Study: does vitamin D improve blood sugar regulation?

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Von: Natur.wiki Autoren-Team

Referenz Javed A., Vella A., Balagopal PB, et al. Die Cholecalciferol-Supplementierung beeinflusst die β-Zellfunktion und die Insulinwirkung bei übergewichtigen Jugendlichen nicht: eine prospektive, doppelblinde, randomisierte Studie. J Nutr. 2015;145(2):284-290. Studiendesign Randomisierte, prospektive, doppelblinde Studie Teilnehmer 46 kaukasische Jugendliche (20 männlich, 26 weiblich), Durchschnittsalter 15 Jahre (±1,9 Jahre), waren zum Abschluss der Studie auswertbar. Die Teilnehmer wurden als fettleibig eingestuft, wenn sie einen Body-Mass-Index (BMI) größer oder gleich dem 95. Perzentil für Alter und Geschlecht gemäß den Wachstumsdiagrammen des US Centers for Disease Control and Prevention aus dem Jahr 2000 aufwiesen. Ausgeschlossen wurden Jugendliche mit hohem Serum-25(OH)D (>100 ng/ml), hohem Serumkalzium …
Reference Javed A., Vella A., Balagopal PB, et al. Cholecalciferol supplementation does not affect the β cell function and insulin effect in overweight young people: a prospective, double-blind, randomized study. Jnutr. 2015; 145 (2): 284-290. Study design randomized, prospective, double -blind study participant 46 Caucasian adolescents (20 male, 26 female), average age 15 years (± 1.9 years), were evaluated at the end of the study. The participants were classified as obese if they had a body mass index (BMI) larger or equal to the 95th percentile for age and gender according to the growth diagrams of the US Center for Disease Control and Prevention from 2000. Young people with a high serum-25 (OH) D (> 100 ng/ml), high serum calcium were excluded ... (Symbolbild/natur.wiki)

Reference

Javed A., Vella A., Balagopal PB, et al. Cholecalciferol supplementation does not affect the β cell function and insulin effect in overweight young people: a prospective, double-blind, randomized study. J Nutr. 2015; 145 (2): 284-290.

study design

randomized, prospective, double -blind study

participant

46 Caucasian teenagers (20 male, 26 female), average age 15 years (± 1.9 years), were evaluated at the end of the study. The participants were classified as obese if they had a body mass index (BMI) larger or equal to the 95th percentile for age and gender according to the growth diagrams of the US Center for Disease Control and Prevention from 2000. Young people with a high serum-25 (OH) D (> 100 ng/ml), high serum calcium (> 10.8 mg/dl), liver or kidney diseases, type 1 or -2-diabetes or malabsorption syndromes (e.g. Zöliakie). ). People who took glucocorticoids, antiepileptics, multivitamins, insulin, metformin or oral hypoglycemic drugs were also excluded from the study.

Intervention

The participants received either 400 IE per day or 2,000 IE per day cholecalciferol supplementation (Biotech Pharmacal, Fayetteville, Arkansas) for 12 weeks.

target parameter

The primary target parameters included the insulin sensitivity and the β-cell function of the pancreas, which were determined using the disposition index using data that were obtained by the 3-hour oral glucose tolerance test. Additional measurements were insulin secretion rates and total cholesterol, high-density lipoprotein cholesterol and triglyceride levels.

important knowledge

After 12 weeks, a light but statistically significant increase in the 25 (OH) D level compared to the starting value in the group was found, the 2,000 IE Cholecalciferol received ( p = 0.04), and this was not observed in the 400 IE per day ( p = 0.39). Insulin sensitivity, disposition index, insulin secretion rate and observed lipid parameters remained unchanged in both groups and compared to each other. BMI and weight remained unchanged for all participants throughout the study.

