with premenopausal women (n = 19, mean ± SD, age 30.7 ± 8.0 year, BMI 25.7 ± 3.4 kg/m2). The MFC supplement (658 mg flavonoids, split dose 8:30, 13:00) contained quercetin, green tea catechins, and anthocyanins from bilberry extract, and 214 mg caffeine. Participants were measured twice in a metabolic chamber for a day, four weeks apart, with outcomes including 22 h EE (8:30-6:30), substrate utilization from the respiratory quotient (RQ), plasma caffeine levels (16:00), and genotyping for the single-nucleotide polymorphism (SNP) rs762551. Areas under the curve (AUC) for metabolic data from the MFC and PL trials were calculated using the trapezoid rule, with a mixed linear model (GLM) used to evaluate the overall treatment effect. The 22 h oxygen consumption and EE were significantly higher with MFC than PL (1582 ± 143, 1535 ± 154 kcal/day, respectively, p = 0.003, trial difference of 46.4 ± 57.8 kcal/day). FATox trended higher for MFC when evaluated using GLM (99.2 ± 14.0, 92.4 ± 14.4 g/22 h, p = 0.054). Plasma caffeine levels were significantly higher in the MFC versus PL trial (5031 ± 289, 276 ± 323 ng/mL, respectively, p < 0.001). Trial differences for 22 h EE and plasma caffeine were unrelated after controlling for age and body mass (r = -0.249, p = 0.139), and not different for participants with the homozygous allele 1, A/A, compared to C/A and C/C (p = 0.50 and 0.56, respectively). In conclusion, EE was higher for MFC compared to PL, and similar to effects estimated from previous trials using caffeine alone. A small effect of the MFC on FATox was measured, in contrast to inconsistent findings previously reported for this caffeine dose. The trial variance for 22 h EE was not significantly related to the variance in plasma caffeine levels or CYP1A2*1F allele carriers and non-carriers.

Counterbalancing the Uncertainties of Medical Nutrition Education with Effective Online Instruction.

Practicing physicians need to recognize nutrition problems in their patients and know what to do about them. It takes at least 25-30 h of medical school instruction to achieve just basic nutrition competencies. Because most medical students get significantly less than this minimum, they are not adequately prepared to deal with common nutrition-related challenges in practice. The majority of all accredited US medical schools require <25 h of nutrition instruction across the entire 4-year curriculum and a few still fail to require any nutrition education at all. Medical schools in other countries struggle with the same instructional deficits and many fail altogether to address the need for proper nutrition training. The greatest deficits exist in teaching clinical practice and practical problem solving. The Nutrition in Medicine (NIM) project (nutritioninmedicine.org), with materials used by a majority of US medical schools as well as institutions in >20 countries, has demonstrated that computer-based nutrition instruction is effective and efficient, particularly as an integral component of clinical training. Interactive components, skill-building exercises, and practice challenges with video-realistic patients allow learners to progress at their own pace and ensure that all of them learn what they need to know.

Examination of muscle morphology and neuromuscular function in normal weight and overfat children aged 7-10 years.

Neuromuscular function in young overweight/obese (OF) children is not well described. AIM: This study examined isometric and isokinetic leg extensor strength, muscle size (mCSA) and tissue composition as measured via echo intensity (mEI), and motor unit (MU) firing rates in normal weight (NW) and OF children aged 7-10 years. METHODS: Fourteen NW (eight girls and six boys, BMI: 15.8 ± 1.4 kg/m2 ) and 15 OF (10 girls and five boys, BMI: 20.8 ± 2.3 kg/m2 ) children volunteered to perform this study. Percentage body fat (%BF) was measured, and mCSA, mEI, and subcutaneous fat (sFAT) of the vastus lateralis (VL) was assessed. MU mean firing rates (MFRs) in relation to recruitment threshold (RT) of the VL were assessed during submaximal isometric contractions. Maximal isokinetic contractions were performed at 1.05 and 4.20 rad/s. The 95% confidence intervals (CI) from the statistical tests are presented. RESULTS: The OF children had greater %BF (95% CI = -15.1 to -7.2), mCSA (95% CI = -4.1 to -1.2), mEI (95% CI = -22.3 to -5.9), and sFAT (95% CI = -0.5 to -0.1), greater rate of strength loss with increasing isokinetic velocities (95% CI = 0.4 to 5.4), and a smaller range of MFRs (95% CI = 0.007 to 7.136) at the steady torque than the NW children. CONCLUSIONS: The OF children had poorer muscle tissue composition, greater velocity-related impairments in muscle strength, and a smaller range of MFRs at the targeted torque that may suggest altered MU recruitment strategies. Interventions in OF children should include exercises and recruit higher-threshold MUs, such as high-intensity resistance exercises.

