Introduction
Hormones modulate many different body processes. A hormone that plays a significant role in our body’s energy regulation is insulin. The food you consume is broken down into glucose.
This hormone made by the pancreas helps blood glucose to be absorbed by the cells in your muscles, fat, and liver, where it is diverted towards the body’s energy requirements. Insulin moderates the blood sugar levels that rise after you eat and keeps glucose in the normal range.
In certain situations like phases of fasting, the liver also produces glucose.
What is Insulin Resistance?
When the cells in your body specifically, your muscles, fat and liver are resistant to absorbing glucose easily from your blood and are not responding well to insulin, they become insulin resistant. This leads to your pancreas creating more insulin. Over time, your blood glucose levels rise as the cells are unable to absorb glucose.
Insulin resistance and insulin sensitivity are inversely related. Having insulin resistance translates into having low insulin sensitivity. While insulin resistance is considered detrimental to your wellbeing, insulin sensitivity is beneficial to it.
What is the Main Cause of Insulin Resistance?
There are numerous factors that could lead to insulin resistance.
1.High amounts of free fatty acids
Studies show that cells in the body can stop responding efficiently to insulin when there is a high load of free fatty acids in the blood. The primary reason for the abundance of free fatty acids in the blood is the overconsumption of calories and excess body fat. In fact, overconsumption, excessive weight gain, and obesity are associated with insulin resistance.
According to a study published in the research journal – Obesity, exploring the core topic, “Why Visceral Fat is Bad: Mechanisms of the Metabolic Syndrome”, visceral fat was found to release inflammatory adipokines and free fatty acids into the blood that lead to insulin resistance. Free fatty acids inhibit insulin-stimulated glucose uptake and glycogen synthesis. According to WebMD, visceral fat is adiposity that wraps around your abdominal organs deep inside your body. While it is widely held that having visceral fat is common among people who have excess body weight, it is important to note that individuals who appear to have flat bellies can also have visceral fat. Visceral fat is also correlated with the build-up of excess lipid in the liver, leading to impairment in insulin signalling.
2.Physical inactivity
The lack of physical activity is also linked to insulin resistance. According to NIDDK, regular physical activity can facilitate changes in your body to regulate blood glucose levels better, thereby increasing insulin sensitivity.
3.Fructose
Studies have linked high fructose consumption from added sugar (not fruit) with insulin resistance. The significant increase in the consumption of dietary fructose, particularly from sucrose and high fructose corn syrup that is a common sweetener used in the food industry, has been a contributor. A high surge of fructose travelling to the liver disrupts glucose metabolism and glucose uptake pathways. This leads to a significantly enhanced rate of denovo lipogenesis (a complex and highly regulated metabolic pathway that converts excess carbs into free fatty acids) and triglyceride (TG) synthesis from fructose catabolism. These disturbances in metabolic health seem to give rise to insulin resistance.
4.Oxidative Stress
The increase in oxidative stress and inflammation in your body can be one of the factors that may lead to insulin resistance. According to NCBI, oxidative stress is a phenomenon caused by an imbalance between the production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products. When there are drastic changes in blood sugar levels, this imbalance leads to oxidative stress. Glucose variability can be caused by a host of factors, including a poor diet, infections, tumours and other conditions.
5.Gut microbiome
Unnatural food items such as High fructose corn syrup have low or no nutritional value. To worsen the consumption, it also causes damage to the gut and brain health. In a study funded by Yale University and the National Institutes of Health, the composition of the gut microbiome was evaluated and was found to be affected by a high intake of sucrose and fructose. In fact, a study conducted on mice found that a high fructose/glucose diet affected a beneficial type of bacteria, the Bacteroides thetaiotaomicron. The species are connected to the ability to process certain food items that are healthy such as vegetables. Sucrose has been found to block the production of something known as ROC, which is a protein that helps in the colonisation of this bacteria in the gut.
Researchers concluded that diets can impact not just the consumption of nutrients but also play an important role in gut microbiota, with carbohydrates like sugars even acting as signals for key bacteria. Thereby, affecting the gut negatively.
Studies suggest that the imbalance in the bacterial environment in your gut can cause inflammation that impairs insulin resistance and affects certain metabolic health parameters. While the studies are at a nascent stage, genetics can be a contributing factor.
6.Stress: Does stress cause insulin resistance?
Cortisol is the body’s natural alarm system which plays an important role in regulating blood pressure and blood sugar levels. In a stressful situation, cortisol increases glucose levels for an immediate energy source, inhibiting sensitivity to insulin production. Over time with chronic stress and chronically elevated glucose levels, the pancreas (which produces insulin to bring down glucose levels in the blood) loses the ability to respond to a high glucose stimulus, causing a reduction in the activity of insulin.
How to Manage(Fix) insulin resistance with Lifestyle choices?
