Insulin and Glucose

Chapter summary

• Insulin is probably the number one factor in balancing blood sugar. A healthy body needs this balance (homeostasis).
• Persistently high sugar acts like a slow-acting poison. It erodes the pancreas’s ability to make insulin. The pancreas overcompensates and insulin rises.
• Complications: hardened arteries, kidney failure, stroke, heart attack, vision loss, weakened immunity, erectile dysfunction, nerve damage, poor circulation and, in extreme cases, amputation.

What insulin does

• Made by the pancreas.
• Moves glucose into brain and muscle cells for energy.
• Stores glucose in fat tissue and converts it to fatty acids.
• Slows the breakdown of fatty acids.
• Helps muscle take up amino acids.
• In the liver it converts glucose to glycogen and reduces new glucose formation.
• Glucagon and epinephrine oppose it.

How much glucose do you need?

• The glucose in your blood is less than a teaspoon, with fasting blood glucose around 83 mg/dL in this example.
• Saying you will die without carbohydrates is not true. Glucose is essential, but also toxic.

Three markers

• Fasting blood glucose (FBG): normal under 99 mg/dL, pre-diabetes 100 to 125, diabetes over 126.
• Post-meal glucose (OGTT): normal under 140, pre-diabetes 140 to 199, diabetes over 200 at two hours.
• Haemoglobin A1c: normal under 6%, pre-diabetes 6 to 6.4, diabetes above 6.4.
• Anything affecting red blood cells skews A1c. The risk of heart disease in non-diabetics doubles for each percentage point above 4.6%. These tests miss 70 to 94% of people with diabetes.

Where views differ

• Conventional view: Keep FBG under 100 and A1c under 6. The American Diabetes Association targets 70 to 130 before meals and under 180 after.
• Challenge: Patients with FBG of 95 had three times the diabetes risk a decade later than those under 90. Risk from glucose is linear, so lower may be better.
• Cancer link: Parekh and colleagues used 60 years of Framingham Heart Study data on 4,615 people and linked glucose and insulin disruption with obesity-related cancers.
• LCHF supporters and a growing number of diabetes researchers say the lower the better. Others caution against targets that are too low without medical supervision.
• The author’s view: Glucose acts as an inflammatory agent. Taubes and others say obesity is a reaction to sugar. If a table edge bruises you every time, you move the table and not buy more bandages.

Take-away points

• Reduce the time spent with blood sugar above 140 after meals. The simple answer is: stop eating so often.
• Cutting sugar and refined carbohydrate lowers insulin.
• Discuss testing and targets with your doctor.

References

• Parekh, N. et al. (2013) Metabolic dysregulation of the insulin-glucose axis and risk of obesity-related cancers in the Framingham Heart Study-Offspring cohort. Cancer Epidemiol Biomarkers Prev.
• Selvin, E. et al. (2005) Glycemic control and coronary heart disease risk in persons with and without diabetes: the ARIC study. Arch Intern Med.
• Kresser, C. (2010) Why your normal blood sugar isn’t normal. chriskresser.com
• Pan, Y. et al. (2012) Inhibition of high glucose-induced inflammatory response and macrophage infiltration by a novel curcumin derivative.
• Zhang, S. et al. (2014) The pathogenic mechanism of diabetes varies with the degree of overexpression and oligomerization of human amylin.