A novel nutritional supplement containing amino acids and chromium decreases postprandial glucose response in a randomized, double-blind, placebo-controlled study.

High postprandial blood glucose levels are associated with increased mortality, cardiovascular events and development of diabetes in the general population. Interventions targeting postprandial glucose have been shown to prevent both cardiovascular events and diabetes. This study evaluates the efficacy and safety of a novel nutritional supplement targeting postprandial glucose excursions in non-diabetic adults. Sixty overweight healthy male and female participants were recruited at two centers and randomized in a double-blind, placebo-controlled, crossover design. The supplement, a water-based drink containing 2.6g of amino acids (L-Leucine, L-Threonine, L-Lysine Monohydrochloride, L-Isoleucine, L-Valine) and 250 mcg of chromium picolinate, was consumed with a standardized carbohydrate-rich meal. The primary endpoint was the incremental area under the curve (iAUC) for venous blood glucose from 0 to 120 minutes. Secondary endpoints included glucose iAUC 0-180 minutes and the maximum glucose concentration (Cmax), for both venous and capillary blood glucose. In the intention-to-treat-analysis (n = 60) the supplement resulted in a decreased venous blood glucose iAUC0-120min compared to placebo, mean (SE) of 68.7 (6.6) versus 52.2 (6.8) respectively, a difference of -16.5 mmol/L•min (95% CI -3.1 to -30.0, p = 0.017). The Cmax for venous blood glucose for the supplement and placebo were 6.45 (0.12) versus 6.10 (<0.12), respectively, a difference of -0.35 mmol/L (95% CI -0.17 to -0.53, p<0.001). In the per protocol-analysis (n = 48), the supplement resulted in a decreased Cmax compared to placebo from 6.42 (0.14) to 6.12 (0.14), a difference of -0.29 mmol/L (95% CI -0.12 to -0.47, p = 0.002). No significant differences in capillary blood glucose were found, as measured by regular bed-side glucometers. The nutritional supplement drink containing amino acids and chromium improves the postprandial glucose homeostasis in overweight adults without diabetes. Future studies should clarify, whether regular consumption of the supplement improves markers of disease or could play a role in a diet aiming at preventing the development of diabetes.

Oral administration of live exopolysaccharide-producing Pediococcus parvulus, but not purified exopolysaccharide, suppressed Enterobacteriaceae without affecting bacterial diversity in ceca of mice.

Growing evidence indicates that the gut microbiota could have an important role in the development of diet- and lifestyle-induced diseases. It has been shown that modulation of the gut microbiota by means of probiotics and prebiotics could improve host health. An oat-based product fermented by the exopolysaccharide (EPS)-producing organism Pediococcus parvulus 2.6 has been reported to have a bifidogenic effect. To find out whether the effect could be attributed to the EPS or the bacterium, mice were fed a diet supplemented with 2% purified EPS or 10(8) CFU/g of live P. parvulus 2.6 for 6 weeks. Both supplementations altered the gut microbiota composition but in different directions. Purified EPS not only significantly lowered the microbial diversity (P < 0.001) but decreased the bifidobacterial population (P = 0.01). In contrast, the live EPS-producing bacterium P. parvulus 2.6 antagonized Enterobacteriaceae without disturbing the homeostasis of the cecal microbiota.

Simultaneous intake of oat bran and atorvastatin reduces their efficacy to lower lipid levels and atherosclerosis in LDLr-/- mice.

The present study aimed to investigate the effects of separate and simultaneous dietary intake of atorvastatin (ATO) and the soluble fiber oat bran on serum and hepatic lipid levels and the degree of atherosclerosis. Ninety female LDL-receptor-deficient (LDLr-/-) mice were fed a Western-type diet containing either low dose (0.0025%), high dose (0.01%) or no ATO, with or without oat bran (27%) (n=15 per group) for 16 weeks. Both ATO and oat bran were effective in reducing serum total cholesterol levels (low ATO: -5.48, high ATO: -9.12, oat bran: -3.82 mmol/l, compared to control (no ATO/no oat bran), all p<0.0001). When oat bran was added to a low dose ATO, the cholesterol-lowering effects of this combination were 50% smaller compared to the low dose ATO diet alone (between-group difference: 2.77 mmol/l, p=0.002), whereas total cholesterol decreased to a similar extent in the groups fed a high dose ATO, with or without oat bran (between-group difference: 1.10 mmol/l, p=0.21). Serum LDL- and HDL-cholesterol, triglycerides, hepatic lipid levels and atherosclerotic lesion development showed a similar pattern. In conclusion, the efficacy of oat bran and atorvastatin to lower lipid levels and atherosclerosis is reduced after simultaneous intake. We hypothesize that oat bran inhibits the intestinal absorption of atorvastatin, and consequently its cholesterol-lowering effects. The effects are likely dependent on the type of statin and dietary fiber, and on the relative timing of intake of the statin and the dietary fiber. Future studies should focus on these aspects to provide further insight into the exact mechanism of this food-drug interaction.

