Current knowledge and interest of French Canadians regarding nutrigenetics

Genetically-Guided Medical Nutrition Therapy in Type 2 Diabetes Mellitus and Pre-diabetes: A Series of n-of-1 Superiority Trials

Type 2 diabetes mellitus (T2DM) is a heterogeneous metabolic disorder of multifactorial etiology that includes genetic and dietary influences. By addressing the latter, medical nutrition therapy (MNT) contributes to the management of T2DM or pre-diabetes toward achieving glycaemic control and improved insulin sensitivity. However, the clinical outcomes of MNT vary and may further benefit from personalized nutritional plans that take into consideration genetic variations associated with individual responses to macronutrients. The aim of the present series of n-of-1 trials was to assess the effects of genetically-guided vs. conventional MNT on patients with pre-diabetes or T2DM. A quasi-experimental, cross-over design was adopted in three Caucasian adult men with either diagnosis. Complete diet, bioclinical and anthropometric assessment was performed and a conventional MNT, based on the clinical practice guidelines was applied for 8 weeks. After a week of “wash-out,” a precision MNT was prescribed for an additional 8-week period, based on the genetic characteristics of each patient. Outcomes of interest included changes in body weight (BW), fasting plasma glucose (FPG), and blood pressure (BP). Collectively, the trials indicated improvements in BW, FPG, BP, and glycosylated hemoglobin (HbA1c) following the genetically-guided precision MNT intervention. Moreover, both patients with pre-diabetes experienced remission of the condition. We conclude that improved BW loss and glycemic control can be achieved in patients with pre-diabetes/T2DM, by coupling MNT to their genetic makeup, guiding optimal diet, macronutrient composition, exercise and oral nutrient supplementation in a personalized manner.

Nutrigenetics, omega-3 and plasma lipids/lipoproteins/apolipoproteins with evidence evaluation using the GRADE approach: a systematic review

OBJECTIVES

Despite the uptake of nutrigenetic testing through direct-to-consumer services and healthcare professionals, systematic reviews determining scientific validity are limited in this field. The objective of this review was to: retrieve, synthesise and assess the quality of evidence (confidence) for nutrigenetic approaches related to the effect of genetic variation on plasma lipid, lipoprotein and apolipoprotein responsiveness to omega-3 fatty acid intake.

DESIGN

A systematic review was conducted using three search engines (Embase, Web of Science and Medline) for articles published up until 1 August 2020. We aimed to systematically search, identify (select) and provide a narrative synthesis of all studies that assessed nutrigenetic associations/interactions for genetic variants (comparators) influencing the plasma lipid, lipoprotein and/or apolipoprotein response (outcomes) to omega-3 fatty acid intake (intervention/exposure) in humans-both paediatric and adult populations (population). We further aimed to assess the overall quality of evidence for specific priority nutrigenetic associations/interactions based on the following inclusion criteria: nutrigenetic associations/interactions reported for the same genetic variants (comparators) influencing the same plasma lipid, lipoprotein and/or apolipoprotein response (outcomes) to omega-3 fatty acid intake (intervention/exposure) in humans-both paediatric and adult populations (population) in at least two independent studies, irrespective of the findings. Risk of bias was assessed in individual studies. Evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach with a modification to further consider biological plausibility.

RESULTS

Out of 1830 articles screened, 65 met the inclusion criteria for the narrative synthesis (n=23 observational, n=42 interventional); of these, 25 met the inclusion criteria for GRADE evidence evaluation. Overall, current evidence is insufficient for gene-diet associations related to omega-3 fatty acid intake on plasma apolipoproteins, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein (LDL)-cholesterol and LDL particle size. However, there is strong (GRADE rating: moderate quality) evidence to suggest that male APOE-E4 carriers (rs429358, rs7412) exhibit significant triglyceride reductions in response to omega-3-rich fish oil with a dose-response effect. Moreover, strong (GRADE rating: high quality) evidence suggests that a 31-SNP nutrigenetic risk score can predict plasma triglyceride responsiveness to omega-3-rich fish oil in adults with overweight/obesity from various ethnicities.

CONCLUSIONS

Most evidence in this area is weak, but two specific nutrigenetic interactions exhibited strong evidence, with generalisability limited to specific populations.

PROSPERO REGISTRATION NUMBER

CRD42020185087.

