NUTRITIONAL SUPPLEMENTS FOR

ATHLETES

LIV ENGELSEN, MS

Ergogenic Aids

OutlineRegulation of nutritional supplementsIn-depth review of 5 popular ergogenic aids

Caffeine Creatine Monohydrate Sodium Bicarbonate β – Alanine HMB

Overview of research to support/refute additional supplements/practices

The best recovery beverage of all time…Summary/Conclusion

DefinitionSubstances, devices or practices that

enhance an athlete’s energy use, production or recovery

Regulation

Regulated by the Dietary Supplement Health and Education Act of 1994 (DSHEA)

http://www.youtube.com/watch?v=3vxrTMYXpZo

Caffeine Most popular social drug in the US

Average adult ingests 3 mg/kg of caffeine daily

Alkaloid stimulant found in coffee, tea, colas, sports drinks, chocolate, etc.

Has been studied for its ergogenic effects for ~100 years Levels of caffeine in foods vary greatly depending on

preparation Coffee: 60-150 mg/cup Tea: 40-60 mg/cup Cola: 40-50 mg/cup Chocolate (1.5 oz): 20 mg dark/9 mg milk

Ergogenic effectiveness varies, depending on:o Age o Gender o Body sizeo Caffeine toleranceo Habituationo Cessation patterns

Mechanisms of Action

Global effects on the CNS Caffeine is a competetive, nonselective adenosine receptor antagonist Leads to delayed fatigue, increased mental alertness, mood improvement,

energetic arousal Enhances concentration, visual acuity, reaction time and self-reported fatigue

Effects on hormonal, metabolic, muscular, cardiovascular, pulmonary and renal functions during rest and exercise. Leads to decreases in respiratory exchange ratio (RER), peripheral fatigue,

rating of perceived exertion (RPE), and threshold for exercise-induced cortisol and B-endorphin release

Leads to increases in oxygen uptake, cardiac output, ventilation, circulating levels of epinephrine, metabolic rate, and fat oxidation during endurance exercise in trained and untrained individuals

Bottom Line: The mechanisms by which caffeine improves athletic performance is multifactorial and extends well beyond any one biologic mechanism!

Effects on Body Systems & Sports Performance

Tolerance Diminished responsiveness resulting from repeated exposure Caffeine tolerance has been associated with increased

adenosine receptor activity and a decrease in β-adrenergic activity

Lower caffeine doses are well tolerated by nonusers Complete tolerance can occur in 5-6 days of moderate caffeine intake Effective strategy for a nonuser: 3-4 days of consecutive caffeine use to aid intense

workout sessions Begin with 1-2 mg/kg and increase progressively over the next few days

Psychological Factors

Withdrawal Withdrawal symptoms peak in 28 to 48 hours Takes an average of 4 to 7 days to return to baseline Main symptom is frequent and severe headaches

2/2 vasodilation of cerebral blood vessels

Resumed or acute caffeine intake almost entirely reverses withdrawal symptoms, including headache

Regular caffeine users can optimize benefits by cutting back, but must be careful to avoid withdrawal symptoms Reduce caffeine intake gradually at least 1 wk before competition Resuming caffeine on the day of competition will again provide the desired

ergogenic effects, as it would for a nonuser

Intake Strategy Caffeine reaches a peak plasma level between 30 and 75

minutes of ingestion Half-life is 4 to 5 hours with modest intake, but longer when

dose exceeds 300 mg In 6 to 7 hours, 75% of caffeine is cleared from the body

because it is rapidly absorbed and metabolized by the liver Intake strategy is crucial for those seeking to improve

athletic performance through caffeine use

Dosing As little as 1 mg/kg to as much as 13

mg/kg had positive effects on time to fatigue in endurance events, sports, and sprint or power events. 1 to 7 cups of coffee 3 to 18 cups of tea or soda

