Diet, folate, and colon cancer

Determination of Folic Acid Using Biosensors-A Short Review of Recent Progress

Folic acid (FA) is the synthetic surrogate of the essential B vitamin folate, alternatively named folacin, pteroylglutamic acid or vitamin B9. FA is an electroactive compound that helps our body to create and keep our cells healthy: it acts as the main character in a variety of synthetic biological reactions such as the synthesis of purines, pyrimidine (thus being indirectly implied in DNA synthesis), fixing and methylation of DNA. Therefore, physiological folate deficiency may be responsible for severe degenerative conditions, including neural tube defects in developing embryos and megaloblastic anaemia at any age. Moreover, being a water-soluble molecule, it is constantly lost and has to be reintegrated daily; for this reason, FA supplements and food fortification are, nowadays, extremely diffused and well-established practices. Consequently, accurate, reliable and precise analytical techniques are needed to exactly determine FA concentration in various media. Thus, the aim of this review is to report on research papers of the past 5 years (2016-2020) dealing with rapid and low-cost electrochemical determination of FA in food or biological fluid samples.

The potential of bifidobacteria as a source of natural folate

AIMS

To screen 19 strains of bifidobacteria for main folate forms composition in synthetic folate-free and complex folate-containing media.

METHODS AND RESULTS

HPLC was used to analyse deconjugated folates extracted from bacterial biomass. Most strains had a total folate content above 4000 μg per 100 g dry matter (DM). The highest value of 9295 μg per 100 g DM was found in Bifidobacterium catenulatum ATCC 27539 and the lowest in Bifidobacterium animalis ssp. animalis ATCC 25527 containing 220 μg per 100 g DM. Ten strains grew in a synthetic folate-free medium (FFM), showing folate autotrophy and suggesting folate auxotrophy of the remaining nine. In the autotrophic strains, a consistently higher folate level was found in FFM as compared to a more complex folate-containing medium, suggesting reduced requirements for folates in the presence of growth factors otherwise requiring folates for synthesis. The contents of total folate, 5-CH(3) -H(4) folate and H(4) folate were strain dependent. 5-CH(3) -H(4) folate dominated in most strains.

CONCLUSIONS

Our results show that bifidobacteria folate content and composition is dynamic, is strain specific and depends on the medium. Suitable selection of the growth conditions can result in high levels of folate per cell unit biomass.

SIGNIFICANCE AND IMPACT OF THE STUDY

This suggests that certain bifidobacteria may contribute to the folate intake, either directly in foods, such as fermented dairy products, or in the intestine as folate-trophic probiotics or part of the natural microbiota.

Effect of race on colon cancer treatment and outcomes in the Department of Defense healthcare system

PURPOSE

The increase in mortality noted in African Americans with colon cancer is attributed to advanced stage at presentation and disparities in treatment received. The aim of this study was to assess the influence of race on the treatments and survival of colon cancer patients in an equal-access healthcare system.

METHODS

This retrospective cohort study included African American and white patients with colon cancer treated at Department of Defense facilities. Disease stage, surgery performed, chemotherapy used, and overall survival were evaluated.

RESULTS

Of the 6958 colon cancer patients identified, 1115 were African American. African Americans presented more frequently with stage IV disease, 23% vs 17% for whites (P < .001). There was no difference in surgical resection rates for African American or whites (85.8% vs 85.5%, respectively; chi2, P > .05). There was no difference in the use of systemic chemotherapy for stage III colon cancer (73.5% for African Americans vs 72.2% for whites; chi2, P > .05) or stage IV colon cancer (56.3% for African Americans vs 54.4% for whites; chi2, P > .05). The overall 5-year survival rate was similar for African American and white patients (56.1% vs 58.5%, respectively; log-rank, P > .05). After adjusting for gender, age, tumor grade, and stage, African American race was not a risk factor for survival in Cox proportional hazard analysis (hazard ratio, 0.981; 95% confidence interval, 0.888-1.084).

CONCLUSIONS

In an equal-access healthcare system, African American race is not associated with an increase in mortality. African American patients undergo surgery and chemotherapy is administered at rates equal to whites for all stages of colon cancer.

Products of the colonic microbiota mediate the effects of diet on colon cancer risk

It is estimated that most colon cancers can be attributed to dietary causes. We have hypothesized that diet influences the health of the colonic mucosa through interaction with the microbiota and that it is the milieu interior that regulates mucosal proliferation and therefore cancer risk. To validate this further, we compared colonic contents from healthy 50- to 65-y-old people from populations with high and low risk, specifically low risk Native Africans (cancer incidence <1:100,000; n = 17), high risk African Americans (risk 65:100,000; n = 17), and Caucasian Americans (risk 50:100,000; n = 18). Americans typically consume a high-animal protein and -fat diet, whereas Africans consume a staple diet of maize meal, rich in resistant starch and low in animal products. Following overnight fasting, rapid colonic evacuation was performed with 2 L polyethylene glycol. Total colonic evacuants were analyzed for SCFA, vitamins, nitrogen, and minerals. Total SCFA and butyrate were significantly higher in Native Africans than in both American groups. Colonic folate and biotin content, measured by Lactobacillus rhamnoses and Lactobacillus plantarum ATCC 8014 bioassay, respectively, exceeded normal daily dietary intakes. Compared with Africans, calcium and iron contents were significantly higher in Caucasian Americans and zinc content was significantly higher in African Americans, but nitrogen content did not differ among the 3 groups. In conclusion, the results support our hypothesis that the microbiota mediates the effect diet has on colon cancer risk by their generation of butyrate, folate, and biotin, molecules known to play a key role in the regulation of epithelial proliferation.

