Vitamin D and vitamin K status in postmenopausal women with normal and low bone mineral density.

OBJECTIVES: Vitamin D and K are believed to promote bone health, but existing evidence is controversial. This study aimed to measure several metabolites of both vitamins by liquid chromatography tandem mass spectrometry (LC-MS/MS) in a cohort of postmenopausal women with low and normal bone mineral density (BMD). METHODS: Vitamin metabolites (25-hydroxyvitamin D (25[OH]D), 24,25-dihydroxyvitamin D (24,25(OH)2D), phylloquinone (K1), menaquinone-4 (MK-4) and MK-7) were measured in 131 serum samples by LC-MS/MS. The vitamin D metabolite ratio (VMR) was calculated. Parathyroid hormone (PTH), type I procollagen-N-terminal-peptide (PINP) and C-terminal telopeptides of type I collagen (CTX-I) were measured by immunoassay. Dual X-ray absorptiometry was performed to identify participants with normal (T-score>-1) and low (T-score<-1) BMD. RESULTS: Mean age was 58.2±8.5 years. BMD was normal in 68 and low in 63 women. Median (interquartile range) for 25(OH)D and total vitamin K concentrations were 53.5 (39.6-65.9) nmol/L and 1.33 (0.99-2.39) nmol/L. All vitamin metabolites were comparable in individuals with normal and low BMD. Furthermore, BMD and trabecular bone score were comparable in participants with adequate and inadequate vitamin status (at least one criterion was met: 25(OH)D <50 nmol/L, 24,25(OH)2D <3 nmol/L, VMR <4 %, total vitamin K <0.91 nmol/L). PTH, but not PINP or CTX-I, was inversely correlated with 25(OH)D, 24,25(OH)2D and VMR. Synergistic effects between vitamin D and K were not observed. CONCLUSIONS: Vitamin D and K status is not related to BMD and trabecular bone quality in postmenopausal women. Inverse associations were only seen between vitamin D metabolites and PTH.

Could Insulin Be a Better Regulator of Appetite/Satiety Balance and Body Weight Maintenance in Response to Glucose Exposure Compared to Sucrose Substitutes? Unraveling Current Knowledge and Searching for More Appropriate Choices.

BACKGROUND: Insulin exerts a crucial impact on glucose control, cellular growing, function, and metabolism. It is partially modulated by nutrients, especially as a response to the intake of foods, including carbohydrates. Moreover, insulin can exert an anorexigenic effect when inserted into the hypothalamus of the brain, in which a complex network of an appetite/hunger control system occurs. The current literature review aims at thoroughly summarizing and scrutinizing whether insulin release in response to glucose exposure may be a better choice to control body weight gain and related diseases compared to the use of sucrose substitutes (SSs) in combination with a long-term, well-balanced diet. METHODS: This is a comprehensive literature review, which was performed through searching in-depth for the most accurate scientific databases and applying effective and relevant keywords. RESULTS: The insulin action can be inserted into the hypothalamic orexigenic/anorexigenic complex system, activating several anorexigenic peptides, increasing the hedonic aspect of food intake, and effectively controlling the human body weight. In contrast, SSs appear not to affect the orexigenic/anorexigenic complex system, resulting in more cases of uncontrolled body weight maintenance while also increasing the risk of developing related diseases. CONCLUSIONS: Most evidence, mainly derived from in vitro and in vivo animal studies, has reinforced the insulin anorexigenic action in the hypothalamus of the brain. Simultaneously, most available clinical studies showed that SSs during a well-balanced diet either maintain or even increase body weight, which may indirectly be ascribed to the fact that they cannot cover the hedonic aspect of food intake. However, there is a strong demand for long-term longitudinal surveys to effectively specify the impact of SSs on human metabolic health.