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Insulin Resistance

Episodes

Posted on January 24th 2024 (over 1 year)

In this clip, Dr. Peter Attia addresses the ideal targets for hemoglobin A1C levels, a key indicator of long-term blood glucose.

Posted on July 9th 2022 (almost 3 years)

Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.

Posted on May 24th 2021 (almost 4 years)

Dr. Michael Snyder discusses personalized medicine and the use of technologies that monitor metabolism and other health markers.

Topic Pages

  • Cold exposure

    Cold exposure may be a hormetic stressor that reduces inflammation, activates antioxidant enzymes, and boosts the immune system to protect against age-related diseases.

  • Ultra-processed Foods (UPFs)

    UPFs are formulations of mostly cheap industrial sources of dietary energy (calories) and nutrients plus additives that have negative effects on human health.

News & Publications

  • Cinnamon is one of the most consumed spices in the world, popular in both sweet and savory dishes in many cuisines. Evidence suggests cinnamon improves lipid profiles and protects against damage induced by oxidative stress. A recent systematic review and meta-analysis found that cinnamon helps maintain healthy blood glucose levels and reduces insulin resistance in people with type 2 diabetes.

    Researchers analyzed the findings of 24 clinical trials investigating the effects of cinnamon supplementation on blood glucose levels. The various trials included more than 1,800 participants from 11 nations.

    The analysis revealed that cinnamon supplementation reduced fasting blood glucose levels, hemoglobin A1c concentrations, and insulin resistance (without lowering insulin) in people with type 2 diabetes. The trials varied in duration from six to 16 weeks, and daily cinnamon doses ranged from 120 to 6,000 milligrams, averaging 2,100 milligrams – roughly a teaspoon.

    These findings suggest that cinnamon improves symptoms of type 2 diabetes and may be a valuable adjunct to traditional therapies. Cinnamon is rich in polyphenols, a broad class of plant bioactive compounds. Learn more about polyphenols in our overview article.

  • Vitamin K2 – a form of vitamin K produced in the gut – plays important roles in blood clotting, bone mass maintenance, and blood vessel contractility. But new research shows that supplemental vitamin K2 also improves diabetes markers. People with type 2 diabetes who took supplemental vitamin K2 had better markers of glycemic control than those who took a placebo.

    Researchers performed a three-part study in humans and mice. First, they conducted a randomized controlled trial involving 60 adults who had type 2 diabetes. Half of the participants took vitamin K2 every day for six months, while the other half took a placebo. Then the researchers transplanted gut microbes from vitamin K2-supplemented mice into obese mice. Finally, they analyzed the gut microbial composition and their metabolites in both humans and mice.

    They found that the participants who received supplemental vitamin K2 experienced marked reductions in levels of fasting blood glucose (13.4 percent), insulin (28.3 percent), and HbA1c (7.4 percent), indicating improved glycemic control. Similarly, the mice demonstrated improved glucose tolerance after receiving the gut microbe transplants. Lastly, the researchers found that certain metabolites that play roles in glucose metabolism, including bile acids and short-chain fatty acids, increased in the feces of both groups. Furthermore, they identified a specific type of bacteria that was responsible for producing these metabolites.

    Vitamin K is a fat-soluble vitamin. The body has limited vitamin K storage capacity, so the body recycles it in a vitamin K redox cycle and reuses it multiple times. Naturally occurring forms of vitamin K include phylloquinone (vitamin K1) and a family of molecules called menaquinones (vitamin K2). Vitamin K1 is synthesized by plants and is the major form found in the diet. Vitamin K2 molecules are synthesized by the gut microbiota and found in fermented foods and some animal products (especially liver).

    These findings suggest that vitamin K2 participates in maintaining glycemic control in people with type 2 diabetes. They also underscore the role of the gut microbiota in this process. Learn about other roles for the gut microbiota in this episode featuring Dr. Eran Elinav.

  • A single night of light exposure during sleep impairs glucose metabolism via activation of the “fight-or-flight” response.

