Correction: Comprehensive Profiling of Plasma Fatty Acid Concentrations in Young Healthy Canadian Adults.

[This corrects the article DOI: 10.1371/journal.pone.

No Difference between the Efficacy of High-Nitrate and Low-Nitrate Vegetable Supplementation on Blood Pressure after 16 Weeks in Individuals with Early-Stage Hypertension: An Exploratory, Double-Blinded, Randomized, Controlled Trial.

Dietary inorganic nitrate lowers blood pressure (BP) in healthy individuals through improved nitric oxide (NO) bioavailability. However, there is limited evidence examining the long-term effects of dietary nitrate for managing hypertension. We aimed to determine whether the sustained intake of dietary nitrate improved BP and cardiovascular disease (CVD) risk factors in individuals with early-stage hypertension.

The Evolution of Science and Regulation of Dietary Supplements: Past, Present, and Future.

Dietary supplement use in the United States is widespread and increasing, especially among certain population groups, such as older Americans. The science surrounding dietary supplements has evolved substantially over the last few decades since their formal regulation in 1994. Much has been learned about the mechanisms of action of many dietary supplement ingredients, but the evidence on their health effects is still building.

Biomarkers of Iron Are Associated with Anterior-Pituitary-Produced Reproductive Hormones in Men with Infertility.

Approximately 16% of North American couples are affected by infertility, with 30% of cases being attributable to male factor infertility. The regulation of reproductive hormones via the hypothalamic-pituitary-gonadal axis is important for spermatogenesis and subsequently male fertility. Maintaining iron homeostasis is critical to normal reproductive physiological function.

Using Mendelian Randomization to Study the Role of Iron in Health and Disease.

Iron has been shown to play a dual role in health and disease, with either a protective or harmful effect. Some of the contradictory findings from observational studies may be due to reverse causation, residual confounding, or small sample size. One approach that may overcome these limitations without the high cost of randomized control trials is the use of Mendelian randomization to examine the long-term role of iron in a variety of health outcomes.

Ascorbic acid is associated with favourable hormonal profiles among infertile males.

Introduction: Infertility affects about 16% of North American couples, with the male factor contributing to ∼30% of cases. Reproductive hormones play an integral role in regulating the reproductive system and consequently, fertility. Oxidative stress reduces testosterone synthesis, and reduction in oxidative stress can improve hormone profiles.

Dietary and plasma retinoids are not associated with fatty acid desaturase indices in healthy young adults.

Past research in rodents suggests that fatty acid (FA) desaturase expression and activity may be modified by vitamin A; however, this has not been investigated in humans. The primary objective of this study was to examine associations between dietary retinoid intakes, plasma retinoid concentrations, and FA desaturase indices in young adults. As a secondary objective, biological sex and estrogen-containing contraceptive (EC) use were investigated due to prior evidence demonstrating that both can influence plasma retinol concentration and FA desaturase indices.

Associations Between Dietary Vitamin C, Serum Ascorbic Acid, and Genotype and Premenstrual Symptoms.

Objective: Premenstrual symptoms are a cyclically occurring combination of adverse psychological and somatic symptoms that impact the quality of life for most females of childbearing age. Growing evidence suggests that diet may attenuate premenstrual symptoms; however, the relationship between vitamin C and premenstrual symptoms remains unclear. The aim of the research was to determine the association between different measures of vitamin C status and premenstrual symptoms.

CYP1A2 Genetic Variation, Coffee Intake, and Kidney Dysfunction.

Importance: Caffeine is detoxified by cytochrome P450 1A2 (CYP1A2), and genetic variation in CYP1A2 impacts the rate of caffeine clearance. Factors that may modify the association between coffee intake and kidney disease remain unclear.

Objective: To assess whether CYP1A2 genotype modifies the association between coffee intake and kidney dysfunction.

The influence of the CYP1A2-163 C>A polymorphism on the hemostatic response to exercise following caffeine supplementation.

Background: Prior work from our group suggests that caffeine increases thrombotic potential after acute exercise. The aim of this study was to determine if hemostatic responses to exercise affected by caffeine are influenced by the CYP1A2-163 C>A polymorphism.

Methods: Forty-two healthy men performed two trials in which a graded maximal exercise test was completed one hour after consuming either 6 mg/kg of caffeine or placebo.

Reproducibility and validity of the Toronto-modified Harvard food frequency questionnaire in a multi-ethnic sample of young adults.

Background/objectives: To assess the reproducibility and validity of a Toronto-modified Harvard food frequency questionnaire (FFQ) among a multi-ethnic sample of young adults.

Subjects/methods: A total of 150 participants recruited from the Toronto Nutrigenomics and Health Study cohort who had existing dietary intakes assessed by FFQ (FFQ1) and reassessment one year later (FFQ2). Of these, 100 participants also completed a three-day food record to evaluate the validity of the FFQ for 38 nutrients (energy, 14 macronutrients, 22 micronutrients, and 1 bioactive).

