(This is one of three Health Insight blogs based on the three parts of Dr Benjamin Bikman’s book: Why we get sick. The three blogs are: INSULIN RESISTANCE AT THE ROOT OF MOST CHRONIC DISEASES, INSULIN RESISTANCE CAUSES, and INSULIN RESISTANCE CURES.)
What is insulin resistance?
When glucose from sugar and other carbohydrates in the diet enters the bloodstream, it signals the pancreas to release the hormone insulin, which acts as the key to open the “doors” to cells and to escort glucose into cells, where the mitochondria process glucose to produce energy. In this way insulin helps to restore blood glucose levels to its normal range.
Insulin resistance refers to the inability of cells (resistance) to respond properly to normal circulating concentrations of insulin. The pancreas compensates for increased amounts of glucose by secreting increased amounts of insulin. When insufficient insulin for the amount of glucose in the bloodstream is secreted, the build-up of glucose remains in the bloodstream instead of entering the cells. As insulin resistance increases, impaired glucose tolerance develops. Ultimately, failure or exhaustion of the pancreatic insulin producing cells results in a relative decrease in insulin secretion. Over time this can lead to type 2 diabetes.
There are a number of scientifically supported ways to improve insulin resistance. In essence, by changing our lifestyles we can effectively address the fundamental causes, and cut the risk of developing insulin resistance, or even remove it after we have developed this disorder. The two major components of lifestyle that influences insulin resistance are how we move and what we eat – namely exercise and diet.
Physical activity influences insulin resistance:
Any kind of physical activity would help to combat insulin resistance, as exercise removes glucose from the blood without involving insulin. As muscles contract, they are able to take in glucose from the blood without using insulin, even when the muscle is resistant to insulin. This means that blood insulin naturally lowers during and shortly after exercise.
Both aerobic and resistance exercise would improve insulin sensitivity, with resistance training being superior. More muscle offers a greater area in which glucose can be deposited, which also lowers insulin. Equally important are the intensity of the training, which should be fairly strenuous, as the more rigorous the exercise, the greater the improvement in insulin sensitivity. It is also important to regularly increase either frequency or intensity to help maximize the insulin-sensitizing effect of exercising.
The food we eat influences insulin resistance:
Most difficult to change, but nonetheless the most powerful influence in the fight against insulin resistance is the food we eat. In terms of the macronutrients that we normally eat, carbohydrates can elicit an increase in insulin about 10 times above normal fasting levels, with the height and the length of the spike depending on the specific carbohydrate, while dietary protein elicits a mild insulin response about two times fasting levels, and dietary fat elicits no insulin effect at all.
This means a diet that limits the insulin spike by restricting carbohydrates (especially refined products) and increases the insulin dampeners – protein and fat – should increase insulin sensitivity.
Interestingly, if you find it hard to resist some of your favorite carbohydrates and can’t live without them, the impact on insulin can be reduced by eating them at the end of your meal. Studies have shown that eating the starchy part of a meal after the protein and vegetables have a smaller effect on blood glucose and insulin levels.
Whenever we are having a meal, insulin levels rise to control glucose levels, which means frequent eating is not effective in controlling insulin. Having fewer meals with longer periods of time between meals means longer periods with normal glucose and insulin levels, which benefits insulin. Studies found that intermittent fasting is very effective at improving insulin sensitivity.
Another interesting phenomenon is the fact that hormones rise and fall throughout the day and night, following the body’s internal clock, referred to as our circadian rhythm. Insulin follows this rhythm and starts to rise at about 05:30 and drops again within about two hours, called the “dawn effect”. This effect results from hormones that climb toward the end of the sleep cycle, such as growth hormone and cortisol (the stress hormone), which act to increase blood glucose.
The interesting aspect of the “dawn effect’ is that we need more insulin to control glucose levels when we eat a slice of toast early in the morning than when eating it in the evening. This means what we eat when we wake up would matter more than what we eat any other time of the day. (Resist those tasty rusks with the first cup of coffee in the morning!)
Studies have shown that carbohydrate restriction prevents or improves insulin resistance. However, not all carbohydrates are created equal. Whether they are “good” or “bad” would depend on the extent in which the food increases insulin. While the glycemic index (GI) measures how quickly the carbohydrate is digested and ends up as glucose in the blood, of more importance is the glycemic load (GL), which helps to distinguish between “good” and “bad” carbohydrates. GL indicates the amount of potential glucose in the food you are eating, not how quickly it gets digested. High GL foods include, for example, sugary drinks, candy, and refined white bread, while low GL foods include beans, lentils, and certain whole-grain breads. Fiber-rich fruit and vegetables are other examples of low GL carbohydrates.
Some of the other mechanisms that contribute to insulin resistance, such as inflammation and oxidative stress, are also improved with a diet that is lower in carbohydrates, which reduces insulin spikes in the blood, a contributing factor to inflammation and oxidative stress. (Oxidative stress is a condition that may occur when there are too many unstable molecules called free radicals in the body and not enough antioxidants to get rid of them, which may lead to cell and tissue damage.)
Some people are lactose intolerant or gluten intolerant, and it stands to reason that some people may have less tolerance to glucose. Glucose intolerance means those bodies have to work harder to move the glucose from the blood into cells. Fat cells, in particular, are known that if they are insulin resistant, glucose intolerance will soon follow.
Typical low-carbohydrate diets are often high in animal fat and protein, but many people avoid animal fat out of fear of saturated fat due to the common belief that saturated fat will clog the cells and block insulin from working. According to Dr Bikman this common belief is, however, not scientifically correct, as animal fat is never exclusively saturated – it is a broad mix of saturated, monounsaturated, and polyunsaturated fat. In addition, the muscle of insulin-sensitive athletes contains just as much fat as the muscle from obese insulin-resistant people.
The type of fat to be concerned about is a type called ceramide, not from your diet, but made in your cells. Ceramide production is activated by inflammation and once activated, turn an innocent saturated fat into ceramide. Ceramide makes the cell less sensitive to insulin. Importantly, ceramide levels are not increased in the tissue of people who follow a carbohydrate restricted but fat-liberal diet, neither is saturated fat increased in their blood. Studies have shown that adding saturated fat (like lard) to a meal reduces blood fats to lower levels than when adding unsaturated fats, such as olive oil. One of the dangers of avoiding saturated fat (lard, butter) is the substitutes that people use, mostly polyunsaturated fat found in seed oils such as sunflower oil and soybean oil, which may actually do more harm.
A very low-carbohydrate diet means less glucose to fuel the cells in the body. Fortunately, the body, unlike a car that cannot switch over to run on either petrol or diesel, can run on either glucose or fat to fuel the body. When running low on glucose and insulin, the liver breaks down fats to create molecules called ketones as a back-up fuel for the cells in the body. Some of the benefits of ketones include increasing the number of mitochondria in the cell, where fats are broken down, as well as reducing oxidative stress and inflammation. A full ketogenic diet replaces carbohydrates with dietary fat, which has minimal effect on insulin, keeping insulin levels low.
Conclusions:
Very few people consider the food they eat in terms of insulin resistance, rather asking what effect the food will have on their weight. The food that we eat matters when we are insulin resistant, in terms of how much and what we eat. Total calories are important, but the type of calories is even more important, whether from carbohydrates, protein, or fats, as the type, through hormones, tells the body what to do with the calories.
Reference:
Why we get sick. The hidden epidemic at the root of most chronic diseases – and how to fight it. Book by Dr. Benjamin Bikman. Published in 2021 by BenBella Books, Inc. Dallas, Texas. USA. P. 259.
HEALTH INSIGHT.
December 2024