Broccoli Effect on Glycated Haemoglobin (HbA1c)

The BETA study is a 36-week randomized, double-blind, placebo-controlled, two-arm crossover intervention study conducted at the Quadram Institute Clinical Research Facility (QI CRF), Norwich, UK. Investigators are seeking adults with pre-diabetes, to determine whether broccoli soups affect glucose metabolism, compared to a similar soup containing courgette. There are a total of 9 clinical visits (1 screening visit, 4 short visits, and 4 oral glucose tolerance testing visits). Investigators will assess blood samples for glycated hemoglobin (HbA1c), fasting plasma glucose, insulin, fructosamine, cholesterol and triglycerides. Investigators will also quantify the metabolites in urine through analytical analysis and determine whether gene expression is altered by the soups through RNA sequencing. Participants will consume one of two soups (broccoli or courgette) for the first intervention period then after a twelve-week washout phase (soup holiday), participants will crossover and consume the other soup for the second intervention period. For each intervention period, soups will be consumed three times a week per twelve-week period. Investigators will ask the participant to complete lifestyle questionnaires regarding their physical activity and dietary pattern.

Inclusion criteria

• Individuals with prediabetes (confirmed through screening)
• Aged 18 and older.
• Body Mass Index (BMI) between 18.5 - 35 kg/m2.
• Living within 40 miles from the Norwich Research Park.

Exclusion criteria

The participant will not be able to take part if they('re):

• Screening test results indicate they are not suitable to take part in this study such as HbA1c level at screening visit of < 42 mmol/mol (healthy) and > 47 mmol/mol (diabetes) and BMI at screening visit < 18.5 kg/m2 (underweight) and > 35 kg/m2 (extremely obese).
• Have a known allergy to any of the components (broccoli, courgette, milk, lactose, or gluten) of the test soups.
• Have been diagnosed or have a history of blood or clotting disorders such as anaemia or thrombosis.
• Have been treated for heart disease, cancer, or diabetes.
• Are immunocompromised due to medications or viral infection such human immunodeficiency virus (HIV).
• Have low or high blood pressure with hypertension medication (≤90/60, ≥160/100 respectively would be classed as abnormal).
• Have any acute or chronic illnesses that affects the outcome of the study such as a gastrointestinal disorder. This will be assessed on a case by case basis by QI medical advisor.
• Plan to become pregnant during the study duration, pregnant or breastfeeding.
• Frequently take medications that may interfere with sugar metabolism or absorption such as laxatives, steroids, dietary supplements, or anti-inflammatory medications. This will be assessed on a case by case basis by QI medical advisor.
• Drink more than 14 alcohol units/week.
• Smoke socially or on occasion more than 12.5 grams or 20 cigarettes/week
• Vegan or any dietary restrictions that prevent the consumption of study soups or follow a diet programme which requires fasting for multiple days.
• Are a registered blood donor and have donated a large quantity of blood within the last 16 weeks. Registered blood donors should abstain from blood donations for the duration of the study.
• Are unable to give written or verbal informed consent
• Unable to provide GP contact details.
• Are participating in another dietary intervention study nor given blood in another dietary study in the last 3 months.
• Are related to or living with any member of the study team or part of the management/supervisory structure of the Chief Investigator.
• Have symptoms of COVID-19, been asked to self-isolate, or have been diagnosed with COVID-19 in the last 14 days.