Dietary Patterns, Genes, and Health: Challenges and Obstacles to be Overcome

Forgetting how we ate: personalised nutrition and the strategic uses of history

Personalised nutrition (PN) has emerged over the past twenty years as a promising area of research in the postgenomic era and has been popularized as the new big thing out of molecular biology. Advocates of PN claim that previous approaches to nutrition sought general and universal guidance that applied to all people. In contrast, they contend that PN operates with the principle that "one size does not fit all" when it comes to dietary guidance. While the molecular mechanisms studied within PN are new, the notion of a personal dietary regime guided by medical advice has a much longer history that can be traced back to Galen's "On Food and Diet" or Ibn Sina's (westernized as Avicenna) "Canon of Medicine". Yet this history is either wholly ignored or misleadingly appropriated by PN proponents. This (mis)use of history, we argue helps to sustain the hype of the novelty of the proposed field and potential commodification of molecular advice that undermines longer histories of food management in premodern and non-Western cultures. Moreover, it elides how the longer history of nutritional advice always happened in a heavily moralized, gendered, and racialized context deeply entwined with collective technologies of power, not just individual advice. This article aims at offering a wider appreciation of this longer history to nuance the hype and exceptionalism surrounding contemporary claims.

Metabolic Syndrome: An Overview on Its Genetic Associations and Gene-Diet Interactions

Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors that includes central obesity, hyperglycemia, hypertension, and dyslipidemias and whose inter-related occurrence may increase the odds of developing type 2 diabetes and cardiovascular diseases. MetS has become one of the most studied conditions, nevertheless, due to its complex etiology, this has not been fully elucidated. Recent evidence describes that both genetic and environmental factors play an important role on its development. With the advent of genomic-wide association studies, single nucleotide polymorphisms (SNPs) have gained special importance. In this review, we present an update of the genetics surrounding MetS as a single entity as well as its corresponding risk factors, considering SNPs and gene-diet interactions related to cardiometabolic markers. In this study, we focus on the conceptual aspects, diagnostic criteria, as well as the role of genetics, particularly on SNPs and polygenic risk scores (PRS) for interindividual analysis. In addition, this review highlights future perspectives of personalized nutrition with regard to the approach of MetS and how individualized multiomics approaches could improve the current outlook.

Diets, nutrients, genes and the microbiome: recent advances in personalised nutrition

As individuals seek increasingly individualised nutrition and lifestyle guidance, numerous apps and nutrition programmes have emerged. However, complex individual variations in dietary behaviours, genotypes, gene expression and composition of the microbiome are increasingly recognised. Advances in digital tools and artificial intelligence can help individuals more easily track nutrient intakes and identify nutritional gaps. However, the influence of these nutrients on health outcomes can vary widely among individuals depending upon life stage, genetics and microbial composition. For example, folate may elicit favourable epigenetic effects on brain development during a critical developmental time window of pregnancy. Genes affecting vitamin B12 metabolism may lead to cardiometabolic traits that play an essential role in the context of obesity. Finally, an individual's gut microbial composition can determine their response to dietary fibre interventions during weight loss. These recent advances in understanding can lead to a more complete and integrated approach to promoting optimal health through personalised nutrition, in clinical practice settings and for individuals in their daily lives. The purpose of this review is to summarise presentations made during the DSM Science and Technology Award Symposium at the 13th European Nutrition Conference, which focused on personalised nutrition and novel technologies for health in the modern world.

Diet quality, excess body weight and cardiometabolic risk factors in adolescents living in São Paulo, Brazil and in the USA: differences and similarities

OBJECTIVE

To compare diet quality and its association with excess body weight (EBW: overweight/obesity), central adiposity (CA) and CVD risk factors (CVDR) among adolescents from Brazil and USA.

DESIGN

Data from two cross-sectional surveys: Health Survey of São Paulo (ISA-Nutrition) and Hispanic Community Health Study/Study of Latino Youth (SOL-Youth). Dietary intake was assessed from 24-h recalls, and diet quality using the Alternate Healthy Eating Index-2010 (AHEI) developed in the USA and the Revised Brazilian Healthy Eating Index (BHEI-R). CVDR was defined as ≥3 of: obesity, elevated blood pressure, dyslipidaemia, high plasma glucose and insulin resistance. Adjusted OR for EBW, CA and CVDR by diet quality were tested using logistic regression.

