A new Current Developments in Nutrition Special Collection, “Multi-omics Characterization of Nutritional Metabolism,” presents cutting-edge research at the intersection of personalized nutrition and the molecular mechanisms underlying nutrient metabolism.  Examining molecular mechanisms that influence nutrition metabolism helps us better understand the critical pathways that link nutrition with disease states.  Moreover, working with “omics” data helps us better understand how individuals respond to food, how genetics affects metabolism, and how nutrients and molecular mechanisms interact to cause or prevent disease.

This special collection was developed by ASN’s Nutrient-Gene Interactions Research Interest Section and guest edited by Bradley S. Ferguson of The University of Nevada, Reno and Whitney L. Do of Emory University.  The collection represents one of the three winners of Current Developments in Nutrition’s Research Interest Section Special Collections Competition.  Announced in 2019, the competition challenged ASN Research Interest Sections to develop special collections that address pressing issues in nutrition science today.

Below are highlights from each of the three papers in this special collection.

Findings demonstrate that maternal vitamin D deficiency induces different liver metabolic effects in different genetic backgrounds.

Maternal Liver Metabolic Response to Chronic Vitamin D Deficiency Is Determined by Mouse Strain Genetic Background, June 2020

Maternal vitamin D deficiency has a detrimental effect on human fetal growth as well as the skeletal and extra-skeletal health of the child.  Vitamin D deficiency may also increase the mother’s risk of gestational diabetes mellitus and pre-eclampsia; however, the molecular mechanisms underlying these adverse health outcomes remain unclear.  In response, Jing Xue et al. investigated the extent to which naturally occurring genetic differences regulate maternal liver metabolic response to vitamin D deficiency, particularly during perinatal periods when these metabolic responses can adversely affect maternal and fetal health.

To conduct their research, the authors worked with a panel of eight inbred Collaborative Cross mouse strains, each with a different genetic background.  Mice were fed either a vitamin D deficient or sufficient diet.  The authors then identified vitamin D-induced metabolite changes influenced by strain genetic background.

The findings from this study demonstrate that maternal vitamin D deficiency induces different liver metabolic effects in different genetic backgrounds.  Specifically, the authors noted, “strains with differing susceptibility and metabolic response to vitamin D deficiency represent unique tools to identify causal susceptibility factors and further elucidate the role of vitamin D-induced metabolic changes in maternal and/or fetal health for ultimately translating findings to human populations.”

Results support findings in which watermelon juice significantly, yet differentially, increased circulating lycopene.

Variation of Serum Lycopene in Response to 100% Watermelon Juice: An Exploratory Analysis of Genetic Variants in a Randomized Controlled Crossover Study, June 2020

In this study, ASN member Kristi M. Crowe-White et al. examined the effect of 100% watermelon juice, a rich source of lycopene, on serum lycopene, lipids, and antioxidant capacity.  Moreover, the study explored genetic influences on lycopene metabolism and bioavailability.

The authors designed the study as a placebo-controlled, randomized, double-blind crossover trial.  Participants, post-menopausal women, maintained low-lycopene diets for a one-week run-in period and throughout the study.  Morning and evening consumption of 100% watermelon juice provided a daily dose of about 14.4 mg of lycopene.  Saliva was collected for genetic analysis of single nucleotide polymorphisms, and fasting blood samples were taken pre– and post–study arms.

In this study, watermelon juice supplementation did not result in improvements in serum lipids or antioxidant capacity; however, results support earlier findings that watermelon juice significantly, yet differentially, increases circulating lycopene.  According to the authors, “genetics appears to explain some of the variability.”  Furthermore, they noted that “given that dose has been shown to overcome individual responsiveness to lycopene interventions, future investigations with varying doses of lycopene-rich foods would be strengthened by genotyping so as to establish personalized nutrition recommendations.”

Each of the three watermelon diets was associated with uniquely expressed genes.

Intake of Watermelon and Watermelon Byproducts: Male Mice Fed a Western-style Obesogenic Diet Alters Hepatic Gene Expression Patterns as Determined by RNA Sequencing, July 2020

Also investigating the impact of watermelon consumption, Mariana Buranelo Egea et al. examined the impact of watermelon flesh, rind, and skin consumption on hepatic gene expression patterns, using an obesogenic mouse model. 

During the ten-week feeding trial, mice were given one of five diets: a low-fat diet, a high-fat diet, or a high-fat plus either watermelon skin, watermelon rind, or watermelon flesh.  Watermelon intake levels were proportional to typical human consumption.  Next, hepatic RNA was isolated and RNA sequencing was performed.  A variety of bioinformatic approaches then determined changes in canonical pathways and gene expression levels for lipid- and xenobiotic-regulating nuclear hormone receptors and related transcription factors.

“Due to the multiple differences in the two control diets,” the authors “chose not to detail the differences between low-fat and high-fat mice.”  The authors’ analysis therefore focused on the differences among the mice fed a high-fat diet and the mice fed a high-fat diet plus the three different types of watermelon.

Study results demonstrated that all three watermelon supplemented groups exhibited changes in gene expression patterns that differed from the high-fat-fed mice.  Moreover, each of the three watermelon diets was associated with uniquely expressed genes.  According to the authors, “these findings indicate that while all three watermelon products had significant impacts on the hepatic transcriptome, they each acted through both different and overlapping mechanisms, as a result of the unique phytochemical composition within each product.”

Because Current Developments in Nutrition is an open-access journal, the full text of these articles is freely accessible to readers around the world.  If you are interested in disseminating your research findings via Current Development in Nutrition, please review the journal’s author guidelines.

Images credit: canva.com