Throughout the winter months of 2010 Accredited Sports Scientist Luke Delvecchio participated in a probiotic supplement study conducted by the Australian Institute of Sport and Griffith University.

The primary aim of the study was to evaluate the effect of two different probiotic supplements on the incidence of upper respiratory tract illness (the common cold) over a 5 month winter period.

The secondary aim was to investigate the effects of probiotic supplementation on discrete aspects of immune function and faecal microbiology in a smaller group of individuals in the study.

Participants in the study were assigned to one of three supplement groups, including:

• Group X; which was a probiotic supplement containing Bifidobacterium animalis subsp. lactis Bl-04;
• Group Y; which was the placebo supplement; and
• Group Z; which was the second probiotic supplement that contained two probiotic species, Bifidobacterium animalis subsp. lactis Bi-07 and Lactobacillus acidophilus NCFM.

Luke Delvecchio was in Group X.

Briefly, the main findings of the study were that, in comparison to the placebo, those supplementing with Bifidobacterium animalis subsp. lactis Bl-04 (Group X) had a substantially lower number of cold episodes (upper respiratory symptoms), chest illnesses (lower respiratory illnesses) and lower use of cold medications.

Those on the multi-strain supplement (Group Z) had a substantially lower number of chest illnesses (lower respiratory illness), lower cold medication use but no substantial difference in cold episodes (upper respiratory illnesses) than those on the placebo supplement.

The health benefits of probiotic supplementation are thought to occur by changing the composition of gut bacteria and enhancing the activity of the immune system. In this study only the group on the multi-strain supplement (Group Z) had a change in the composition of gut bacteria (as measured in faeces). Furthermore, there were no substantial effects on the immune measures in either probiotic group.

This study is one of the first to examine the consumption of a probiotic in powder form rather than in a capsule. The rationale for using a powder was to examine whether exposing the respiratory tract directly to probiotics would have a beneficial effect. In powder form the probiotics are unlikely to have survived transit through the stomach so it is not surprising that the gut bacteria were not altered.

While no evidence for altered immunity was evident we caution making conclusions regarding the effects of probiotics on immune function. The immune system is recognised as being a complicated, multi-dimensional system. Our focus was on two discrete aspects of immunity in blood. It may be that other immune parameters in the respiratory tract may have been enhanced and further investigation is required before a definitive conclusion is reached on this issue.

Take home message: the conclusion of the research team from this study is that these particular probiotic supplements reduce the rate of respiratory illnesses and the use of cold and flu medication in healthy, physically active individuals.