Some studies have found better ergogenic effect with lower dose (3-6 mg/kg) than higher doses No evidence of greater ergogenic effects with

more than 9 mg/kg Higher caffeine intake may blunt cognitive

performance

Gender differences Men tolerate higher doses than women

Safety Concerns The common belief that caffeine leads to dehydration and

causes poor athletic performance is a misconception! Claims of adverse effects of caffeine on the cardiovascular

system are inconclusive. The high levels of antioxidants found in coffee and tea have

been linked to a number of health benefits Protection against heart disease and type II DM

ResearchAuthor &

YearSubjects & Methods

Measures Treatment Results

Cox, et al., 2002

Effect of different protocols of

caffeine intake on metabolism and endurance perf.

12 trained cyclists/triathletes in study A, 8 in study B

Plasma/ urinry caff, rate of fat

oxidation,

1) Precaf2) Durcaf3) Coca-cola4) Placebo

Coca-cola was equally effective

in enhancing endurance

Hogervorst et al., 2008

Caffeine improves physical and

cognitive performance during exhaustive exercise

24 well-trained cyclists in a

RCCT

Series of cognitive and physiological

tests

1) CHO (CHO)2) Caffeine

+CHO (CAF)3) Placebo

(BEV)

Faster after CAF on both complex info processing

Maridakis et al., 2007

Caffeine attenuates delayed onset muscle pain

following eccentric exercise

9 low-caffeine consuming

females

Pain intensity, force loss during

eccentric and MVIC exercise

1) Caffeine2) Placebo

Large reduction in pain following

caffeine ingestion

Pedersen et al., 2008

High rates of muscle glycogen resynthesis after

exhaustive exercise when CHO is

coingested with caff

7 trained cyclists/triathlet

es in a Randomized, DB

Crossover design

BG, insulin, caff levels, muscle metabolites,

muscle glycogen,

protein kinases

1) CHO2) CHO + Caff

After 4 hrs of recovery, muscle

glycogen was higher in Caff

Think Fast!

What has the highest caffeine content?

a) Brewed teab) Shot of espressoc) Brewed coffeed) Dark chocolate bar

Creatine Monohydrate

An amine found naturally in some foods, particularly meat products.

Can be formed in the kidney and liver from glycine and arginine

Delivered to the muscle and combined with phosphate to create phosphocreatine: a high-energy phosphagen in the ATP-PCr energy system. ATP-PCr energy system is important for rapid energy production, such as in

speed and power events

Supplements come in various forms; powders, pills, candy, gels, etc.

Marketed to both strength and endurance athletes Appears most effective for activities that involve repeated short bouts of high-

intensity physical activity

Ergogenic Benefits Recent studies have shown significant improvements in:

Total and maximal force in repetitive isometric muscle contractions Muscular strength and endurance in isotonic strength tests Muscular force/torque and endurance in isokinetic strength testing Cycle ergometer performance in maximal tests ranging from 6 to 30 seconds Field performance tests such as jumping, running, swimming, and skating.

Less consistent, but overall favorable

Exogenous Sources Average adult needs to replace ~2 grams of creatine/day for

maintenance of normal creatine and PCr levels. Daily creatine intake of carnivores is ~1 g/day Daily intake may be nearly zero for vegetarians

Endogenous creatine formation helps complement dietary sources to achieve 2 grams

Excessive amounts of exogenous creatine will not be stored, but will be excreted unchanged in the urine

Proposed Mechanisms Most of the creatine in the body is stored in the muscles

Research suggests that performance benefits are related to increased creatine within type II muscle fibers

60% of total muscle creatine is PCr, and 40% is free creatine Increasing the amount of PCr will provide more

substrate for generating ATP during high-intensity exercise, and higher levels of free creatine will help re-synthesize PCr.

Alternative theory: creatine supplementation and anabolic hormones?

