Association of breakfast skipping with cardiovascular outcomes and cardiometabolic risk factors: an updated review of clinical evidence.

"Eat breakfast like a king, lunch like a prince and dinner like a pauper" (Adelle Davis, 1904-1974) is a concept that appears to align with some contemporary evidence concerning the appropriate proportioning of daily meals. At the same time, with the popular and scientific dissemination of the concepts of intermittent fasting and time-restricted feeding, well-controlled clinical trials have emerged showing the safety or even possible benefits of skipping breakfast. In this comprehensive literature review, we discuss recent evidence regarding breakfast intake, cardiovascular outcomes and cardiovascular risk markers. Overall, breakfast omission appears to be associated with a higher risk for atherosclerotic and adverse cardiovascular outcomes. However, caution should be employed when deciphering these data as many complex, unmeasured confounders may have contributed. Unfortunately, long-term randomized, clinical trials with detailed dietary control that have assessed clinical outcomes are sparse. Notwithstanding the observational findings, current trials conducted so far-albeit apparently smaller number-have shown that breakfast addition in subjects who do not habitually consume this meal may increase body weight, particularly fat mass, through caloric excess, whereas skipping breakfast may be a feasible strategy for some people aiming for calorie restriction. To date, definitive benefits of breakfast omission or consumption are not supported by the best evidence-based research, and the question of whether skipping breakfast per se is causally associated with cardiovascular outcomes remains unresolved.

Low-carbohydrate diets: Effects on metabolism and exercise - A comprehensive literature review.

BACKGROUND & AIMS: Low-carbohydrate diets (LCD) have gained substantial attention in recent years for their potential in health promotion and treatment of diseases, but they remain controversial in nutrition guidelines and exercise performance. Herein, through a literature review, we discuss the current evidence base by considering management of LCD and potential coupling of these dietary regiments with physical exercise. METHODS: We performed a comprehensive literature review with no date limits as a means of including seminal to current studies. RESULTS: Reduction of CHO intake decreases muscle glycogen, yielding greater fat oxidation and associated metabolic benefits. LCD may promote fat mass loss and regulation of biochemical parameters, such as lipid and glycemic biomarkers. The therapeutic potential of LCD towards noncommunicable diseases, particularly obesity and its comorbidities, is therefore reasonable as a dietary candidate in this context. Potential benefits to this approach are linked to enhancement of mitochondrial gene expression and mitochondrial biogenesis. As such, LCD may be a feasible tool in a 'periodized nutrition' for athletes and within clinical scenarios. Long-term observational follow-up studies have demonstrated increased mortality and cardiovascular implications of LCD. However, harmful associations may depend on the food source (e.g., animal-based vs. plant-based foods). CONCLUSION: LCD may decrease body mass, waist circumference, and improve fat and carbohydrate metabolism. When combined with exercise, LCD seems to be an effective strategy in regulating metabolic factors of cardiovascular diseases. Conversely, LCD may be associated with higher mortality and metabolic dysregulations if it contains large amounts of animal-based foods, particularly saturated fat.

Small dense low-density lipoprotein-cholesterol (sdLDL-C): Analysis, effects on cardiovascular endpoints and dietary strategies.

Lipid profile screening is crucial for the prevention, evaluation and treatment of cardiovascular (CV) disease (CVD). Small dense low-density lipoprotein-cholesterol (sdLDL-C) is an emerging biomarker associated with CVD and several comorbidities. The aim of this literature review is to discuss the potential importance of sdLDL-C as a surrogate biomarker for managing CVD by explaining its pathophysiology and promising treatments. The current synthesis demonstrates the impact of sdLDL-C on CV ailments, which are related to arterial pathologies and dysregulated lipid profiles. Several drug classes used for the treatment of dyslipidemia decrease the sdLDL-C concentrations. For instance, statins, fibrates, ezetimibe, nicotinic acid, resin and orlistat are pharmacological sdLDL-C-lowering agents. Regarding nutritional strategies, simple carbohydrate types, such as fructose, are common in Western diets and should be reduced or avoided due to their potential in increasing synthesis of sdLDL-C subclasses. Dairy products, avocado, pistachios, soy-based diet (except for hydrogenated soybean oil) and corn oil seem to be suitable food choices for a therapeutic diet aiming to control sdLDL-C concentrations. However, thus far dietary supplementation with omega-3 fatty acids is unsubstantiated for decreasing sdLDL-C concentration. In conclusion, coupled with the traditional lipid profile, measurement or even the estimation of sdLDL-C as a routine screening should be encouraged, whereas more insights into the control of sdLDL-C are imperative. Appropriate clinical reference ranges for sdLDL-C are also needed.

Lipoprotein(a): Current Evidence for a Physiologic Role and the Effects of Nutraceutical Strategies.

