Ancient man had quite a different lifestyle from us, being hunters for meat and gatherers of edible plant material. They were very fit, having to walk long distances in search of food. Out of necessity they were also fleet of feet, in those days you never knew when you’d bump into a sabertoothed tiger, or worse.
Stress levels increase short term when in danger, returning to normal levels when the danger has passed, and they probably experienced little or no chronic stress, as long as they avoided extended contact with those long in the tooth tigers. They also enjoyed a good night’s sleep, lasting the full hours of darkness.
Our ancestor’s bodies were equipped with inherent survival mechanisms, such as high cytokine immune system responses to eradicate injury, mild insulin resistance as protection against starvation, and sodium preservation for maintenance of body fluid.
Insulin resistance, in particular, would have been an essential part of normal homeostasis (keeping the body’s chemical processes in balance) to facilitate the redirection of nutrients to pivotal organs as well as a physiological adaptive mechanism in aid of survival during critical conditions, such as infection, famine, physical stressors (tigers in the area), and trauma.
However, in modern times those same survival mechanisms can be activated on a chronic basis, resulting in the manifestation of insulin resistance and other conditions such as hypertension. Insulin resistance plays such a major role in many health conditions that it warrants being highlighted.
What is insulin resistance?
For various reasons the harmony in which all the biochemical processes work can be disturbed, affecting the efficient functioning of the body. For example, when glucose from sugar and other carbohydrates in the diet enters the bloodstream, it signals the pancreas to release the hormone insulin, which enable cells to absorb the glucose for processing inside the cells, and in this way restoring blood sugar concentration to its normal range. The mitochondria in cells process glucose to form energy.
Insulin resistance can be viewed as the inability of cells (resistance) to respond properly to normal circulating concentrations of insulin. To maintain a normal concentration of glucose in the blood, 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 prediabetes and type 2 diabetes.
The Insulin Resistance Tree:
There are a number of root causes that contribute to the development of insulin resistance. The effects of insulin resistance in the body can be compared to a tree bearing toxic fruit.
The root causes of insulin resistance:
Chronic stress:
When faced with stressful situations, the body develops a stress response, which involves interaction between different body systems to cope with the stressors. The stress response starts in the brain, where cognitive appraisal of perceived threats and stressors in the environment is mediated by the brain, to activate the responding cardiovascular, immune, and neuroendocrine processes.
During short term (acute) stressful situations the brain sends a distress signal to the adrenal glands, which responds by releasing high doses of adrenalin into the bloodstream.
Adrenalin spikes immediately affects the body, such as causing acceleration of the heartbeat and raising blood pressure for improved blood circulation, dilating the pupils to allow more light into the eyes for improved vision, increasing respiration, and constricting blood vessels in the skin to limit bleeding from wounds, if any. The liver responds by releasing more glucose and free fatty acid levels into the bloodstream for energy, while the immune system is activated, and molecules called endorphins are released to reduce our perception of pain. While these responses give us super-senses and the ability to react instantly, it comes at a cost to the body, as some body systems need to shut down to enable the “fight-or-flight” response. Blood flow is restricted to the skin (ever noticed how pale you are in a scary situation?), as well as to the reproductive and digestive systems.
After the initial surge in adrenalin that activates the immune system, the brain signals the adrenal glands after about 20 minutes to release another hormone, called cortisol, which helps to regain balance by returning the immune system back to normal levels, to prevent the immune system from becoming overactive and potentially destructive. The acute short-term responses to stress have no ill-effects on the body.
Chronically elevated levels of cortisol do have ill-effects on the body, such as suppressing the functioning of the immune system, or causing resistance to cortisol in cells and tissues, leaving the door open to inflammatory related diseases or even autoimmune disorders. Other detrimental effects on the body include over-eating or binge eating with increased fat storage, leading to weight gain and insulin resistance.
Ultra-processed food:
Ultra-processed foods refer to products that have been manufactured by industrial processes, which are characterized by poor nutritional value, being high in ingredients such as sugar, sodium, highly refined grains, saturated fats, and trans fats. These ingredients are linked to multiple adverse health condition, for example cardiovascular diseases, obesity, high (unhealthy) LDL cholesterol levels, increased blood sugar levels, insulin resistance, and diabetes.