Creatine Dosing Very effective quick strategy

20-30 g/day (5-7 g per dose over the course of the day) Significant effects seen after only 2 days

Long-term supplementation at lower dose is just as effective 4-5 g/day Significant effects seen after 6 days

Once loaded, ~2 g/day for maintenance Creatine supplementation appears safe when the

recommended loading and maintenance doses are followed

Special Considerations Research suggests people may be responders or non-responders

Characteristics of nonresponers include :1) Higher initial levels of creatine and PCr2) Fewer type II muscle fibers

Individuals with initially low levels of intramuscular creatine are more responsive to supplementation Vegetarians

Caffeine counteracts the ergogenic action of muscle creatine loading! Vandenberghe et al., 1996

Effect on body mass >50 studies have shown an increase in body mass

during the first week of creatine supplementation Increased creatine in the muscle draws water

Formulation- creatine monohydrate Theoretically, dehydration, muscle cramps

and heatstroke can occur Drink plenty of water!!!!!

Creatine supplementation enhances muscular performance during high-intensity resistance

exerciseVolek et al., 1997

Subjects & Methods

Measures Treatment Results

•14 active men

•DB RCT

•Bench press (PB)protocol and jump squat (JS) protocol

•Three different occasions(T1, T2, T3)

•Each separated by 6 days

•Total reps for bench press•Peak power output for jump squats•Body mass•Skinfold thickness•Pre and post- exercise lactate

PL: PlaceboCR: Creatine

Prior to T1: No supplementation

Prior to T2: Everyone got placebo

Prior to T3: CR group took 25g/day for 6 days

•Lifting performance was not altered for either exercise after PL•CR improved peak power output during all 5 sets of JS and improvement in reps during all 5 sets of BPs. •CR increased body mass by 1.4 kg

Think Fast!

For maintenance of normal creatine and PCr levels, the average adult needs to replace

___ of creatine/day

a) 1 gb) 2 gc) 3 gd) 4 g

Sodium Bicarbonate Alkaline (buffer) salt found naturally in the body that helps

control pH and avoid excess acidity Increases pH Decreases H and lactate ions

During high intensity anaerobic exercise, energy needs are mainly provided by anaerobic glycolysis This is associated with a high level of lactic acid production Accumulation of excess lactic acid in the muscle cell interferes with

the optimal functioning of various enzymes, resulting in fatigue Increased perception of effort and decreased force production

Marketed to athletes as part of a sports supplement Not as popular as some of the other ergogenic aids available

Baking soda is a commercial version

Proposed Benefits Sodium bicarbonate supplementation increases serum pH

Desired effect is to buffer lactic acid

Reduces acidosis in the muscle cell, decreases the psychological sensation of fatigue, and increases performance in high-intensity anaerobic exercise tasks to exhaustion (~1-3 min of maximal exercise) 400 or 800-meter sprint 100 meter swims 5 km bicycle races

50% of well-controlled studies have demonstrated these effects

There is still conflicting research on the topic

Great individual variability in response

Safety & Side Effects

Possible side effects of acute sodium bicarbonate supplementation GI distress including nausea, diarrhea and cramping

Possibly due to an increase in gastric emptying following the ingestion of alkalotic agents Increased osmolality of the GI tract

Symptoms may be alleviated by drinking extra water with supplementation, however this may also impact the degree of alkolosis obtained

Dosage & Timing Supplements should be given 1-3 hours prior to exercise

event (90 minutes seems ideal) Leads to increased blood pH levels before, during and after an event

Most studies had subjects ingest 0.15- 0.30 g/kg 0.30 g/kg appears to be the optimum dose, with higher dosages providing no

additional benefit This is less than 1 oz for the average adult and appears to be effective and safe

Supplementation with lower doses over longer periods of time may be just as effective, with lower risk of adverse effects Take the same dose over 6 day period instead of at one time

