Insulin Resistance and Fertility, What You Need To Know
You may have heard of the hormone insulin in the context of diabetes. You might also know the term insulin resistance (IR), if you are into things health-related, as it’s a topic that’s often discussed in the realm of weight loss. Maybe you’ve heard about IR if you are a person who has PCOS (polycystic ovary syndrome), as it is a major driver of the hormonal patterns we see in that clinical picture. But what is lesser known about this condition is the role it plays in infertility.
I want to bring your attention to this link, not only because I think you should be as well versed in your hormonal system as possible when you’re navigating fertility care. But also because I’ve been seeing a lot of insulin resistance in clinic lately, so it’s something I want to get the word out about.
So let’s get into it: insulin resistance and your fertility, what you need to know.
First: what is insulin?
Insulin is a hormone produced by the pancreas (in everyone except for those who have type 1 diabetes), so most of us make insulin. When you consume carbohydrates, they get converted to glucose which starts to raise your blood sugar. In response to elevated blood sugar, your pancreas secretes insulin - I think of insulin like a shuttle bus, that picks up free-floating sugar from the blood stream, and delivers it to the cells of the body to be used as fuel for energy production. Insulin knocks on the door of the cell, and ideally the cell responds by letting glucose in and burning it. In that sense - insulin is a storage hormone, it takes sugar from the blood stream and moves it into your cells.
If there is any excessive energy that cannot be used by the cells, it gets stored for the long-term in our fat cells. Insulin plays a role with these cells as well - it actually blocks the breakdown of stored fat (hence its role in the weight loss realm).
When there are times of very low food intake (fasting or famine), low blood sugar signals to the liver to make some glucose out of stored glycogen to keep the brain cells functioning. Insulin also is triggered by the glucose that is pumped out by your liver in these scenarios.
Insulin plays other important roles in the body, which we won’t go into detail on - but know that it effects protein and fat breakdown/storage, influences gene expression and DNA synthesis, and impacts apoptosis/autophagy and other cellular metabolic processes.
When your insulin is working properly, and your cells respond to insulin properly, all is good: you use the fuel from the food you eat to make energy.
So what is insulin resistance?
In the face of what’s called “chronic overnutrition” - or, in basic terms, over-eating - we get excessive lipid (fat) accumulation at the tissue level (in our muscles and liver predominantly), and these cells stop responding as well to the knock of insulin. As the cells respond less well to insulin, high circulating glucose has to go somewhere, so it gets stored in more and more adipose tissue in these tissues. As adipocytes (fat cells) get larger, more and more inflammatory cytokines get released from them - the inflammation impairs insulin signaling even further. In the liver, insulin resistance leads to alterations in the production of glucose by the liver.
People who have PCOS very often have insulin resistance. The high androgens that are a hallmark of the condition (elevated testosterone, DHEA, and androstenedione) affect both the adipocytes and the liver, making both of these cells more susceptible to insulin resistance. People with PCOS may have a harder time falling pregnant for many different reasons - they may not ovulate regularly (or at all), their follicular cells don’t nourish their oocytes as well so their egg quality may be low, for example.
How does insulin resistance impact fertility?
There are several ways that insulin resistance impacts fertility, aside from the PCOS connection.
- Insulin resistance impairs follicle health and egg quality
The follicular fluid in people experiencing IR is higher in glucose and free fatty acids that can cause damage to the mitochondria. These elevated nutrients also disrupt meiosis (the process of the egg splitting and containing the right number of chromosomes) and affect the transfer of mitochondria from the oocyte to the embryo. All of these result in poorer quality oocytes and embryos.
- Insulin resistance affects sperm quality
There is good data showing that men with unexplained oligozoospermia (low sperm count) are more likely to have IR than men from control groups. In rats, over-nutrition that resulted in high blood sugar, high blood insulin levels, and high cholesterol also results in poorer sperm concentration and motility.
