ESSENTIALS: SCIENCE

"The common coexistence of (obesity, hypertension, glucose intolerance and hypertriglyceridemia) suggests a shared pathogenesis."

Why the fights against the obesity and diabetes epidemics have failed and what people need to do to reverse obesity.

This 2017 review argues insulin therapy increases cardiovascular and mortality risk in Type 2 diabetics. Given that effective alternatives exist for establishing glycemic control in this population, exogenous insulin use should be de-emphasized for most patients.

A 2014 review argues traditional risk factors such as changes to lipids and blood pressure account for only half of the elevated cardiovascular risk observed in diabetics. The review authors suggest efforts to manage heart disease risk in diabetic and prediabetic subjects should focus directly on managing insulin and glucose levels and insulin resistance, not merely on improving lipid profiles and blood pressure.

“Any person presenting with any signs of sexual dysfunction should consider screening for insulin resistance,” Dr. Priyanka Wali, MD, claims. In this presentation, Wali examines the relationship between metabolic and sexual health. She calls for a reexamination of doctors’ responses to patients presenting with sexual dysfunction: Instead of prescribing a pill to treat the symptoms of sexual dysfunction, she recommends screening for and treating the potential underlying metabolic disorder.

The human brain is nearly 60% fat by total weight and needs to be provided with certain types of fats — both saturated and unsaturated — throughout life to provide a balance of structural integrity and fluidity to its cells. Mary Dan Eades, MD, outlines the stakes of limiting dietary fat intake at various stages in life and lists the various food sources one should seek or avoid to keep the brain functioning optimally.

This 2020 mouse study indicates a diet rich in soybean oil, compared to a diet containing a similar amount of saturated fat, leads to changes in the expression of genes associated with inflammation, neuroendocrine function, and neurological signaling. These shifts suggest mechanisms by which soybean oil may have contributed to the rise in obesity and diabetes, given the dramatic increase in the oil’s consumption in the 20th century.

A small 2007 study indicates defects in the insulin sensitivity of skeletal muscle play a major role in the development of the metabolic syndrome, suggesting interventions to maintain and improve the ability of muscle cells to take up glucose in response to insulin, including exercise, may play a particularly important role in the prevention and/or amelioration of the metabolic syndrome.

"In the wake of the Cancer Genome Atlas project's failure to provide a legible roadmap to a cure for cancer, science writer Travis Christofferson illuminates a promising blend of old and new perspectives on the disease. Tripping Over the Truth follows the story of cancer’s proposed metabolic origin from the vaunted halls of the German scientific golden age to modern laboratories around the world. The reader is taken on a journey through time and science that results in an unlikely connecting of the dots with profound therapeutic implications."

A 2020 review establishes the significance of the hypothesis that defective glucose metabolism plays a role — potentially multiple roles — in the development of Alzheimer’s disease.

Non-sugar artificial sweeteners (NAS) have been alternately hailed and demonized as the sweet, low-calorie saviors of the diabetic and obese on the one hand and destroyers of health on the other. Mary Dan Eades, MD, surveys the medical literature and discusses studies that have found an association between artificial sweeteners and Type 2 diabetes (T2DM).

In the generally accepted model for Type 2 diabetes (T2D), excess calorie consumption is thought to lead to obesity, which then causes insulin resistance. Here, Malcolm Kendrick, MD, shares evidence that contradicts this model, instead suggesting insulin is itself obesogenic, which means reducing insulin levels may aid in weight loss and reverse Type 2 diabetes.

In 2015, Richard Feinman, Ph.D., and 25 other expert researchers and clinicians wrote a review recommending carb-restricted diets for the treatment of Type 2 diabetes. Feinman notes that the paper’s points have never been refuted but have “largely been ignored” by the organizations that produce guidelines for diabetes patients.

Dr. Malcolm Kendrick, MD, discusses two populations that exhibit high levels of Type 2 diabetes (T2D) and explains how they can help to further illuminate the underlying cause of T2D in the general population.

An extensive 2018 review summarizes the biological underpinnings of brain aging and proposes how metabolic dysfunction may contribute to their progression.

A 2017 review links hyperinsulinemia and other components of the metabolic syndrome to the development and progression of Alzheimer’s disease.

In the first article in his new series on diabetes, Dr. Malcolm Kendrick, MD, discusses the long history of diabetes research and introduces several models for understanding the causes of the disease, as well as its progression. While the mechanism underlying Type 1 diabetes is generally agreed upon, debate continues over whether Type 2 is related to fat consumption or raised insulin levels resulting from carbohydrate intake.

Several studies support the hypothesis that diet, particularly carbohydrate consumption, affects vision. One study compares the eyesight of hunter-gatherer and industrialized groups. Another study explores the mechanism behind dietary contribution to myopia and finds increases in insulin promote eyeball elongation in animal models. A third explores dietary sugar’s links to glaucoma, cataracts, diabetic retinopathy, and macular degeneration.

A 2015 review explores behavioral and mechanistic links between diabetes and depression.

Georgia Ede argues the dramatic fluctuations in glucose and insulin levels caused by eating high-glycemic-index foods lead to a variety of negative psychological effects.