Sugar:
A single molecule of sugar consists of equal amounts of glucose and fructose, which gets separated early during the digestive process in the small intestine. After separation, they follow different pathways in the body and have different effects when metabolized.
When glucose enters the bloodstream, it signals the pancreas to release the hormone insulin, which enables cells to absorb the glucose for processing inside the cells, and in this way restoring blood sugar concentration to its normal range. The mitochondria in cells process glucose to form energy. Levels of the most critical energy molecule, called adenosine triphosphate (ATP), is tightly maintained in the cell.
Excess glucose is stored in the liver as glycogen. Glucose can also be converted into fats, usually as triglycerides, and stored in fat cells.
Too much sugar, too often, results in the body being regularly flooded with glucose, which causes repeated spikes in insulin levels. Cells usually become insulin resistant when they are already filled with enough fuel and protect themselves from being overstuffed, by not wanting to take any more glucose in.
Insulin resistance is like having two sides to a coin – on the one side glucose cannot enter some cells as usual and more and more insulin is needed to counter high levels of glucose in the bloodstream. On the other side of the coin, high levels of insulin affect many other processes in some cells. For example, high insulin levels drive the body into fat storage mode, as insulin instructs the body not to burn fat, also instructing the liver and fat tissues to turn glucose into fat, and instructing fat stores to hold on to fat, meaning the fat stores get bigger.
While glucose is the currency of energy in the body, fructose is the currency of energy storage. When liver cells are flooded by excess amounts of fructose, most of this excess are converted to fat, called triglycerides, which are reflected as rising triglyceride levels in the bloodstream. This fat is lodged in liver cells and via the bloodstream in fat cells in the body. Although fructose does not affect insulin directly, the build-up of fat in the liver can result in insulin resistance in the liver.
Lack of sleep:
The quality and quantity of sleep is important for metabolic health and plays an important role in the control of hormones and blood glucose. The body moves into a relaxed state during sleep and the nervous system switches into repair and recovery mode, while maintenance processes take place in the brain. Sleep allows cells in the body to repair and regrow, allowing the body to restore itself.
Sleep may help to protect the cells in the body against insulin resistance, by keeping the cells healthy and balancing the release of insulin, the hormone that helps the cells use glucose (sugar) for energy.
Refined carbohydrates:
Refined carbohydrates are also known as processed carbohydrates or simple carbohydrates. The two main types are sugars, such as refined and processed table sugar, and refined grains, which have had the fibrous and nutritious parts removed, such as refined white flour. As refined carbohydrates have been stripped of almost all fiber, vitamins, and minerals, they are regarded as empty calories. During the refining process, the bran and germ are removed, along with their nutrients.
Refined carbohydrates are digested quickly, leading to rapid blood sugar spikes and insulin levels after a meal. Diets high in refined carbohydrates have been linked to an increased risk of diseases such as heart disease, diabetes, obesity, certain cancers, digestive problems, and insulin resistance.
Sedentary lifestyles:
Most working adults spend much time sitting at work, which contributes to the overall sitting time associated with a sedentary lifestyle, which is also characterized by sitting in front of the TV and other electronic devices at home.
Physical inactivity is usually accompanied by chronic stress levels, both a severe threat to body homeostasis. The incidence of insulin resistance that is linked to physical inactivity is increasing even among younger adults, and it is no longer regarded as an aging problem only.
A sedentary lifestyle and physical inactivity can induce insulin resistance through lowering energy expenditure, dysregulating lipid (fat) homeostasis, and enhancing lipid storage. Physical inactivity is also linked to various molecular mechanisms, such as the impairment of pancreatic beta cell function (affecting the release of insulin), mitochondrial dysfunction, and inducing chronic low-grade systemic inflammation.
Seed oils:
Seed oils, with polyunsaturated fat as its main constituent, have in the past been blamed for a number of adverse health condition, such as increasing the risk of weight gain, heart disease, insulin resistance, diabetes, and obesity.
Polyunsaturated fat is more prone to oxidation and can result in the formation of undesirable free radicals. Oxidized LDL cholesterol contributes to plaque build-up in the arteries. LDL cholesterol that contains high levels of omega 6 – of which high concentrations are found in polyunsaturated fat – are particularly prone to oxidation. The build-up of plaque happens when LDL particles penetrate arterial walls, where they become oxidized and are attacked by white blood cells, resulting in inflammation.
