None listed
Conditions
Brief summary
This project aims to measure biomarkers of nitrate metabolism in the body after vegetable and meat intake. To assess this, we will examine biomarkers (nitrate, nitrite and N-nitrosamines) in urine and faecal (stool) samples. The study hypothesis is that eating nitrate-rich vegetables with meats that do not contain added nitrate or nitrite will not increase potentially harmful N-nitrosamines in the body, whereas eating nitrate-rich vegetables with meats that do contain added nitrate or nitrite will increase these compounds, despite the natural protective substances found in vegetables.
Interventions
This study uses a crossover design, with each participant completing all three dietary interventions in randomised order. Each intervention phase will be separated by a 1-week washout period. All foods and drinks will be provided by the research team to standardise dietary intake and ensure compliance. Participants’ diets will be matched across visits.
Dietary standardisation:
Day before study visit: Participants will consume a standardised diet consisting of one of four breakfast options (whi
This study uses a crossover design, with each participant completing all three dietary interventions in randomised order. Each intervention phase will be separated by a 1-week washout period. All foods and drinks will be provided by the research team to standardise dietary intake and ensure compliance. Participants’ diets will be matched across visits. Dietary standardisation: Day before study visit: Participants will consume a standardised diet consisting of one of four breakfast options (white bread toast with eggs, peanut butter, jam, or cheese), a lunch of pumpkin soup with white bread, and a low-nitrate vegetarian dinner with basmati or jasmine rice. Participants will be asked to refrain from coffee, alcohol, and exercise for 24 hours prior to the study visit. Day of study visit: Participants will arrive fasting. Breakfast and lunch will consist of the intervention meals. A standardised low-nitrate vegetarian dinner will be provided after data collection. Participants will again refrain from coffee, alcohol, and exercise for the duration of the 24-hour urine collection period following the first intervention. Interventions: 1. High-nitrate vegetables plus meat with nitrate additive Composition: 100g spinach + 50g salami + 35g ham served on white bread (sandwich format), provided at breakfast and lunch. Estimated nitrate content: ~103mg. Purpose: to determine whether adding high-nitrate vegetables to meats containing nitrate as an allowed additive influences N-nitrosamine formation (reflecting both endogenous and exogenous sources). 2. High-nitrate vegetables plus meat without added nitrate Composition: 100g spinach + 65g pork mince (no nitrate permitted as additive) served on white bread at breakfast and lunch. Estimated nitrate content: ~102mg. Purpose: to assess whether consuming high-nitrate vegetables with meats not containing added nitrate leads to endogenous N-nitrosamine formation, and whether vegetable constituents protect against such increases. Meal consumption and adherence monitoring: Participants will consume each meal within 30 minutes under direct supervision at the study unit. All foods and water will be provided by study staff to ensure full control of dietary intake and adherence across study periods.
Sponsors
Edith Cowan University
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Blinded (masking used) (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
Healthy, ambulant, community-dwelling men and women aged between 18 to 80 years old and with no history of major chronic disease, from the Perth general population.
Exclusion criteria
Current or recent ( 160 mmHg ; diastolic blood pressure > 100 mmHg; any major illness such as cancer, psychiatric illness, diagnosed diabetes; use of any of the following medications: statins, antihypertensives, nitric oxide donors, antithrombotic medication, anti-coagulant medication, anti-arrhythmic drugs, beta-blockers, regular aspirin use, regular proton pump inhibitor use; alcohol consumption > 30g/day; women who are pregnant, lactating, or wishing to become pregnant during the study; use of antibiotics within the previous 12 weeks of the study; regular use of mouthwash and not willing to cease mouthwash use for the duration of the study; participation on other research studies; major GIT condition e.g. Crohn’s disease and inflammatory bowel disease; and inability or unwillingness to follow the study protocol.
Outcome results
None listed