Strategies to avoid/minimize GI distress during an event:a) Trial supplementation during trainingb) Drink plenty of water during treatmentc) After chronic ingestion for 5-6 days, d/c supplementation 2 days before the

eventd) Intravenous infusion

Sodium bicarbonate can be used as an ergogenic aid in high-intensity, comptetive cycle ergometry of 1 h duration

McNaughton et al., 1999

Subjects & Methods

Measures Treatment Results

•10 male, well trained cyclists

•3 tests, in a RDB fashion

Blood samples taken:

•90 min prior•every 30 min prior•10 min intervals throughout•1,3,5,10 min post-ex

Blood Analysis:•pH•Blood NaHCO3

•PO2

•PCO2•Blood lactate

Ergometer Data:•Work output•Power output•Heart rate

C: control60 min ride

P: placebo60 min ride + equimolar dose of NaCl

E: experimental60 min ride + 300 mg/kg NaHCO3

•Subjects in E completed greater amounts of work than either C or P•Subjects in E had greater power output than C or P •No change in peak power or power:mass •Blood pH was increased in E prior to testing•Blood lactate was lower in E throughout test

Think Fast!

Which of the following is NOT a strategy to avoid or limit GI distress when taking

NaHCO3?

a) Drink plenty of water during treatmentb) Intravenous infusion c) After chronic ingestion for 5-6 days, increase dose 2 days before

the eventd) Trial supplementation during training

β - Alanine

Precursor for carnosine, a dipeptide found in high concentrations in skeletal muscle

Carnosine is synthesized from the amino acids L-histidine and β–alanine β –alanine is the rate-limiting component in the process

Chronic ingestion of β–alanine can elevate the carnosine content of human muscle by up to 80%

Carnosine plays an important role in homeostasis of contracting muscle cells, especially during high rates of anaerobic energy delivery.

Carnosine Latin for “meat/flesh” Produced and stored in the skeletal muscle of animals but

virtually absent from other organs Absent from plants

Lacking in vegetarian diet Content is especially high in animals involved in sprint exercise

Chickens, greyhound dogs, horses

Muscle carnosine content is highly individualized Lower in women Declines with age Likely lower in vegetarians

β- alanine supplementation is one of the

most powerful means to elevate muscle

carnosine content More effective than carnosine ingestion alone

Proposed Mechanisms Carnosine loading leads to improved performance in high-

intensity exercise likely due to the following mechanisms

pH buffering Undisputable physiological role as determined by its molecular structure

Protection of proteins against glycation by acting as a sacrificial peptide

Preventing the formation of protein-protein cross-links Acting as an antioxidant Increasing calcium sensitivity in muscle fibers enhancing

force production and total work output

Dosing Considerations Daily doses of β –alanine in the amount of 4.8-6.4 grams can

elevate muscle carnosine content by 60% in 4 weeks 80% in 10 weeks

Baguet et al., showed that the increased carnosine content in calf muscles remained elevated for > 9 weeks following supplement cessation

Doses of >10 mg/kg should be avoided Can induce paraesthesia symptoms

No other side efects of β –alanine supplementation have been reported

Further research on the safety and possible side effects of β –alanine as a nutritional supplement is warranted.

Effects of β-alanine supplementation and high intensity interval training on endurance

performance and body composition in men; a double-blind trial

Smith et al., 2009

Subjects & Methods

Measures Treatment Results

•46 active college- aged men

•DB RCT

•6 weeks of HIIT consisting of 5-6 bouts of a 2:1 cycling work to rest ratio

Determination of VO2 peak•VO2 peak•VO2 TTE•VTCycling test•TTE•TWD•WBody composition•% body fat•Fat mass•Lean body mass

PL: placebo16.5 g dextrose

BA: β-alanine 1.5 g β-alanine + 15 g dextrose

First 21 days:4x/day (6 g/day)

Next 21 days:2x/day (3 g/day)

•Improvements in VO2 peak, VO2 TTEand TWD after 3 wks in both groups

•Increases in VO2

peak, VO2 TTEand TWD and LBM were only significant for the BA group after 2nd 3 wks of training