- Derangements in insulin levels impact other hormones - cortisol and thyroid hormones
All of your hormones affect each other. It’s not surprising to know that when blood sugar and insulin (a hormone) levels are off, we are more likely to see issues with both cortisol production and thyroid hormone production. These imbalances may also impact fertility (for example, hypothyroidism makes it more likely someone will miscarry).
- People with insulin resistance are more likely to experience implantation failure and/or suffer from miscarriages
Lots of pregnancy losses are related to oocyte health - the majority, in fact. As we know IR impacts oocyte health, it’s likely a factor in at least some of these miscarriages. We have some data on IR and pregnancy loss that I’ll share here.
In female rats who have IR, high glucose levels in the blood impact the transition of the embryo from zygote to blastocyst - even if the egg cell was donated from a non-diabetic female. We know that in humans, obesity correlates with a reduced likelihood of pregnancy unless the oocytes came from a lean mother. The placentas of mothers with IR in early pregnancy are significantly altered compared to controls, and during pregnancy, mothers with IR are more likely to suffer gestational diabetes which results in more inflammation.
How do I know if I’m insulin resistant?
There are some physical signs of insulin resistance that are present in some, but certainly by no stretch all, cases of IR.
Put simply: if you have any of these signs, you are highly likely to have IR. If you don’t have these signs, you still could certainly have IR but you’ll have to test for it.
Signs and symptoms:
- Belly fat: an increased weight to height ratio is a classic sign of IR
- Skin tags
- Fatigue: could be many things but is definitely common in IR
- Dark skin patches: called acanthosis nigricans - it’s common to see dark skin on the neck, under the arms, and in other areas where skin folds on itself
- Cravings for sugar and/or carbohydrates
How can we test for insulin resistance?
There are a couple of ways to test for IR. My favourite way is to start by testing both your fasting glucose and your fasting insulin, on the same morning, and then making a calculation called HOMA-IR. This HOMA-IR gives a value of the degree of insulin resistance the person is experiencing. The higher the number, the worse the insulin resistance. In general, you don’t want your fasting insulin higher than 50. But interpreting it along with glucose gives us the best idea of what’s happening in your sugar regulation and insulin system.
Another way to test for IR is to do an oral glucose challenge test with insulin assay - this is similar to the Glucola test that is done for gestational diabetes, but at each time point we’re looking at not just glucose but also insulin. This is useful when we think you have IR but your fasting values look normal. Some people with IR can only detect elevated insulin in a post-meal scenario - where it spikes very high, and sometimes doesn’t come back down within 2 hours. Both are signs of IR and should be treated.
What can we do about it?
So many things! I always start with dietary strategies - they have to be part of the plan. If you have IR and keep getting back on the blood-sugar roller coaster by over consuming sugars and carbs, no drug or natural therapy can compete. Follow the principles in the Acubalance Fertility Diet (free to download here!) - make sure your carbs are slow/power carbs, not refined flours. Don’t consume foods with added sugar, and make sure that you get adequate protein (at least 25g/meal) and fat at each meal. These things keep your blood sugar more stable so your pancreas is less stimulated to release more insulin.
There are a number of natural therapeutics that help with insulin resistance, that you could ask your doctor about to see if they’re right for you.
A few of my favourites include:
- Inositols (myo-inositol and D-chiro-inositol, caution with high dose DCI in fertility as it may impair egg quality - MI improves egg quality, and a 40:1 ratio of MI:DCI might be preferable if you have PCOS)
- Resistant starch (potato starch, green banana flour, larch arabinogalactan)
In addition, if you are dealing with IR and trying to conceive, you may want to increase your intake of antioxidants to protect oocytes and sperm against inflammation and oxidative stress. Nutrients like CoQ10, PQQ, NAC, glutathione, and carnitine are good considerations, along with Omega3-rich fish oil (EPA in particular) to really mitigate inflammation and boost oocyte and sperm health.
If you’d like to discuss testing for insulin resistance or how else we can support you on your fertility journey, book a free 15-minute discovery call. I can’t wait to work with you.