SETTING

São Paulo, Brazil; and Chicago, IL; Miami, FL; Bronx, NY; San Diego, CA.

PARTICIPANTS

Adolescents (12-16 years) living in São Paulo (n 189) and USA (n 787).

RESULTS

ISA-Nutrition individuals with EBW (v. without) had marginally lower (unhealthier) scores for whole grains using BHEI-R and sugary beverages using AHEI. SOL-Youth individuals with EBW had lower scores of nuts/legumes using AHEI, and Na using BHEI-R, but higher scores of whole grains and dairy using BHEI-R. In ISA-Nutrition, BHEI-R was inversely associated with EBW (OR = 0·87; 95 % CI 0·80, 0·95) and CVDR (OR = 0·89; 95 % CI 0·80, 0·98). In SOL-Youth, AHEI was inversely associated with EBW (OR = 0·93; 95 % CI 0·87, 0·99).

CONCLUSIONS

Dietary improvements should be made by adolescents in both USA and Brazil. Healthier diet quality as measured with the country-specific index was associated with lower odds of EBW in Brazilian and USA-Hispanic/Latino adolescents, and with lower CVDR in Brazilian adolescents.

Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention

BACKGROUND

Risk of cardiovascular disease is lower in individuals with blood type O and increased in individuals with blood type A, compared with those in other blood groups. However, little evidence is available regarding whether individuals with different blood types benefit from different diet recommendations.

OBJECTIVE

As part of a larger intervention trial using a low-fat vegan diet, this study ascertained whether changes in cardiometabolic outcomes were associated with ABO blood type.

DESIGN

A secondary analysis among intervention-group participants in a 16-week randomized clinical trial.

PARTICIPANTS/SETTING

In a larger study of overweight individuals randomly assigned to follow a low-fat vegan diet or to make no diet changes for 16 weeks, ABO blood typing was conducted on 68 intervention-group participants.

INTERVENTION

Intervention-group participants were asked to follow a low-fat vegan diet and attend weekly educational classes to aid in diet adherence.

MAIN OUTCOME MEASURES

Body weight, fat mass, visceral fat volume, blood lipid levels, fasting plasma glucose levels, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES PERFORMED

Student t tests compared participants with blood type A to all other participants, and individuals with blood type O to all other participants.

RESULTS

There were no significant differences in any outcome between individuals of blood type A and all other participants, or between individuals of blood type O and all other participants. Mean body weight change was -5.7 kg for blood type A participants and -7.0 kg for all other participants (P = 0.09), and was -7.1 kg for type O participants and -6.2 kg for all other participants (P = 0.33). Mean total cholesterol decreased 17.2 mg/dL in the type A group and 18.3 mg/dL for all other participants (P = 0.90), and decreased 17.4 mg/dL among type O participants and 18.4 mg/dL for all other participants (P = 0.89).

CONCLUSIONS

Blood type was not associated with the effects of a plant-based diet on body weight, body fat, plasma lipid concentrations, or glycemic control.

A Personalised Dietary Approach-A Way Forward to Manage Nutrient Deficiency, Effects of the Western Diet, and Food Intolerances in Inflammatory Bowel Disease

This review discusses the personalised dietary approach with respect to inflammatory bowel disease (IBD). It identifies gene–nutrient interactions associated with the nutritional deficiencies that people with IBD commonly experience, and the role of the Western diet in influencing these. It also discusses food intolerances and how particular genotypes can affect these. It is well established that with respect to food there is no “one size fits all” diet for those with IBD. Gene–nutrient interactions may help explain this variability in response to food that is associated with IBD. Nutrigenomic research, which examines the effects of food and its constituents on gene expression, shows that—like a number of pharmaceutical products—food can have beneficial effects or have adverse (side) effects depending on a person’s genotype. Pharmacogenetic research is identifying gene variants with adverse reactions to drugs, and this is modifying clinical practice and allowing individualised treatment. Nutrigenomic research could enable individualised treatment in persons with IBD and enable more accurate tailoring of food intake, to avoid exacerbating malnutrition and to counter some of the adverse effects of the Western diet. It may also help to establish the dietary pattern that is most protective against IBD.

