Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men

What Was Tested

The paper reports a study of NAD+ in the context of insulin resistance, prediabetes & type 2 diabetes, published as a randomized controlled trial.

The researchers aimed to determine if dietary NR supplementation in middle-aged, obese, insulin-resistant men affects mitochondrial respiration, content and morphology in skeletal muscle.

Why It Was Studied

This is the first long-term human clinical trial to report on effects of nicotinamide riboside (NR) on skeletal muscle mitochondrial function, content and morphology.

NR supplementation does not affect NAD metabolite concentrations in skeletal muscle.

Who Took Part

The study group was 40 participants.

PubMed indexes the participants as middle-aged adults, men only.

Protein abundance and mRNA expression were measured by Western blot and quantitative PCR analyses, respectively, and in a subset of the participants (placebo n = 8; NR n = 8) the researchers quantified mitochondrial fractional area and mitochondrial morphology by laser scanning confocal microscopy.

How the Study Was Run

The researchers set it up as a randomized and placebo-controlled study.

The participants were allocated by chance, so the NAD+ group and the comparison group should start out alike.

Some participants received a placebo instead of NAD+, giving a reference point.

What Was Measured

However, steady-state NAD+ levels as well as gene expression and protein abundance of other NAD+ biosynthetic enzymes remained unchanged.

Topics PubMed links to this paper include Insulin Resistance, Mitochondria, Muscle, Muscle, Skeletal, NAD, Niacinamide, Nicotinamide Phosphoribosyltransferase and Obesity.

Author keywords: NAD+, NAMPT, human skeletal muscle and nicotinamide riboside.

What This Means in Plain Language

The paper is a randomized and placebo-controlled study of NAD+ in 40 participants in people with insulin resistance, prediabetes & type 2 diabetes.

The publication is from 2020 (The Journal of physiology), a journal based in England.

More context: the NAD+ compound page, Insulin resistance, prediabetes & type 2 diabetes research.