A Functional Medicine Physician on Hormones, Thyroid Health, and the Stress Response
By Dr. Lienna Wilson, Licensed Psychologist | Vagus Vitality
Many women in midlife know the experience well: they feel exhausted, anxious, or simply not like themselves, yet their lab results come back “normal.” Dr. Ruth Vanderkooi knows it from both sides of the exam table. After decades in conventional primary care, she spent years struggling with her own thyroid issues while going through menopause, and it was functional medicine that finally helped her feel well again.
Today, her practice is called Dr. Ruth, MD Consulting (www.FunctionalHormoneHealth.com), a functional medicine consulting practice in Colorado focused on thyroid and hormone health. I asked her what a standard workup can miss, how chronic stress ripples through the hormonal system, how she supports women through perimenopause and menopause, and where the gut and the vagus nerve fit into the picture. Her answers return again and again to one idea: the body works as a connected whole, and lasting change starts with the basics.
When “Normal” Doesn’t Feel Normal
Dr. Ruth’s move toward functional medicine grew out of a pattern she noticed across her years in practice. “I saw that in general, patients were not optimizing their health,” she says. “Key aspects of their health picture were overlooked in conventional medicine.”
Then she experienced it herself. “I went many years under the care of conventional medicine for my thyroid issues while also going through menopause,” she says. “These were miserable years. When I started implementing functional medicine concepts on myself, that’s when I really started feeling great again.”
That experience shapes the care she offers now. “Many patients find me when they’re in a similar miserable place,” she says. “I like to help patients discover their own path back to wellness.” Part of that is practical support, since she also helps patients navigate a healthcare system she describes as complex. Part of it is a shift in goals. “Through my own health journey, I learned the value of not just ‘treating symptoms,’ but actually increasing whole-person health and quality of life,” she says, “improving the function of the body’s systems as a whole, to function optimally again.”
Looking Beyond the Standard Thyroid Workup
When a woman tells her that she feels exhausted or anxious despite normal labs, Dr. Ruth starts by looking more broadly. A standard thyroid screen often relies on thyroid-stimulating hormone (TSH) alone. “Besides TSH, I routinely check FT4 and FT3 and sometimes reverse T3,” she explains. She also measures thyroid antibodies, “which indicate an autoimmune process.”
Finding autoimmunity is only the first step. “I also try to find the root cause of autoimmunity, which can include toxins, infections, gut health, nutrition, and stress,” she says. “Sometimes a thyroid ultrasound gives clues.”
With sex hormones such as estradiol, progesterone, and testosterone, she aims higher than the reference range. “We aim for optimal levels, not levels in the ‘normal’ range,” she says. She is also candid about the limits of blood tests. “I realize the limitation of serum hormone testing, as it’s not measuring what’s going on inside the cell, but I use labs along with signs and symptoms to help guide the patient.”
Hormones as a Symphony
To explain how chronic stress affects hormone health, Dr. Ruth reaches for a musical image. “Hormones are like a symphony: they work together and need to be balanced,” she says. When one section plays too loudly, the others are thrown off. “Stress increases cortisol, which affects thyroid and sex hormones, as well as increasing blood sugar and insulin.”
Research on the endocrine effects of stress supports that picture. A review of stress and hormones describes how stress can suppress the release of TSH through the action of cortisol-like hormones on the brain, lowering thyroid hormone levels, and how ongoing stress can contribute to disruptions in reproductive hormones (Ranabir & Reetu, 2011). For a body stuck in a constant stress response, the effects rarely stay in one place.
Perimenopause, Sleep, and Starting Low
Perimenopause and menopause often bring new anxiety, poor sleep, or a feeling of being on edge. Before turning to hormones, Dr. Ruth starts with lifestyle. “We start with lifestyle optimization, as this is essential for hormone and neurotransmitter production and to increase receptor sensitivity,” she says. “The basis is a good circadian rhythm, sleep, nutrition, gut health, exercise, social relations, and having meaning and purpose.”
Hormone levels can shift dramatically during perimenopause, and in her experience, progesterone and testosterone tend to decline first. That is often where she begins, with a careful approach. “We like to start low and go slow,” she says.
Sleep is frequently the first thing to improve. “Many perimenopausal and menopausal women find oral micronized progesterone to improve their sleep, which then helps many other things,” she says. Research points in the same direction. In a small randomized, placebo-controlled study of healthy postmenopausal women, three weeks of oral micronized progesterone reduced time spent awake during the night compared with placebo (Schüssler et al., 2008).
“Low dose topical testosterone cream (compounded, as there is no FDA-approved testosterone for women) can also be used,” she adds. “Later, estradiol is added for its bone, heart, brain, and skin benefits.”
There is one option she avoids. “I don’t do pellets, which can cause super high hormone levels that can take a long time to wear off.”