Personalised nutrition and health

Jose Ordovas and colleagues consider that nutrition interventions tailored to individual characteristics and behaviours have promise but more work is needed before they can deliver

Dietary and genetic risk scores and incidence of type 2 diabetes

Background

Both lifestyle and genetic predisposition determine the development of type 2 diabetes (T2D), and studies have indicated interactions between specific dietary components and individual genetic variants. However, it is unclear whether the importance of overall dietary habits, including T2D-related food intakes, differs depending on genetic predisposition to T2D. We examined interaction between a genetic risk score for T2D, constructed from 48 single nucleotide polymorphisms identified in genome-wide association studies, and a diet risk score of four foods consistently associated with T2D in epidemiological studies (processed meat, sugar-sweetened beverages, whole grain and coffee). In total, 25,069 individuals aged 45–74 years with genotype information and without prevalent diabetes from the Malmö Diet and Cancer cohort (1991–1996) were included. Diet data were collected with a modified diet history method.

Results

During 17-year follow-up, 3588 incident T2D cases were identified. Both the diet risk score (HR in the highest risk category 1.40; 95% CI 1.26, 1.58; P trend = 6 × 10⁻¹⁰) and the genetic risk score (HR in the highest tertile of the genetic risk score 1.67; 95% CI 1.54, 1.81; P trend = 7 × 10⁻³⁵) were associated with increased incidence of T2D. No significant interaction between the genetic risk score and the diet risk score (P = 0.83) or its food components was observed. The highest risk was seen among the 6% of the individuals with both high genetic and dietary risk scores (HR 2.49; 95% CI 2.06, 3.01).

Conclusions

The findings thus show that both genetic heredity and dietary habits previously associated with T2D add to the risk of T2D, but they seem to act in an independent fashion, with the consequence that all individuals, whether at high or low genetic risk, would benefit from favourable food choices.

Electronic supplementary material

The online version of this article (10.1186/s12263-018-0599-1) contains supplementary material, which is available to authorized users.

Replication of a Gene-Diet Interaction at CD36, NOS3 and PPARG in Response to Omega-3 Fatty Acid Supplements on Blood Lipids: A Double-Blind Randomized Controlled Trial

BACKGROUND

Modulation of genetic variants on the effect of omega-3 fatty acid supplements on blood lipids is still unclear.

METHODS

In a double-blind randomized controlled trial, 150 patients with type 2 diabetes (T2D) were randomized into omega-3 fatty acid group (n = 56 for fish oil and 44 for flaxseed oil) and control group (n = 50) for 180 days. All patients were genotyped for genetic variants at CD36 (rs1527483), NOS3 (rs1799983) and PPARG (rs1801282). Linear regression was used to examine the interaction between omega-3 fatty acid intervention and CD36, NOS3 or PPARG variants for blood lipids.

FINDINGS

Significant interaction with omega-3 fatty acid supplements was observed for CD36 on triglycerides (p-interaction = 0.042) and PPAGR on low-density lipoprotein-cholesterol (p-interaction = 0.02). We also found a significant interaction between change in erythrocyte phospholipid omega-3 fatty acid composition and NOS3 genotype on triglycerides (p-interaction = 0.042), total cholesterol (p-interaction = 0.013) and ratio of total cholesterol to high-density lipoprotein cholesterol (p-interaction = 0.015). The T2D patients of CD36-G allele, PPARG-G allele and NOS3-A allele tended to respond better to omega-3 fatty acids in improving lipid profiles. The interaction results of the omega-3 fatty acid group were mainly attributed to the fish oil supplements.

INTERPRETATION

This study suggests that T2D patients with different genotypes at CD36, NOS3 and PPARG respond differentially to intervention of omega-3 supplements in blood lipid profiles.

Genomic Influence in the Prevention of Cardiovascular Diseases with a Sterol-Based Treatment

