Influence of prebiotics and antioxidants in bread on the immune system, antioxidative status and antioxidative capacity in male smokers and non-smokers.

Interest in functional foods is increasing. The aim of the present study was to investigate breads supplemented with functional components. One was bread supplemented with inulin, linseed and soya fibre (prebiotic bread). The other was a prebiotic antioxidant bread (pre-aox-bread), which additionally contained green tea powder, herbs and tomato paste. The effects of these two breads on immunological and antioxidative parameters were compared with control bread (placebo). Twenty smokers and eighteen non-smokers were enrolled in the randomised parallel study, which consisted of a control period and an intervention period, each lasting for 5 weeks. Daily intake of bread and nutrients did not differ between the intervention and the control period. Most of the twenty-three investigated immunological parameters measured in peripheral blood were unaffected. However, the percentage of CD19 increased after intervention with prebiotic bread, whereas intercellular adhesion molecule-1 (ICAM-1) and CD3+NK+ (P < 0.05) decreased in both intervention arms. The ferric reducing ability of plasma (FRAP) was increased after consumption of the pre-aox-bread for non-smokers (1256 v. 1147 micromol/l; P = 0.019) and remained unchanged for smokers consuming the pre-aox-bread. All analysed carotenoids (P

Bread enriched with green coffee extract has chemoprotective and antigenotoxic activities in human cells.

Recent studies have shown that bread supplemented with functional ingredients was more chemoprotective than nonsupplemented bread. Here we investigated components of a German wheat bread supplemented with green coffee antioxidants (GC) to assess basic biological activities in human cells in culture. We analyzed chlorogenic acid (ChA) in the bread and determined antioxidative activities. Human colon (HT29) and liver (HepG2) cells were incubated with GC and with aqueous extracts of freeze-dried breads, after which cell survival (4' ,6-diamino-2- phenylindole dihydrochloride assay) and H(2)O(2)-induced DNA damage (comet assay) were determined. GC and supplemented bread contained 7- and 880-fold more ChA than normal bread and were significantly more antioxidative (ferric reducing ability of plasma assay, 2.9- and 265-fold; Trolox equivalent antioxidant capacity assay, 1.3- and 24-fold, respectively). Treatment of cells for 24 to 72 h with the samples resulted in a significant inhibition of cell survival in a dose-dependent manner. HepG2 liver cells were more susceptible than HT29 colon cells. No genotoxicity or cytotoxicity was observed after treatment of cells with GC, ChA, or the bread samples. H(2)O(2)-induced DNA damage was reduced significantly after treatment with GC, ChA, and supplemented bread. In conclusion, the supplementation of bread with GC improves the chemoprotective property of normal bread under these in vitro cell culture conditions. Supplementation also increases ChA content and antioxidative capacity. The treatment of the cells with supplemented bread increases resistance of colon and liver cells against H(2)O(2), a source of oxidative stress.

Butyrate is only one of several growth inhibitors produced during gut flora-mediated fermentation of dietary fibre sources.

Dietary fibre sources are fermented by the gut flora to yield short-chain fatty acids (SCFA) together with degraded phytochemicals and plant nutrients. Butyrate, a major SCFA, is potentially chemoprotective by suppressing the growth of tumour cells and enhancing their differentiation. Conversely, it could lead to a positive selection pressure for transformed cells by inducing glutathione S-transferases (GST) and enhancing chemoresistance. Virtually nothing is known about how butyrate's activities are affected by other fermentation products. To investigate such interactions, a variety of dietary fibre sources was fermented with human faecal slurries in vitro, analysed for SCFA, and corresponding SCFA mixtures were prepared. HT29 colon tumour cells were treated for 72 h with individual SCFA or complex samples. The growth of cells, GST activity, and chemoresistance towards 4-hydroxynonenal were determined. Fermentation products inhibited cell growth more than the corresponding SCFA mixtures, and the SCFA mixtures were more active than butyrate, probably due to phytoprotectants and to propionate, respectively, which also inhibit cell growth. Only butyrate induced GST, whereas chemoresistance was caused by selected SCFA mixtures, but not by all corresponding fermentation samples. In summary, fermentation supernatant fractions contain compounds that: (1) enhance the anti-proliferative properties of butyrate (propionate, phytochemical fraction); (2) do not alter its capacity to induce GST; (3) prevent chemoresistance in tumour cells. It can be concluded that fermented dietary fibre sources are more potent inhibitors of tumour cell growth than butyrate alone, and also contain ingredients which counteract the undesired positive selection pressures that higher concentrations of butyrate induce in tumour cells.