This begins a series of posts on chronic diseases. Nearly half of Americans suffer from at least one chronic disease. Chronic diseases include diabetes mellitus, high blood pressure, cancer, stroke, heart disease, respiratory diseases, arthritis, obesity, and oral diseases. Chronic diseases are responsible for 7 out or every 10 deaths in the United States. Almost of these diseases can be prevented or managed successfully.

Type 2 Diabetes mellitus has reached epidemic proportions in the United States. One in every ten people in the United States has type 2 diabetes mellitus. It is the 7th leading cause of death in the U.S. In this post I will talk about the causes of type 2 diabetes mellitus, how it can be prevented, and how it can be treated by diet and exercise modification.

Terminology

The correct terminology for excesssive blood sugar is diabetes mellitus.The greek word from which the word diabetes comes means ”a large discharge of urine.” Mellitus comes from the greek word meaning “sweet.” There is another kind of diabetes (large discharge of urine) called diabetes insipidus, which is a completely different disease. Diabetes insipidus is caused by a deficiency of a hormone called vasopressin that is secreted at the base of the brain.

There are two types of diabetes mellitus and they both cause high blood glucose but they have completely different causes. Type 1 diabetes mellitus is an autoimmune disease that destroys the beta cells in the pancreas, which are the cells that produce insulin. It usually occurs in childhood, often following a viral infection. It is much less common than type 2. People with type 1 diabetes mellitus have high blood glucose because they produce no insulin at all and have to be treated with insulin. People with type 2 diabetes mellitus make plenty of insulin, at least in the beginning of the disease. Their bodies are resistant to insulin, and even though their insulin levels are high, the insulin can’t carry glucose into the body’s cells like it is supposed to and the blood glucose rises. In the rest or this post I’m going to talk exclusively about type 2 diabetes mellitus.

Causes of type 2 diabetes mellitus

Type 2 diabetes mellitus is caused by a complex interaction between genetics and environment.

Heredity

Type 2 diabetes mellitus tends to run in families. The lifetime risk of developing type 2 diabetes mellitus is 40% for individuals who have one parent with type 2 diabetes (I will leave off the mellitus from here on out for the sake of brevity) and 70% if both parents are affected. We know some of the genes that are associated with risk of developing type 2 diabetes but they only account for about 20% of the heredity, so there are a lot more genes to find. Genetic risk is not destiny, though. Environment plays a huge role in the development of type 2 diabetes.

Causes of Insulin Resistance

Insulin resistance is the hallmark of type 2 diabetes. Insulin resistance starts well before the onset of diabetes. At first your pancreatic beta cells make enough extra insulin to keep your blood sugar normal. Eventually, though, they can’t keep up and blood sugar starts to rise. A number of things can lead to insulin resistance, which I will outline below.

Abdominal body fat

Increased waist circumference (greater than 40 inches for men and 35 inches for women) is a marker for what is called visceral fat, which means fat around the internal organs. Visceral fat is one of the main causes of insulin resistance. Just being over fat in general is also a cause of insulin resistance.

Sedentary Lifestyle

Lack of regular exercise causes insulin resistance. I will talk more about exercise later on when I discuss preventing and treating type 2 diabetes.

Diet

A diet high in processed foods with starchy carbohydrates and sugar (or high fructose corn syrup) causes increased insulin release and can eventually lead to insulin resistance.

Microbiome

The microbiome refers to the 100 trillion bacteria that live in our intestinal tracts. The bacteria in the microbiome help digest our food, regulate our immune system, protect against other bacteria that cause disease, and produce vitamins including B vitamins B12, thiamine and riboflavin, and Vitamin K, which is needed for blood coagulation. It turns out that the microbiome may also promote or reduce insulin resistance depending on what kinds of bacteria live in our intestine. Research about this is just beginning, but here is what we know so far. People with type 2 diabetes have a lower diversity of bacterial species in their gut. They specifically lack bacterial species that produce something called butyric acid. Increased bacterial diversity in the microbiome and especially bacteria that produce butyrates are associated with lower insulin resistance. At this point we don’t know if changing the microbiome will help treat or prevent diabetes, but this is an exciting possibility.

