The effect of a dietary ketone on immunity and tolerability in recreationally active, healthy males at rest.

Experimental procedure: Participants will arrive at the laboratory at 06:00 h having fasted from 23:00 h the previous day and having abstained from caffeine, alcohol and strenuous exercise for the previous 24 h. Upon arrival, participants will have a cannula inserted into their antecubital vein and will rest quietly for ~10 min prior to initial blood and saliva samples, ketone levels and tolerability scores being collected (baseline measures). Participants will be asked to void their bladder before their body mass (shorts only), height and sum of 8 skinfolds are measured by an International Society for the Advancement of Kinanthropometry Level 1 Accredited Anthropometrist. To standardise nutritional status, participants will complete a 24-hour food diary the day before the trial and will be asked to follow this during the 24-hour prior to the second, third and fourth trials. Participants will then consume a 200 ml citrus flavoured drink at two time points; 06:30 and 08:00 h. The drinks will be formulated to provide a series of different doses of 1,3-butanediol (1,3-BD); a) 0g/kg and 0g/kg; b) 0.5g/kg and 0g/kg; c) 0.7g/kg and 0g/kg and; d) 0.35 g/kg and 0.35 g/kg. Participants will be blinded to the dose of 1,3-BD in a randomised crossover design. Blood and saliva samples will be collected at 30, 120, 150 and 210 min spot the initial intake of 1,3-BD. Ketone levels will be measured at 15, 30, 45, 60, 75, 90 120, 150 and 210 min post the initial intake of 1,3-BD . Tolerability scores will be collected 30, 150, 210 and 480 min post the initial intake of 1,3-BD. Participants will be asked to describe additional symptoms experienced that were not specified on the questionnaire. Participants will be asked to identify what drink they consumed. Participants will be unable to consume food or beverages throughout the duration of the trial (i.e. 06:00 h to ~10.00 h), however, water can be consumed ad libitum. 10 min prior to each saliva collection, participants will be asked to refrain from drinking. Participants will remain in the Sport Research Institute of New Zealand (SPRINZ) laboratory, where they will remain resting. All samples will be collected and tolerability questionnaires will be completed in the SPRINZ laboratory. Following completion, participants will be provided with 400 ml of a carbohydrate drink and recommended to return to their normal dietary patterns and asked to return to the laboratory after 3 – 10 days for each subsequent trial. Drink formulation: Citrus flavoured drinks will be made using Food Chemicals Codex (FCC) approved, food grade 1,3-BD (Product Number 02-59620; Penta Manufacturing Ltd, Livingston, USA). Safety monitoring: Participant tolerability, side-effects and abnormal haematological values will be immediately reported to a medical doctor. This study will be immediately terminated when advised the medical doctor or following intractable symptoms after 1,3-BD consumption in 2 trial arms (i.e. 10% of trials). Participants will be followed up 3 days and 1 week after the consumption of 1,3-BD to ascertain if any adverse effects occurred. Participants will also be encouraged to report any symptoms following consumption of 1,3-BD by email, phone or text.