Insulin resistance can be managed and controlled. It can also be completely reversed with the right lifestyle and consumption choices.
Here are four ways to increase insulin resistance:
1.Physical activity
Increasing physical activity has proved to be a good way to improve insulin sensitivity. Studies suggest that its effects are almost immediately noticeable. In the past decade, huge progress has been made towards enhancing the understanding of the molecular basis underlying the benefits of physical activity in stimulating the entry of glucose into insulin-sensitive tissues. It is now a well known and accepted fact that regular physical activity can be a therapeutic intervention in insulin-resistant people. Through physical activity and other effective methods, the reduction of visceral fat around the main organs can help further reduce insulin resistance.
While the number of hours of physical activity is dependent on the individual, WHO recommendations for ages 18 to 64 state that:
- One should do at least 150–300 minutes of moderate-intensity aerobic physical activity or at least 75–150 minutes of vigorous-intensity aerobic physical activity; or an equivalent combination of moderate- and vigorous-intensity activity throughout the week
- One should also do muscle-strengthening activities at moderate or greater intensity that involve all major muscle groups on 2 or more days a week, as these provide additional health benefits
- One may increase moderate-intensity aerobic physical activity to more than 300 minutes; or do more than 150 minutes of vigorous-intensity aerobic physical activity; or an equivalent combination of moderate- and vigorous-intensity activity throughout the week for additional health benefits
- One should limit the amount of time spent being sedentary. Replacing sedentary time with physical activity of any intensity (including light intensity) provides health benefits
- To help reduce the detrimental effects of high levels of sedentary behaviour on health, all adults and older adults should aim to do more than the recommended levels of moderate- to vigorous-intensity physical activity
2.Stress Management
Cortisol plays an important role in glucose metabolism. Managing chronic stress could help manage insulin resistance. One could adopt approaches like journaling and activities like forest bathing to activate the parasympathetic nervous system for regulating stress levels.
3.Sleep
The importance of getting sufficient sleep is widely studied. Recent findings suggest that sleep performs the function of housekeeping by removing toxins that build up in your brain while you are awake.
Poor sleep may disrupt the important biochemical processes in the body. Sleep disorders are known to have a tremendous impact on public health. The evidence around the correlation between sleep loss/sleep disorders and metabolism disequilibrium has been mounting.
Lab studies have shown that sleep deprivation can alter glucose metabolism and affect the hormones that are involved in regulating metabolism. Specifically, it can lead to decreased levels of leptin, a hormone that inhibits hunger and regulates energy balance, and it can cause ghrelin levels to increase, the hunger hormone that increases appetite.
According to the sleep foundation, adults between the age of 26-64 years old require 7- 9 hours of sleep.
4.Nutrition
The most crucial aspect in reversing insulin resistance is nutrition.
Choosing low glycemic index and glycemic load foods
Consumption of low glycemic index foods is known to keep blood sugar levels low or to reduce them. While Glycemic Index (GI) isn’t the perfect metric it does help measure how the body absorbs or digests foods, affecting the rate at which blood glucose levels rise.
According to medicine.net, foods that are low GI (upto 55) to moderate GI (56-69) include legumes, barley, yoghurt, oats, beans etc.
Another way to measure food is through Glycemic Load (GL). GL takes into account the amount of carbohydrate in a product and its GI. A food’s GL levels are calculated by multiplying its glycemic index by the amount of carbohydrate it contains. In general, a glycemic load of 20 or more is high, 11 to 19 is medium, and 10 or under is low.
Foods that could help manage insulin resistance includes
Fibre-rich foods such as vegetables, oats, barley, certain types of fresh fruit like apples and berries etc
A low carbohydrate diet also may help with reducing insulin resistance. A study concluded that a low-carbohydrate diet, high in saturated fat, improved insulin-resistant dyslipoproteinemia and lipoprotein(a), without adverse effect on LDL cholesterol.
It is also important to avoid high levels of sugary foods and drink, trans fats and simple carbohydrates or high glycemic index and glycemic load foods.
Another diet that may help in reducing insulin resistance is the Mediterranean diet. It is based on consuming seasonal, plant-based foods, eating certain fruits for dessert and for fat, using olive oil. In this diet, people also consume fish, poultry, legumes and nuts, having these foods as the primary protein sources.
Conclusion
While insulin resistance is detrimental to health, there are numerous ways that can help you tame it. The combination of good nutrition consisting of low glycemic index foods, avoiding sugary foods and drinks, sufficient physical activity of at least 300 minutes a week, stress management and getting good quality and requisite quantity of sleep are important factors in optimal glucose metabolism. These lifestyle modifications may lead to a reduction in oxidative stress, visceral fat, and free fatty acids, ultimately leading to management or in some cases reversal of insulin resistance.