(Oxygen can be destructive to the cells in the body when free radicals (unstable molecules) are formed that subject the cells to continuous damage, known as oxidative stress or oxidation. This process causes damage to the body such as making us age faster, converting healthy cells into cancerous ones, elevating blood pressure, hardenings of the arteries, and promoting inflammation and insulin resistance. Nutrients called antioxidants help the body repair cell damage due to free radicals.)
Seed oils are relatively inexpensive and used in a variety of packaged products, such as chips, baked goods, crackers, mayonnaise, margarine, and salad dressings. These foods also contribute refined carbohydrates, plenty of calories, salt, and sugars. Seed oils are also used to fry foods in restaurants. When they are heated up time and again for deep-frying, it results in a build-up of damaging chemicals.
From a long-term health perspective, cold pressed extra virgin olive oil is simply the best choice for cooking at home, as it is monounsaturated, high in antioxidants, and can be used for cooking, baking or as a salad dressing.
The toxic fruits of the insulin resistance tree:
Shortened telomeres:
The spirally chromosomes in the cells, looking a bit like shoelaces, are strands of DNA that house our genes and is the blueprint to make new, young cells. The body must duplicate cells to grow or to repair cells due to aging, and this process is called mitosis. During mitosis each parent cell divides into two new cells, with the original genetic material duplicated. To ensure that the genetic material is passed on correctly to each new cell, the strands of chromosomes (“shoelaces”) have protective caps – called telomeres – at the ends of the strands, like the tips of shoelaces. Telomeres prevent chromosome “strands” from losing base pair sequences at their ends and stop chromosomes from fusing with each other. Every time a cell divides, some part of the telomere is lost and becomes shorter. When the telomeres become too short, the chromosomes can no longer replicate. The cell becomes old and dies.
Certain unhealthy lifestyle factors potentially increase the rate of telomere shortening, such as insulin resistance, obesity, lack of physical activity, high levels of stress, and smoking.
Fatty liver:
When the body produces too much fat or is unable to metabolize fat efficiently, excess fat is stored in the liver cells, where it accumulates. Small amounts of fat in the liver are normal, but an increased build-up of fat (more than 5% of the liver’s weight) can cause inflammation, which can damage liver cells and create fibrosis or scarring. In severe cases fibrosis can lead to cirrhosis and liver failure.
Several risk factors can make it likely to develop non-alcoholic fatty liver disease, such as:
- A high intake of fructose, from sugar and sweetened food and beverages, is associated with insulin resistance, diabetes, obesity, and fatty liver disease. All the fructose is taken up by the liver. Liver cells, if flooded by fructose, converts most of it to fat, called triglycerides, reflected by rising triglyceride levels in the bloodstream. Most of this fat is deposited in liver cells and with continued intake of fructose, results in a fatty liver. Other products also formed in the liver during fructose metabolism are uric acid and damaging free radicals.
- A high fructose intake is also linked to high blood sugar levels and insulin resistance.
- Having insulin resistance, prediabetes and type 2 diabetes are all risk factors for developing fatty liver disease.
Inflammation:
The body’s immune system is the guardian that protects us from disease and infection. When the guardian detects a harmful substance (for example viruses, bacteria, toxins, even cancer cells), chemicals from the white blood cells attack these harmful substances. This raging battle results in inflammation in the affected area. Once these harmful substances have been destroyed, the immune system reverts to its observational role and the inflammation comes to an end.
However, an over-active immune response doesn’t call an end to the attack mode and can result in healthy cells in the body becoming the new targets to attack and eliminate, leading to one of the many types of auto-immune disorders. As the control mechanisms that would normally end the inflammation no longer functions properly, the attack on these cells and the accompanying inflammation carries on unabated.
This makes the body less responsive to insulin and increases the risk for insulin resistance.
Certain cancers:
Research over the past decade has indicated that cancer may well be a “software” disease, based on the incorrect functioning of the biochemical processes taking place inside the cell.
The metabolic processes taking place in the cell, in a nutshell, means that biochemical energy is harvested from the food we eat, for example glucose from carbohydrates, and then stored in energy-carrying biomolecules (ATP), to be used in the activities in the cell that require energy. Mitochondria are of particular interest in the latest cancer research, as defects in the energy generating pathways of the mitochondria can lead to many different types of symptoms in the body.