CASAnova: a multiclass support vector machine model for the classification of human sperm motility patterns.

The ability to accurately monitor alterations in sperm motility is paramount to understanding multiple genetic and biochemical perturbations impacting normal fertilization. Computer-aided sperm analysis (CASA) of human sperm typically reports motile percentage and kinematic parameters at the population level, and uses kinematic gating methods to identify subpopulations such as progressive or hyperactivated sperm. The goal of this study was to develop an automated method that classifies all patterns of human sperm motility during in vitro capacitation following the removal of seminal plasma. We visually classified CASA tracks of 2817 sperm from 18 individuals and used a support vector machine-based decision tree to compute four hyperplanes that separate five classes based on their kinematic parameters. We then developed a web-based program, CASAnova, which applies these equations sequentially to assign a single classification to each motile sperm. Vigorous sperm are classified as progressive, intermediate, or hyperactivated, and nonvigorous sperm as slow or weakly motile. This program correctly classifies sperm motility into one of five classes with an overall accuracy of 89.9%. Application of CASAnova to capacitating sperm populations showed a shift from predominantly linear patterns of motility at initial time points to more vigorous patterns, including hyperactivated motility, as capacitation proceeds. Both intermediate and hyperactivated motility patterns were largely eliminated when sperm were incubated in noncapacitating medium, demonstrating the sensitivity of this method. The five CASAnova classifications are distinctive and reflect kinetic parameters of washed human sperm, providing an accurate, quantitative, and high-throughput method for monitoring alterations in motility.

Guide for Current Nutrigenetic, Nutrigenomic, and Nutriepigenetic Approaches for Precision Nutrition Involving the Prevention and Management of Chronic Diseases Associated with Obesity.

Chronic diseases, including obesity, are major causes of morbidity and mortality in most countries. The adverse impacts of obesity and associated comorbidities on health remain a major concern due to the lack of effective interventions for prevention and management. Precision nutrition is an emerging therapeutic approach that takes into account an individual's genetic and epigenetic information, as well as age, gender, or particular physiopathological status. Advances in genomic sciences are contributing to a better understanding of the role of genetic variants and epigenetic signatures as well as gene expression patterns in the development of diverse chronic conditions, and how they may modify therapeutic responses. This knowledge has led to the search for genetic and epigenetic biomarkers to predict the risk of developing chronic diseases and personalizing their prevention and treatment. Additionally, original nutritional interventions based on nutrients and bioactive dietary compounds that can modify epigenetic marks and gene expression have been implemented. Although caution must be exercised, these scientific insights are paving the way for the design of innovative strategies for the control of chronic diseases accompanying obesity. This document provides a number of examples of the huge potential of understanding nutrigenetic, nutrigenomic, and nutriepigenetic roles in precision nutrition.

Proceedings of the 11th Congress of the International Society of Nutrigenetics and Nutrigenomics (ISNN 2017).

