This study will evaluate the effects of substituting red and processed meat in the diet with Quorn; a meat replacement product, on biomarkers of gut health. This will be a crossover design where participants will take part in 2 study periods where they will consume a diet containing red and processed meat during one of the study periods, whereas in the other study period, they will consume a diet containing Quorn.

There is a strong association between a diet which is high in red and processed meat, while low in fibre, and the incidence of colorectal cancer. This study aims to evaluate the effects of replacing red and processed meat in the diet with an alternative meat product such as Quorn, on biomarkers of gut health that may be associated with colorectal cancer.

Quorn is a product which has a considerable fibre component; thus, the replacement of red and processed meat with Quorn, will not only reduce the amount of compounds implicated to have deleterious effects in the gastrointestinal tract (E.G. haem, nitroso compounds, heterocyclic amines), but will also increase the delivery of fibre into the gastrointestinal system, that may well have an overall positive impact on gut health.

In this study, the participants will consume 240 grams (raw weight) of either red and processed meat, or Quorn each day for a 2 week period, this will be followed by a 4 week period where they will return to their usual dietary habits; before swapping to consume the alternative food (red/processed meat or Quorn) for another 2 week period.

Inclusion Criteria:

• Male
• 18-50 years.
• Not been diagnosed with colorectal cancer, or adenomas.
• Habitual omnivorous dietary pattern.
• BMI ≥18-30 kg/m2.
• Blood HbA1c <58mmol/mol (<6.5%) (not diagnosed with diabetes)
• Fasting total cholesterol<7.8 mmol/l
• Triglycerides <2.3 mmol/l
• Normal liver function (assessed by measuring liver enzymes in the screening blood sample).
• Blood pressure lower than BP <140/90 mmHg.
• Not suffering any cardiovascular diseases/ heart diseases e.g. stroke in the past 12 months.
• Do not suffer from chronic gastrointestinal problems (e.g. Inflammatory Bowel Disease, Irritable Bowel Syndrome, coeliac disease)
• Do not take supplements or medication that effects gastrointestinal health
• Not participated in a pre-/probiotic or laxative trial within the previous 3 months.
• Not been prescribed and/or taken antibiotics in the previous 6 months.
• No history of alcohol misuse based on self-reported alcohol intake and measurement of liver enzymes in the screening blood sample.

Exclusion Criteria:

• Been diagnosed with colorectal cancer and/or colorectal adenomas.
• Been diagnosed with gastrointestinal disorders (e.g. Inflammatory bowel disease, irritable bowel syndrome, coeliac disease)
• Adherence to a dietary pattern which excludes foods from an animal origin.
• Abnormal blood biochemistry based on standard clinical cut- offs, as well as blood markers not fitting the inclusion criteria set.
• Have history of food intolerances/allergies (e.g. gluten or dairy) or intolerances (e.g. lactose).
• Taking, or unwilling to stop taking anti-oxidant supplements (e.g. vitamin C, vitamin E, Multivitamin tablets, polyphenol supplements)
• Received antibiotics in the previous 6 months.
• Have participated in similar dietary or prebiotic/probiotics study in the previous 3 months.
• Current smoker.

De-identified individual participant data for all primary and secondary outcome measures will be made available.

Data will be available within 18 months of study completion

Northumbria University has plans to acquire a data repository for sharing data in the near future.