Research has shown that the energy metabolism of tumour cells varies greatly from normal cells. The most common structural problem in most cancer cells is abnormal or dysfunctional mitochondria. Insulin resistance is a critical cause of metabolic dysfunctions, which is common in patients with cancer. Research has indicated that patients with a cancer diagnosis are markedly insulin resistant.
Gout:
Gout is a form of inflammatory arthritis, where high levels of uric acid build up and form needle-like crystals in the joints, resulting in sudden attacks of extreme pain in affected joints. It often affects one joint at a time, most commonly at the base of the big toe.
In the case of gout, high levels of uric acid can also cause a person to develop insulin resistance and studies have shown that uric acid buildup can lead to worsened insulin resistance, increasing the risk for diabetes.
Alzheimer’s disease:
Insulin is intimately related to Alzheimer’s disease by several mechanisms. After insulin molecules did their duty by lowering glucose, the body must degrade the insulin to prevent the blood glucose dropping too low, which is done by, amongst others, an enzyme called insulin-degrading enzyme. When not breaking down insulin, these enzymes are involved in breaking down amyloid-beta, which otherwise forms the sticky synapse-destroying plaques in Alzheimer’s disease. However, insulin-degrading enzyme cannot do both at the same time. Chronically high levels of insulin in the brain (due to insulin resistance) divert insulin-degrading enzymes from destroying amyloid, leading to increased amyloid-beta levels – increasing the risk for Alzheimer’s disease.
Brain insulin resistance also inhibits the uptake of glucose, resulting in the neurons (brain nerve cells) lacking sufficient amounts of glucose to function effectively, especially in the hippocampus (center of memory and learning) and the cerebral cortex. Studies have linked brain insulin resistance to Alzheimer’s disease, as this deficiency can result in typical symptoms of Alzheimer’s disease, such as impaired functioning of memory, judgement, and the ability to reason.
High blood pressure:
Insulin contributes to the regulation of blood pressure, as it induces vasorelaxation (widening of blood vessels) by stimulating the production of nitric oxide in the smooth muscle cells within the blood vessel walls. Insulin further contributes to the regulation of blood pressure by regulating sodium homeostasis by enhancing sodium reabsorption in the kidneys.
Recent studies have shown that insulin resistance not only develop in the classic insulin-responsive tissues, but also in cardiovascular tissues. Insulin resistance and high blood pressure are both components of metabolic syndrome and studies have indicated that about 50% of people with high blood pressure also have insulin resistance.
Arthritis:
Arthritis refers to joint inflammation symptoms such as joint pain, stiffness, and swelling in the areas where bones come together, such as the knees, hips, elbows, wrists, fingers, and toes.
More than 100 different types of arthritis and related conditions have been identified, which can be classified in two broad categories, namely degenerative arthritis and inflammatory arthritis.
Insulin acts as a crucial modulator of the inflammatory response in arthritis through its integrated signalling network, where insulin regulates cellular pathways in immune cells, in cartilage, and in synovial tissue (which is a highly specialized tissue that keeps the articular joint lubricated as well as providing nutrients to the articulate surface).
Inflammatory arthritis carries an increased risk of metabolic disorders, including insulin resistance. Emerging evidence from recent studies suggests that the cause-effect relationship between arthritis and metabolic abnormalities might be bidirectional.
Stroke:
The most common type of stroke is ischemic stroke, caused by a blocked artery leading to the brain. It causes reduced blood flow, known as ischemia, and prevents oxygen and nutrients from reaching the brain and brain cells begin to die in minutes. When the interruption of blood flow to the brain is temporary and doesn’t cause permanent damage, it is called a transient ischemic stroke.
The other type of stroke is a haemorrhagic stroke, resulting from leaking or ruptured blood vessels in the brain, which causes bleeding in the brain. The bleeding increases pressure on brain cells and damages them.
Insulin is essential for brain function and insulin resistance is an independent risk factor for stroke, as insulin resistance promotes the formation of thrombosis (blood clots) and atherosclerosis (hardening of the arteries). Insulin resistance contributes to a poor prognosis in the event of a stroke, as it intensifies the inflammatory response, oxidative stress, and damage to brain cells.
Type 2 diabetes:
Type 1 diabetes refers to people unable to produce insulin, and type 2 diabetes refers to people whose bodies produce insulin but can’t use it as intended.
