Sports foods for Sports Nutrition – The facts, the fiction and the myths
‘Dietary supplements’, ‘sports foods’, ‘nutritional ergogenic aids’ and ‘therapeutic nutritional supplements’- these are some of the terms used to describe the range of products that collectively form the sports supplement industry.
Supplement use is a widespread and accepted practice by athletes, with a high prevalence of use and a large range of different types and brands of products. But how do we know which ones to take and which ones actually work? This article will endeavour to answer this question.
Much emphasis is placed on protein, muscle recovery, energy and sports drinks and people spend a lot on money on these products based on what the salesperson says. Here we aim to tell you the pros and cons and let you decide for yourself based on your individual needs. If you are still unsure the Australian Institute of Sport constantly updates and analyses current research in the field. However you will still need to use your own judgment as they are not always focused on health and wellness long term.
Popular sports supplements
Protein supplementation is based on the premise that it aids the repair of exercise-induced muscle fibre damage; promotes training-induced adaptations in muscle fibre and increases muscle size.
Generally a westerner will consume a sufficient amount of protein in the diet. An exercising individual utilises protein very efficiently, often requiring less then a sedentary individual who has poor protein utilization. Requirements vary depending on the diet, digestive health and type of exercise undertaken.
Protein is not usually used as an energy source during exercise; it is inefficient and “steals” it from muscle. The energy used is glucose mainly derived from carbohydrates which will be discussed later.
Excessive intakes of animal protein causes calcium and other mineral losses from the body when the excess protein is excreted, calcium and other minerals are drained from the body. This puts pressure on the kidneys causing hyperfiltration. Furthermore calcium is required for muscle contraction therefore potentially affecting contractility of the muscle during training.
Excessive protein consumption can lead to exponential levels of amino acid oxidation with no further increase in protein synthesis.
Research demonstrates that contrary to popular belief, people who exercise don’t need to consume extra protein. Studies show that weight-trainers who don’t eat extra protein still gain muscle at the same rate as weight-trainers who supplement their diets with protein. Furthermore, pre-exercise protein consumption was not found to benefit post-exercise muscle protein.
On the other hand there is research that supports the use of protein, stating that post exercise protein feeding induced stimulation of muscle protein synthesis,2.
Difference between protein supplements
With a plethora of different types of protein powders on the market it is easy to get lost in the marketing material. Some common ones include soy, whey, sprouted rice and pea, this discloses where the protein in the product was sourced from.
Soy- Soy protein isolate is made from defatted soy meal. Most of the fats and carbohydrates have been removed, yielding a product with 90% soy protein. Because most of the soy carbohydrates are removed, it will reduce gas caused by bacterial flatulence. Soy protein isolate has a very neutral flavour compared to other soy products.
Soy protein isolate contains about 90% protein and is a complete vegetable protein which is a highly digestible source of amino acids. Soy protein isolate also has a very low fat content, as well as low calories and cholesterol.
Research suggests that the drawback with soy protein is for pre-menopausal females and young males, due to effect soy has on hormones (source of phytoestrogens). Therefore it should only be consumed occasionally or short term in these individuals. However soy may be beneficial in post-menopausal women due to the oestrogenic effects,,.
Whey- derived from dairy whey, a collective term referring to a group of proteins found in milk.
Whey Protein Concentrate
The amount of protein in whey protein concentrate can vary between 25-89%. The whey protein powder supplements that you find in health and nutrition stores often list the amount of whey protein concentrate on the label.
Hydrolyzed Whey Protein
The long protein chains in the whey protein have been broken down into shorter chains called peptides. This makes the whey protein more easily absorbed by the body and may reduce the potential for allergic reactions.
Whey Protein Isolate (WPI)
WPI is the purest form of whey protein available and contains between 90-95% protein. It is a good protein source for individuals with lactose intolerance as it contains little to no lactose. The cost will be slightly higher than the latter due to the purity and higher protein content of the product.
