Coenzyme Q10 Deficiency may Increase the Risk of Insulin Resistance and Pre-diabetes
After each meal our blood glucose level increases and to counter this, the pancreas, an organ located behind the stomach, secrets a hormone called insulin. This hormone plays a major role in metabolism by guiding the way body utilizes glucose, a simple sugar, in the form of energy once the food is digested. Insulin also promotes the uptake of glucose from muscle, fat tissue, and liver cells from the bloodstream thus help in maintaining normal blood glucose levels in the body.
Insulin Resistance and Associated Health Consequences
However, under certain conditions like obesity or physical inactivity, glucose doesn’t get absorbed by muscle, fat and liver cells. As a result, the glucose level in the bloodstream goes up leading to an increased demand for insulin. To meet this demand, the pancreas keeps producing and secreting more insulin until glucose levels decrease and normalize. However, over time, this process can become defective. Meaning that, the pancreas fails to meet the body's increased demand for insulin, resulting in excess glucose in the blood, leading to ‘insulin resistance.’ This condition is where muscle, fat and liver cells do not respond to insulin properly.
Insulin resistance further gives rise to ‘pre-diabetes’, a condition wherein blood glucose levels are higher than normal but not high enough to be categorized as diabetes. Insulin resistance and pre-diabetes are the direct contributors to type 2 diabetes, and other serious diseases like cardiovascular disease, cancer, and even premature death generally due to excess and abnormal glycation.
Coenzyme Q10: A Key Molecule in Energy Production
The conversion of food we eat into a useable source of energy is vital to performing bodily functions. Inside every cell of our body, there are tiny organelles known as ‘mitochondria,’ popularly called ‘the power-house of the cell.’ These ‘power-houses’ help convert nutrients such as fats and sugars into molecules called adenosine triphosphate (ATP), also known as the ‘high energy molecule.’ATP is “molecular currency” of intracellular energy transfer that is essential to carry out almost all biological processes.
However, mitochondrial by-products have been reported to play a significant role in the development of insulin resistance as ATP production can also give rise to ‘reactive oxygen species’ or ‘oxidants’ (e.g. superoxide, hydrogen peroxide), potentially harmful intermediates of energy production. Several studies have demonstrated that increased production of these mitochondrial oxidants may damage cells and contribute to insulin resistance.
Coenzyme Q10 (CoQ10, ubiquinone) is a natural antioxidant found in almost every cell of the human body. This simple molecule plays an important role in ATP production by acting as an ‘electron-carrier’ required for the flow of electricity to the cell's 'motor' in the mitochondria. Additionally, CoQ10 protects cells from damage caused by harmful free radicals. It also helps in absorbing other essential nutrients and regenerates vitamin C and vitamin E, thus enhancing their effect.
Levels of CoQ and Insulin Resistance: A Close Link
Though several factors have been known to trigger insulin resistance including mitochondrial oxidative stress, underlying mechanisms that cause increased oxidant production in mitochondria and their precise source was not known until recently.
In a recently published study, Fazakerley et al. established a correlation between the levels of CoQ10 and insulin resistance. The study was the part of an ambitious research collaboration between the University of Sydney, Victor Chang Cardiac Research Institute, Duke University School of Medicine, Garvan Institute of Medical Research, Genentech Inc., and the University of New South Wales. In this study, researchers analyzed the levels of proteins and oxidants in different cell-based experimental models, animal models, and human tissue samples. Results suggested that levels of CoQ10 were selectively decreased in insulin-resistant adipocytes (fat cells), and insulin-resistant fat and muscle tissue from mice as well as humans. It was further demonstrated that decreased levels of mitochondrial CoQ10 were linked to increased oxidant production and in turn, insulin resistance.
Furthermore, the influence of CoQ10 supplementation was evaluated in all the experimental models. Replenishing the mitochondria in fat cells, as well as mice and human tissue samples reversed the mitochondrial oxidants to ‘normal’ levels and restored ‘insulin sensitivity’ to normal by reversing the resistance.
Overall, it was concluded that mitochondrial CoQ10 deficiency and resultant production of the higher amount of oxidants, such as superoxides or hydrogen peroxide have a direct link to insulin resistance. Thus, any attempt made to improve mitochondrial CoQ10 levels, such as the use of CoQ10 supplements, may be effective in preventing or reversal of insulin resistance and pre-diabetes.
Reference: Fazakerley et al. Mitochondrial CoQ deficiency is a common driver of mitochondrial oxidants and insulin resistance. eLife (2018). DOI: 10.7554/eLife.32111