Researchers believe that type II diabetes encompasses four kinds of diabetes.
- Severe insulin-deficient diabetes. The onset of this severe form of diabetes is also usually at a young age, also not overweight, and is characterized by the body not producing enough insulin, probably due to a deficiency in the beta cells in the pancreas that produce insulin. These people have a high risk of retinopathy that can lead to loss of vision (17,5% of patients)
- Severe insulin-resistant diabetes usually occurs in overweight people whose bodies produce insulin, but their cells are not responding to it (insulin resistance). These people have the highest risk of liver and kidney disease resulting from this severe form of diabetes (15,3 % of patients)
- Mild obesity-related diabetes usually occurs in obese people, and it is a milder form of diabetes with less metabolic problems (21.6% of patients). It responds well to lifestyle changes.
- Mild age-related diabetes is also a milder form of diabetes, but with the onset of diabetes at a higher age. This is the most common form of diabetes (39,1% of patients). It responds well to lifestyle changes.
Dementia:
The brain depends on glucose as its main source of energy and is truly a real glutton for glucose. While the brain comprises only about 2% of the human body’s mass, it uses an estimated 20% of the energy supply (glucose in the bloodstream) daily as fuel for the brain.
Although insulin receptors are found throughout the brain, they are expressed at higher levels in certain areas, such as the hypothalamus, hippocampus, cerebellum, and cortex. The hippocampus, where memory resides in the brain, has a very high metabolic rate, about 2-3 times higher than neighboring areas in the brain. There are high levels of glucose in the hippocampus, but when the insulin is not working well due to insulin resistance, there is an energy gap in this area. Cells in the hippocampus can become insulin resistant, just like liver cells and fat cells.
Insulin resistance in this area means glucose absorption is inefficient and the brain cells in the hippocampus end up starving. This starvation is manifested as cognitive deficit and even dementia, as memory and learning are forced to operate at lower levels.
Obesity:
Obesity can trigger diabetes that is associated with insulin resistance, as obesity is linked to higher amounts of fatty acids, hormones, glycerol (a naturally occurring 3 carbon alcohol in the body), and pro-inflammatory cytokines being released by adipose (body fat) tissue.
Obesity can cause chronic and low-grade inflammation leading to the emergence of insulin resistance linked diabetes, which can be a two-way street, as insulin resistance in turn can contribute to the development of obesity. In addition, excess fat in fat cells can result in insulin resistance, even without inflammation.
Erectile dysfunction:
Insulin resistance drives erectile dysfunction through several complex mechanisms, such as endothelial dysfunction, inflammation, atherosclerosis (the build-up of plaque inside arteries), and impaired vasodilation. Insulin resistance and inflammation are underlying mechanisms that contribute to the cardiovascular risk factors that are also linked to erectile dysfunction, such as obesity, diabetes, and hypertension.
In the state of insulin resistance, basal levels of insulin are elevated, which disrupts erectile function by inducing vasoconstriction (narrowing of blood vessels), increasing activity of the sympathetic nervous system, and promoting hypertension.
Studies have shown that among younger men, insulin resistance was the most common risk factor for erectile dysfunction, with a prevalence of more than 50%.
Osteoarthritis:
Degenerative arthritis, such as osteoarthritis, refers to the types of arthritis where mechanical abnormalities result in degradation of joints, such as when the protective cartilage (the hard, slippery coating) at the ends of bones wears down over time or gets damaged through an injury. When the ends of bones are no longer protected by the cartilage, bones may be exposed and get damaged. As the cartilage wears away and the cushioning surface at the ends of bones degenerates, bone starts to rub against bone. Apart from the pain in the joint, swelling and stiffness can also be experienced, and the pain can become chronic.
Aging plays a major role in the degeneration of joints, but not all elderly people experience osteoarthritis. Causes of degenerative arthritis can be hereditary, developmental, mechanical, or metabolic, such as insulin resistance.
Sarcopenia:
Sarcopenia refers to the aging related involuntary loss of skeletal muscle mass and strength, as well as muscle function. The decline in muscle strength gradually takes place in a linear fashion, starting in the 4th decade of live, with a dramatic decline during the 8th decade of life, with up to 50% of muscle mass and strength lost by then. Muscle degeneration is a common condition in elderly people and is associated with disability, functional decline, frailty and fall related injuries. It is estimated that about half of those over the age of 80 are impaired with sarcopenia, also known as muscle loss – literally meaning “lack of flesh”.