Raised serum cholesterol concentration is a well-established risk factor in cardiovascular disease. In addition, genetic load may have an indirect influence on cardiovascular risk. Plant-based sterol-supplemented foods are recommended to help reduce the serum low-density lipoprotein cholesterol level. The objective was to analyse the influence of different polymorphisms in hypercholesterolemia patients following a dietary treatment with plant sterols. A randomised double-blind cross-over controlled clinical trial was carried out in 45 people (25 women). Commercial milk, containing 2.24 g of sterols, was ingested daily during a 3-week period, and then the same amount of skim milk, without sterols, was consumed daily during the 3-week placebo phase. Both phases were separated by a washout period of 2 weeks. At the beginning and end of each phase, blood draws were performed. Genes LIPC C-514T and APOA5 C56G are Ser19Trp carriers and greatly benefit from sterol intake in the diet. LIPC C-514T TT homozygous carriers had lower low-density lipoprotein cholesterol (LDL-c) levels than CC homozygote and CT heterozygote carriers after the ingestion of plant sterols (p = 0.001). These two genes also showed statistically significant changes in total cholesterol levels (p = 0.025; p = 0.005), and no significant changes in high-density lipoprotein (HDL) cholesterol levels (p = 0.032; p = 0.003), respectively. No statistically significant differences were observed for other genes. Further studies are needed to establish which genotype combinations would be the most protective against hypercholesterolemia.

Nutritional Genomics and Direct-to-Consumer Genetic Testing: An Overview

The increasing prevalence in polygenic diseases, such as obesity, cardiovascular disease, and type 2 diabetes, observed over the past few decades is more likely linked to a rapid transition in lifestyle rather than to changes in the sequence of the nuclear genome. In the new era of precision medicine, nutritional genomics holds the promise to be translated into tailored nutritional strategies to prevent and manage polygenic diseases more effectively. Nutritional genomics aims to prevent, treat, and manage polygenic diseases through targeted therapies formulated from individuals' genetic makeup and dietary intake. Direct-to-consumer genetic testing (DTC-GT) has become commercially available to equip individuals with information on their genetic vulnerability to different diseases. This information may potentially prompt behavioral changes against adverse factors. However, scientific evidence behind the clinical recommendations is a matter of continuous debate, and behavioral modifications after disclosing genetic information remain inconclusive. In this review, we provide an overview of nutritional genomics and related nutritional DTC-GT services and discuss whether available data are sufficient to be translated into clinical recommendations and public health initiatives. Overall, the scientific evidence supporting the dissemination of genomic information for nutrigenomic purposes remains sparse. Therefore, additional knowledge needs to be generated, particularly for polygenic traits.

The RS4939827 polymorphism in the SMAD7 GENE and its association with Mediterranean diet in colorectal carcinogenesis

Background

The objective of our investigation is to study the relationship between the rs4939827 SNP in the SMAD7 gene, Mediterranean diet pattern and the risk of colorectal cancer.

Methods

We examined 1087 cases of colorectal cancer and 2409 population controls with available DNA samples from the MCC-Spain study, 2008–2012. Descriptive statistical analyses, and multivariate logistic mixed models were performed. The potential synergistic effect of rs4939827 and the Mediterranean diet pattern was evaluated with logistic regression in different strata of of adherence to the Mediterranean diet and the genotype.

Results

High adherence to Mediterrenean diet was statistically significantly associated with colorectal cancer risk. A decreased risk for CRC cancer was observed for the CC compared to the TT genotype (OR = 0.65 and 95% CI = 0.51–0.81) of the rs4939827 SNP Also, we could show an association between the Mediterranean diet pattern (protective factor) and rs4939827. Although the decreased risk for the CC genotype was slightly more pronounced in subjects with high adherence to Mediterrenean diet, there was no statistically significant synergistic effect between genotype CC and adherence to the Mediterranean dietary pattern factors.

Conclusion

The SMAD7 gene and specifically the allele C could be protective for colorectal cancer. An independent protective association was also observed between high adherence Mediterranean diet pattern and CRC risk. Findings form this study indicate that high adherence to Mediterranean diet pattern has a protective role for CRC cancer probably involving the Tumor Growth Factor- β pathway in this cancer.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0485-5) contains supplementary material, which is available to authorized users.

Translation of Nutritional Genomics into Nutrition Practice: The Next Step

Genetics is an important piece of every individual health puzzle. The completion of the Human Genome Project sequence has deeply changed the research of life sciences including nutrition. The analysis of the genome is already part of clinical care in oncology, pharmacology, infectious disease and, rare and undiagnosed diseases. The implications of genetic variations in shaping individual nutritional requirements have been recognised and conclusively proven, yet routine use of genetic information in nutrition and dietetics practice is still far from being implemented. This article sets out the path that needs to be taken to build a framework to translate gene–nutrient interaction studies into best-practice guidelines, providing tools that health professionals can use to understand whether genetic variation affects nutritional requirements in their daily clinical practice.