The International Society of Nutrigenetics and Nutrigenomics (ISNN) held its 11th annual Congress in Los Angeles, California, between September 16 and 19, 2017. In addition to 2 keynote lectures, 4 plenary sessions included presentations by internationally renowned speakers on cutting-edge areas of research and new discoveries in genetics/genomics, the microbiome, and nutrition. Scientific topics included multi-omics approaches; diet and the microbiome; cancer, longevity, and metabolism; moving the field forward; and translational/educational aspects and the future of medicine. There was also an accepted oral abstracts session designed specifically to provide young investigators and trainees with the opportunity to present their work, as well as a session focused on industry-academic partnerships, which included a roundtable discussion afterwards. Overall, the 11th ISNN Congress was an exciting and intellectually stimulating meeting focused on understanding the impact of biological interactions between genes and nutrients on health and disease. These efforts continued the decade-long tradition of the annual ISNN Congress to provide an interdisciplinary platform for scientists from various disciplines to discuss research ideas and advance the fields of nutrigenetics and nutrigenomics.

Guide and Position of the International Society of Nutrigenetics/Nutrigenomics on Personalized Nutrition: Part 2 - Ethics, Challenges and Endeavors of Precision Nutrition.

Nutrigenetics considers the influence of individual genetic variation on differences in response to dietary components, nutrient requirements and predisposition to disease. Nutrigenomics involves the study of interactions between the genome and diet, including how nutrients affect the transcription and translation process plus subsequent proteomic and metabolomic changes, and also differences in response to dietary factors based on the individual genetic makeup. Personalized characteristics such as age, gender, physical activity, physiological state and social status, and special conditions such as pregnancy and risk of disease can inform dietary advice that more closely meets individual needs. Precision nutrition has a promising future in treating the individual according to their phenotype and genetic characteristics, aimed at both the treatment and prevention of disease. However, many aspects are still in progress and remain as challenges for the future of nutrition. The integration of the human genotype and microbiome needs to be better understood. Further advances in data interpretation tools are also necessary, so that information obtained through newer tests and technologies can be properly transferred to consumers. Indeed, precision nutrition will integrate genetic data with phenotypical, social, cultural and personal preferences and lifestyles matters to provide a more individual nutrition, but considering public health perspectives, where ethical, legal and policy aspects need to be defined and implemented.

Guide and Position of the International Society of Nutrigenetics/Nutrigenomics on Personalised Nutrition: Part 1 - Fields of Precision Nutrition.

Diversity in the genetic profile between individuals and specific ethnic groups affects nutrient requirements, metabolism and response to nutritional and dietary interventions. Indeed, individuals respond differently to lifestyle interventions (diet, physical activity, smoking, etc.). The sequencing of the human genome and subsequent increased knowledge regarding human genetic variation is contributing to the emergence of personalized nutrition. These advances in genetic science are raising numerous questions regarding the mode that precision nutrition can contribute solutions to emerging problems in public health, by reducing the risk and prevalence of nutrition-related diseases. Current views on personalized nutrition encompass omics technologies (nutrigenomics, transcriptomics, epigenomics, foodomics, metabolomics, metagenomics, etc.), functional food development and challenges related to legal and ethical aspects, application in clinical practice, and population scope, in terms of guidelines and epidemiological factors. In this context, precision nutrition can be considered as occurring at three levels: (1) conventional nutrition based on general guidelines for population groups by age, gender and social determinants; (2) individualized nutrition that adds phenotypic information about the person's current nutritional status (e.g. anthropometry, biochemical and metabolic analysis, physical activity, among others), and (3) genotype-directed nutrition based on rare or common gene variation. Research and appropriate translation into medical practice and dietary recommendations must be based on a solid foundation of knowledge derived from studies on nutrigenetics and nutrigenomics. A scientific society, such as the International Society of Nutrigenetics/Nutrigenomics (ISNN), internationally devoted to the study of nutrigenetics/nutrigenomics, can indeed serve the commendable roles of (1) promoting science and favoring scientific communication and (2) permanently working as a 'clearing house' to prevent disqualifying logical jumps, correct or stop unwarranted claims, and prevent the creation of unwarranted expectations in patients and in the general public. In this statement, we are focusing on the scientific aspects of disciplines covering nutrigenetics and nutrigenomics issues. Genetic screening and the ethical, legal, social and economic aspects will be dealt with in subsequent statements of the Society.