HMB

Hydroxy-beta-methylbutyrate A leucine-derived metabolite Positive effects on sports performance and as a therapeutical

supplement Demonstrated by Nissen et al. in 1996 Literature is conflicting

Reduces muscle damage and muscle catabolism and reinforces protein synthesis Used to minimize muscle wasting in AIDS patients

Background Branched-chain amino acids (BCAAs)

Leucine Isoleucine Valine

Leucine and its metabolite α-ketoisocaproate (KIC) have been known to be potent anti-catabolic compounds for >35 years Mechanisms not clearly established Isoleucine and valine are not able to trigger these effects

HMB may be one of the key elements in the anti-catabolic effect of leucine

HMB appears to be safe at doses of 3 g/day and may even have positive impacts on overall health Decreases in TC and LDL Decreases in systolic BP

Effects of amino acids supplement on physiological adaptations to resistance training

Kraemer et al., 2009

Subjects & Methods

Measures Treatment Results

17 healthy men in a DB RCT

Performed 12 wks of heavy resistance training

Blood samples taken every 2 wks

•Body mass•Lean body mass•% body fat•Muscle circumference•Maximal power•Testosterone•Cortisol•Growth Hormone•Creatine kinase

MA: Muscle Armor1.5 g HMB, 7 g arginine, 7 g glutamine, 3 g taurine, and dextrose

CON: ControlIsocaloric control

•MA led to greater gains in LBM, muscle strength and power•MA promoted increases in resting and exercise-induced testosterone and GH•MA decreased CK, indicating recuction in muscle damage

Limited/Unsupportive ResearchSupplement Proposed

ActionResearch to Support

Side Effects Legality

Carnitine Increases fat metabolism

Refutes, no benefits

None Legal

Chromium Increases lean muscle mass

Refutes, no benefit unless

prior deficiency

Potentially dangerous if >400 mg/day

Legal

Coenzyme Q10

Enhances electron

transport, improves

endurance

Limited, does not support use for

athletes

Appears safe Legal

DHEA(dehydroepiandrostero

ne)

Prohormone that increases lean muscle mass

Refutes, no benefits for

athletes

None Legal

MCT Increases energy and muscle cell

mass, delays fatigue

Limited Intestinal cramping and

diarrhea

Legal

Zinc Increases endurance,

mental alertness/concen

t.

Limited None if taken in recommended

doses

Legal

Supportive Research

Supplement Proposed Action

Research to Support

Side Effects Legality

Anabolic Steroids

Increases strength, LMM &

Motivation

Supports Significant, dangerous

Illegal

Blood doping Increases aerobic capacity

Supports Significant, dangerous

Illegal

Energy Gels & Sports Drinks

Increases endurance by

supplying CHO, fluid and lytes

Supports None Legal

Growth Hormone

Increases LMM, strength & power

Supports Enlargement of organs &

increased risk of disease

Banned by WADA

Protein Optimizes muscular growth

& repair

Supports None unless underlying cond.

Legal

Chocolate milk

“Chocolate milk as a postexercise recovery aid appears to be as effective as another carbohydrate replacement beverage.” Pritchett et al., 2009

Summary Dietary supplements for athletes are not well regulated

May be contaminated May contain substances not on the label, or may not contain what it claims

to contain Research on most ergogenic aids is limited and often

conflicting – interpret with caution Most studies used low number of subjects Often poorly controlled

Role of the RD Inform clients of the efficacy and safety issues surrounding nutritional

supplements Focus on those that are evidence-based (there aren’t many)! Caution of those with limited/unsupportive research

Stress the importance of proper diet and fluid intake for athletic performance Hydration – 20-24 oz fluid replacement for every pound lost CHO & quality protein to fuel workouts – 3-4 hrs prior Anabolic window – up to 30 min post workout

References

Cox GR, Desbrow B, Montgomery PG, Anderson ME, Bruce CR, Macrides TA, Martin DT, Moquin A, Roberts A, Hawley JA, Burke LM. Effect of different protocols of caffeine intake on metabolism and endurance performance. J Appl Physiol. 2002; 93: 990-999. 

