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1.
Iron Metabolism: Interactions with Energy and Carbohydrate Availability.
McKay, AKA, Pyne, DB, Burke, LM, Peeling, P
Nutrients. 2020;(12)
Abstract
The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.
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2.
Diabetes Canada Position Statement on Low-Carbohydrate Diets for Adults With Diabetes: A Rapid Review.
Canadian journal of diabetes. 2020;(4):295-299
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3.
Dietary Patterns, Carbohydrates, and Age-Related Eye Diseases.
Francisco, SG, Smith, KM, Aragonès, G, Whitcomb, EA, Weinberg, J, Wang, X, Bejarano, E, Taylor, A, Rowan, S
Nutrients. 2020;(9)
Abstract
Over a third of older adults in the U.S. experience significant vision loss, which decreases independence and is a biomarker of decreased health span. As the global aging population is expanding, it is imperative to uncover strategies to increase health span and reduce the economic burden of this age-related disease. While there are some treatments available for age-related vision loss, such as surgical removal of cataracts, many causes of vision loss, such as dry age-related macular degeneration (AMD), remain poorly understood and no treatments are currently available. Therefore, it is necessary to better understand the factors that contribute to disease progression for age-related vision loss and to uncover methods for disease prevention. One such factor is the effect of diet on ocular diseases. There are many reviews regarding micronutrients and their effect on eye health. Here, we discuss the impact of dietary patterns on the incidence and progression of age-related eye diseases, namely AMD, cataracts, diabetic retinopathy, and glaucoma. Then, we focus on the specific role of dietary carbohydrates, first by outlining the physiological effects of carbohydrates on the body and then how these changes translate into eye and age-related ocular diseases. Finally, we discuss future directions of nutrition research as it relates to aging and vision loss, with a discussion of caloric restriction, intermittent fasting, drug interventions, and emerging randomized clinical trials. This is a rich field with the capacity to improve life quality for millions of people so they may live with clear vision for longer and avoid the high cost of vision-saving surgeries.
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4.
The Role of Dietary Carbohydrates in Gestational Diabetes.
Mustad, VA, Huynh, DTT, López-Pedrosa, JM, Campoy, C, Rueda, R
Nutrients. 2020;(2)
Abstract
Gestational diabetes (GDM) is hyperglycemia that is recognized for the first time during pregnancy. GDM is associated with a wide range of short- and long-term adverse health consequences for both mother and offspring. It is a complex disease with a multifactorial etiology, with disturbances in glucose, lipid, inflammation and gut microbiota. Consequently, its management is complex, requiring patients to self-manage their diet, lifestyle and self-care behaviors in combination with use of insulin. In addition to nutritional recommendations for all pregnant women, special attention to dietary carbohydrate (CHO) amount and type on glucose levels is especially important in GDM. Dietary CHO are diverse, ranging from simple sugars to longer-chain oligo- and poly- saccharides which have diverse effects on blood glucose, microbial fermentation and bowel function. Studies have established that dietary CHO amount and type can impact maternal glucose and nutritional recommendations advise women with GDM to limit total intake or choose complex and low glycemic CHO. However, robust maternal and infant benefits are not consistently shown. Novel approaches which help women with GDM adhere to dietary recommendations such as diabetes-specific meal replacements (which provide a defined and complete nutritional composition with slowly-digested CHO) and continuous glucose monitors (which provide unlimited monitoring of maternal glycemic fluctuations) have shown benefits on both maternal and neonatal outcomes. Continued research is needed to understand and develop tools to facilitate patient adherence to treatment goals, individualize interventions and improve outcomes.
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5.
Involvement of the Autophagy-ER Stress Axis in High Fat/Carbohydrate Diet-Induced Nonalcoholic Fatty Liver Disease.
Zhou, X, Fouda, S, Li, D, Zhang, K, Ye, JM
Nutrients. 2020;(9)
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease that can progress from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH), and even further to liver cirrhosis or liver cancer. Overconsumption of high fat and/or carbohydrate are among the most common lifestyle factors that drive the development and progression of NAFLD. This review evaluates recent reports on the involvement of autophagy and endoplasmic reticulum (ER) stress in the pathogenesis of NAFLD. Here, we reveal a mechanism of an intrinsically linked axis of impaired autophagy and unresolved ER stress that mediates the development and progression of NAFLD resulting from the overconsumption of high fat and/or carbohydrate.
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6.
Preoperative carbohydrates: what is new?
Gianotti, L, Sandini, M, Hackert, T
Current opinion in clinical nutrition and metabolic care. 2020;(4):262-270
Abstract
PURPOSE OF REVIEW The aim of this review is to give an overview of recently published articles covering preoperative carbohydrate loading in surgical patients. RECENT FINDINGS Between January 1, 2017, and December 31, 2019, 26 publications addressing the effect of carbohydrate load were retrieved through a systematic search. Seventeen were randomized clinical trials, three prospective observational studies and six retrospective series with case-control comparison. Most of the studies were underpowered, addressed surrogate endpoints, and variability among dose and timing of carbohydrate (CHO) treatment was high. The most recent literature endorses preoperative carbohydrate loading up to 2 h before operations as a safe treatment. The new evidence confirm that this strategy is effective in reducing perioperative insulin resistance and the proportion of hyperglycemia episodes, and improving patient well-being and comfort but without affecting surgery-related morbidity. SUMMARY Further properly designed randomized clinical trials, addressing more clinically relevant endpoints such as length of hospitalization and morbidity rate, are warrant.
