Why must I prevent (or reverse) Insulin Resistance?
"In fact, two slices of whole wheat bread increase blood sugar to a higher level than a candy bar does. And then, after about two hours, your blood sugar plunges and you get shaky, your brain feels foggy, you're hungry."
~ William Davis
What is insulin and what is its job?
Your body gets glucose from the carbohydrates in food. As you eat, your blood glucose (also known as blood sugar) levels increase. In response your pancreas releases insulin to lower your blood glucose level back to the normal range. Everyone makes insulin (unless they are Type 1 diabetic).
There are insulin receptors on every type of cell in our body, and as insulin flows past (as a result of elevated blood sugar levels), it binds on to that receptor. The binding of insulin to the cell instructs it to open up and let the glucose in.
Although insulin does have a hand in other bodily processes, its key role is in the regulation of blood glucose.
Problems occur when insulin levels are too high or too low. If you have too much insulin, the excess gets deposited in your blood and causes problems (more below). If your insulin levels are too low, your liver continually produces glucose, stressing the organ.
What is Insulin Resistance?
This means that when insulin arrives at a cell, it can’t unlock it to let in the glucose. The cells have been over-exposed to glucose and have had enough. When this happens, more insulin is produced by the pancreas in an attempt to lower blood glucose levels back into the healthy range. What cant get into the cells, gets stored as fat (this is why people gain weight. It’s not because of eating fat, its because of all the extra glucose from carbs that gets converted to fat). So, Insulin Resistance is characterised by consistently high levels of insulin and glucose in the blood.
However, the beta (insulin-producing) cells in your pancreas may not be able to keep up with the excessively high insulin demand indefinitely. This leads to prediabetes and, without appropriate dietary and lifestyle changes, Type 2 diabetes.
Some people may go for years without knowing they have insulin resistance as it often has no symptoms, and some symptoms may be confused with other health issues.
What causes Insulin Resistance?
High levels of glucose/insulin circulating in your blood
High level of inflammation in your body
Factors that may increase the risk of insulin resistance include:
Being overweight or obese
A high-sugar, high-carbohydrate, or high-calorie diet
Sedentary lifestyle
Chronic stress
Smoking
High blood pressure
Sleep issues
Using high doses of steroids for an extended period
Fat burning vs Sugar burning
Human metabolism is fuelled by two sources: fat and glucose. At any moment the body is obtaining all its energy needs from a one of these two fuels. Insulin dictates which fuel to use. When carbs are consumed, insulin will be secreted shifting the body to sugar-burning mode. All energetic needs will be met wholly by blood sugar.
Once food is digested insulin and blood sugar levels will go back to normal, and the body will shift to fat-burning mode. If you eat a meal with very low carb content, you may stay in fat burning mode. This shifting between sugar-burning and fat-burning is called Metabolic Flexibility, which is good and healthy. However this only happens in people who are Insulin Sensitive. This is the opposite state to insulin resistant.
In an Insulin Resistant person, insulin is chronically elevated. If they then eat starch or sugar, insulin is bumped up even higher and they are stuck in sugar-burning mode. It is near impossible to lose weight if insulin is chronically elevated. You cannot burn fat mass if you are stuck in sugar-burning mode.
Insulin Resistance and Inflammation
One of the hallmarks of Insulin Resistance is chronic inflammation. Chronic inflammation is the root cause of most disease and chronic pain that so many people today suffer from. Insulin stimulates the release of pro-inflammatory proteins called cytokines from human fat cells. Therefore a diet that repeatedly elevates blood glucose levels increases inflammation throughout the body. High insulin levels also inhibit certain immune cells, such as the natural killer (NK) cells, while also causing the production of Insulin-like Growth Factor type 1. (IFG-1 is a hormone that promotes tissue growth and it has a powerful effect at several key stages of cancer).
Some degree of inflammation is necessary to heal, so we don’t want to shut it down completely, but we don’t want it on all the time.
Insulin Resistance and Hypertension (High Blood Pressure)
If someone has hypertension without any known aggravator, eg a hormone or a kidney disorder, it’s a safe bet that the cause is Insulin Resistance.
Firstly, Insulin Resistance won’t allow insulin to dilate blood vessels. In a healthy person, insulin will bind on to the receptors of the endothelial cells (the cells that line blood vessels) and induce the production of something called nitric oxide. This molecule causes the muscles around the blood vessel to relax and the blood vessels to dilate (vasodilation). As the vessels expand, blood pressure decreases. An insulin resistant person’s endothelial cells don’t respond to insulin in the blood and insulin cannot do its work of causing vasodilation. The blood vessels therefore stay constricted and blood pressure stays high.