The individual proteins found in whey protein:
50 – 55%: Beta-lactoglobulin provides an excellent source of the essential and branched chain amino acids (BCAAs). BCAAs are believed to help prevent muscle breakdown and spare glycogen during exercise.
20 – 25%: Alpha-lactalbumin is high in tryptophan, with potential benefits for increased serotonin production, sleep regulation, and mood improvement under stress.
10 – 15%: Immunoglobulins are proteins made by the immune systems to combat certain antigens. Immunoglobulins provide immunity enhancing benefits.
5 – 10%: Bovine Serum Albumin is a major protein found in blood serum and occurs in all body tissues and secretions.
1 – 2%: Lactoferrin is an iron binding globular glycoprotein and inhibits growth of bacteria and fungi due to its ability to bind iron.
0.1%: Lysozyme is an enzyme naturally present in milk and contains immunity enhancing properties.
You can also get grain and vegetable proteins; if you are following an alkalising diet you should aim for a sprouted protein or soy powder and/or consume a diet with sufficient protein. A nutritionist or dietician can calculate your protein, carbohydrate and fat requirements for you.
* If you are going to supplement your diet with a protein powder try to avoid ones with additives, sugar and unnecessary fillers.
The most important element of exercise is sufficient carbohydrates; glucose is the major fuel source for the production of ATP (energy). Restoration of glucose/glycogen stores used during exercise is imperative to avoid muscle catabolism.
During exercise muscles use glucose (usable energy) and glycogen (stored energy) for fuel. These stores are limited, this causes the hormone cortisol to be secreted, this is your body’s “stress” hormone and it has catabolic effects (breaking down). Cortisol uses muscle tissue protein and converts it into glucose. A process called gluconeogenesis ensues, producing glucose from these amino acids (‘stolen’ from muscles) in the liver.
Jeukendrup’s (2010) review emphasised the importance of carbohydrates in exercise and found that multiple transportable carbohydrates compared with a single carbohydrate showed improved exercise performance and reduced fatigue. This demonstrates that whole foods such as fruits can prove an important dietary inclusion in sports nutrition.
It is recommended to consume a low GI meal pre-training and a high GI post-training. For example: brown rice and vegetables pre and a banana nut smoothie post. It is critical to get the carbohydrates to the muscle cells quickly as the elevated insulin levels (from the high GI food) will help to drive nutrients into the muscle cells.
Dietary energy and carbohydrate intake increases protein synthesis and slows down protein breakdown.
*You can add your protein powder with a banana, honey, almond milk and some greens to provide sufficient nutrition for recovery post training. Greens are important to offset the acidity from the protein powder and acid build up from exercise, this will be discussed later.
During post-exercise rehydration, the replacement of electrolyte losses, particularly sodium, must occur to fully restore fluid balance. Rehydrating with fluids low in electrolytes (e.g. water) can lower plasma sodium levels causing a reduced thirst and increased urine output resulting in decreased voluntary fluid intake and inadequate fluid retention (mostly in exercise lasting >30 minutes). The ingestion of multi-dextrin/isotonic drinks helps spare muscle glycogen delaying muscle fatigue.
Fluid replacement sports drinks have grown astronomically but they are still essentially water, sugar, salt, and some flavouring and colouring (See the article on additives for more information LINK). Instead it would be more beneficial to try one of the following options as they not only replace electrolytes but are also beneficial for your health.
To include electrolytes in your smoothie you could use:
- Potassium- banana
- Calcium- sesame seeds/ tahini
- Magnesium- almonds (you could use almond milk) and/or molasses
Or just add a little fruit juice and celtic sea salt to your water bottle.
Coconut water contains a plethora of nutrients including electrolytes, carbohydrates and protein making it excellent for rehydrating and dealing with free radicals formed during exercise. The electrolyte concentration in coconut water can generate an osmotic pressure comparable to that of blood.