Ethical considerations in the implementation of nutrigenetics/nutrigenomics

Awareness of ethical issues that may be raised by the implementation of nutrigenetic/nutrigenomic (NGx) testing and personalized nutrition, at an individual or a public health level, is crucial to ensure the latter's sound and effective implementation. NGx tests that are currently offered or developed have different natures and scopes. We provide an example of NGx testing on the MTHFR gene to illustrate the current challenges when it comes to grasp the meaning of the results of such testing. In addition, NGx testing is developed within an evolving landscape of new genomic technologies and occurs at a time when public health policies mainly focus on preventive and predictive healthcare, with an emphasis on increased individual responsibility. The ethical issues raised by such a context and the genetic nature of NGx testing both should be carefully evaluated.

Assessment of Body Condition in African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos and Management Practices Associated with High Body Condition Scores

Obesity has a negative effect on health and welfare of many species, and has been speculated to be a problem for zoo elephants. To address this concern, we assessed the body condition of 240 elephants housed in North American zoos based on a set of standardized photographs using a 5-point Body Condition Score index (1 = thinnest; 5 = fattest). A multi-variable regression analysis was then used to determine how demographic, management, housing, and social factors were associated with an elevated body condition score in 132 African (Loxodonta africana) and 108 Asian (Elephas maximus) elephants. The highest BCS of 5, suggestive of obesity, was observed in 34% of zoo elephants. In both species, the majority of elephants had elevated BCS, with 74% in the BCS 4 (40%) and 5 (34%) categories. Only 22% of elephants had BCS 3, and less than 5% of the population was assigned the lowest BCS categories (BCS 1 and 2). The strongest multi-variable model demonstrated that staff-directed walking exercise of 14 hours or more per week and highly unpredictable feeding schedules were associated with decreased risk of BCS 4 or 5, while increased diversity in feeding methods and being female was associated with increased risk of BCS 4 or 5. Our data suggest that high body condition is prevalent among North American zoo elephants, and management strategies that help prevent and mitigate obesity may lead to improvements in welfare of zoo elephants.

Nutrition recommendations and science: next parallel steps

This article examines nutrition recommendations in relation to developments in nutrition science. Combining data on the genome, metabolome and microbiota is likely to open possibilities for personalized nutrition planning, but we are still far from practical applications. However, even these new steps are unlikely to challenge the role and importance of population-based nutrition recommendations as a tool to promote dietary patterns, policies and public health. Developments in science could help in deriving more benefits from nutrition recommendations. For instance, improved accuracy of dietary intake assessment is needed both for surveillance and for understanding the quantitative interplay between diet and health. Applying metabolomics together with food diaries or questionnaires, and also modern technologies such as digital photography, are potentially interesting methods in this respect. Research on consumer behaviour, attitudes and policy interventions, such as taxation of unhealthy foods and nutrition labelling, are needed to gain more insight into how to change eating behaviour for better health at the population level.

Associations between Dietary Factors and Self-Reported Physical Health in Chinese Scientific Workers

BACKGROUND

Scientific workers play an important role in the development of science and technology. However, evidence is lacking with regard to the associations between their dietary factors and their health-related quality of life (HRQOL).

METHODS

A cross-sectional survey was conducted among 775 scientific workers from multiple universities and institutes in the Southwest region of China. A self-administered food-frequency questionnaire was used to collect the food consumption information, and the 36-item Short-Form Health Survey was used to assess physical HRQOL. Hierarchical multiple regression analysis was used to identify the factors associated with scientific workers' HRQOL.

RESULTS

Physical HRQOL was negatively associated with age and intake of fresh pork (fat) and animal viscera, whereas consumption of vegetables, fruits, refined cereals and dairy products were positively correlated with physical HRQOL. Participants with daily intake of vegetable oils or mixed oils showed higher physical HRQOL scores than those with intake of animal oils.

CONCLUSIONS

Dietary habits are closely associated with the physical HRQOL of scientific workers. The dietary patterns that had more vegetables and fruits, less fresh pork (fat) and animal viscera, and used vegetable oils during cooking corresponded to higher physical HRQOL scores. These findings are important for planning dietary strategies to improve physical health in scientific workers.