The Gut, Hormones, and the Vagus Nerve
Gut health is one of Dr. Ruth’s specialties, and she sees it as tightly woven into both hormone health and the nervous system. “Scientists have now identified a gut-brain axis,” she says. “What’s happening in the gut, such as inflammation or dysbiosis, influences the brain and neurotransmitters.” Researchers describe this as a two-way communication network between gut microbes and the brain, with the vagus nerve as one of its key routes (Cryan et al., 2019).
The hormonal system has its own command center. “The pituitary gland is the origin of many signals for hormone synthesis and release,” she explains. And the vagus nerve reaches further than many people realize. “The vagus nerve talks not only to the gut and brain, but to the immune system and heart as well.” One well-known example is the inflammatory reflex, a circuit in which the vagus nerve helps detect inflammation and signals the body to dampen it (Tracey, 2002).
For Dr. Ruth, these connections are the reason she treats the body as a whole rather than one organ at a time. “We take a systems biology approach, and all are interconnected,” she says.
Telling the Nervous System It’s Safe
Asked what she recommends for supporting the nervous system and vagus nerve, Dr. Ruth starts with something free. “Slowing breathing down stimulates the vagus nerve and aids in relaxation and digestion,” she says. A systematic review of slow-breathing techniques, under 10 breaths per minute, found they were associated with increased heart rate variability and parasympathetic activity, along with greater feelings of relaxation and comfort (Zaccaro et al., 2018).
Much of her advice is about the rhythm of daily life. “Eating slow, sit-down meals, having fun and interesting activities throughout the day, without overbooking yourself, and taking time to rest,” she says. “These are all ways to tell the nervous system it’s safe.”
She also pays attention to nutrients. “Optimizing nutrients such as vitamin D, vitamin K, omega-3s, and methylated B complex helps support the nervous system,” she says, noting that the right amount can differ from one person to the next.
Where to Start: Protein, Color, and Sleep
For a woman who feels depleted and doesn’t know where to begin, Dr. Ruth’s first suggestion is on her plate. “Eat adequate protein throughout the day,” she says, “typically around 30 grams three times a day.”
She also recommends limiting processed food and sugar, since a diet heavy in refined carbohydrates drives insulin up and can lead to blood sugar dips, and can feed less helpful bacteria in the gut. In their place, she encourages color and healthy fats. “Eat the rainbow of colors of vegetables and fruits, plenty of them,” she says. “Eat good fats such as extra virgin olive oil and avocados. Prioritize sleep.”
Dr. Ruth’s approach reflects the path she walked herself: look further when the labs say “normal” but the person doesn’t feel it, remember that hormones, the gut, and the nervous system play as one orchestra; and build on the everyday foundations of sleep, food, rest, and calm before reaching for anything more.
About Ruth Vanderkooi, MD, FMCP-M, ABFM
Dr. Ruth earned her medical degree from the University of Iowa and completed a family medicine residency through the University of Michigan. Board-certified in family medicine, she practiced outpatient primary care for several decades, always taking a holistic approach. She became an Institute for Functional Medicine Certified Practitioner in 2024 and opened her functional medicine consulting practice. She has completed additional training in bioidentical hormone replacement therapy through WorldLink Medical and a one-year mentorship with Dr. Dan Kalish. She lives in Denver, has two grown children, and is looking forward to becoming a grandmother. Learn more at functionalhormonehealth.com.
Note: Hormone therapy has benefits and risks that vary from person to person, and decisions about it are best made with a qualified clinician. Supplements and the other approaches discussed here are best considered as part of an individualized care plan. Nothing here is a substitute for medical care, which should be addressed with your healthcare provider.
References
Cryan, J. F., O’Riordan, K. J., Cowan, C. S. M., Sandhu, K. V., Bastiaanssen, T. F. S., Boehme, M., ... & Dinan, T. G. (2019). The microbiota-gut-brain axis. Physiological Reviews, 99(4), 1877–2013. https://doi.org/10.1152/physrev.00018.2018
Ranabir, S., & Reetu, K. (2011). Stress and hormones. Indian Journal of Endocrinology and Metabolism, 15(1), 18–22. https://doi.org/10.4103/2230-8210.77573
Schüssler, P., Kluge, M., Yassouridis, A., Dresler, M., Held, K., Zihl, J., & Steiger, A. (2008). Progesterone reduces wakefulness in sleep EEG and has no effect on cognition in healthy postmenopausal women. Psychoneuroendocrinology, 33(8), 1124–1131. https://doi.org/10.1016/j.psyneuen.2008.05.013
Tracey, K. J. (2002). The inflammatory reflex. Nature, 420(6917), 853–859. https://doi.org/10.1038/nature01321
Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., Neri, B., & Gemignani, A. (2018). How breath-control can change your life: A systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 353. https://doi.org/10.3389/fnhum.2018.00353