Recent research evaluating the use of coconut water as a potential electrolyte beverage proves promising. Kalman et als (2012) research showed young coconut water had similar effects to a carbohydrate-electrolyte sports drink. Previous studies by Saat et al (2002) also concluded young coconut water to be efficient as an electrolyte drink in exercise training. The applicable properties of the studies is let down by the small sample sizes used; however the evidence behind coconut waters constituents and physiological properties proves promising and warrants further research.
In the mean time young coconut water is a healthy, nutritious beverage that could be consumed in a healthy diet and exercise regime.
Individual amino acids
It is important to mention that supplementing with individual amino acids can upset the body’s total balance of amino acids by taking just one. Therefore the recommendation would be to take them in combination with each other.
L-glutamine, mainly recommended due its immune support and muscle recovery functions. Exercising individuals commonly experience a depleted immune system and all require muscle recovery.
Acetyl-L-carnitine is thought to help burn fat, maximize energy, increase focus and improve sports training endurance. This hypothesis is based on its important roles in energy metabolism. It is also thought to increase in maximal oxygen uptake and decrease plasma lactate. However evidence of this is lacking and the only available studies are of poor quality.
Arginine is used in sports nutrition as a vasodilator (nitric oxide), its role in the secretion of endogenous growth hormone and its involvement in the synthesis of creatine. Research is still lacking in evidence of its efficacy in sports nutrition.
Branched Chain Amino acids (BCAA) have been reported to increase performance in endurance athletes in hot environmental conditions. BCAA are thought to offset the accelerated degradation of skeletal muscle preventing the metabolic side effects associated with NH3 accumulation (acidity). Da Luz et al (2011) concluded that BCAA may have the potential to reduce certain biochemical markers associated with muscle soreness. While Shimomura et al (2006) posited that BCAAs may be beneficial for muscle recovery post exercise.
Creatine- not for continuous use
Creatine is a naturally occurring compound found in large amounts in skeletal muscle and brain as a result of dietary intake and endogenous synthesis from amino acids.
Phosphorylated creatine provides a number of important functions related to fuel supply in the muscle. The most well-known role is as a source of phosphate to regenerate ATP. The phosphocreatine system is the most important fuel source for sprints or bouts of high-intensity exercise lasting up to 10 seconds.
Condoning supplementation has conflicting evidence; it has been shown to enhance performance but whether this enhancement lasts is under scrutiny.
Not everyone responds to creatine supplementation; some sports medicine authorities have estimated that 30% of users see no beneficial effect. It is only to be used short term which is sometimes ignored and individuals incur the consequences. It may also have deleterious effects on the liver and kidney.
Creatine phosphate has an affinity for water, causing water retention, which may decrease performance.
* Note high doses of creatine do not further enhance creatine stores.
* Creatine taken with carbohydrates further increases muscle creatine levels.
Caffeine benefits exercise capacity and performance via its central nervous system effects. These effects reduce the perception of fatigue and allow optimal outcomes to be maintained for longer.
Caffeine, a naturally occurring alkaloid, is a central nervous system and metabolic stimulant. Similar to alcohol and nicotine as they all are able to cross the blood/brain barrier. In the brain, caffeine acts as an antagonist and a competitive inhibitor of adenosine. This means that in the presence of caffeine, adenosine cannot complete its functions, thereby allowing caffeine to excite the central nervous system with continued stimulation of neurons. When caffeine is in the brain it suspends the central nervous system in an unnatural excited state, and does not allow adenosine to switch off neurotransmitters when required.
Caffeine theoretically increases lipolysis (fat breakdown) via catecholamine action and has a direct effect on cyclic AMP (which regulates energy metabolism). This increases the supply of free fatty acids to working muscles, sparing glycogen in endurance events. To date there is conflicting evidence in regards to caffeine and exercise benefits,,.
When we exercise we produce free radicals via contracting heart and skeletal muscle. It is believed that consumption of antioxidants will help buffer the free radicals produced. Furthermore it is thought that free radicals contribute to muscle fatigue.
