Stacking- A popular practice is to combine supplements in order to enhance their ergogenic actions.
Positive examples include:
  • β-Alanine and creatine can work together to delay fatigue.
  • Creatine and β-hydroxy β-methylbutyrate (HMB) work together to promote growth and maintenance of lean body mass.
  • Creatine and bicarbonate can aid in buffering exercise-induced acid production to allow for higher repetitions of high intensity exercises.
However, unintentional combinations of supplements can lead to negative side effects.  For example,
  • The authors stated that caffeine will negate the benefits of iron supplements because it decreases the absorption of iron from the gut.  EAS ACADEMY NOTE:  It is likely that decreased iron absorption resulting from coffee ingestion is more likely due to complexing of iron with polyphenolic compounds in the coffee, rather than the caffeine.
  • Different supplements may have the same ingredients and unintentional overdosing can occur.  For example, toxic levels of zinc can occur when consuming many sports supplements that are enriched with zinc.
Athletes should carefully note the ingredients, including added vitamins and minerals, and research interactions that their favorite supplements may have in order to maximize their effects and reduce the risk of side effects.

Taurine- Taurine is commonly found in energy drinks.  It is an organic acid and has an amino group, but lacks the carboxylic acid that is found in the amino acids in food proteins. Supplementation with taurine has shown to be positive in skeletal muscle function in rodents, but these claims have yet to be demonstrated in human subjects.  In contrast, most studies that have been performed with taurine alone do not yield benefits to performance or metabolism.

Theobromine and theophylline- Theobromine and theophylline are present naturally in chocolate, tea, and several other plants.  They are also metabolites of caffeine in humans.  Several studies showed that theophylline can increase oxygen capacity, though not all studies reach this same conclusion.  It is thought the most beneficial effects of theobromine and theophylline may be potentiating the effects of other stimulants, such as ephedrine, but this hypothesis requires most thorough investigation.

Key practice applications: Athletes who consume supplements and functional foods tend to combine ingredients, either intentionally or unintentionally.  It is important for athletes to be aware of what they are combining to prevent negative interactions and overdoses, as well as to increase the effects of their supplements.  More research is also encouraged on the effects of combining popular supplements in order to maximize their acceptability and ergogenic effects.

Key search terms for this article (5-7 terms): creatine, HMB, β-alanine, theobromine, theophylline, asthma, chocolate, taurine, stacking