The Effects of Foods on Cell Damage Study

Randomised 6-week, Parallel Group, Placebo Controlled Intervention Trial to Investigate the Effects of White Carrots on Inflammatory Markers and Lymphocyte DNA Damage

Studies have shown that certain compounds inside vegetables can reduce the risk of cancer. Carrots in particular have an association with reduced incidence of colorectal, bladder and breast cancer. Compounds in carrots, called polyacetylenes, have been studied in isolated cells that have shown a reduction in cancer cells as well as inflammatory markers which have been associated with an increased risk of cancer. These polyacetylenes have not been well studied in the human body and it is unclear whether they are able to affect the biomarkers of health (disease) including DNA damage and inflammatory markers. The aim of this research project is to determine whether eating a portion of white carrots every day for 6 weeks can lead to a reduction in DNA damage and inflammatory markers compared to a control period of 6 weeks consuming a polyacetylene-free diet and a control food of a high fibre oat biscuit.

White carrots contain compounds called polyacetylenes, including falcarinol, falcarindiol and falcarindiol-3-acetate.

The 3 oat biscuits contain the same amount of fibre and sugar as the white carrot but without the polyacetylenes.

Change in lymphocyte DNA damage from baseline after 6 weeks of carrot or oat supplementation in the diet, and after 6 weeks wash out (no carrots or oats).

Lymphocyte DNA damage will be measured by comet assay. Comet 'tail length' represents the number of single strand breaks in the DNA that leave the nucleus when the cells undergo electrophoresis - the longer the 'tail' the more strand breaks. Tail length will be measured from lymphocyte DNA samples at baseline, after 6 weeks of the intervention period and again after 6 weeks of the wash out period. Statistical analysis will compare the extent of damage after supplementation of carrots or oats in the diet (intervention period) to damage at baseline and to damage after the wash out period.

Change in inflammation from baseline after 6 weeks of carrot or oat supplementation in the diet, and after 6 weeks wash out.

Inflammatory markers (blood CRP, TNF-alpha, IL-6 and urine PE2M) will be measured by ELISA assay. at baseline, after 6 weeks of the intervention period and again after 6 weeks of the wash out period. Statistical analysis will compare the inflammation levels after supplementation of carrots or oats in the diet (intervention period) to inflammation at baseline and inflammation after the wash out period.

Analysis of faecal water from baseline after 6 weeks of carrot or oat supplementation in the diet, and after 6 weeks wash out to determine toxicity to colon epithelial cells.

Faecal samples will be collected at baseline, after intervention and after wash-out. Faecal water will be removed from the samples and used in cell culture with colon epithelial cells. After culture, the cells will undergo comet assay to determine the amount of strand breaks that occur in each of the three treatments. Tail length will be measured from colon epithelial cell DNA samples from baseline, intervention period and the wash out period samples. Statistical analysis will compare the extent of damage to epithelial cells after exposure to faecal water made during supplementation of carrots or oats in the diet (intervention period) to damage with baseline and wash out period faecal water.

Inclusion Criteria: Non -smokers BMI between 18.5 and 30 Exclusion Criteria: smoking taking anti-inflammatories taking aspirin or aspirin-like drugs antibiotic use in the last 3 months metabolic conditions or conditions affecting the metabolism or digestion