Δ5 and Δ6 desaturase indices are not associated with zinc intake as determined by dietary assessment or modified by a zinc-FADS1 rs174547 SNP interaction in young Canadian adults.

Background: Zinc is an essential trace mineral that serves as a cofactor for the delta-5 and delta-6 desaturases (D5D, D6D) that are critical for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis. While plasma zinc levels are generally reported to be associated with D5D and D6D indices in humans, it remains unclear if dietary zinc intake can be similarly associated with desaturase indices. Therefore, the present investigation examined if zinc intake determined by food frequency questionnaire (FFQ) is associated with desaturase indices in young Canadian adults.

Plasma Carotenoids and Premenstrual Symptoms in a Multi-Ethnic Population of Young Women.

Premenstrual symptoms are experienced by most women of reproductive age, but effective therapies are limited. Carotenoids may have an attenuating effect on premenstrual symptoms; however, studies to date are equivocal. The objective of the present study was to examine the association between plasma concentrations of seven carotenoids and premenstrual symptom severity in 553 women from the Toronto Nutrigenomics and Health study.

Variation in the vitamin D receptor gene, plasma 25-hydroxyvitamin D, and risk of premenstrual symptoms.

Background: Vitamin D status has been associated with the presence and severity of several premenstrual symptoms (PMSx) in some, but not all studies. Inconsistencies among findings may be explained by unaccounted genetic variation in the vitamin D receptor (VDR).

Objective: To determine whether associations between vitamin D status and individual PMSx are influenced by VDR genotype.

Caffeine, genetic variation and anaerobic performance in male athletes: a randomized controlled trial.

Purpose: The effect of caffeine on anaerobic performance is unclear and may differ depending on an individual's genetics. The goal of this study was to determine whether caffeine influences anaerobic performance in a 30 s Wingate test, and if 14 single nucleotide polymorphisms (SNPs) in nine genes, associated with caffeine metabolism or response, modify caffeine's effects.

Methods: Competitive male athletes (N = 100; 25 ± 4 years) completed the Wingate under three conditions: 0, 2, or 4 mg of caffeine per kg of body mass (mg kg), using a double-blinded, placebo-controlled design.

Soy Consumption, but Not Dairy Consumption, Is Inversely Associated with Fatty Acid Desaturase Activity in Young Adults.

Past research using hepatic rat microsomes showed that soy protein suppressed delta-6 desaturase activity (D6D) compared to casein (a dairy protein). The effects of soy and dairy on desaturase pathway activity in humans remain poorly investigated. The objective of this analysis was to investigate the association between soy and dairy consumption with plasma fatty acids and estimate the desaturase pathway activity in a multiethnic Canadian population of young adults.

Neither low salivary amylase activity, cooling cooked white rice, nor single nucleotide polymorphisms in starch-digesting enzymes reduce glycemic index or starch digestibility: a randomized, crossover trial in healthy adults.

Background: It was suggested that low salivary-amylase activity (SAA) and cooling or stir-frying cooked starch decreases its digestibility and glycemic index.

Objective: We determined the effects of SAA, cooling, and single-nucleotide polymorphisms (SNPs) in the salivary amylase (AMY1), pancreatic amylase (AMY2A, AMY2B), maltase-glucoamylase (MGAM), and sucrase-isomaltase (SI) genes on starch digestibility and glycemic index of cooked polished rice.

Methods: Healthy subjects [pilot, n = 12; main, n = 20 with low-SAA (<50 U/mL), and n = 20 with high-SAA (>105 U/mL)] consumed test meals containing 25 g (pilot) or 50 g (main) available carbohydrate at a contract research organization using open-label (pilot) or assessor-blinded (main), randomized, crossover, Latin-square designs (trial registration: NCT03667963).

CYP1A2 Genotype Modifies the Effects of Caffeine Compared With Placebo on Muscle Strength in Competitive Male Athletes.

Caffeine is commonly used to improve athletic performance across a variety of sports. Previously, the CYP1A2 gene has been shown to modify the effects of caffeine on endurance performance. The effect of caffeine on strength and power activities is unclear and may differ depending on an individual's CYP1A2 genotype.

Recent advances and current controversies in genetic testing for personalized nutrition.

Purpose Of Review: Considerable interest in personalized nutrition exists among the general public, policymakers, healthcare organizations and the private sector, but there is also skepticism of its utility. The present review aims to provide a summary of current controversies in the field of nutrigenomics, and to highlight recent research on the potential impact of implementing genetic testing for personalized nutrition in practice.

Recent Findings: Numerous companies already offer genetic testing for personalized nutrition based on research developments in nutritional genomics.

Nutrition, genetic variation and male fertility.

Infertility affects nearly 50 million couples worldwide, with 40-50% of cases having a male factor component. It is well established that nutritional status impacts reproductive development, health and function, although the exact mechanisms have not been fully elucidated. Genetic variation that affects nutrient metabolism may impact fertility through nutrigenetic mechanisms.