Derave W, Everaert I, Beeckman S, Baguet A. Muscle carnosine metabolism and beta-alanine supplementation in relation to exercise and training. Sprots Med. 2010; 40(3): 247-263.

Hogervorst E, Bandelow S, Schmitt J, Jentjens R, Oliveira M, Allgrove J, Carter T, Gleeson M. Caffeine improves physical and cognitive performance during exhaustive exercise. Med. Sci. Sports Exerc. 2008; 40(10): 1841-1851.

Kraemer WJ, Hatfield DL, Volek JS, Fragala MS, Vingren JL, Anderson JM, Spiering BA, Thomas GA, Ho JY, Quann EE, Izquierdo M, Hakkinen K, Maresh CM. Effects of amino acids supplement on physiological adaptations to resistance training. Med. Sci. Sports Exerc. 2009; 41(5): 1111-1121.

Maridakis V, O’Connor PJ, Dudley GA, McCully KK. Caffeine attenuates delayed-onset muscle pain and force loss following eccentric exercise. Journal of Pain. 2007; 8(3): 237-243. 

McNaughton L, Dalton B, Palmer G. Sodium bicarbonate can be used as an ergogenic aid in high-intensity, competitive cycle ergometry of 1 h duration. Eur J Appl Physiol. 1999; 80: 64-69.

Pedersen DJ, Lessard SJ, Coffey VG, Chruchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA. High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. J Appl Physiol. 2008; 105: 7-13. 

Pritchett K, Bishop P, Pritchett R, Green M, Katica C. Acute effects of chocolate mild and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance. Appl Physiol Nutr Metab. 2009; 34: 1017-1022. 

ReferencesRequena B, Zabala M, Padial P, Feriche B. Sodium bicarbonate and sodium citrate: ergogenic

aids? J. Strength Cond. Res. 2005; 19(1): 213-224. Smith AE, Walter AA, Graef JL, Kendall KL, Moon JR, Lockwood CM, Fukuda DH, Beck TW,

Cramer JT, Stout JR. Effects of β –alanine supplementation and high-intensity interval training on endurance performance and body composition in men; a double-blind trial. Journal of the International Society of Sports Nutrition. 2009; 6:5. 

Sokmen B, Armstrong LE, Kraemer WJ, Casa DJ, Dias JC, Judelson DA, Maresh CM. Caffeine use in sports: considerations for the athlete. J Strength Cond Res. 2008; 22(3): 978-986.

Terjung RL, Clarkson P, Eichner R, Greenhaff PL, Hespel PJ, Israel RG, Kraemer WJ, Meyer RA, Spriet LL, Tarnopolsky MA, Wagenmakers AJM, Williams MH. The physiological and health effects of oral creatine supplementation. Med Sci Sports Exerc. 2000; 32(3): 706-717. 

Vandenberghe K, Gillis N, Van Leemputte M, Van Hecke P, Vanstapel F, Hespel P. Caffeine counteracts the ergogenic action of muscle creatine loading. J Appl Physiol. 1996; 80(2): 452-457.

Volek JS, Kraemer WJ, Bush JA, Boetes M, Incledon T, Clark KL, Lynch JM. Creatine supplementation enhances muscular performance during high-intensity resistance exercise. J Am Diet Assoc. 1997; 97: 765-770.

Zanchi NE, Gerlinger-Romero F, Guimaraes-Ferreira L, Alves de Siqueira Filho M, Felitti V, Lira FS, Seelaender M, Lancha AH. HMB supplementation: clinical and athletic performance-related effects and mechanisms of action. Amino Acids. 2010; 130: 1937-1945

Questions?