Neurological, Inflammatory and Metabolic Effects of Acute Mushroom Intervention in Older Adults
Condition: Cognitive Change; Mood; Metabolism; Inflammatory Response; Satiety
Study type: Interventional

Summary: 
      This randomized crossover trial (RCT) investigates the acute effect (over a 6-hour period) of
      a meal containing varying serving sizes (doses) of freeze-dried oyster mushroom powder, on
      the cognitive behaviour and markers of metabolism and inflammation related to neuronal health
      in healthy adults aged 60-80 years old. The study will involve a screening visit and four
      testing visits, with a week interval between each. During the four testing visits,
      cognitive-mood battery tests will be taken at baseline and then at 2-, 4- and 6-hour
      intervals following the consumption of the intervention meal. Also, a blood draw will be
      taken at the end of each testing visit day to allow the determination of inflammatory,
      metabolic and neuronal markers.
    

Detailed description: 
      The Pleurotus oyster species is a common edible mushroom rich in ergothioneine, a bioactive
      compound with known neurocognitive benefits. The aim of the OYSACO RCT is to provide a
      clearer understanding of how a meal containing varying serving sizes (doses) of freeze-dried
      oyster mushroom powder, may acutely regulate cognitive improvements in humans during the
      immediate postprandial period. The investigators will investigate the neurological and
      physiological changes underlying these benefits.

      During the OYSACO RCT, participants will attend the University of Reading, Psychology
      department on five separate occasions, with a week interval between each visit. Specifically,
      in the pre-screening phase, to check for eligibility, the participants interested in our
      study will be sent a link to REDCap containing online versions of a Health and Lifestyle
      Questionnaire containing basic demographic questions (eg age, sex, heigh, weight,
      nationality, disease history and medication use) and the Epic Norfolk Food Frequency
      Questionnaire (FFQ), to assess their habitual dietary intake. Then, participants, will be
      contacted to attend a 2-hour screening session at our department, during which the
      participant's weight, height and blood pressure will be checked, along with a finger-prick,
      to ensure that the participants are not anaemic. Three drops of blood will be taken from the
      tip of the either the index or ring finger for this measure. Furthermore, participants will
      complete the Raven's Progressive Matrices (RPM) measure of fluid intelligence and will
      perform the cognitive battery tasks twice to control for practice effects in the run up to
      the test session days.

      One week after the screening visit, each participant will attend a further four test
      sessions, each separated by a week, where they will receive a different dose of freeze-dried
      oyster mushrooms. The order of intervention will be randomised, and participants will be
      asked to follow a low fibre and flavonoid diet for 48 hours in advance of testing. Before
      each test visit, the participants will be asked to fast for 12-hours and then to consume only
      a slice of toast with butter and 1 glass of water at 07:00 a.m., before attending the
      university. As soon as the participants arrive at our laboratory at 08:00 a.m., baseline
      cognitive and mood tests will be completed. After completing the baseline measures, the
      participants will receive one of the 3 mushroom interventions or the control intervention.
      The procedure on each test day will be identical except for the intervention meal.
      Specifically, the intervention meals will consist of a noodle soup containing the equivalent
      of 0.5, 1 and 2 servings of powdered Pleurotus oyster mushroom or a calorie-matched control
      non-mushroom noodle soup containing a mixture of maltodextrin and cornflour. The ingredients
      present in the intervention meals are all standard ingredients used in the food industry and
      are included at safe levels. Allergy information will be available on request. The dried
      oyster mushroom powder was prepared according to the Federal Good Manufacturing Practices and
      US Food Guidelines and is certified free from unauthorised pesticides, and microbiological
      and other contaminants.

      Two-hours after consuming the intervention, the participants will be asked to complete the
      same cognitive and mood tests, and a calorie-matched lunch will then be provided between
      12:00-12:30 p.m. containing a chicken sandwich, a packet of crisps and a glass of water.
      Participants will then be asked to complete the cognitive and mood tests a further two times
      (4-hours and 6-hours post-intervention) and a blood test will be drawn at the end of the
      visit.

      In addition to the cognitive tests, palatability measures will be taken immediately after the
      consumption of the intervention meal while at the end of each cognitive test session (at
      baseline, 2-, 4- and 6-hours), ratings of subjective appetite and fullness will be recorded
      using an online analogue scale. At the end of the 5-week study, participants will be asked to
      complete a brief dietary questionnaire, consisting of specialised questions, relating to
      their habitual mushroom intake.

