Abstract
Wheat bran cereals are an important source of dietary fibre. The aim of the study was to investigate if a high intake (120 g) of fibre rich breakfast cereal (which delivers the UK Government guidelines for fibre intake in one serving but is three-fold higher than the manufacturers recommended serving) has additional potential health benefits compared to the recommended serving (40 g, containing 11 g of dietary fibre). To assess this, the study determined the short chain fatty acid (SCFA) profiles in human faecal, urine and plasma samples after consumption of two different servings of fibre-rich cereal. Inhibition of prostanoid production was measured (ex vivo) in human colonic fibroblast cells after cytokine (IL-1β) inflammation stimulation. Eight healthy volunteers, 18-55 years old; BMI (18-30 kg/m2) consumed the wheat bran-rich “ready to eat cereal”, at both the high (120 g) serving and recommended (40 g) serving. Faecal, urine and plasma samples were collected at baseline, throughout the five-hour intervention period and approximately 24 hours following consumption. Faecal butyrate showed the largest increase (p<0.05) of more than a two-fold change following the consumption of the recommended serving of wheat bran cereal (from 13.95 ± 9.17 to 31.63 ± 20.53 mM) and no significant change following the higher serving (from 21.96 ± 11.03 to 22.9 ± 12.69 mM). ANOVA analysis also found a weak serving effect (p = 0.046) of the portion size (high vs. recommended) only for butyrate in urine 24 hours after consumption of the bran cereal. The physiological nutritionally relevant concentrations of faecal SCFAs, as determined in the volunteers’ faecal samples showed significant anti-inflammatory activity or the individual faecal SCFAs; acetate (p<0.001), propionate (p<0.001) and butyrate (p<0.01), as well as in combination. Plasma folate was also increased after consumption of both wheat bran servings and was significant (p = 0.037) at the three-hour time point following consumption of the high wheat bran serving. The consumption of the recommended serving (40 g) of wheat bran cereal increased the total microbial SCFAs levels (from 96.88 to 136.96 mM) compared to the higher serving (120 g) (from 110.5 to 117.64 mM) suggesting that the intake of the higher portion size is likely to promote a faecal bulking effect and thereby decrease colonic SCFA levels. These data indicate that consumption of the recommended serving of wheat bran cereal serving would therefore be sufficient to promote microbial butyrate formation, reduce colonic inflammation and increase plasma folate levels in humans.
Highlights
In 2015, as part of the initiative to promote a healthy balanced diet, the UK government changed the guidelines on the daily recommended dietary fibre intake to 30 g per day [1], representing 23 g of non-starch polysaccharides (NSP), a 5 g increase over the previous 18 g NSP recommendation [2]
The highest increase in faecal short chain fatty acid (SCFA) concentration when compared with baseline values was following consumption of wheat bran cereal (WB) serving for butyrate Table 1
Samples collected following the intervention showed no significant changes in faecal samples weights and total faecal waters produced between baseline and first sample produced following HWB consumption (p>0.05, t test) and WB consumption (p>0.05, t test) (Table S1, supplementary information)
Summary
In 2015, as part of the initiative to promote a healthy balanced diet, the UK government changed the guidelines on the daily recommended dietary fibre intake to 30 g per day [1], representing 23 g of non-starch polysaccharides (NSP), a 5 g increase over the previous 18 g NSP recommendation [2]. This dietary fibre value (30 g/day) refers to AOAC fibre, meaning measured by the Association of Official Analytical Chemists' (AOAC) method [2]. The role of folic acid in gut heath is still a subject of debate [9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
