Glucose Spikes & Insulin Insensitivity

Glucose spikes, also known as hyperglycemia, and insulin insensitivity, or insulin resistance, are implicated in a range of common metabolic illnesses and associated health risks. Chronically elevated insulin concentrations (hyperinsulinemia), often occurring in tandem with insulin resistance, are detrimental to body functions.

The common metabolic illnesses caused or exacerbated by glucose spikes and insulin insensitivity include:

Type 2 Diabetes Mellitus (T2DM)

    ◦ T2DM is a highly prevalent chronic disease with cardiometabolic implications. It is a primary outcome associated with the development of metabolic syndrome and excessive sugar intake. Insulin resistance is an established risk factor, often preceding T2DM by 10 20 years.

    ◦ Complications of T2DM include diabetic nephropathy, diabetic retinopathy, and diabetic foot.

Obesity

    ◦ Hyperinsulinemia significantly increases the risk of obesity by favoring energy storage over usage, inhibiting lipolysis, and promoting lipogenesis. Fasting and diurnal insulin levels are a determinant of obesity risk. Obesity is common in T2DM patients and is strongly correlated with excessive sugar intake.

Metabolic Syndrome (MetS)

    ◦ The development of metabolic syndrome is associated with added caloric sweeteners and excessive fructose consumption, which also contributes to insulin resistance. A person with metabolic syndrome is classified by having at least three of the following: obesity, low high-density lipoprotein cholesterol, elevated blood triglycerides and glucose, and high blood pressure.

Cardiovascular Disease (CVD)

    ◦ Hyperinsulinemia and insulin resistance significantly increase the risk of cardiovascular disease, which is the leading cause of mortality worldwide.

    ◦ Specific manifestations include:

        ▪ Hypertension (elevated blood pressure): The combination of hyperinsulinemia and insulin resistance promotes hypertension by impairing nitric oxide production, activating the renin-angiotensin system, and enhancing renal sodium reabsorption.

        ▪ Atherogenesis: Hyperinsulinemia and insulin resistance promote atherogenesis by mechanisms such as impaired nitric oxide production and enhanced macrophage lipoprotein lipase activity.

        ▪ Endothelial dysfunction and increased vascular tone: Insulin resistance suppresses the activation of endothelial nitric oxide synthase (eNOS) and promotes calcium ion influx into vascular smooth muscle cells, leading to increased vascular tone and stiffness.

        ▪ Myocardial infarction: Genetically predicted high insulin levels are associated with an increased risk of myocardial infarction.

        ▪ Dyslipidemia: Elevated blood pressure and dyslipidemia are major risk factors for CVD, which can be improved by glycemic control.

Nonalcoholic Fatty Liver Disease (NAFLD) and Nonalcoholic Steatohepatitis (NASH)

    ◦ Excessive intake of sugars, particularly fructose, is highly correlated with fatty liver. Uncontrolled fructose catabolism in the liver stimulates fat accumulation, leading to NAFLD. NAFLD is now the leading cause of liver failure globally.

Chronic Inflammation

    ◦ Excessive fructose consumption contributes to inflammation, which can exacerbate chronic inflammation and promote liver inflammation.

Kidney Dysfunction

    ◦ High sugar intake is linked to kidney dysfunction. The enhanced reabsorption of sodium ions in renal tubules due to elevated insulin levels contributes to the risk of hypertension.

Cancer (specifically Colorectal Cancer, CRC)

    ◦ Sugar overconsumption is linked to an increased incidence of cancer, and evidence suggests a positive association between sugar intake, particularly high fructose intake and obesity, with CRC prevalence and progression.

Cognitive Decline

    ◦ Hyperinsulinemia in mice impairs electrophysiological functions of neurons and protein turnover, causing a transition to a senescent cell state and accompanying cognitive decline.

Decreased Health Span and Life Expectancy

    ◦ Prolonged high insulin concentrations and hyperinsulinemia decrease health span and life expectancy.

Disruptions of the Intestinal Barrier and Increased Gut Permeability

    ◦ Both hyperglycemia and excessive sugar intake disrupt the intestinal barrier, increasing gut permeability and causing profound gut microbiota dysbiosis, which enhances infection susceptibility.

Musculoarticular Disorders

    ◦ Overweight resulting from excess caloric intake is associated with musculoarticular disorders.

Inflammatory Bowel Diseases (IBDs)

    ◦ High sugar intake and the consumption of ultra-processed foods (which are high in sugar) are associated with an increased risk and aggravation of IBDs.

Oxidative Damage/Stress

    ◦ Repeated spikes of blood glucose levels are more likely to cause oxidative damage than sustained levels. Prolonged conditions of elevated glucose concentrations cause dysfunction of numerous cell types via increased oxidative stress. Hyperinsulinemia also suppresses the nuclear factor Nrf2, which is central to the protective response against oxidative stress, thereby increasing cellular susceptibility to such stress and DNA damage. Uncontrolled fructose catabolism can lead to high uric acid production, linked to oxidative damage.