Insulin resistance, if not treated, can trigger a number of complications – including causing women to ovulate irregularly or to not ovulate at all, resulting in infertility.
Introduction
Glucose, or blood sugar, is the primary source of energy in every organism. Cellular respiration - the process by which cells generate energy (ATP), depends on glucose. Organs, muscles, and the nervous system could not survive without glucose. In fact, neurons, or brain cells, rely exclusively on glucose metabolism to generate energy. We need blood sugar for our survival.
Insulin, a hormone secreted by the pancreas, has as its main responsibility the task of carrying glucose to the cells. The cells then convert this “fuel” – blood sugar into “energy” - ATP. Cells have receptors for different hormones and when the right hormone triggers the right receptor the cell gets activated. Like a lock and key mechanism where each hormone (key) fits exactly into its receptor (lock). Only those parts of the body that have the receptor (lock) can respond to the hormone (key). In the case of insulin, insulin receptors exist on all mammalian cells. When glucose, which is being carried by insulin, activates an insulin receptor of a cell, the cell opens up and allows the glucose to enter so that the cell can use it as energy.
Insulin resistance
Cells have a built-in mechanism to protect themselves when their receptors are being over stimulated. When insulin receptors are continuously exposed to insulin they go through a process known as downregulation where cells “turn off” many of their receptors. For example, an average cell has about 20,000 insulin receptors, but under downregulation it might have less than 5,000 active receptors. A paper published by the American Diabetes Association revealed that under downregulation there can be up to an 80% loss of insulin receptors.
As the cells begin to downregulate themselves due to an excessive amount of glucose caused by a diet rich in sugar, less glucose is allowed to enter the cells resulting in an excess of sugar in the blood. As blood sugar begins to increase, the patient becomes a candidate for diabetes.
Insulin resistance and fertility
Insulin resistance is a common finding in PCOS patients, and many fertility experts agree that PCOS is the primary disrupter of fertility. The excess insulin (hyperinsulinemia) found in PCOS patients inhibits testosterone from converting to estrogen and as a result the PCOS patient ends up having too much testosterone. All estrogens begin as testosterone, in both men and women, and with normal levels of insulin, testosterone is converted as expected.
In males, erectile dysfunction is a major cause of infertility. According to a study published by Fertility and Sterility, erectile dysfunction affects more than half of men over the age of 40. In his book “Why We Get Sick”, Dr. Bikman explains that erectile dysfunction is “not a disease of the hyperinsulinemia per se, but it's insulin resistance.” Normal levels of insulin help to dilate the blood vessels - a requirement for erection to take place. When the blood vessels are insulin-resistant, they remain constricted and erection does not take place. Nitric oxide, a chemical considered a vasodilator because it helps to relax the inner muscles of blood vessels causing them to widen to increase blood flow, has been shown by several studies to decrease in quantity in the presence of insulin resistance. Because nitric oxide is required to keep blood vessels healthy, unhealthy levels of this chemical have a systemic effect. For example, a study published in 2013 by the journal of Clinical Research in Cardiology, titled “Erectile dysfunction may be the first clinical sign of insulin resistance and endothelial dysfunction in young men”, concluded that: “ED may be the first clinical sign of endothelial dysfunction and a clinical marker of cardiovascular and metabolic diseases”. In addition, a paper published by Current Pharmaceutical Design, a peer-reviewed medical journal which covers issues related to pharmacology and medicinal chemistry, concluded that:
“Coronary Artery Disease (CAD) and erectile dysfunction (ED) are cardiovascular complications frequently occurring in patients with diabetes.”
Sperm quality can also be negatively affected by insulin resistance. In 2023 the International Journal of Environmental Research and Public Health published a study where they recognized that insulin resistance is a factor in decreased sperm quality.
