Vitamin D may not improve biomarkers of insulin resistance, and inflammation; says AHA

Experimental and observational studies have suggested a link between vitamin D and cardiovascular and metabolic disease, but this has not been confirmed in randomized controlled trials. Researchers sought to determine whether vitamin D supplementation reduces biomarkers of insulin resistance, inflammation, neurohormonal activation, and lipids.

This was a prespecified, secondary analysis of the DAYLIGHT (Vitamin D Therapy in Individuals at High Risk of Hypertension) randomized controlled trial. They measured circulating homeostatic model assessment of insulin resistance, hs‐CRP (high‐sensitivity C‐reactive protein), N‐terminal pro‐B‐type natriuretic peptide, renin, aldosterone, and lipids at baseline and at 6 months in 289 individuals with low vitamin D status (25‐hydroxyvitamin‐D [25‐OH‐D] ≤25 ng/mL) receiving low‐dose (400 IU/d) versus high‐dose (4000 IU/d) vitamin D3 for 6 months. A meta‐analysis of randomized controlled trials reporting biomarker changes after vitamin D supplementation was then performed.

Results put forth some facts.

• Levels of 25‐OH‐D increased in the high‐dose relative to the low‐dose vitamin D group (+15.5 versus +4.6 ng/mL, P<0.001).
• Changes in biomarkers of glycemia, inflammation, and neurohormonal activation did not differ by dose.
• Lipids did not differ between groups, other than triglycerides, which increased in the high‐dose compared with the low‐dose group (+11.3 versus −6.2 mg/dL, P<0.001).
• The meta‐analysis showed potential modest decreases in homeostatic model assessment of insulin resistance and hs‐CRP, but no changes in low‐density lipoprotein, after vitamin D supplementation compared with control groups.

"In this secondary analysis of the DAYLIGHT (Vitamin D Therapy in Individuals at High Risk of Hypertension) randomized controlled trial, individuals randomized to high‐dose vitamin D supplementation did not experience improvements in biomarkers of insulin resistance, inflammation, neurohormonal activation, or lipids.High‐dose vitamin D supplementation does not improve biomarkers of glycemia, inflammation, neurohormonal activation, or lipids in otherwise healthy individuals with low vitamin D status."the research team concluded.

For full article follow the link: https://doi.org/10.1161/JAHA.120.017727

Source: Journal of the American Heart Association