PURPOSE: Cardiovascular (CV) diseases account for most worldwide mortality, and a higher level of lipoprotein (Lp)-(a) is recognized as a prevalent contributing risk factor. However, there is no consensus regarding nutritional strategies for lowering Lp(a) concentration. Thus, the purposes of this literature review were to: (1) critically examine data concerning the effects of dietetic interventions and nutraceutical agents on Lp(a) level; and (2) review the feasibility and utility of their clinical use. METHODS: A literature search was conducted for studies published between August 2018 and March 2019. The search was performed using the Cochrane, Medline, and Web of Science databases. In order to expand the research, there were no delimitations on the type or year of the studies. A total of 1932 articles were identified using this search procedure. After duplicates were eliminated, 740 abstracts of articles written in English were screened to identify those of highest relevance. In the final tally, a total of 152 full-text articles were included in this review. FINDINGS: Several foods and decreases in saturated fat and ethanol intake, especially red wine intake, may lower Lp(a) concentration, but limits are necessary. Coffee and tea intake may decrease Lp(a) level; further investigation is crucial before they can be considered potent Lp(a)-lowering agents. Among supplementation strategies, only l-carnitine and coenzyme Q10 are promising clinical candidates to lower Lp(a) level. Since both l-carnitine and coenzyme Q10 supplementation are commonly used for CV support, they deserve further exploration regarding clinical applicability. In contrast, despite potential CV benefits, current research fails to justify use of higher intakes of vitamin C, soy isoflavones, garlic, and ω-3 for decreasing Lp(a) concentration. IMPLICATIONS: Definitive long-term clinical trials are needed to confirm the effects of dietetic interventions and nutraceutical agents on Lp(a) concentration when anticipating improved CV outcomes.

Glycemic, inflammatory and oxidative stress responses to different high-intensity training protocols in type 1 diabetes: A randomized clinical trial.

AIMS: To investigate the effects of high-intensity interval training (HIIT) and/or strength training (ST) on inflammatory, oxidative stress (OS) and glycemic parameters in type 1 diabetes (T1DM) patients. METHODS: After a 4-week control period, volunteers were randomly assigned to 10-week HIIT, ST or ST + HIIT protocol, performed 3×/week. Blood biochemistry, anthropometric, strength and cardiopulmonary fitness variables were assessed. Outcomes were analyzed via generalized estimating equations (GEE), with Bonferroni post hoc analysis. RESULTS: ST, HIIT and ST + HIIT improved glycemic (HbA1c and fasting glucose) and antioxidant parameters (total antioxidant capacity, catalase and superoxide dismutase activities), but not plasma inflammatory (C-reactive protein, TNF-α and IL-10) or OS markers (thiobarbituric acid-reactive substances, 8-hydroxy-2-deoxyguanosine and oxLDL) levels. Noteworthy, interventions reduced soluble receptors for advanced glycation end products levels. However, intracellular heat shock protein 70 content increased only after HIIT. While daily insulin dosage decreased only in the ST + HIIT group, all training models induced anthropometric and functional benefits. CONCLUSIONS: Similar benefits afforded by ST, HIIT or ST + HIIT in T1DM people are associated with enhanced antioxidant systems and glucose-related parameter, even in a few weeks. From a practical clinical perspective, the performance of ST + HIIT may be advised for additional benefits regarding insulin dosage reduction.

Effects of fructose consumption on postprandial TAG: an update on systematic reviews with meta-analysis.

The aim of this study was to re-examine the chronic effect (>7 d) of fructose consumption on postprandial TAG, in adolescents and adults. The research was carried out in March 2017 and used different electronic databases, such as Medline ® (Pubmed®), Embase® and Cochrane. The review considered clinical trials (parallel or crossed) that evaluated the effect of fructose consumption for a period longer than 7 d, in humans. Two investigators independently performed data extraction. The outcome was the absolute delta of TAG concentration in a 4-h postprandial period. The results were presented with delta mean difference between treatments with 95 % CI. The calculations were made based on random-effect models. Statistical heterogeneity of treatment effects between studies was assessed by Cochrane's 'Q Test' and 'I 2' inconsistency test. The meta-analysis of the twelve selected interventions (n 318) showed that fructose generated larger variation (δ) of TAG concentrations during the postprandial period, compared with other carbohydrates (mean difference: 8·02 (95 % CI 0·46, 15·58) mg/dl (0·09 (95 % CI 0·01, 0·18) mmol/l); I 2: 74 %). High heterogeneity was generated almost exclusively by one study, and its withdrawal did not alter the result. We concluded that chronic consumption of fructose (>7 d) has a negative role on postprandial TAG in healthy adolescents and adults, as well as in overweight/obese individuals, but not in diabetics.

Impact of intermittent fasting on the lipid profile: Assessment associated with diet and weight loss.

Intermittent fasting, whose proposed benefits include the improvement of lipid profile and the body weight loss, has gained considerable scientific and popular repercussion. This review aimed to consolidate studies that analyzed the lipid profile in humans before and after intermittent fasting period through a detailed review; and to propose the physiological mechanism, considering the diet and the body weight loss. Normocaloric and hypocaloric intermittent fasting may be a dietary method to aid in the improvement of the lipid profile in healthy, obese and dyslipidemic men and women by reducing total cholesterol, LDL, triglycerides and increasing HDL levels. However, the majority of studies that analyze the intermittent fasting impacts on the lipid profile and body weight loss are observational based on Ramadan fasting, which lacks large sample and detailed information about diet. Randomized clinical trials with a larger sample size are needed to evaluate the IF effects mainly in patients with dyslipidemia.