Losing muscle mass decreases insulin sensitivity, as the muscle tissue acts as a reservoir for the disposal of glucose, contributing to insulin resistance.
PCOS:
Polycystic ovary syndrome (PCOS is a hormonal condition that affects women of reproductive age and is a leading cause of infertility. PCOS can cause hormonal imbalances, irregular periods, and excess androgen (sex hormone) levels. It is a lifelong health condition.
Women with PCOS are often insulin resistant, as their bodies can make insulin but cannot use it effectively. This increases the risk for type 2 diabetes. The incidence of insulin resistance in patients with PCOS is amplified by obesity.
Heart disease:
Heart disease happens when blocked arteries cause problems with blood flow. There are many ways in which insulin resistance can affect blood vessels and the heart.
- High blood sugar due to insulin resistance leads to inflammation, which can damage the lining inside arteries, leading to plaque buildup in arteries.
- High blood sugar and inflammation resulting from insulin resistance can damage the nerves that control the heart.
- Insulin resistance goes hand in hand with diabetes and people with diabetes tend to have high cholesterol, in particular the unhealthy small, dense LDL cholesterol, which can easily enter blood vessel linings and create the buildup of plaque.
- Insulin resistance is associated with weight gain and being overweight can strain the heart and lead to heart failure.
Migraines:
Studies have indicated that insulin resistance is related to migraine in various ways. Insulin resistance is believed to lead to impaired neurotransmitter release, altered regulation of brain cell receptors, and inflammatory responses. The severity of migraine attacks was found to be higher in patients with insulin resistance.
Studies have also linked migraine to patients with a higher waist circumference and abdominal obesity. Fat tissue is viewed as an endocrine gland from which many pro-inflammatory cytokines are produced, and these levels increase just before a migraine attack.
Conclusion:
Insulin resistance is considered as one of the “diseases of civilization”, something our ancient forefathers did not have to face, although a sabertoothed tiger is way more fearsome.
As there is no effective drug to treat insulin resistance, the individual has got to understand the condition and handle it through lifestyle changes, by following the eat well, sleep well, stress less, move more lifestyle option.
References:
Relationship between ultra-processed food consumption and risk of diabetes mellitus: A mini review. Published June 2022 in the journal Nutrients. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Why refined carbs are bad for you. Published online and updated 21 April 2023. Healthline. (www.healthline.com)
Pathophysiology of physical inactivity-dependent insulin resistance: A theoretical mechanistic review emphasizing clinical evidence. Published in Journal of Diabetes Research. Volume 2021/Article ID 7796727. Hindawi. (www.hindawi.com)
Do seed oils make you sick? Published 31 May 2022. Consumer Reports. (www.consumerreports.org)
Link between insulin resistance and hypertension: What is the evidence from evolutionary biology? Published January 2014. Diabetology & Metabolic Syndrome Journal. BioMed Central. (www.dmsjournal.biomedcentral.com)
Insulin resistance and risk for stroke. Published September 2002 in the journal Neurology. American Academy of Neurology. (www.neurology.org)
Insulin resistance in ischemic stroke: Mechanisms and therapeutic approaches. Published December 2022 in the journal Frontiers in Endocrinology. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Obesity, insulin resistance, and Type 2 diabetes: Associations and therapeutic implications. Published October 2020 in the journal Diabetes, Metabolic Syndrome, and Obesity. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Insulin resistance & erectile dysfunction. Published online. Biotics Research. (www.bioticsresearch.com)
PCOS (Polycystic Ovary Syndrome) and diabetes. Published online and reviewed 30 December 2022. Centres for Disease Control and Prevention. USA. (www.cdc.gov)
Insulin resistance in polycystic ovarian syndrome. Published October 2022 in the journal Cureus. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Insulin resistance and your heart. Published online and reviewed 11 January 2022. WebMD. (www.webmd.com)
The potential impact of insulin resistance and metabolic syndrome on migraine headache characteristics. Published November 2022 in the journal BMC Neurology. BioMed Central. (www.bmcneurol.biomedcentral.com)
Insulin Resistance Tree image originally by Health Results, with minor editing by Health Insight.
HEALTH INSIGHT
December 2023