The winter months see a natural peak in the incidence of the common cold and respiratory infections. Athletes, especially those at an elite level are at an increased risk of respiratory infections. Prolonged intense exercise causes a state of physiological stress and affects the body’s ability to fight infections. In what’s been referred to as an “open window” of impaired immunity (which may last 3-72 hours after intense exercise), the body’s resistance to infection is lowered, and it is during this time that infection may take hold.1
Nutritional supplements may help to support the immune system in helping with the prevention of respiratory infections, and also reducing the severity and duration of symptoms. Taking supplements such as vitamin D, lactoferrin, colostrum and probiotics during the winter months or periods of intense training may help athletes offset these changes in the immune system.
Vitamin D is one of our most important immune-boosting nutrients. The results of a recent review of the scientific literature showed that vitamin D supplementation significantly reduced respiratory tract infection related events when compared to placebo.2 Observational studies have also linked low vitamin D status to an increased risk of respiratory tract infections.3
Lactoferrin is an important protein produced by the body that is involved in the first line of defence against infections.4 A recent Australian study has shown that a lactoferrin/immunoglobulin combination significantly decreased the incidence of colds and the number of cold-related symptoms, indicating its potential as a preventative treatment.5
Bovine colostrum is rich in macro and micronutrients including proteins essential for immune function. Colostrum can help to maintain immune function and increase resistance to respiratory infections in athletes undertaking heavy training.6
“Good” bacteria (probiotics) can compete with pathogens that cause infection and help to regulate the immune response. A major review of clinical trials involving over 3000 participants found that probiotics were effective for reducing respiratory tract infections.7
- Walsh NP, Gleeson M, Pyne DB, et al. Position statement. Part two: Maintaining immune health. Exerc Immunol Rev 2011;17:64-103.
- Charan J, Goyal JP, Saxena D, Yadav P. Vitamin D for prevention of respiratory tract infections: A systematic review and meta-analysis. J Pharmacol Pharmacother 2012 Oct;3(4):300-3.
- Jolliffe DA, Griffiths CJ, Martineau AR. Vitamin D in the prevention of acute respiratory infection: Systematic review of clinical studies. J Steroid Biochem Mol Biol 2012 Dec 7. pii: S0960-0760(12)00250-6.
- Conneely OM. Antiinflammatory activities of lactoferrin. J Am Coll Nutr 2001 Oct;20(5 Suppl):389S-395S.
- Vitetta L, Coulson S, Beck SL et al. The clinical efficacy of a bovine lactoferrin/whey protein Ig-rich fraction (Lf/IgF) for the common cold: A double blind randomized study. Complement Ther Med 2013 Jun;21(3):164-71.
- Davison G. Bovine colostrum and immune function after exercise. Med Sport Sci 2012;59:62-9.