Wholegrains and health: Many benefits but do contaminants pose any risk?

Since pre‐historic times, humans have consumed grains as part of their diet. Being rich in carbohydrates, grains typically form a key part of all food‐based dietary guidelines, with wholegrains recommended as healthy dietary choices. However, grains are also exposed to contaminants from air, soil, water, insects, animals, microbes, humans, storage and shipping containers, and handling and processing equipment and can be one of the main dietary sources of food‐borne contaminants by virtue of their frequent consumption. Recent scientific reports positively highlight wholegrains as foods with inherent health properties, which, because they provide fibre and micronutrients such as B vitamins and zinc, can improve the quality of carbohydrate intake as part of sustainable, healthy diets. This article describes potential health‐protective properties inherent to wholegrains and contends that the presence of contaminants in wholegrains, including mycotoxins, heavy metals and acrylamide, merits continued monitoring but that any such risk does not outweigh the known benefits of wholegrain consumption.     

Fibre – Need to increase intake according to new recommendations

In its report on Carbohydrates and Health, the Scientific Advisory Committee on Nutrition (SACN) has recommended increases in the dietary reference values for fibre to 30 g/day for adults and 15–30 g/day for children, depending on their age. Intakes are currently much lower than this, at an average of 18 g/day in adults, less in children, and there are socio‐economic differences, with lower intakes in the lowest income quintile compared to the highest. Dietary modelling shows that achieving these recommendations is possible but will require substantial changes to dietary patterns for many, with meals based around fibre‐rich starchy foods (such as wholegrain and high‐fibre options of bread, breakfast cereals, pasta and rice, and jacket potatoes), supplemented by inclusion of high‐fibre snacks such as unsalted nuts and considerable amounts of vegetables and fruit, daily. This article discusses the challenges associated with communicating these new recommendations, in the context of current labelling legislation.     

Optimal preservation of porcine cardiac tissue prior to diffusion tensor magnetic resonance imaging

The effects of ex vivo preservation techniques on the quality of diffusion tensor magnetic resonance imaging in hearts are poorly understood, and the optimal handling procedure prior to investigation remains to be determined. Therefore, 24 porcine hearts were examined in six groups treated with different preservation techniques, including chemical fixation and freezing. Diffusion properties of each heart were assessed with diffusion tensor imaging in terms of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr). Tractography was performed to visualize the course of the cardiomyocytes, assuming greater diffusivity in the longitudinal than the transverse axis of individual cardiomyocytes. Significant differences in MD, Da and Dr were found, as well as in FA between groups (P < 0.001). Freezing of specimens resulted in the lowest mean FA of 0.21 (0.06) and highest Dr of 8.92 (1.5) mm² s⁻¹. The highest mean FA was found to be 0.43 (0.11) in hearts perfusion-fixed with formalin. Calculated tractographies were indistinguishable among groups except in frozen specimens, where no fibres could be tracked. Perfusion fixation with formalin provided the best tractography, but immersion fixation yielded diffusion data most similar to fresh hearts. These findings suggest that parameters derived from diffusion tensor imaging in ex vivo hearts are sensitive to fixation and storage methods. In particular, freezing of specimens should be avoided prior to diffusion tensor imaging investigation due to significant changes in diffusion parameters and subsequent image deteriorations.     

Evaluation of digestive tolerance of a soluble corn fibre

Background: To assess consumers’ acceptance of a new fibre, it is essential to evaluate its digestive tolerance after ingestion. We aimed to determine the tolerance of increasing dosages of Promitor? Soluble Gluco Fibre (SGF; Tate&Lyle, Hoffman Estates, IL, USA) up to 70 g fibre per day using a validated gastrointestinal composite score. Methods: A composite score of gastrointestinal tolerance integrating gastrointestinal symptoms, stool frequency and consistency was applied. To statistically validate this composite score, the gastrointestinal tolerance of inulin (10 g versus 20 g containing, respectively, 9 g versus 18 g of fibre) was assessed in 18 healthy volunteers in a randomised double‐blind placebo‐controlled cross‐over study. Second, in a double‐blind placebo‐controlled cross‐over study with 20 healthy volunteers, the gastrointestinal tolerance of SGF in both acute and ‘spread over the day’ conditions of consumption was assessed. Results: By contrast to 10 g, 20 g of inulin demonstrated a significant difference in composite score compared to placebo [P < 0.001, difference = 7.6; 95% confidence interval (CI) = 3.8–11.3]. These values were considered as reference during the second study. In acute conditions, 40 g of SGF fibre was the highest (threshold) dose tested that indicates the digestive tolerance criteria (difference from placebo on the composite score <7.6 and upper limit of the 95% CI <11.3); this is twice the amount tolerated for inulin. In ‘spread over the day’ conditions, 65 g of SGF fibre was the threshold dose (P < 0.001, difference = 6.5; 95% CI = 3.4–9.5). Conclusions: The results of the present study demonstrate that 40 g of SGF fibre, when consumed as a single dose, and 65 g of SGF fibre, when consumed in multiple‐doses, across the day are well‐tolerated by healthy volunteers.