Diet and lifestyle
When it comes to insulin resistance, diet and life style play a big role. People that are more sedentary and consume an unhealthy diet are more prone to become insulin resistant. In the conclusion section of a systematic review published in 2022 by Nutrients, an open access peer-reviewed scientific journal that publishes research papers on all aspects of nutrition, it mentioned that “The current literature review showed that all types of exercise (aerobic, resistance and combined training) effectively reduce insulin resistance. In addition, the review also mentioned that a dietary approach is an important strategy to address insulin resistance. Perhaps the most important part of the conclusion of this review is the demand for programs of healthy lifestyle starting in childhood to offer a better preventive strategy to prevent insulin resistance.
Most studies confirm a beneficial influence of recreational physical activity on the quality of semen both among healthy and infertile men. However, other studies showed a negative effect of a particular physical activity on the quality of semen - such were the conclusions of studies on the influence of cycling on the quality of semen.
BMI
Body Mass Index (BMI), which is the person's weight in kilograms divided by the square of height in meters (BMI Calculator), is usually used to predict the quality of semen in male patients. A BMI between 25 and 30 is considered overweight and greater than 30 is considered obese. Obesity and overweight is often connected with insulin resistance. Studies have shown a negative impact of overweight on semen volume, concentration, and total progressive motile sperm count.
Testing for Insulin resistance
There are biomarkers that could be used to determine if a patient is becoming insulin resistant that are very easy and affordable to do. Because in the early stage of insulin resistance there are no obvious symptoms, anyone who has been trying to conceive for more than a year should have their blood sugar and insulin levels checked. A test by the name of hemoglobin A1C (HbA1C) is a blood test that shows the average blood sugar (glucose) level over the past three months. A normal A1C level is below 5.7%, a level of 5.7% to 6.4% indicates prediabetes, and a level of 6.5% or more indicates diabetes. This test is highly recommended for fertility patients, males or females, who have been trying to conceive for over a year.
Acupuncture and insulin resistance
The endocrine system and the nervous system co-regulate the metabolic activities in our bodies and they influence each other significantly. For example, the acupuncture point found below the eighth thoracic vertebra (Yishu) has been used in TCM for over 2,000 years to lower levels of insulin. It is interesting to note that from an anatomical point of view, the nerve coming out of the eighth vertebra innervates the pancreas. In addition, a common symptom of pancreatitis is pain or sensitivity around the eighth thoracic vertebra.
A study published in 2018 by BioMed Research International, where they reviewed 5 years of relevant research regarding acupuncture in the treatment of diabetes, commented that:
“Acupoint therapy has been repeatedly confirmed to have evident effects on decreasing blood glucose"
The study not only offers a lot of very well-researched information, but it also provides acupuncturists with a protocol or foundation to be used with patients with insulin resistance. The study concluded by saying that:
“As the circumstance of diabetes grows increasingly severe all over the world, acupoint therapy, as one of the most important parts of Chinese medicine, plays an indispensable role in the treatment of diabetes and its complications"
Another study published in 2010 by Diabetes, Obesity and Metabolism, a journal of pharmacology and therapeutics, concluded that: “Numerous experimental studies have demonstrated that acupuncture can correct various metabolic disorders such as hyperglycemia, overweight, hyperphagia, hyperlipidemia, inflammation, altered activity of the sympathetic nervous system and insulin signal defect, all of which contribute to the development of insulin resistance”. The study also mentions that:
“ Pharmacological treatments available for insulin resistance are limited due to their adverse effects. And because acupuncture has been practiced for thousands of years in China, it has been increasingly used worldwide for insulin resistance-related diseases."
Conclusion
The prevalence of insulin resistance worldwide ranges from 15.5 to 46.5% among adults. There are many serious disorders caused by this complex condition including cardiovascular disease, fatty liver, and metabolic syndrome to name a few. In addition, when it comes to fertility, PCOS in women and male factor infertility in men are almost always caused by insulin resistance. Lifestyle changes are a must to reverse insulin resistance, as well as supplementation with the right supplements and weekly acupuncture treatments.