Nutritional Supplements 2- App Physio PDF

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Final summary for the nutritional supplements exam question. Grade achieved A3...

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Nutritional Supplements 2- Applied Physiology Definition “A food, food component, nutrient, or non-food compound that is purposefully ingested in addition to the habitually consumed diet with the aim of achieving a specific health and/or performance benefit.” (Maughan et al., 2018) Functional foods - e.g. mineral/vitamin fortified Formulated foods and sports foods – mainly for convenience e.g. CHO drinks etc. Single nutrients – e.g. calcium, iron, vit D Multi-ingredient products – e.g. combinations of the above designed for similar outcomes Why do athletes use supplements:

Considerations: Risk to benefit analysis • Is it effective? • Large market, but only a few have a good evidence base (caffeine, nitrate, creatine, buffering agents) • Is it safe? • Is it permitted for use? • Is there a chance it could be contaminated? • Is it appropriate for the stage of maturation? • Can the athlete afford it financially? • Does it work for the athlete in question?

Genetics, interactions with the microbiome, habitual diet can all affect individual responses Assessing the evidence: •

Critical thinking is key! Randomised, double blind, placebo-control crossover trails are the gold standard Often ecological validity is restricted by methodological considerations Further questions; Was it adequately powered? Were the participants elite? Would a small statistical effect translate to a real life performance improvement? Consensus statements – Expert opinion translate findings into recommendations. Should be re-evaluated regularly

Supplemental checklist: • What is the supplement and who may benefit? • Describe the proposed physiological mechanisms underlying the effects. • Describe the optimum dosage strategy – i.e. amount, timing etc. • Critically review the evidence of an ergogenic effect – examples with positive and no or negative effects. Is there consensus? • Health or side effects?

Sodium Bicarbonate: Sodium Bicarbonate is the monosodium salt of carbonic acid with alkalinizing and electrolyte replacement properties

Molecular formula - NaHCO3 Commonly known as baking soda. Many uses; cooking, cleaning, personal hygiene Which athletes benefit? • • • •

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Used for over 80 years as an extracellular blood buffer, potential ergogenic effect in high-intensity exercise Events involving high rates of anaerobic glycolysis 1-7 min strenuous exercise (or intermittent/sustained) (Siegler et al., 2016) Intra-individual variability is high Duration of exercise important > benefits in ~60 s high-intensity efforts (performance enhancement of ~2%) < benefit in events of ~10 min or longer > benefits (>8% improvement) with greater number of sprints (Peeling et al., 2017) May be more effective in untrained individuals

Physiological Mechanisms • Blood Bicarbonate (HCO3-) is part of the acid base homeostatic bicarbonate buffer system • Sodium Bicarbonate (NaHCO3) enhances extracellular buffering of hydrogen ions (alkalising agent) • Increases coupled transport of lactate and H+ ions across muscle cell membrane into extracellular fluid • Therefore, reduces acidity excess acidity inhibits energy transfer and contractile proteins • Chronic manipulation of pH-level may supply a protective effect on mitochondria, leading to improved mitochondrial function and improved performance (Driller et al., 2013; Edge et al., 2006). Dosage: • 300 mg/kg 1-2 h before exercise can temporarily increase blood bicarbonate concentrations • Acute NaHCO3 doses of 0.2–0.4 g/kg BM reported to improve performance • Chronic; 5 days of 500mg/Kg BM split into four doses per day • Smaller doses over longer periods may reduce GI distress • Positive effects observed up to 2 days after cessation of supplement Side effects: • Severe alkalosis if taken in excess • Vomiting, gastrointestinal discomfort, bloating, and diarrhoea (more likely if not consumed with water) • Consumption with small carbohydrate-rich meal may alleviate GI distress ( ∼1.5 g/kg BM carbohydrates) (Carr, Slater, et al., 2011) • Sodium citrate is an alternative often reported to have less side effects (Requena et al., 2005)...