Acute, randomized, placebo controlled, double blind, 4 arm crossover study to determine the effect of different combinations of plant based extracts on cognitive function and cerebral blood flow.

The objectives of this study are to assess the effects of oral consumption of three differing combinations of plant based extracts, on cognitive function and cerebral blood flow (using Near infrared Spectroscopy) in comparison to placebo. The primary outcome will be change in cognitive function and mental fatigue during extended performance of the Cognitive Demand Battery (CDB) at 1, 3 and 6 hours post- consumption.

Inclusion Criteria:

• Are over 18 or under 49 years of age
• Self-report of good health
• Are not excluded on the basis of the following exclusion criteria
• English is first language (some of the cognitive tests have only been validated in native English speakers)

Exclusion Criteria:

• Are below 18 or above 49 years of age
• Are a smoker
• Have food allergies or sensitivities to any of the ingredients contained in the investigational product or any other foodstuff
• Currently take medication except the contraceptive pill
• Have habitually used dietary supplements within the last month (defined as more than 3 consecutive days or 4 days in total)
• Have sleep disturbances and/or are taking sleep aid medication
• Have a Body Mass Index (BMI) outside of the range 18-35 kg/m2
• Have high blood pressure (systolic over 139 mm Hg or diastolic over 89 mm Hg)
• Have a history of neurological, vascular or psychiatric illness including epilepsy or seizures (excluding depressive illness and anxiety)
• Have a current diagnosis of anxiety or depression
• Are pregnant, trying to get pregnant or breast feeding
• Have a recent history of (within 12 months of screening visit) or strong potential for alcohol or substance abuse. Alcohol abuse is defined as more than 60g (men) / 40g (women) pure alcohol per day (7 / 5.5 units)
• Are (or are seeking to become) pregnant or are lactating
• Have learning difficulties, dyslexia or colour blindness
• Have visual impairment that cannot be corrected with glasses or contact lenses
• Have frequent migraines that require medication (more than or equal to 1 per month)
• Have disorders of the blood
• Have a heart disorder or a history of vascular illness
• Have a respiratory disorder that requires regular medication (Note: participants with asthma who only take their medication occasionally/as required are eligible for this study)
• Have type I or type II diabetes
• Have a history of renal or hepatic disease, or other severe diseases of the gastrointestinal tract (e.g. iron accumulation, iron utilization disorders, hypercalcaemia, hypercalciuria), that are likely to interfere with metabolism/absorption/secretion of the product under investigation
• Have any health condition that would prevent fulfillment of the study requirements
• Are currently or have in the past 4 weeks participated in other clinical or nutrition intervention studies
• Do not have a bank account (required for payment)