In her book Good Energy, Dr. Casey Means boils down the complex concept of metabolism into a relatively simple one: our bodies can create energy, and it can be either good or bad energy. Too much bad energy (also known as mitochondrial dysfunction, chronic inflammation, and oxidative stress) makes certain ‘check engine’ lights come on in our bodies. These check engine lights are easy to spot and a part of any routine well-woman visit you may have at your doctor’s office. If you have too many of these check engine lights, you may be diagnosed with something called metabolic syndrome.
For many of us, metabolic syndrome is a fairly new term, but it describes a set of characteristics that we are all familiar with: high blood sugar, high blood pressure, high triglycerides, low “good” cholesterol (high-density lipoprotein or HDL), and too much body fat. Metabolic syndrome is also extraordinarily common—about 1 in 3 Americans currently meets the definition. Even worse, 93.2% of Americans have at least one metabolic syndrome check engine light on (Good Energy, pg. 268), meaning that they’re already on the spectrum of metabolic dysfunction.
While Dr. Means focuses her attention in Good Energy on how metabolic health can cause chronic health issues like diabetes and cancer, it can also be a factor in infertility. If you’re wondering if you might have metabolic syndrome and whether it might be affecting your fertility, read on.
What is metabolic syndrome?
You have metabolic syndrome if you can check off at least three out of five markers. These are all standard tests that can be run by your primary care doctor and should be a part of your yearly physical.
- Too much abdominal body fat. This is defined as being more than 40 inches around the waist for men or more than 35 inches around the waist for women.
- High blood pressure. You have a blood pressure of more than 130/85 mm/Hg or you have to take medication in order to keep your blood pressure in check. It still counts if only one of your blood pressure numbers (i.e. just the top number or just the bottom number) is too high.
- High triglyceride levels. Triglycerides are a type of fat found in the bloodstream that can contribute to the hardening of arteries and cause heart disease. You have high triglycerides if your levels are over 150 mm/dL or you are on medications in order to lower your triglycerides.
- Low HDL cholesterol. HDL cholesterol is known as the “good cholesterol” and is beneficial for heart health. You have low HDL if your levels are less than 40 mg/dL if you’re a man or less than 50 mg/dL if you’re a woman.
- High fasting blood sugar. Fasting blood sugar is your blood sugar reading taken first thing in the morning. You have high fasting blood sugar if your reading is over 100 mg/dL or you’re taking medication to lower your blood sugar. If your fasting glucose reading is between 100 and 125 mg/dL then you are also considered prediabetic. A fasting blood sugar above 125 mg/dL is common in type 2 diabetics.
If you have three or more markers, you have metabolic syndrome
While you must check off at least three of these markers in order to officially be diagnosed with metabolic syndrome, having just one or two of these markers indicates that you’re on the path. Just like how type 2 diabetes is the final destination of a road that begins with insulin resistance and progresses to prediabetes, we can also start to have signs of decreasing metabolic health that crop up over time and continue to progress. The vast majority of Americans have at least one of these check engine lights on their health dashboard, so it’s important to have a yearly physical to check your vitals and blood work.
How does metabolic health affect fertility?
While it’s clear that metabolic syndrome is linked to many chronic health conditions like heart disease and type 2 diabetes, its effects on fertility might seem a little less obvious. Increasingly, research ties metabolic unfitness to infertility, as more and more Americans are considered metabolically unhealthy each year.
One narrative review that looked at all studies published between 2006 and 2020 on how female fertility is impacted by metabolic syndrome found that all aspects of metabolic syndrome can have negative effects on fertility [1]. Women who are obese have a three-fold higher risk of infertility than women who are not obese, and oxidative stress is also closely linked with difficulties conceiving [2].
Oxidative stress occurs when the body has too many free radicals and not enough antioxidants to combat them [3]. It commonly occurs in those who are exposed to environmental toxins and/or have poor diet and lifestyle, such as consuming a diet largely made up of ultra-processed foods (which also cause the five check engine lights of metabolic syndrome to turn on) [4]. Unfortunately, this means that the majority of Americans likely experience high levels of oxidative stress, as over 54% of Americans have diets that are high in ultra-processed foods. Higher levels of oxidative stress are intrinsically linked to both male and female infertility [5].
Metabolic syndrome affects male fertility, too
Even though it’s common to focus mainly on a woman’s health when a couple struggles to get pregnant, male factor infertility may be present in up to half of couples who have fertility issues [6]. Many men with decreased fertility have lower levels of testosterone, and several studies have found that high BMI and insulin levels (which the body produces in response to high blood sugar) are both linked with lower testosterone [7]. Diabetes is also a driver of infertility for men, as increased blood glucose levels affect the quality and quantity of sperm cells [8]. Overall, the less metabolically healthy a man is, the more difficult it might be for him to achieve pregnancy with his wife or partner [6].
Metabolically unhealthy women face many of the same fertility problems as metabolically unhealthy men, but they suffer more sexual dysfunction after being diagnosed with metabolic syndrome [9]. This is especially true for women who are postmenopausal—a time in which metabolic diseases like type 2 diabetes and heart disease skyrocket [10].
