Food is essential in all biological processes of the human body. Food provides human body with all nutrients needed to maintain its tissue structure and run its functions. Furthermore, food is an important factor affecting the course of oncological disease one can change. There is some evidence showing that one third of all cancers can be prevented. Prostate cancer is the second most common cancer in men worldwide, while it is the first most common cancer and second leading cause of death from cancer in Latvian men. The high prevalence and often slow progression of prostate cancer makes it suitable for prevention. The low incidence and prevalence of prostate cancer in Asia suggests that nutrition may play a role in the progression of prostate cancer. It has been suggested that the protective effect found in Asia may be due to soy products rich in phytoestrogens. Lignans are the most important phytoestrogen sources in the Western countries. In North Europe, rye bread is the main source of lignans, which is also rich in fiber. Bread ‘fiber complex’ is linked to many bioactive compounds, including lignans and alkylresorcinols. An insufficient concentration of vitamin D is another possible risk factor of prostate cancer because vitamin D may have not only immunomodulating, but also anticarcinogenic effects. The objective of this thesis was to find out alkylresorcinol metabolites most suitable to estimate rye bread and rye bread fiber intake and also to evaluate relationships between metabolites of alkylresorcinols and lignans and their links to the risk of prostate cancer. The second objective was to assess any possible effect of whole grain rye bread on the progression of prostate cancer. The third objective of the thesis was to evaluate any possible links between vitamin D and the risk of prostate cancer. We detected alkylresorcinols and lignans, bioactive compounds, in Latvian breads while carrying out dietary assessment. This included intake of bread, rye bread, fiber, alkylresorcinols, lignans and vitamin D, concentrations of alkylresorcinols` metabolites (DHPPA-3-(3,5-dihydroxyphenyl)-1-propanoic acid and DHBA –3,5-dihydroxy-benzoic acid), and lignan metabolite (ENL – enterolactone) in plasma, 12-h day and 12-h night urine and serum concentration of vitamin D in prostate cancer in the group of PC patients and the control group. Using dietary intervention of rye bread, we investigated the effects on prostate cancer progression by assessing Prostate Specific Antigen (PSA), metabolites of alkylresorcinols and lignans in plasma, sex hormones and morphological examination before and after the intervention. The results show that alkylresorcinol and fiber concentration are high in Latvian breads. Alkylresorcinols` concentration in bread may be used as a marker of bran and fiber amount in bread. Alkylresorcinol and lignan intake were also found to be high. Seed and rye breads were found to be the main dietary sources of lignans. There was no difference found between the prostate cancer and control groups in the dietary intake data, including bread quantity and bread types, alkylresorcinol and lignan intake. DHPPA in 12 h overnight urine may be the most suitable alkylresorcinol metabolite to estimate the intake of rye bread and rye fiber. Differences were found between the prostate cancer and the control group regarding associations between alkylresorcinol metabolite concentrations in plasma, urine and food intake data, possibly due to a delay in the metabolism of alkylresorcinols in the prostate cancer group. It was found that enterolactone, a lignan metabolite, is linked to the intake of lignans only under the conditions of intervention. The results of the intervention study reveal a possible delay in the progression of prostate cancer via elevated concentration of sex hormone binding globulin, enterolactone and alkyresorcinols metabolites in the group of prostate cancer, which resulted in lower rates of PSA and presumably increased apoptosis. We suggest the future studies on this subject with longer time periods covered, with larger numbers of participants and the use of bread with higher concentrations of rye fiber. We found that vitamin D deficiency and/or insufficiency is highly prevalent in the group of prostate cancer and in men aged over 45 in the control group. There were no differences found between the groups in the concentration of vitamin D in serum. Vitamin D dietary intake was found to be insufficient in both study groups. To assess possible vitamin D protective effect in the prevention of prostate cancer, it is advisable to reach higher concentrations of the vitamin using vitamin D supplementation, also a higher amount of fish in the diet.
|Translated title of the contribution||Alkylresorcinol, Lignan Metabolites and Vitamin D in Prostate Cancer Patients|
|Place of Publication||Riga|
|Publication status||Published - 2014|
- Doctoral Thesis
Field of Science*
- 3.2 Clinical medicine
- 4. Doctoral Thesis