Dietary carbohydrate rather than protein intake drives colonic microbial fermentation during weight loss.

PURPOSE: High protein weight loss diets are effective in aiding body weight management. However, high protein and low carbohydrate intakes can alter colonic fermentation profiles in humans and may impact on colonic health. This study aims to identify the most important dietary contributors to colonic fermentation during diet-controlled weight loss. METHODS: Overweight or obese male volunteers (n = 18) consumed a body weight maintenance diet (fed at 1.5× basic metabolic rate, BMR) followed by three weight loss diets (fed at 1× BMR) for 10 days each in a cross-over design. Weight loss diets were designed as normal protein (NPWL, 15% of energy from protein, 55% from carbohydrate), normal protein enriched with free amino acids and moderate amounts of carbohydrate (NPAAWL, 15% of energy from protein, 15% from free AA, 40% from carbohydrate) or high protein containing moderate amounts of carbohydrate (HPWL, 30% of energy from protein, 40% from carbohydrate). Faecal samples collected at the end of each diet period were profiled for dietary metabolites using LC-MS/MS. RESULTS: This study shows that the NPWL diet only induced very minor changes in the faecal metabolome, whereas NPAAWL and HPWL diets decreased carbohydrate-related metabolites (butyrate, ferulic acid) and increased protein-related metabolites. Most faecal metabolites were correlated with dietary carbohydrate and not protein intake. CONCLUSION: This study demonstrates that dietary carbohydrate is the main driver of colonic fermentation in humans and that a balance between dietary carbohydrate and protein should be maintained when designing safe, effective and healthy weight loss diets.

Phytochemical profile of commercially available food plant powders: their potential role in healthier food reformulations.

Reformulation of existing processed food or formulation of new foods using natural products (plant-based) will inherently confer to new products with less calories, fat, salt, phosphates and other synthetic components, and higher amounts of fibre, antioxidants, vitamins and other beneficial components. Plant ingredients, such as food plant powders, are currently being used in food manufacturing, predominantly for flavouring and colouring purposes. To expand their use as a food ingredient, freeze-dried powders representing major vegetable groups were characterised by targeted LC-MS/MS analysis of their phytochemicals. All the plant powders were found to be rich in flavonoids, phenolic acids and derivatives; total content in these compounds varied from around 130 mg kg(-1) (green pea) to around 930 mg kg(-1) (spinach). The food plant powders' phytochemical content represents valuable information for the food industry in the development of healthier novel foods and for the reformulation of existing food products in relation to antioxidants, food preservatives and alternatives to nitrite use.

Bound phytophenols from ready-to-eat cereals: comparison with other plant-based foods.

Whole-grain diets are linked to reduced risk of several chronic diseases (heart disease, cancer, diabetes, metabolic syndrome) and all-cause mortality. There is increasing evidence that these benefits are associated with the gut microbiota and that release of fibre-related phenolic metabolites in the gut is a contributing factor. Additional sources of these metabolites include fruits and vegetables, but the evidence for their protective effects is less well established. With respect to the availability of bound phytophenols, ready-to-eat cereals are compared with soft fruits (considered rich in antioxidants) and other commonly consumed fruits and vegetables. The results demonstrated that when compared with an equivalent serving of fruits or vegetables, a recommended portion of whole-grain cereals deliver substantially higher amounts of bound phytophenols, which are available for metabolism in the colon. The increased amount of these phenolic metabolites may, in part, explain the evidence for the protective effects of whole-grain cereals.

Extent of incorporation of hydroxycinnamaldehydes into lignin in cinnamyl alcohol dehydrogenase-downregulated plants.

Down-regulation of cinnamyl alcohol dehydrogenase leads to an accumulation of cinnamaldehydes available for incorporation into the developing lignin polymer. Using electron spin resonance spectroscopy we have demonstrated that the parent radical of 4-hydroxy-3-methoxycinnamaldehyde is generated by peroxidase catalysed oxidation. The extent of radical generation is similar to that of 4-hydroxy-3-methoxycinnamyl alcohol and is increased by further aromatic methoxylation. From the distribution of the electron-spin density, it was predicted that the regiochemistry of 4-hydroxy-3-methoxycinnamaldehyde coupling would be similar to that of the corresponding alcohol, with the possibility of a higher degree of 8-O-4 linkages occurring. These predictions were confirmed by polymerisation studies, which also showed that after radical coupling the alpha,beta-enone structure was regenerated. This suggests that, although the cross-linking and physical properties of cinnamaldeyde rich lignins differ from that of normal lignins, cinnamaldehydes are incorporated into the lignin polymer under the same controlling factors as the cinnamyl alcohols.

Oxidative coupling during lignin polymerization is determined by unpaired electron delocalization within parent phenylpropanoid radicals.

The high degree of selectivity observed in the incorporation of phenylpropanoids into lignin may be a consequence of the influence exerted by methoxyl substituents on the ambident radicals generated during biosynthesis. Since unpaired electron distribution may be regarded as an important factor in determining positional selectivity during oxidative coupling, electron spin resonance spectroscopy and Austin Model 1 molecular computation were used to study the effects of methoxyl substitution on unpaired electron distribution in lignin precursor radicals. The data obtained were used to predict the effect of substitution on coupling and were compared with the linkage types observed in complementary dehydrogenation polymerization studies employing each of the lignin precursors. We report that methoxyl substitution increases unpaired electron density on the phenolic oxygen of the precursor phenylpropanoid radicals and that this subsequently determines the nature of the bond formation during polymerization.

Mummy of the "Elder Lady" in the tomb of Amenhotep II: Egyptian museum catalog number 61070.

An unidentified female mummy found in a cache of great kings and queens in 1898 in the Valley of the Kings was examined from the viewpoint of Egyptology, x-ray cephalometry, biostatistics, and biochemistry. The result was the identification of Queen Tiye, of the Eighteenth Dynasty, wife of Amenhotep III and mother of Akhenaton.

Motor neurone disease. Further evidence for an abnormality of nerve metabolism.

Physiological and biochemical studies were carried out on 16 patients with motor neurone disease (MND). It was confirmed that the peripheral nerves in cases of MND are often unusually resistant to ischaemia especially as regards the large sensory fibres. Biochemical investigations demonstrated a tendency to carbohydrate intolerance and abnormal pyruvate metabolism. When compared with other related studies in MND it seems very likely that there is a metabolic abnormality present in MND which demands further study.