Development of Personalized Nutrition: Applications in Lactose Intolerance Diagnosis and Management

Recent discoveries in the “omics” field and the growing focus on preventive health have opened new avenues for personalized nutrition (PN), which is becoming an important theme in the strategic plans of organizations that are active in healthcare, food, and nutrition research. PN holds great potential for individual health optimization, disease management, public health interventions, and product innovation. However, there are still multiple challenges to overcome before PN can be truly embraced by the public and healthcare stakeholders. The diagnosis and management of lactose intolerance (LI), a common condition with a strong inter-individual component, is explored as an interesting example for the potential role of these technologies and the challenges of PN. From the development of genetic and metabolomic LI diagnostic tests that can be carried out in the home, to advances in the understanding of LI pathology and individualized treatment optimization, PN in LI care has shown substantial progress. However, there are still many research gaps to address, including the understanding of epigenetic regulation of lactase expression and how lactose is metabolized by the gut microbiota, in order to achieve better LI detection and effective therapeutic interventions to reverse the potential health consequences of LI.

The "Virtual Digital Twins" Concept in Precision Nutrition

Nutritional and lifestyle changes remain at the core of healthy aging and disease prevention. Accumulating evidence underscores the impact of genetic, metabolic, and host gut microbial factors on individual responses to nutrients, paving the way for the stratification of nutritional guidelines. However, technological advances that incorporate biological, nutritional, lifestyle, and health data at an unprecedented scale and depth conceptualize a future where preventative dietary interventions will exceed stratification and will be highly individualized. We herein discuss how genetic information combined with longitudinal metabolomic, immune, behavioral, and gut microbial parameters, and bioclinical variables could define a digital replica of oneself, a "virtual digital twin," which could serve to guide nutrition in a personalized manner. Such a model may revolutionize the management of obesity and its comorbidities, and provide a pillar for healthy aging.

Effect of Incorporating Genetic Testing Results into Nutrition Counseling and Care on Dietary Intake: An Evidence Analysis Center Systematic Review-Part I

Consumer interest in personalized nutrition based on nutrigenetic testing is growing. Recently, multiple, randomized controlled trials have sought to understand whether incorporating genetic information into dietary counseling alters dietary outcomes. The objective of this systematic review was to examine how incorporating genetic information into nutrition counseling and care, compared to an alternative intervention or control group, impacts dietary outcomes. This is the first of a 2-part systematic review series. Part II reports anthropometric, biochemical, and disease-specific outcomes. Peer-reviewed randomized controlled trials were identified through a systematic literature search of multiple databases, screened for eligibility, and critically reviewed and synthesized. Conclusion statements were graded to determine quality of evidence for each dietary outcome reported. Reported outcomes include intake of total energy and macronutrients, micronutrients, foods, food groups, food components (added sugar, caffeine, and alcohol), and composite diet scores. Ten articles representing 8 unique randomized controlled trials met inclusion criteria. Of 15 conclusion statements (evidence grades: Weak to Moderate), 13 concluded there was no significant effect of incorporating genetic information into nutrition counseling/care on dietary outcomes. Limited data suggested that carriers of higher-risk gene variants were more likely than carriers of low-risk gene variants to significantly reduce intake of sodium and alcohol in response to nutrition counseling that incorporated genetic results. Included studies differed in quality, selected genetic variants, timing and intensity of intervention, sample size, dietary assessment tools, and population characteristics. Therefore, strong conclusions could not be drawn. Collaboration between the Academy of Nutrition and Dietetics and professional nutrigenetic societies would likely prove valuable in prioritizing which genetic variants and targeted nutrition messages have the most potential to alter dietary outcomes in a given patient subpopulation and, thus, should be the targets of future research.

Knowledge and Attitudes Towards Nutrigenetics: Findings from the 2018 Unified Forces Preventive Nutrition Conference (UFPN)

Background: Nutrigenetics indicates that individual genetic variability results in altered health outcomes necessitating personalized nutrition adaptation. Registered dietitians are recognized as the clinical nutrition experts, but their knowledge and attitudes regarding nutrigenetics has not been delineated. Methods: This cross sectional online survey was conducted in a convenience sample of 169 national nutrition conference attendees. The survey queried demographics, knowledge, and attitudes towards nutrigenetics and information on training in nutrigenetics. Results: The majority of participants were registered dietitians and female, 45% of whom held advanced degrees. Personalized nutrition was perceived by 93.5% of participants as highly important or important; however, 94% of respondents indicated they are not sufficiently knowledgeable in personalized nutrition and only 9.5% had received training in nutrigenetics. The mean nutrigenetics knowledge score was 6.89 ± 1.67 (out of a possible 12). A multivariate regression model of knowledge score identified education as the only independent predictor of this outcome. Conclusion: Personalized nutrition is a rapidly developing field that incorporates genetic data into clinical practice. Dietitians recognize the importance of advanced studies to acquire knowledge in nutrigenetics. Only by acquiring the necessary knowledge can dietitians accurately translate this nutrigenetics into clinical practice.