    Light is the primary signal that entrains the body’s master clock to set its 24-hour circadian cycle. Consequently, the body is synchronized to external light-dark cycles. In recent decades, exposure to light from artificial sources has increased, especially during the evening and nighttime hours, with negative effects on human health. Findings from a recent study suggest that a single night of light exposure impairs glucose metabolism via activation of the sympathetic nervous system.

    The sympathetic nervous system is a division of the autonomic nervous system. It responds to both endogenous and exogenous stressors and is widely referred to as the coordinator of the body’s “fight-or-flight” response. The outcome of sympathetic nervous system activation is an increase in heart rate, cardiac output, and blood glucose levels, as well as other physiological responses that prepare the body for action. Evidence suggests that increased sympathetic nervous system activity alters sympathovagal balance (the balance between the sympathetic and parasympathetic nervous systems), driving poor heart rate variability.

    The investigators recruited 20 healthy adults (average age, 26 years) who did not have sleep disorders. Participants spent two nights in a sleep laboratory, where they ate all their meals and went to bed at their habitual times. Half of the participants spent one night in dim light conditions (less than 3 lux, very dark) and one night in room light conditions (100 lux, from four 60-watt incandescent bulbs). The other half spent both nights in the dim light conditions. Participants provided blood samples and underwent oral glucose tolerance tests each morning.

    The investigators found that participants who were exposed to room light conditions during sleep had increased nighttime heart rate, decreased heart rate variability, and increased morning insulin resistance, compared to when they slept in a dark room. They also spent less time in deep, slow-wave sleep.

    These findings suggest that a single night of exposure to room light during sleep impairs glucose metabolism via activation of the sympathetic nervous system. Learn how light from devices impairs sleep in this clip featuring sleep expert Dr. Matthew Walker.

  • Metabolic diseases, such as type 2 diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD), represent a major public health burden. Dietary factors such as excess sugar intake are associated with greater metabolic disease risk; however, it is unclear how different types of sugars (e.g., glucose, fructose, or sucrose) differentially impact metabolic health. In this report, researchers investigated the effects of sugar-sweetened beverages on fatty acid synthesis, blood triglycerides, and hepatic insulin resistance in healthy males.

    Following the consumption of glucose, the pancreas secretes insulin into the bloodstream so that insulin-sensitive organs such as the liver, skeletal muscle, and adipose tissue can transport glucose into their cells. Excess sugars are converted to fats in the liver via a process called de novo lipogenesis and then stored in adipose tissue; however, as fat levels in adipose tissue rise (i.e., overweight and obesity), fat accumulates in the liver leading to the development of NAFLD. Fructose, the main sweetener found in sugar-sweetened beverages, does not require insulin to be absorbed and is preferentially taken up by the liver, accelerating NAFLD development independent of weight gain.

    The authors recruited 94 healthy lean males (average age, 23 years) and assigned them to consume beverages sweetened with moderate amounts of either glucose, fructose, or sucrose (a sugar that contains both glucose and fructose) in addition to their normal diet for seven weeks. The beverages contained an amount of sugar found in about two cans of non-diet soda. The researchers assigned a fourth group of participants to consume their normal diet with no added sugar-sweetened beverages. They assessed fatty acid and triglyceride synthesis by the liver and whole-body fat metabolism.

    Daily consumption of beverages sweetened with fructose and sucrose, but not glucose, led to a twofold increase in the production of free fatty acids in the liver. Fructose intake did not increase triglyceride production in the liver or whole-body fat metabolism. Participants from all four groups consumed about the same amount of calories, and while body weight tended to increase for all groups, this relationship was only statistically significant for the group consuming glucose-sweetened beverages. Glucose and insulin tolerance did not change with sugar-sweetened beverage consumption.

    The investigators concluded that consumption of beverages sweetened with fructose and sucrose increased free fatty acid production in the liver. While they did not observe changes in other metabolic markers such as insulin tolerance, they hypothesized that the alterations in fat production by the liver pave the way for metabolic disease development.