Cynthia Thurlow: On Women’s Health, Intermittent Fasting, Protein Intake & Hormone Therapy |TUH #207

Menstrual Cycle and Intermittent Fasting

Cynthia emphasizes early on how crucial a woman's menstrual cycle is to overall health—on par with vital signs such as blood pressure and pulse. The loss of menstruation outside of pregnancy signals that the body is under excessive stress. She draws attention to how women often do not respond well to popular fasting practices, especially when done using "one-size-fits-all" approaches modeled after men or athletic partners. Cynthia recounts seeing numerous women experience hormonal imbalances and metabolic disruptions, such as elevated cortisol and thyroid suppression, from engaging in overly narrow feeding windows or extremely restrictive fasting protocols. This can lead to paradoxical weight gain, disrupted sleep, and cycle irregularities.

Cynthia advocates for bio-individuality when applying intermittent fasting, emphasizing that younger, lean, and athletic women generally should not fast extensively, while those with metabolic issues such as obesity or polycystic ovarian syndrome might benefit from time-restricted feeding. Importantly, she recommends at least 12 hours of fasting as a form of digestive rest without formal, prolonged fasting, and stresses aligning fasting practices with menstrual cycle phases for optimal results. She also warns against adding fasting during periods of emotional or life stress, underscoring the need first to manage sleep and cortisol levels before introducing additional dietary strain.

Protein and Muscle

A major theme Cynthia explores is the frequent underconsumption of protein among women, particularly during midlife transitions. Muscle mass is described as "metabolic currency," vital not only for body composition but also for immune competence, connective tissue health, and hormone regulation. She highlights that many women, despite appearing thin or within a healthy weight range, suffer from muscle loss and metabolic slowdown due to insufficient protein intake combined with excessive fasting and calorie restriction.

Cynthia champions awareness around adequate protein portions, encouraging women to target at least 100 grams of protein daily, distributed reasonably across meals, to support muscle protein synthesis. Essential amino acid supplements are promoted as a way to ensure amino acid availability without excessive caloric intake, particularly helpful for older adults or those with limited appetite. The discussion also debunks common misconceptions around supplements such as creatine, reframing it as a critical nutrient not just for muscle strength but also for cognitive function and bone health in women. She recommends high-quality creatine monohydrate supplements, especially around stressors like travel or sleep disruption, for overall resilience.

Gut Health

The conversation turns thoughtfully to the gut microbiome and its far-reaching influence on women's health, especially in hormonal transitions. Cynthia outlines the gut as a complex ecosystem intersecting with various organ systems—immune, neurological, reproductive—through axes such as the gut-lung and gut-ovarian axes. The gut microbiome's impact on neurotransmitter production, immune defense, estrogen recycling (through the estrobolome), and inflammation establishes it as foundational to conditions ranging from anxiety and digestive troubles to bone health and hormone metabolism.

Cynthia describes how modern lifestyle factors—ultraprocessed foods, chronic stress, poor sleep, and frequent eating—negatively affect the microbiome and exacerbate symptoms like bloating, constipation, and food sensitivities, which many peri- and menopausal women experience. She advocates personalized evaluation, often beginning with elimination diets (e.g., Whole30) and stool testing to pinpoint microbial imbalances or digestive insufficiencies such as low stomach acid or enzyme deficiencies. Practical interventions like hydration, magnesium supplementation, fiber from flax and chia seeds, and establishing relaxed eating environments highlight simple steps that can dramatically improve gut function.

Hormone Therapy

Perhaps one of the most significant parts of the episode centers on hormone replacement therapy (HRT) for women in perimenopause and menopause. Cynthia, drawing from her clinical and personal experience, robustly supports HRT as a tool to improve quality of life and mitigate risks associated with declining estrogen, such as cardiovascular disease, bone loss, cognitive decline, and overall inflammation. She addresses the enduring fear fueled by the 2002 Women's Health Initiative study, clarifying that much of the initial data was misinterpreted due to population specifics (older women over 10 years post-menopause, many with comorbidities) and the use of non-bioidentical hormones.

Thurlow outlines how bioidentical hormones (estradiol, progesterone, and testosterone) provide targeted benefits, with progesterone's significance extending beyond reproduction to brain and bone health via neurosteroids promoting restful sleep. She encourages shared decision-making and testing (blood, saliva, and Dutch panel urine tests) to tailor hormone therapies safely with ongoing monitoring. Importantly, she cautions against pellet therapies due to dosing unpredictability and favors adjustable routes like sublingual or patches.

Linking HRT to lipid metabolism, Cynthia explains estrogen's role in nitric oxide production and vascular health, with implications for heart disease risk—the leading cause of death in women. She advocates expanded lipid testing including apolipoprotein B and lipoprotein(a), which influence cardiovascular risk more than standard cholesterol panels and may necessitate interventions including hormone therapy or specialized drugs for elevated lipoprotein(a).

Personal Stories

Throughout the episode, Cynthia interweaves her personal health journey—navigating perimenopausal symptoms such as brain fog, anxiety, and weight loss resistance, through recovery from a serious abdominal illness that decimated her muscle mass—to underscore the lived realities behind the science. She conveys the frustration many women face when conventional medicine dismisses their symptoms as "just aging" and emphasizes the need for proactive, personalized care that honors female biology.

She also acknowledges the cultural damage caused by equating thinness with health, cautioning against damaging fasting or exercise extremes that jeopardize hormone balance and metabolic health in women. Her holistic approach integrates lifestyle medicine, gut health, nutrition, and appropriately managed hormone therapy as components of thriving through midlife and beyond.