Search

BackgroundThe Dietary Guidelines for Americans (DGA) recommends consuming >1.75g/wk of long-chain omega-3 fatty acids to reduce the risk of cardiovascular disease (CVD) through triglyceride reduction, however individual responses to treatment vary.ObjectiveWe sought to determine if a DGA-conforming diet (DGAD) can increase the omega-3 index (OM3I), a diet-sensitive biomarker of omega-3 fatty acid status, into a health promoting range and reduce fasting triglycerides in 8 weeks. We further explored determinants of the basal OM3I and its response to treatment.DesignThis is a secondary analysis of a randomized, double-blind 8wk dietary intervention of overweight/obese women fed an 8d rotating DGAD (n =22) or typical American diet (TAD; n =20) registered at www.clinicaltrials.gov as NCT02298725. The DGAD and TAD provided individuals with 16 ± 2 g/wk and 1.2 ± 0.12 g/wk of eisocapentaenoic acid (EPA) + docosahexaenoic acid (DHA), respectively. Habitual diet and body composition were determined at baseline. OM3I, fasting triglycerides, glucose and insulin were measured at 0, 2 and 8wk.ResultsBaseline OM3I (5.8 ± 1.3; n =42) was positively correlated to the dietary (EPA+DHA):dietary fat ratio (p =0.006), negatively correlated to the android fat mass (p =0.0007) and was not different between diet groups. At 8wk, while the TAD-group average OM3I was unchanged (5.8 ± 0.76), the DGAD-group OM3I increased (7.33 ± 1.36; p 8%. Subgroup analyses of the DGAD-group revealed that body fat content and distribution influenced the baseline-dependent response to treatment. Fasting triglyceride and OM3I changes did not correlate.ConclusionsAn 8wk TAD stabilized the OM3I in a healthy range, while a DGAD increased the OM3I into a health-promoting range, but did not reduce fasting triglycerides. Fat distribution and basal omega-3 status are primary factors influencing omega-3 efficacy in overweight/obese women.

Background: Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, but there is insufficient data regarding its effects on performance and metabolism in this population. The purpose of this investigation was to examine the effects of a 16/8 TRF dietary pattern on exercise performance in trained male endurance runners. Methods: A 4-week randomized crossover intervention was used to compare an 8-h TRF to a 12-h normal diet (ND) feeding window. Exercise training and dietary intake were similar across interventions. Runners completed a dual-energy X-ray absorptiometry (DXA) scan to assess body composition, a graded treadmill running test to assess substrate utilization, and ran a 10 km time trial to assess performance. Results: There was a significant decrease in fat mass in the TRF intervention (−0.8 ± 1.3 kg with TRF (p = 0.05), vs. +0.1 ± 4.3 kg with ND), with no significant change in fat-free mass. Exercise carbon dioxide production (VCO2) and blood lactate concentration were significantly lower with the TRF intervention (p ≤ 0.02). No significant changes were seen in exercise respiratory exchange ratio or 10 km time trial performance (−00:20 ± 3:34 min:s TRF vs. −00:36 ± 2:57 min:s ND). Conclusion: This investigation demonstrated that adherence to a 4-week 16/8 TRF dietary intervention decreased fat mass and maintained fat-free mass, while not affecting running performance, in trained male endurance runners.

Endurance athletes use nutritional guidelines and supplements to improve exercise performance and recovery. However, use is not always based on scientific evidence of improved performance, which type of athlete would benefit most, or the optimal dose and timing of a particular supplement. Health professionals that give advice to athletes need to target their recommendations on the energy systems and muscle fiber types used for the athlete's sporting event, the goal of the training block, the time of the competitive season, and the characteristics and food preferences of the individual athlete. This review aims to summarize the most current research findings on the optimal calorie, carbohydrate, and protein intake for athlete health, performance, and recovery. We also summarized new findings on fluid intake and the optimal dose and timing of beetroot and caffeine supplementation on time trial performance in endurance athletes.

Background Few interventions directly compare equivalent calcium and vitamin D from dairy vs. supplements on the same bone outcomes. The radioisotope calcium-41 (41Ca) holds promise as a tracer method to directly measure changes in bone resorption with differing dietary interventions. Objective Using 41Ca tracer methodology, determine if 4 servings/day of dairy foods results in greater 41Ca retention than an equivalent amount of calcium and vitamin D from supplements. Secondary objective was to evaluate the time course for the change in 41Ca retention. Methods In this crossover trial, postmenopausal women (n = 12) were dosed orally with 100 nCi of 41Ca and after a 180 day equilibration period received dairy (4 servings/day of milk or yogurt; ~ 1300 mg calcium, 400 IU cholecalciferol (vitamin D3/day)) or supplement treatments (1200 mg calcium carbonate/day and 400 IU vitamin D3/day) in random order. Treatments lasted 6 weeks separated by a 6 week washout (WO). Calcium was extracted from weekly 24 h urine collections; accelerator mass spectrometry (AMS) was used to determine the 41/40Ca ratio. Primary outcome was change in 41/40Ca excretion. Secondary outcome was the time course for change in 41Ca excretion during intervention and WO periods. Results The 41/40Ca ratio decreased significantly over time during both treatments; there was no difference between treatments. Both treatments demonstrated a significant retention of 41Ca within 1–2 weeks (p = 0.0007 and p, Highlights • Investigated, using 41Ca tracer, whether bone response to calcium and vitamin D differed based on the source of nutrients, foods vs. supplements. • There was no difference in the bone response by treatment group. • Both dairy foods and supplements resulted in reduce 41Ca excretion in urine. • Reduction in 41Ca excretion occurred with 2 weeks of initiating the interventions. • Removal of interventions resulted in 41Ca excretion returning to pre-intervention levels

Linoleic acid (LA; 18:2 n-6), the most abundant polyunsaturated fatty acid in the US diet, is a precursor to oxidized metabolites that have unknown roles in the brain. Here, we show that oxidized LA-derived metabolites accumulate in several rat brain regions during CO2-induced ischemia and that LA-derived 13-hydroxyoctadecadienoic acid, but not LA, increase somatic paired-pulse facilitation in rat hippocampus by 80%, suggesting bioactivity. This study provides new evidence that LA participates in the response to ischemia-induced brain injury through oxidized metabolites that regulate neurotransmission. Targeting this pathway may be therapeutically relevant for ischemia-related conditions such as stroke.