Table 1 Characteristics of included studies
Study (country) | Sample size | Age, years | Proportion of males | Inclusion criteria | Exclusion criteria | Intervention, dose, frequency/timing, duration, diluter | Placebo |
|---|---|---|---|---|---|---|---|
Crooks et al. 2006 [16] (New Zealand) | BC: 18 PLA: 17 | Median (range) BC: males, 46 (35–57), females, 43 (30–53) | 0.48 | Pack runs ≥ 1 week, marathon training over last 5 years, age < 60 year | Lactose intolerant, allergy to cows milk, whey-protein supplements, treatment for any diagnosed condition | Oral BC (Immulac, NZMP Ltd, Auckland, New Zealand), 26 g of powdered sachets/day corresponding to 10 g of BC, daily, 12 weeks, chocolate powder with 125 ml water | Skim milk matched for equivalent digestible protein content. Flavours and colours added to match BC |
PLA: males, 48 (36–56) females, 51 (41–58) | |||||||
Crooks et al. 2010 [17] (New Zealand) | BC: 12 PLA: 13 | Mean ± standard error BC: males, 17 ± 1 females, 20 ± 1 | 0.57 | Participating in training program prior to The Auckland Swimming Championships | Lactose intolerant, allergy to cows milk, whey-protein, immunological-modulating supplements, treatment for any diagnosed condition | Oral BC (Immulac, NZMP Ltd, Auckland, New Zealand), 52 g of powdered sachets/day corresponding to 20 g of BC, 10 g morning & evening, 10 weeks, 125 ml water | Skim milk powder, matched for equivalent protein, fat and carbohydrate content |
PLA: males, 19 ± 1, females, 18 ± 1 | |||||||
Jones et al. 2014 [14] (Wales) | BC: 25 PLA: 28 | Mean ± standard deviation BC: 31 ± 14 PLA: 32 ± 13 | 1.00 | ≥3 h moderate-vigorous endurance exercise/week | Smoker, medication or other supplements, infectious illness in 4 weeks prior to study | Oral BC (Neovite, UK, London), 20 g/day, 10 g with morning & evening meal, 12 weeks | Isoenergetic/isomacronutrient PLA as described elsewhere |
Shing et al. 2007 [18] (Australia) | BC: 14 PLA: 15 | Mean ± standard error BC: 29 ± 1 PLA: 27 ± 2 | 1.00 | Cyclists racing competitively ≥ 2 months, consistent training volumes ≥ 2 months | Dietary supplements 1 month prior to study | Oral BC (Numico Research Australia, South Australia, Australia), 10 g/day, morning, 8 week 1 day, 50 ml water + 100 ml milk | Whey protein (Alacen 80; Fonterra Co-op group Limited, Auckland, New Zealand) |
Shing et al. 2013 [19] (Australia) | BC: 4 PLA: 6 | Mean ± standard error BC: 22 ± 3 PLA: 23 ± 2 | 1.00 | Cyclists racing competitively ≥3 months. Consistent training volumes ≥ 2 months | None reported | Oral BC (Numico Research Australia, South Australia, Australia), 10 g/day, morning, 8 weeks and 5 days, 50 ml water + 100 ml milk | Whey protein concentrate (Alacen 80; Fonterra Co-op group Limited, Auckland, New Zealand) |