Metabolite profiling of human colon carcinoma--deregulation of TCA cycle and amino acid turnover

Background

Apart from genetic alterations, development and progression of colorectal cancer has been linked to influences from nutritional intake, hyperalimentation, and cellular metabolic changes that may be the basis for new diagnostic and therapeutic approaches. However, in contrast to genomics and proteomics, comprehensive metabolomic investigations of alterations in malignant tumors have rarely been conducted.

Results

In this study we investigated a set of paired samples of normal colon tissue and colorectal cancer tissue with gas-chromatography time-of-flight mass-spectrometry, which resulted in robust detection of a total of 206 metabolites. Metabolic phenotypes of colon cancer and normal tissues were different at a Bonferroni corrected significance level of p = 0.00170 and p = 0.00005 for the first two components of an unsupervised PCA analysis. Subsequent supervised analysis found 82 metabolites to be significantly different at p < 0.01. Metabolites were connected to abnormalities in metabolic pathways by a new approach that calculates the distance of each pair of metabolites in the KEGG database interaction lattice. Intermediates of the TCA cycle and lipids were found down-regulated in cancer, whereas urea cycle metabolites, purines, pyrimidines and amino acids were generally found at higher levels compared to normal colon mucosa.

Conclusion

This study demonstrates that metabolic profiling facilitates biochemical phenotyping of normal and neoplastic colon tissue at high significance levels and points to GC-TOF-based metabolomics as a new method for molecular pathology investigations.

Administration of folate-producing bifidobacteria enhances folate status in Wistar rats

To develop a probiotic that provides the host with folate, we administered folate-overproducing bifidobacteria (Bifidobacteria adolescentis MB 227, B. adolescentis MB 239, and B. pseudocatenulatum MB 116) to Wistar rats with induced folate deficiency. Four groups of rats were fed a solid, low-folate diet with no supplements, folate-producing bifidobacteria [probiotic (PRO)], oligofructose [prebiotic (PRE)], or PRO plus PRE [symbiotic (SYM)] for 14 d. The SYM group also had a significantly higher (16.4 +/- 3.7 nmol/L) than in the PRO group (9.1 +/- 0.3 nmol/L), which was greater than in the control (4.8 +/- 0.5 nmol/L) and PRE groups (5.3 +/- 1.4 nmol/L). The SYM group also had a significantly higher hepatic folate concentration than in the other groups, whereas the kidney folate concentration did not differ among the groups. In the unsupplemented group, the pH of feces did not change during the trial, whereas diets containing bifidobacteria and/or oligofructose led to significant acidification due to enhanced saccharolytic metabolism. As a consequence of feeding rats PRE, PRO, and SYM diets, lactobacilli and bifidobacteria were significantly greater than in controls, whereas coliforms and enterococci were lower. This experiment showed that B. adolescentis MB 227, B. adolescentis MB 239, and B. pseudocatenulatum MB 116 exert both the beneficial effects of probiotics and produce folate in vivo, positively affecting the folate status of rats. The simultaneous administration of oligofructose and folate-producing bifidobacteria enhance their effectiveness on folate status. This study provides new perspectives on the specific use of probiotics to deliver important vitamins such as folate.

Coeliac disease: a diverse clinical syndrome caused by intolerance of wheat, barley and rye

Coeliac disease is a lifelong intolerance to the gluten found in wheat, barley and rye, and some patients are also sensitive to oats. The disease is genetically determined, with 10% of the first-degree relatives affected and 75% of monozygotic twins being concordant. Of the patients with coeliac disease 95% are human leucocyte antigen (HLA)-DQ2 or HLA-DQ8 positive. Characteristically, the jejunal mucosa becomes damaged by a T-cell-mediated autoimmune response that is thought to be initiated by a 33-mer peptide fragment in A2 gliadin, and patients with this disorder have raised levels of anti-endomysium and tissue transglutaminase antibodies in their blood. Coeliac disease is the major diagnosable food intolerance and, with the advent of a simple blood test for case finding, prevalence rates are thought to be approximately 1:100. Classically, the condition presented with malabsorption and failure to thrive in infancy, but this picture has now been overtaken by the much more common presentation in adults, usually with non-specific symptoms such as tiredness and anaemia, disturbance in bowel habit or following low-impact bone fractures. Small intestinal biopsy is necessary for diagnosis and shows a characteristically flat appearance with crypt hypoplasia and infiltration of the epithelium with lymphocytes. Diet is the key to management and a gluten-free diet effectively cures the condition. However, this commitment is lifelong and many aisles in the supermarket are effectively closed to individuals with coeliac disease. Compliance can be monitored by measuring antibodies in blood, which revert to negative after 6-9 months. Patients with minor symptoms, who are found incidentally to have coeliac disease, often ask whether it is necessary to adhere to the diet. Current advice is that dietary adherence is necessary to avoid the long-term complications, which are, principally, osteoporosis and small bowel lymphoma. However, risk of these complications diminishes very considerably in patients who are on a gluten-free diet.