practice implications

vitamin D supplements do not seem to improve dysglycemia in this study; We should not assume that the prescription of vitamin D improves blood sugar control.
It has become common practice to prescribe patients with metabolic syndrome (METS), prediabetes, type 2 diabetes and polycystic ovarian syndrome (PCOS) vitamin D, on the ground that vitamin D increases insulin sensitivity and reduces glucose dysregulation. This conviction comes from ongoing studies that connect abnormal glucose tolerance profiles with low vitamin D levels.
Our assumption that a nutritional supplement will reverse these conditions and improve sugar regulation has not been supported in recent clinical studies. A meta-analysis published in June 2015 examined the connection between serum vitamin D with metabolic and endocrine dysregulation in women with PCOS and determined the effects of cholecaliferol supplementation on metabolic and hormonal functions in these patients. In the 30 selected studies (n = 3,182), vitamin D deficiency (VDD) was associated with metabolic and hormonal disorders: "PCOS patients with VDD were more likely to have dysglycaemia (z resistance index (Homa-IR)) compared to those without Vdd." Vitamin D supplementation improved these conditions: “This meta-analysis found no evidence that a vitamin D supplementation reduced or mitigated or mitigate metabolic and hormonal dysregulation in PCOS. VDD can be a comedy manifestation of PCOS or a secondary path for PCOS-associated metabolic and hormonal dysmodulation be. “ 1
solar exposure also stimulates the production of nitrogen monoxide, and it is not unlikely that this could be responsible for part of the cardiovascular protection, which we usually associate with higher vitamin D mirrors.
There are a few exceptions in which vitamin D seems to improve glycemic control. A positive response was observed in a clinical study carried out in Iran in 2014, in which 50 obese young participants received a 12-week study on the chance. Those who received vitamin D received a total of 300,000 IE (~ 25,000 IE/week) during the study. Only 21 patients in the vitamin D arm concluded the study, but in these patients "the serum insulin and triglyceride concentrations as well as Homa -ir and C-Mets decreased significantly, both in comparison to the initial value and the placebo group." Slight advantages for subjects who received 4,000 IE per day. While there were "no significant differences in the BMI, the inflammatory markers in the serum or the plasma lukose concentrations between the groups ... the participants had a supplementation with vitamin D3 [decreased] Soberinulin (‒6.5 compared to +1.2 μu/ml for placebo), [decreased] Homa-IR (‒1.363 in comparison to +0.27 for placebo; showed.
in a randomized placebo-controlled study, which was carried out in the Netherlands and published in July 2014, researchers gave 130 non-western immigrants with prediabetes for 16 weeks either cholecalciferol (1,200 IE/D) or a placebo. While supplementation increased the vitamin D serum mirror, "there was no significant effect on insulin sensitivity and β-cell function." 4 In September 2013, Wongwathananukit et al. received a supplementation with vitamin D to increase serum-D mirrors, but had no influence on insulin sensitivity.
Although most of these studies do not find improved glycemic control, studies continue to be published that claim that a vitamin D deficiency is clearly associated with sugar problems. A study of June 2015 reported that a low vitamin D mirror is associated with an increased risk of METS or its individual components, in particular increased blood pressure and insulin resistance (IR). 6 confirmed a further overview published in June 2015: "Most data show that an inadequate vitamin D status with an increased prevalence of METS or its individual components, Mainly blood pressure and IR, are often independent of general obesity or abdominal obesity. ” 7 These conclusions reflect results that were reported in two studies from May 2015. The first reported that a low vitamin D mirror is connected to the characteristic features of meters for overweight or obese adults: High BMI and IR. 8 The second reported that older working adults with vitamin D deficiency had 2.5 times higher risk, to diabetes fall ill. 9
These contradictory results - that vitamin D is associated with dysglycemia, but that supplementation rarely improves symptoms - raise an important question that tends to ignore practitioners and the public. While alternative ideas were proposed to explain these confusing results in vitamin D studies, the simplest answer is that the vitamin D level is just a marker for past solar exposure and not the active active ingredient that benefits. Sunlight can trigger some other changes in the body that offer the advantages that we usually associate with a high vitamin D content.
For example, sunlight stimulates the production of P53. This is the enzyme that regulates the apoptosis and the key to protecting the body against cancer is. 10 sunlight also stimulates the production of nitrogen monoxide (NO), and it is not inaccessible that this could be responsible for part of the cardiovascular protection, which we usually connect with higher vitamin D levels. According to an article published in the published in the American Heart Association , "an impaired generation and signal transmission of nitrogen monoxide (NO) contributes significantly to the cardiovascular (CV) risk (CVR), which is associated with high -profile, hyperlipidemia and diabetes mellitus. Processes are modulated by NO. ” 11 could it be that solar exposure and the resulting increased NO-production limit all of these conditions that we often attribute vitamin D because they help prevent them?
Against this background, we emphasized patients this summer to rely less on vitamin D supplements and instead rely on solar exposure to stimulate vitamin D production (accompanied by this recommendation with the mandatory warnings before sunburn). The advantages of vitamin D may not be as far -reaching as we once thought; Some of these advantages can be attributed to the sun's rays themselves than the formation of vitamin D triggered by the sun.

note of the publisher: Megan Chmelik wrote this article under the direction of Jacob Schor, ND, Fabno, a co -editor of this magazine.

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