Ties to PCOS
One of the most obvious connections between metabolic syndrome and female fertility lies in a separate diagnosis entirely: polycystic ovary syndrome (PCOS). PCOS affects anywhere between 7-10% of women in the United States and is the number one cause of infertility. PCOS rates have increased by nearly 65% over the past decade [11]. Symptoms of PCOS are also more severe now than they once were.
At its core, PCOS is a metabolic disorder characterized by hormonal imbalances and metabolism issues, which can lead to other problems like obesity and diabetes. Women with PCOS have a higher risk of becoming insulin resistant and then later developing type 2 diabetes and also face higher rates of obesity and hypertension than women who don’t have PCOS [12]. Almost half of adult women who have PCOS are also classified as having metabolic syndrome, and nearly one-third of teenagers with PCOS have metabolic syndrome [13].
The overlap between metabolic syndrome and PCOS is largely because insulin resistance is so common in those who have PCOS. Approximately 50-80% of women with PCOS also have insulin resistance [14]. These women will most likely have additional markers of metabolic syndrome, including struggling with obesity.
Improving your metabolic health
Trying to find ways to improve your metabolic health is a bit like falling down a rabbit hole, as countless researchers scramble for answers to help the hundreds of millions of Americans who are metabolically unhealthy. A great place to start if you’re wanting to reverse your metabolic syndrome and turn off your ‘check engine lights’ is to read books that center on good nutrition with practical, approachable advice for making good diet and lifestyle decisions. Good Energy, in particular, uses layman’s terms to delve into what metabolic syndrome is and how it can be fixed.
Luckily, metabolic syndrome is reversible and oftentimes comes down to losing weight and balancing your blood sugar. One resource I’ve discovered for learning about how you can balance your blood sugar and reverse insulin resistance is Jessie Inchauspe, aka the Glucose Goddess. Inchauspe is a French biochemist whose work helps women focus on simple nutritional changes that won’t feel like sheer food deprivation.
If you also struggle with PCOS, this article is a good starting place for learning more about what to eat in order to decrease your symptoms and help improve your fertility. Another great resource on improving your fertility through food (both for those with or without PCOS) is Real Food for Fertility by dietician Lily Nichols and fertility awareness expert Lisa Hendrickson-Jack. Although this book doesn’t focus specifically on metabolic syndrome, it does give detailed recommendations for women who are insulin resistant and/or diagnosed with PCOS, as well as general guidance on improving both female and male factor fertility.
The bottom line
Metabolic syndrome is only becoming more common in the United States, and it has known negative effects on fertility, but that doesn’t mean it’s inevitable. Diet and lifestyle interventions are shown to be highly effective in reversing it, which also might mean improvements in fertility if your infertility is related to poor metabolic health [15].
References:
[1] Westerman R, Kuhnt AK. Metabolic risk factors and fertility disorders: A narrative review of the female perspective. Reprod Biomed Soc Online. 2021 Oct 1;14:66-74. doi: 10.1016/j.rbms.2021.09.002. PMID: 34765754; PMCID: PMC8569630. [2] Lauren A. Wise, Kenneth J. Rothman, Ellen M. Mikkelsen, Henrik Toft Sørensen, Anders Riis, Elizabeth E. Hatch, An internet-based prospective study of body size and time-to-pregnancy, Human Reproduction, Volume 25, Issue 1, January 2010, Pages 253–264, https://doi.org/10.1093/humrep/dep360 [3] Pizzino G, Irrera N, Cucinotta M, Pallio G, Mannino F, Arcoraci V, Squadrito F, Altavilla D, Bitto A. Oxidative Stress: Harms and Benefits for Human Health. Oxid Med Cell Longev. 2017;2017:8416763. doi: 10.1155/2017/8416763. Epub 2017 Jul 27. PMID: 28819546; PMCID: PMC5551541. [4] Martínez Leo EE, Peñafiel AM, Hernández Escalante VM, Cabrera Araujo ZM. Ultra-processed diet, systemic oxidative stress, and breach of immunologic tolerance. Nutrition. 2021 Nov-Dec;91-92:111419. doi: 10.1016/j.nut.2021.111419. Epub 2021 Jul 19. PMID: 34399404. [5] Mannucci A, Argento FR, Fini E, Coccia ME, Taddei N, Becatti M, Fiorillo C. The Impact of Oxidative Stress in Male Infertility. Front Mol Biosci. 2022 Jan 5;8:799294. doi: 10.3389/fmolb.2021.799294. PMID: 35071326; PMCID: PMC8766739. [6] Kasturi SS, Tannir J, Brannigan RE. The metabolic syndrome and male infertility. J Androl. 2008 May-Jun;29(3):251-9. doi: 10.2164/jandrol.107.003731. Epub 2008 Jan 24. PMID: 18222914. [7] Tsai EC, Matsumoto AM, Fujimoto WY, Boyko EJ. Association of bioavailable, free, and total testosterone with insulin resistance: influence of sex hormone-binding globulin and body fat. Diabetes Care. 2004 Apr;27(4):861-8. doi: 10.2337/diacare.27.4.861. PMID: 15047639.References, Cont.
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