Secondly, high insulin will stimulate a hormone called Aldosterone (produced by the adrenal glands) to be over produced. Aldosterone tells the kidneys to retain salt. But where there is salt, water goes. With too much water in the system, blood pressure rises. The kidneys are desperate to dump this excess water, but they can’t because the insulin won’t let them.
A sufferer of high blood pressure can follow a diet to lower insulin (ie cut carbs) and within a day their systolic blood pressure can drop by 10 to 20 points.
In conventional medicine, people with high blood pressure are typically advised to go on a low salt diet. Salt isn’t the root cause. This is treating the downstream effect of an upstream issue; it’s not a salt, but an insulin issue. A low insulin diet is what is needed to help the kidneys get rid of the extra water.
One of the unintended consequences of the war on salt is insulin resistance. If you start to restrict salt below the levels the body requires, the kidneys are going to conserve as much salt as possible. One of the mechanisms by which they achieve this is to increase insulin (thus increasing aldosterone etc etc) causing insulin resistance.
Insulin and Autophagy
Mitochondria are the sites within our cells where fuels are burned for energy. Insulin is key for mitochondrial production and function. Chronically elevated insulin or insulin resistance inhibits one of the essential parts of the mitochondrial cycle – autophagy.
Autophagy (“self-eating” in Ancient Greek) is the process whereby the body cleans out any unnecessary or damaged cell components. It is key to longevity, but it is inhibited by elevated insulin. One of the main ways to live a long and healthy life is to keep our cells functioning optimally. To achieve this within each 24 hour period, insulin needs to be low enough to allow our cells to enter autophagy. Most people don’t let this happen.
The average person wakes up in the morning, when insulin has finally gone back to its baseline level and breaks the fast with a carbohydrate centred breakfast. This starts the insulin cycle that goes on throughout the rest of the day. With elevated insulin there is no chance of fat burning and there is no chance for autophagy.
You will notice a huge difference in your energy levels if you achieve autophagy, particularly in your brain. There are 10,000 mitochondria per neuron in your brain, 1,000-2,000 per muscle cell and 5,000 per heart cell. Alzheimer’s is in part an inability of the brain to go through autophagy.
Insulin Resistance and the Brain
An increasing number of researchers now call Alzheimer’s disease Type III Diabetes. Research has shown that insulin resistance is one of the main reasons behind memory loss and dementia that can lead to Alzheimer’s disease.
The brain has among the highest demands for energy of any part of the body. The problem is that when the brain becomes insulin resistant, it is no longer able to meet its energy needs. A constant high starch/sugar diet locks the body into sugar-burning mode. In the average person 100% of the brain’s energy comes from glucose, as there is no other fuel available. As the brain becomes increasingly insulin resistant, its ability to get the energy it needs is compromised.
If a person suffering chronic conditions is able to fuel their energy deficit with fat rather than sugar, there is evidence their problems may start to resolve. Epileptics can live without seizures, people with migraines can go from having 1-2 per week to 1-2 per 6 months and an immediate improvement in cognition can be detected amongst Alzheimer’s sufferers.
Insulin Resistance and Cardiovascular disease (CVD)
Insulin resistance is a big cause of CVD. The high level of insulin in the blood that are generated by the insulin resistant state, causes weight gain around the midriff (visceral adiposity). One in four deaths in UK are due to CVD. Two-thirds of CVD is not caused by fat and cholesterol, but by sugar and refined carbs causing insulin resistance. In fact the central feature of almost all age-related disease - CVD, cancer, diabetes, dementia, hormone imbalance, is insulin resistance. So it is key for your health to focus on being or becoming insulin sensitive.
If you found a group of 100 year olds with clean arteries, they would all have one thing in common: they would be insulin-sensitive - meaning they can perfectly regulate their blood sugar with very little insulin. This is the key to healthy aging.
Conclusion
I hope I have persuaded you that maintaining balanced insulin levels within the normal range is vital for your health. Future articles will set out how you can do that, and also how to diagnose whether you are indeed insulin resistant or even pre-diabetic.
Diabetes and cognitive decline take years to develop. The good news is that through appropriate dietary and lifestyle choices, both can be prevented. I am a great fan of lifestyle approaches that get the body to a state of lower insulin - not just for people with problems, but for everyone. The more we are in a state of low insulin, the healthier we are going to be and the longer we will live.