Prediabetes

When genetic predisposition and environment interact, insulin resistance starts to develop. There is a condition called prediabetes. It develops up to ten years before people develop frank type 2 diabetes. There are two tests used to diagnose prediabetes (or actual type 2 diabetes). One is called fasting blood glucose. The blood glucose is tested after fasting overnight. Another test is called hemoglobin A1C. It turns out that glucose in the blood forms a molecular bond with the hemoglobin in red blood cells. This molecular bond lasts for the life of the red cell, which is about 90 days. The amount of hemoglobin that is bonded to glucose is proportional to the average blood glucose level over the 90 day life of the red cell. We can measure the amount of hemoglobin bonded to glucose and that gives us a pretty good measure of the average blood glucose over the last 3 months.

Prediabetes is defined as a fasting blood glucose of 100-125 and/or a hemoglobin A1C of 5.7%-6.4%. If either one of these values is higher, then that makes the diagnosis of type 2 diabetes.

The importance of finding prediabetes is that by making diet and lifestyle changes people can prevent the onset of type 2 diabetes. It is much easier to prevent type 2 diabetes than it is to treat it once you already have it.

How to prevent or reduce insulin resistance (whether you have prediabetes or have progressed to frank type 2 diabetes).

• Reduce body fat especially if you have excessive abdominal fat. Refer to my previous post (The Psychology of Eating and How to Use It Your Advantage) for tips on how to do this sustainably.
• Increase your exercise. The CDC recommends 150 minutes a week of moderate exercise (brisk walking for 30 minutes, 5 days a week, for example) or 75 minutes per week of vigorous exercise (jogging or running for 25 minutes 3 days a week for example).
• Avoid highly processed foods with added sugar, honey, maple syrup and especially high fructose corn syrup. Replace them with fresh fruit, fresh vegetables, fish and poultry.
• Increase the soluble fiber in your diet. Soluble fiber promotes growth of diversity in your microbiome. Here is a link to an article from Healthline.com that identifies the top 20 foods with soluble fiber: Top 20 Foods High in Soluble Fiber
• Eat fermented foods with live bacteria in them such as plain yogurt (sweeten with added fruit or berries, not sugar) sauerkraut, or kimchi. These add healthy bacteria to your microbiome. Here is another link to Healthline.com that lists a number of fermented foods that are good for you: 8 Fermented Foods and Drinks to Boost Digestion and Health.

Dietary Treatment of Type 2 Diabetes

If you already have type 2 diabetes you can do all of the things listed above to decrease insulin resistance, which means you may be able to get by on less or no medicines. If you are on any diabetic medicines other than metformin, you should let your doctor know of any changes you plan to make in your diet or exercise. He or she may want to reduce your medicines so you don’t get your blood sugar too low.

There are some additional dietary changes that may help your blood glucose be under better control and reduce or eliminate your diabetic medicines. These are things you definitely need to check with your doctor before you try them.

Ketogenic Diet

There is good evidence that a ketogenic diet is very good for people with type 2 diabetes.

What are ketones?

Normally your body uses glucose for energy for the brain and other body functions. Insulin carries the glucose into cells so they can use it for energy. If you don’t take in enough carbohydrates to produce glucose for energy, then your body starts to mobilize fat. Fat cannot be broken down to glucose, but it can be broken down to something called ketones. Your body and brain can switch over to using ketones for energy. Ketones require little or no insulin to get into cells.

What do you eat on a ketogenic diet?

A ketogenic diet is a very low carbohydrate high fat diet. That sounds unhealthy and it can be if you eat mostly saturated fats. A good ketogenic diet uses mostly healthy unsaturated fats. Here is a link to another Healthline.com article that discusses ketogenic diets for type 2 diabetes: How the Ketogenic Diet Works for Type 2 Diabetes. Do not start a ketogenic diet without checking with your doctor first!

Intermittent Fasting

Intermittent fasting means exactly that. Fasting means not taking in any calories for certain periods. There are all sorts of ways to do intermittent fasting. Most commonly, people fast for 24 hours every other day or they eat all their meals within a limited time period, between 7AM and 3PM for example. There is increasing evidence that intermittent fasting improves control of type 2 diabetes over and above the fat loss that results. Here is a link to a recent review article about the benefits of intermittent fasting for type 2 diabetes: Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians.

It is important to drink plenty of water when doing intermittent fasting. If doing fasting for longer that 24 hours, one needs to drink liquids with electrolyes rather than plain water. People with type 2 diabetes should NOT start an intermittent fasting program without checking with their doctor.

Further Reading

If you want to read more about diet and lifestyle treatment of type 2 diabetes, here is a link to an excellent book by Dr. Jason Fung: The Diabetes Code: Prevent and Reverse Type 2 Diabetes Naturally.