There is a plethora of research articles out there both for and against, using different antioxidants. If you choose to use any form of antioxidants, functional foods is a good place to start as they will have a myriad of other health benefits as well. Taking antioxidant supplements comprising of a singular nutrients may not be as beneficial; the USDA stated that “There is increasing evidence that consumption of whole foods is better than isolated food components”.
Alkalising products such as chlorophyll, spirulina, vegetable extracts
Your body when at rest or doing every day activity’s is taking the food you eat and breaking it down in a process in which energy (ATP) is formed for the body to use . The process occurs in the presence of oxygen because as we know our red blood cells are using haemoglobin to deliver oxygen to all the tissues of our body.
When we exercise our muscle cells are not receiving adequate oxygen. This means the process of energy production (food →ATP) is occurring in the absence of oxygen. In the absence of oxygen the process changes and lactic acid is produced. Glucose (from carbohydrates) is fed into the cycle, this produces only 2 ATP’s (2 units of energy) and lactic acid.
This lactic acid can build up in the muscle which eventually causes failure of the muscle to contract properly; this causes the individual to have to stop exercising and rest to let the lactic acid be removed and neutralized by alkalising minerals or the cori cycle. By consuming an alkalising diet, there are more alkalising minerals available to remove the lactic acid, therefore it is possible for the individuals endurance to increase.
Put simply, exercise lowers blood pH and produces lactic acid which can lead to acidity which is believed to effect fatigue and performance.
Anaerobic (without oxygen) glycolysis provides the primary fuel source for exercise of near-maximal intensity lasting longer than about 30 seconds. High-intensity exercises (anaerobic) involve the utilisation of carbohydrates (muscle glycogen).
High rates of anaerobic glycolysis in the muscle can produce hydrogen ions in excess of intracellular buffering capacity; however, increasing the extracellular pH can enhance the efflux of the accumulating H+ in the muscle into the extracellular space for disposal. This tactic has been used as an ergogenic strategy for sporting events which are dependent on the generation of energy via anaerobic glycolysis.
As glycogen stores are depleted, there is a subsequent increase in hydrogen ion (H+) concentrations and lactic acid in blood and muscle. The increase in H+ inhibits calcium release from the sarcoplasmic reticulum and an inhibition of the interaction between actin and myosin.
To simplify the events involving high rates of energy generation from anaerobic glycolysis, they are limited by the body’s capacity to manage the progressive increase in the acidity of the intracellular environment. Although the direct role of hydrogen ion accumulation in muscle fatigue is unclear, the dietary strategies that decrease blood pH (e.g. intake of acid salts) impair capacity in high-intensity exercise, while strategies that increase alkalosis such as the intake of bicarbonate improve such performance.
To offset this acidity it is possible to use alkalising supplements:
Chlorophyll contains alkalising minerals (particularly magnesium). Stores of alkaline minerals in the blood are limited, when not adequately supplied; the body steals them from bone stores, muscles and cells. Alkalising may help maintain bone mass by preventing bone resorption of calcium used to buffer the acidic pH.
The analogy between chlorophyll and haemoglobin is evident in the structure of their porphy-rin heads. With the key variance being the central metal atom, chlorophyll has magnesium and haemoglobin, iron. This is relevant to alkalising as oxygenation of the cells aids the removal of toxins, increases cellular health and frees up more haemoglobin for buffering acidity in the system.
Chlorophyll can be found in products such as spirulina, barley grass, wheat grass, chlorella, kelp and green vegetables.
The information contained in this article is based on published nutritional research. It is in no way designed to diagnose or treat specific medical conditions. If you suffer from any chronic health problem; take prescription medication or are pregnant or lactating, please speak to your health professional.
*Sports nutrition supplements are not a sole source of nutrition and should be consumed in conjunction with a nutritious diet and an appropriate physical training or exercise program. Not suitable for children under 15 years of age or pregnant women.
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