Effects of Two Combined Exercise Designs Associated With High-Fat Meal Consumption on Postprandial Lipemia, Insulinemia, and Oxidative Stress.

Farinha, JB, Macedo, CEO, Rodrigues-Krause, J, Krüger, RL, Boeno, FP, Macedo, RCO, Queiroz, JN, Teixeira, BC, and Reischak-Oliveira, A. Effects of two combined exercise designs associated with high-fat meal consumption on postprandial lipemia, insulinemia, and oxidative stress. J Strength Cond Res 32(5): 1422-1430, 2018-Impaired postprandial lipemia (PPL) response after the consumption of a high-fat meal (HFM) is linked to diabetes, oxidative stress, and cardiovascular events. The aim of this study was to investigate lipid and glucose metabolism and oxidative stress responses of 2 different combined exercise designs associated with HFM consumption. Eleven healthy and physically active men (27.36 ± 5.04 years) participated in this study. After the pretrial visits, participants were randomly assigned to perform 2-day trials in 3 different conditions (interspaced by at least 1 week): resting (REST), circuit combined exercise (CIRC), or traditional combined exercise (COMB), on the evening of day 1. On the morning of day 2, an HFM was provided and blood samples were obtained before and after 1, 3, and 5 hours of HFM consumption. No differences were found with respect to glucose, thiobarbituric acid-reactive substances, or total thiol levels in between time points or conditions. One-way analysis of variance demonstrated a difference between REST and CIRC (p = 0.029; reduction of 35.29%) and between REST and COMB (p = 0.041; reduction of 33.41%) conditions with incremental area under the curve (iAUC) for triacylglycerol levels. A difference between REST and CIRC (p = 0.03; reduction of 34.22%) conditions in terms of iAUC for insulin was also found. Both CIRC and COMB exercise designs can reduce PPL associated with HFM consumption. Moreover, CIRC reduces the iAUC for insulin, suggesting additional benefits for prescribing this type of exercise.

Glucose control can be similarly improved after aquatic or dry-land aerobic training in patients with type 2 diabetes: A randomized clinical trial.

OBJECTIVES: To compare the effects of two aerobic training methods in water and on dry-land on glycemic, lipid, inflammatory, hormonal, cardiorespiratory, and functional outcomes in patients with type 2 diabetes. DESIGN: Randomized clinical trial. METHODS: Thirty-five patients with type 2 diabetes were randomly assigned to aquatic aerobic training group (n=17) or dry-land aerobic training group (n=18). Exercise training interventions had duration of 12 weeks, performed in three weekly sessions (45min/session), with intensity progressing from 85% to 100% of heart rate of anaerobic threshold during interventions. All outcomes were evaluated at baseline and 12 weeks later. RESULTS: Patients were 56.7±7.9 years old. Decreases in glycated hemoglobin were observed in both groups (AT: -0.42±0.28%, DLT: -0.35±1.8%). Total cholesterol, high density lipoprotein, low density lipoprotein levels, plasma renin activity, angiotensin II concentrations, C-reactive protein, systolic blood pressure, resting heart rate, and timed up and go test performed at the usual speed also decreased in both groups in response to both interventions (p<0.05), without between-group differences. Both groups increased the ratio between oxygen uptake at the anaerobic threshold and oxygen uptake of peak (p=0.01). CONCLUSIONS: Aerobic training in an aquatic environment provides effects similar to aerobic training in a dry-land environment in patients with type 2 diabetes.

Acylated Ghrelin and Circulatory Oxidative Stress Markers Responses to Acute Resistance and Aerobic Exercise in Postmenopausal Women.

BACKGROUND: Since exercise increases the production of reactive oxygen species in different tissues, the objective of this study is to evaluate, compare and correlate the acute effects of aerobic and resistance exercise in circulatory markers of oxidative stress and acylated ghrelin (AG) in postmenopausal women. METHODS: Ten postmenopausal women completed different protocols: a control session (CON), an aerobic exercise session (AERO); and a single-set (SSR) or 3-set (MSR) resistance exercise protocol. RESULTS: After exercise, both MSR (P = .06) and AERO (P = .02) sessions showed significant increased lipid peroxidation compared with baseline levels. CON and SSR sessions showed no differences after exercise. No differences were found between sessions at any time for total glutathione, glutathione dissulfide or AG concentrations. CONCLUSIONS: Exercise significantly increased lipid peroxidation compared with baseline values. As pro oxidant stimuli is necessary to promote chronic adaptations to the antioxidant defenses induced by exercise, our findings are important to consider when evaluating exercise programs prescription variables aiming quality of life in this population.