      In terms of cognitive testing, there will be four cognitive task battery sessions taking
      place at baseline and then at 2-, 4-and 6-hours post-intervention, to assess participants'
      episodic and working memory, psychomotor and executive function and mood domains. Each
      battery will be matched for difficulty and order of presentation will be randomised. Although
      the exact cognitive battery is yet to be confirmed, all tasks will be completed on the
      computer and should take no longer than 45 minutes to complete. The battery is likely to
      contain the following or similar tasks:

        -  Positive and Negative Affect Schedule (PANAS-SF)- In this mood task, participants are
           asked to rate their emotion on a 5-point Likert scale, in response to 20 mood related
           adjectives (10 relating to positive emotions and 10 to negative emotions).

        -  Rey Auditory Verbal Learning Task (RAVLT)- This episodic memory task consists of 5
           consecutive free recalls of the same 15 nouns presented as an auditory list (list A),
           followed by recall of a further 15 nouns presented as an interference list (list B)
           which is recalled only once. List A is subsequently recalled straight after list B and
           then again after a longer delay of around 30 minutes.

        -  Corsi block tapping task (CBTT)- In this spatial working memory task, participants are
           shown with 9 arranged blocks positioned on a computer screen and are asked to reproduce
           given sequence by clicking on the blocks (using the mouse) in the same sequence as they
           see them.

        -  Simple and complex finger tapping task- In this motor function task, participants tap on
           a key as quickly as possible with the index finger of their dominant hand for 1 minute.
           They then tap out a specific sequence using 4 fingers, again for 1 minute.

        -  Task Switching Task (TST) - In this executive function task, participants view 8 spaced
           radii of a circle above and below a bold line and a stimulus digit selected from 1-9
           (except 5) appears clockwise in each segment, either above or below the bold line.
           Depending on the stimulus position in the segments, participants perform different tasks
           with each being switched in every 4 trials.

        -  RAVLT word recall- After a period of time, participants are asked to recall as many
           words as possible from list A.

        -  RAVLT word recognition- In this delayed memory task, participants are shown a sequential
           list of 50 nouns containing the words from lists A and B from the previously described
           RAVLT task plus 20 additional words not previously heard, and are asked to indicate
           those from list A.

      During each test day, participants will have one 9-millilitre blood draw taken from their
      arm, 6-hours after receiving the intervention meal. Following each draw, the serum will be
      separated via centrifuge and stored at at -80°C until analysis is complete. Whole blood
      samples will not be stored at any point during the study. Blood serum will be analysed for
      anti-inflammatory and metabolic ability by measuring the levels of fasting glucose and lipids
      in the blood, the markers of inflammation, as well as the levels of the brain derived
      neurotrophic factor (BDNF), a signalling protein known to be related to neuronal signalling
      and memory function.
    

Intervention name(s): Instant noodle soup containing containing the equivalent of 2 servings (18.78g) of powdered Pleurotus oyster mushroom.; Instant noodle soup containing containing the equivalent of 1 serving (9.39g) of powdered Pleurotus oyster mushroom.; Instant noodle soup containing containing the equivalent of 0.5 serving (4.70g) of powdered Pleurotus oyster mushroom.; Control instant noodle soup
Intervention type(s): Other; Other; Other; Other
Intervention description(s): Ingredients: celery, garlic, ginger, gluten, polyphosphate, parsley, pepper, potassium carbonates, dried Pleurotus oyster mushroom, salt, sodium, sunflower oil, turmeric, yeast extract and wheat flour.; Ingredients: cornflour, celery, garlic, ginger, gluten, polyphosphate, parsley, pepper, potassium carbonates, dried Pleurotus oyster mushroom, maltodextrin, salt, sodium, sunflower oil, turmeric, yeast extract and wheat flour.; Ingredients: cornflour, celery, garlic, ginger, gluten, polyphosphate, parsley, pepper, potassium carbonates, dried Pleurotus oyster mushroom, maltodextrin, salt, sodium, sunflower oil, turmeric, yeast extract and wheat flour.; Ingredients: cornflour, celery, garlic, ginger, gluten, polyphosphate, parsley, pepper, potassium carbonates, maltodextrin, salt, sodium, sunflower oil, turmeric, yeast extract and wheat flour.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Cognition; Mood; Inflammation; Metabolism