Insulin resistance is getting a lot of attention right now in the health and wellness world. And for good reason, it plays a big role in our metabolic function and is estimated to affect over 80 million Americans. While insulin resistance (IR) affects both men and women, the implications for women are big and affect each stage of our reproductive years. In this blog, I will be sharing how this common condition directly affects a woman’s fertility journey.
In the coming months I will share a blog on IR and its impact on pregnancy and postpartum, as well as a blog on IR and the perimenopause transition. Because insulin resistance impacts so many, there is a lot of information available and it can be overwhelming. Let’s talk about what is important to know and what you can do to manage insulin resistance and support your fertility journey.
What is Insulin Resistance?
Before we jump right into how insulin resistance impacts fertility, I want to define what it is and how insulin resistance can present in women because it is not always obvious.
Insulin resistance is a state in which cells have become desensitized to insulin. The pancreas is overproducing insulin in response to try to keep the elevated blood sugar stable but the cells become resistant and unresponsive. On a cellular level, this means your cells, which should pick up insulin, aren’t registering and the insulin can’t bind to the cells. This causes an inability to maintain insulin balance and functioning in the body. When we are under stress, our body will release more glucose into the bloodstream for energy, which releases more cortisol, more glucose, and more insulin leading to a vicious cycle. As you can imagine, this imbalance can cause many issues in the body including inflammation, excess cortisol, and hormonal challenges.
Insulin resistance disrupts your metabolism by causing extra glucose to be converted into visceral abdominal tissue- a specific kind of belly fat that operates around the organs and creates an enormous amount of inflammatory chemicals and confusion in hormonal cross talk and hormonal signaling.
Insulin Resistance and PMOS
One of the ways that insulin resistance impacts fertility is through PMOS. PMOS, previously known as PCOS, was renamed recently to Polyendocrine Metabolic Ovarian Syndrome. This change is to better describe the multi system impact the condition has. PMOS may involve some or all of these features- insulin resistance, metabolic issues, anovulation or ovulatory dysfunction, cyst development, and hyperandrogenism (acne, hirsutism, hair loss). In PMOS, the ovary is producing follicles but due to the hormonal dysregulation, the follicles become arrested in their development and never fully mature, which disrupts the cycle, ovulation will not occur properly and because the follicle doesn’t rupture the corpus luteum is unable to create and secrete progesterone. Progesterone is the hormone that we need to sustain a pregnancy.
While the issue doesn’t start in the ovary, the ovary is the downstream location where the disruption happens. In fact, unlike muscle tissue or other cells in the body, ovaries are hyper sensitive to insulin and this alters the communication between the pituitary and ovaries.
Because things don’t occur properly in the follicular phase due to the arrest of the follicle, the LH surge before ovulation is inadequate. When the ovary senses higher circulating insulin, it triggers an androgen surge, it will begin to produce more testosterone, and the liver consequently produces less SHBG leading to higher circulating free testosterone in the body leading to hyperandrogenism. These androgens flood the ovary and the cycle goes haywire. This is why we see signs of hirsutism, acne, and hair loss.
Inflammation, Oxidative Stress, and GLUT4
I mentioned earlier that a primary symptom of insulin resistance is chronic inflammation. One of the ways that this inflammation impacts fertility is by decreasing the mitochondrial function necessary for oocyte development, embryo quality, endometrial tolerance and overall ovarian function.
In addition to inflammation, insulin resistance also activates oxidative stress which is when the body cannot neutralize free radicals with antioxidants. This oxidative stress impairs both egg and sperm quality and function, which then impacts fertility.
There is another key component of insulin resistances’ impact on fertility, which is how GLUT4 is impacted. Glucose Transporter Type 4 is a protein which moves glucose from the bloodstream to your muscles and fat cells. When the body is experiencing insulin resistance, glucose stays in the bloodstream because the chemical chain reaction of GLUT4 is weakened or blocked and glucose does not get transported to the muscles and fat cells. This transportation is important for the proper maturation of endometrial glandular tissue (the inner lining of the uterus). When there is low expression of GLUT4, the endometrium does not grow normally which can lead to embryo implantation failure and increase the risk of miscarriage.
The Endometrium
As you learned in the last paragraph, IR directly impacts the endometrium. During implantation, the endometrium needs to be in a state of receptivity, this allows the embryo to attach, invade and successfully implant. This is part of a process called decidualization. This is able to happen because of stromal changes to the endometrial tissue. When endometrial receptivity is impacted by insulin resistance it leads to inhibited decidual differentiation. This coordination and differentiation of the decidua is vital for the implantation and development of the embryo.
Supporting the Body through Insulin Resistance
If you experience insulin resistance, I want to share a few recommendations for supplements, diet and lifestyle to support your body both to improve insulin sensitivity and fertility.
First, there are a few supplement recommendations that may be helpful. There is strong evidence to support the use of inositol in the amount of 4 grams each day (safe for TTC and pregnancy), 400mg of berberine 3 times a day (not for use in pregnancy, ok when TTC cycle days 1-14), there is mixed evidence to support the use of 1.5 grams of ceylon cinnamon a day, 300mg of alpha lipoic acid twice a day (safe for TTC and pregnancy), and 2,000-4,000 IU of Vitamin D a day (strongly recommended while TTC and pregnancy). These daily supplements are found to benefit insulin sensitivity in the body.
For dietary recommendations from a Chinese Medicine perspective, I suggest a Spleen Qi supportive diet. This diet focuses on warm, cooked foods and small amounts of naturally occurring sweetness from honey, maple syrup, and sweet potatoes for example. Focus on meals with protein and complex carbohydrates and non-starchy vegetables. Soups, stews and broths are all excellent meals for boosting spleen qi and should be enjoyed daily.
A few other dietary and lifestyle recommendations are to try to eat within an hour of waking up, and to eat at regular times throughout the day. You should also avoid cold or raw foods and iced drinks, avoid intermittent fasting, and limit alcohol and caffeine.
Movement, especially weight bearing exercises combined with high intensity training, are very helpful for supporting insulin resistance. Not only will this help with IR, it will also help boost mitochondrial function. Nutrition and exercise are excellent places to start to begin to create more insulin sensitivity in the body.
If you are on or just beginning your fertility journey and also experience insulin resistance, I hope this provides helpful information and recommendations to support your journey. As a reminder, insulin resistance impacts millions of women of all reproductive ages and health stages, so you are not alone.
In the next blog I will share how insulin resistance impacts pregnancy, so keep an eye out for more information and recommendations to support you and your pregnancy journey!
References:
Lei R, Chen S, Li W. Advances in the study of the correlation between insulin resistance and infertility. Front Endocrinol (Lausanne). 2024 Jan 26;15:1288326. doi: 10.3389/fendo.2024.1288326. PMID: 38348417; PMCID: PMC10860338.
Romm, A. (2021). Hormone Intelligence: the complete guide to calming hormone chaos and restoring your body’s natural blueprint for well-being. HarperOne.
Nichols, L., & Hendrickson-Jack, L. (2024). Real food for fertility: Nurturing your body for preconception and pregnancy. Lily Nichols LLC.
Keshel TE, Coker RH. Exercise Training and Insulin Resistance: A Current Review. J Obes Weight Loss Ther. 2015 Jul;5(Suppl 5):S5-003. doi: 10.4172/2165-7904.S5-003. Epub 2015 Jul 30. PMID: 26523243; PMCID: PMC4625541.