Intrinsic labelling of common beans with 2H2O to enable estimates of protein digestibility.

BACKGROUND: The use of plant protein intrinsically labelled with stable isotopes provides an innovative solution to assess the efficiency of protein intake by humans. Here, the incorporation of 2H has been applied to intrinsically labelled plant protein in the common bean. This study aimed to evaluate which is the best phenological phase of seed maturation to incorporate the heavy hydrogen isotope 2H into seed amino acids. Common beans (Phaseolus vulgaris L.) were grown in pots, then, after 50 days sowing, 2H2O dissolved in irrigation water was applied, then again at an interval of either 3, 6, 9, and 12 days. RESULTS: Applications of 2H2O at 6, 9, and 12 days after the first application, in the full-flowering stage, were the best treatments for enriching protein-bound amino acids in the bean seed with 2H. CONCLUSION: All treatments resulted in enrichment above 500 ppm, so the treatments (quantity and timing of 2H2O addition) were deemed successful for enriching bean seeds. This makes the intrinsically labelled seeds suitable for preparing test meals to assess the digestion and essential amino acid absorption of common bean amino acids in human subjects.

Effects of the Consumption of Milk Biofortified with Selenium, Vitamin E, and Different Fatty Acid Profile on Immune Response in the Elderly.

SCOPE: Nutrition is a major contributing factor for immunocompetence. The aim was to assess the immune status of older people after consuming milk produced by lactating cows fed with one of the following diets: control diet (C), C + vitamin E + selenium (C + A), C + sunflower oil (C + O), and C + sunflower oil + vitamin E + selenium (A + O). METHODS AND RESULTS: Sixty elderly people received one of these biofortified milks for 12 weeks. Immune response was assessed by measurement of the expression of COX-1, COX-2, MCP-1, PPAR (δ, α, and ß/δ) genes, neutrophil production of oxygen reactive species induced by immune complexes, neutrophil phagocytosis and lytic activity of the alternative pathway of the complement system, and cytokine levels. Variables were assessed before and after treatment. Our findings showed stability of some inflammatory mediators (complement activity and neutrophils burst) in treatment groups, except complement activity in C + A, and an increase of these markers in C, especially reactive oxygen species production and phagocytic activity. TNF-α was significantly increased in all groups. In C + A, IL-4 and IL-2 increased after treatment, and in the group that received the milk produced by cows fed with "O" diet, CCL20 and IL-27 increased. CONCLUSION: Overall, as compared to C, milk biofortification was associated with stabilization of the activity of alternative complement pathway and the neutrophils burst, and modulated different cytokines levels.