Effects of oat bran, processed to different molecular weights of beta-glucan, on plasma lipids and caecal formation of SCFA in mice.

In the present study, we evaluated the cholesterol-lowering effects of different oat bran (OB) preparations, differing regarding their peak molecular weight (MWp) of beta-glucans (2348, 1311, 241, 56, 21 or < 10 kDa), in C57BL/6NCrl mice. The diets were designed to be atherogenic (0.8 % cholesterol and 0.1 % cholic acid), and they reflected the Western diet pattern (41 % energy fat). All OB preparations that were investigated significantly reduced plasma cholesterol when compared with a cellulose-containing control diet, regardless of the molecular weight of beta-glucan. Moreover, the difference in viscous properties between the processed OB (from 0.11 to 17.7 l/g) did not appear to play a major role in the cholesterol-lowering properties. In addition, there was no correlation between the molecular weight of beta-glucan and the amount of propionic acid formed in caecum. Interestingly, however, there was a significant correlation between the ratio of (propionic acid+butyric acid)/acetic acid and the MWp of beta-glucans: the ratio increased with increasing molecular weight. The results of the present study suggest that the molecular weights and viscous properties of beta-glucan in oat products may not be crucial parameters for their cholesterol-lowering effects.

Effects of oats on plasma cholesterol and lipoproteins in C57BL/6 mice are substrain specific.

Cholesterol-lowering effects of oats have been demonstrated in both animals and human subjects. However, the crucial properties of oat-containing diets that determine their health effects need to be further investigated to optimise their use. A mouse model would be a valuable tool, but few such studies have been published to date. We investigated the effects of oat bran on plasma cholesterol and lipoproteins in two substrains of C57BL/6 mice. Western diet was made atherogenic by the addition of 0.8 % cholesterol and 0.1 % cholic acid. After 4 weeks on atherogenic diet, total plasma cholesterol had increased from 1.86-2.53 to 3.77-4.40 mmol/l. In C57BL/6NCrl mice, inclusion of 27 and 40 % oat bran reduced total plasma cholesterol by 19 and 24 %, respectively, reduced the shift from HDL to LDL+VLDL and caused increased faecal cholesterol excretion. There was no effect of oat bran on plasma levels of the inflammatory markers fibrinogen, serum amyloid A or TNF-alpha. Contrary to findings in C57BL/6NCrl mice, there was no sustained effect of oat bran (27 or 40 %) on plasma cholesterol in C57BL/6JBomTac mice after 4 weeks of feeding. Thus, C57BL/6NCrl mice fed an atherogenic diet are a good model for studies of physiological effects of oats, whereas a substrain derived from C57BL/6J, raised in a different breeding environment and likely possessing functional genetic differences from C57BL/6N, is considerably less responsive to oats. The present finding that two substrains of mice respond differently to oats is of practical value, but can also help to elucidate mechanisms of the cholesterol-lowering effect of oats.

Improved iron bioavailability in an oat-based beverage: the combined effect of citric acid addition, dephytinization and iron supplementation.

BACKGROUND: Iron deficiency in children is a major worldwide nutritional problem. An oat beverage was developed for 1- to 3-year-old children and different treatments were used to improve the iron bioavailability. AIM OF THE STUDY: To investigate the effects of citric acid addition, phytase treatment and supplementation with different iron compounds on non-heme iron absorption in human from a mineral-supplemented oat-based beverage. METHODS: A 240 g portion of a 55Fe-labeled test product (T) or a 59Fe-labeled reference dose (R) was served as breakfast after overnight fasting on four consecutive days in the order of TRRT. On day 18 the retention of 59Fe was measured by a whole-body counter and the erythrocytes uptake of 55Fe and 59Fe by a liquid-scintillation counter. Forty-two healthy subjects (men and women) were randomized into four study groups, members of each being given one of the studied four products (A, B, C, and D) supplemented with Fe (1.3 mg/portion), Zn, Ca, Se and P. Ferric ammonium citrate (FeAC) was added to products A, B, and C and ferric pyrophosphate (FePP) to product D. Citric acid (60 mg/portion) was added to products B, C, and D and phytase treatment applied to products C and D. RESULTS: Citric acid improved iron absorption by 54% from 3.9% in product A to 6.0% in product B (p = 0.051). Phytase treatment increased iron absorption by 78% (from 6.0 to 10.7%, p = 0.003) by reducing the phytate-phosphorus content per portion from 16.3 mg in product B to 2.8 mg in product C. The two compounds gave similar iron absorption rates (p = 0.916). CONCLUSIONS: A combination of citric acid addition, dephytinization and iron supplementation significantly increased the iron absorption in an oat-based beverage. Such a beverage can be useful in the prevention of iron deficiency in 1- to 3-year-old children.