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7.
[Low Fermentable Oligo-, Di- and Monosaccharides and Polyols (FODMAP) diet in the treatment of patients with irritable bowel syndrome: basic principles and methodology].
Kuvaev, RO, Yakovenko, EP, Nikonov, EL, Zaytsev, SV, Pospelova, EE, Krashenkova, AV
Voprosy pitaniia. 2020;(6):38-47
Abstract
Fermentable oligo-, di-, monosacc harides, and polyols (FODMAP) are a large class of small nondigestible carbohydrates, which are poorly absorbed in the small bowel. The microscopic size, high osmotic activity, and the higher fermentation of unabsorbed FODMAPs by colonic bacteria lead to bloating, abdominal pain, and flatulence in patients with irritable bowel syndrome. Therefore, low FODMAP diet appears to be promising treatment approach in the management of patients with irritable bowel syndrome (IBS). In this review, we analyzed available publications on efficacy and safety of low FODMAP diet in the treatment of IBS patients. Based on the current data we outlined basic principles and methodology of low FODMAP diet usage in clinical practice, and constructed the detailed list of low and high FODMAP products for designing a food regimen in patients with IBS.
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8.
Destigmatizing Carbohydrate with Food Labeling: The Use of Non-Mandatory Labelling to Highlight Quality Carbohydrate Foods.
Marinangeli, CPF, Harding, SV, Glenn, AJ, Chiavaroli, L, Zurbau, A, Jenkins, DJA, Kendall, CWC, Miller, KB, Sievenpiper, JL
Nutrients. 2020;(6)
Abstract
Dietary carbohydrates are components of healthy foods, but many carbohydrate foods have recently been stigmatized as primary causes of diet-related risk factors for chronic disease. There is an opportunity to enhance efforts within the food landscape to encourage the consumption of higher quality carbohydrate foods. The use of labelling is one strategy that permits consumers to identify healthy carbohydrate foods at the point-of-purchase. This review discusses the regulatory frameworks and examples of associated non-mandatory food labelling claims that are currently employed to highlight healthy carbohydrate foods to consumers. The existing labelling frameworks discussed here align with established measures of carbohydrate quality, such as 1. dietary fibre nutrient content claims and associated dietary fibre-based health claims; 2. the presence of whole carbohydrate foods and ingredients that are intact or reconstituted, such as whole grains; and 3. low glycemic index and glycemic response claims. Standards from Codex Alimentarius, and regulations from Australia and New Zealand, Canada, Europe, and the United States will be used to illustrate the means by which food labelling can be used by consumers to identify quality carbohydrate foods.
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9.
Carbohydrate restriction: Friend or foe of resistance-based exercise performance?
Cholewa, JM, Newmire, DE, Zanchi, NE
Nutrition (Burbank, Los Angeles County, Calif.). 2019;:136-146
Abstract
It is commonly accepted that adequate carbohydrate availability is necessary for optimal endurance performance. However, for strength- and physique-based athletes, sports nutrition research and recommendations have focused on protein ingestion, with far less attention given to carbohydrates. Varying resistance exercise protocols, such as differences in intensity, volume, and intraset rest prescriptions between strength-training and physique-training goals elicit different metabolic responses, which may necessitate different carbohydrate needs. The results of several acute and chronic training studies suggest that although severe carbohydrate restriction may not impair strength adaptations during a resistance training program, consuming an adequate amount of carbohydrate in the days leading up to testing may enhance maximal strength and strength-endurance performance. Although several molecular studies demonstrate no additive increases in postexercise mammalian target of rapamycin 1 phosphorylation with carbohydrate and protein compared with protein ingestion alone, the effects of chronic resistance training with carbohydrate restriction on muscle hypertrophy are conflicting and require further research to determine a minimal carbohydrate threshold necessary to optimize muscle hypertrophy. This review summarizes the current knowledge regarding carbohydrate availability and resistance training outcomes and poses new research questions that will better help guide carbohydrate recommendations for strength and physique athletes. In addition, given that success in physique sports is based on subjective appearance, and not objective physical performance, we also review the effects of subchronic carbohydrate ingestion during contest preparation on aesthetic appearance.
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10.
Considerations for ultra-endurance activities: part 1- nutrition.
Costa, RJS, Hoffman, MD, Stellingwerff, T
Research in sports medicine (Print). 2019;(2):166-181
Abstract
Ultra-endurance activities (≥ 4h) present unique challenges that, beyond fatigue, may be exacerbated by sub-optimal nutrition during periods of increased requirements and compromised gastrointestinal function. The causes of fatigue during ultra-endurance exercise are multi-factorial. However, mechanisms can potentially include central or peripheral fatigue, thermal stress, dehydration, and/or endogenous glycogen store depletion; of which optimising nutrition and hydration can partially attenuate. If exercise duration is long enough (e.g. ≥ 10h) and exercise intensity low enough (e.g. 45-60% of maximal oxygen uptake), it is bio-energetically plausible that ketogenic adaptation may enhance ultra-endurance performance, but this requires scientific substantiation. Conversely, the scientific literature has consistently demonstrated that daily dietary carbohydrates (3-12g/kg/day) and carbohydrate intake (30-110g/h) during ultra-endurance events can enhance performance at individually tolerable intake rates. Considering gastrointestinal symptoms are common in ultra-endurance activities, effective dietary prevention and management strategies may provide functional, histological, systemic, and symptomatic benefits. Taken together, a well-practiced and individualized fuelling approach is required to optimize performance in ultra-endurance events.