Understanding the Menstrual Cycle & Hormone Imbalance: A Science-Backed Guide

Understanding the menstrual cycle can be empowering - especially if you experience symptoms that disrupt your daily life. As we move through the different phases of the cycle, our hormones fluctuate significantly, and these shifts can affect everything from mood and energy, to sleep and appetite.

Unfortunately, not everyone moves through these phases with ease. If hormones don’t rise and fall in the expected way, we may experience what is often called a hormonal imbalance. The good news? With the right nutrition and lifestyle support, we may often help to address some of these imbalances and start to feel more in sync with our cycle.

Let’s explore the four phases of the menstrual cycle, what happens hormonally and physiologically, and how nutrition and lifestyle strategies may help support balance.

The uterus responds to hormonal changes orchestrated by the brain and ovaries and this communication drives the monthly cycle of menstruation.

Phase 1: Menstrual Phase (Days 1 - 5)

Hormonal Profile

Menstruation begins due to a drop in both oestrogen and progesterone, leading to the shedding of the endometrial lining. Prostaglandin release causes uterine contractions and can trigger cramping and inflammation (Smith, 2007).

Common Symptoms

Low energy, cramps, fatigue, mood changes

Nutrition & Lifestyle Support

• Iron-rich foods (e.g., red meat, lentils, spinach) to help replenish iron lost through bleeding.

• Vitamin C (e.g., bell peppers, kiwi, citrus) to enhance iron absorption.

• Anti-inflammatory foods like turmeric, ginger, and omega-3-rich fatty fish may help reduce cramping and inflammation.

• Hydration is key for reducing water retention and supporting circulation.

Evidence

Studies show that iron stores may decrease with heavy menstrual bleeding (Milman et al., 2012). Anti-inflammatory compounds like curcumin have been shown to reduce menstrual pain severity (Jaafari et al., 2020).

Phase 2: Follicular Phase (Days 6 - 14)

Hormonal Profile

FSH (follicle-stimulating hormone) stimulates follicle growth. Rising oestrogen thickens the endometrium and supports bone, brain, and mood. Energy may feel higher in this phase due to improved mitochondrial efficiency and neurotransmitter modulation (Barth et al., 2015).

Common Symptoms

Improved energy, strength, mental clarity.

Nutrition & Lifestyle Support

• Quality proteins and complex carbohydrates to fuel increased energy demands and support muscle synthesis.

• Fermented foods (e.g., kimchi, kefir) to support gut and oestrogen metabolism.

• Cruciferous vegetables (e.g., broccoli, cauliflower) to support phase I and II liver detoxification of oestrogens.

• Healthy fats (e.g., avocado, nuts) for hormone production and satiety.

Evidence

The liver plays a critical role in in oestrogen clearance via glucuronidation and sulfation (Zhu et al., 2022). Cruciferous vegetables support detoxification enzymes involved in oestrogen metabolism (Seow et al., 2021).

Ovulation (approx. Day 14)

Hormonal Profile

A surge in luteinising hormone (LH) causes the dominant follicle to rupture and release the egg. Oestrogen peaks just before ovulation, influencing libido, mood, and skin. Inflammatory-like responses (e.g., mild abdominal pain) may occur as the follicle bursts (Espey, 1994).

Common Symptoms

Heightened libido, increased energy and social confidence.

Nutrition & Lifestyle Support

• Vitamin B6-rich foods (e.g., poultry, bananas) to support progesterone synthesis.

• Zinc-rich foods (e.g., pumpkin seeds, shellfish) for egg quality, immune support, and reducing inflammation.

• Anti-inflammatory foods to offset the slight systemic inflammation that accompanies ovulation.

• Lighter meals may feel more comfortable due to potential gastrointestinal sensitivity.

Evidence

Zinc has been shown to modulate ovarian steroidogenesis and reduce systemic inflammation (Oteiza et al., 2021). B6 is essential for the biosynthesis of neurotransmitters and supports luteal progesterone production (Schindler, 2004).

Phase 4: Luteal Phase (Days 15–28)

Hormonal Profile

The corpus luteum forms and secretes progesterone, preparing the uterine lining for implantation. If fertilisation doesn't occur, progesterone and oestrogen fall, triggering menstruation. Progesterone has calming, thermogenic, and anti-anxiety effects (Schmidt et al., 1998).

Common Symptoms

Cravings, irritability, anxiety, bloating, breast tenderness, disrupted sleep.

Nutrition & Lifestyle Support

• Magnesium-rich foods (e.g., dark leafy greens, pumpkin seeds, cacao) may support progesterone, reduce cramping, and ease PMS.

• High-fibre foods (e.g., oats, legumes, flaxseeds) to support hormone clearance and bowel regularity.

• Complex carbohydrates to stabilise blood sugar and possibly reduce mood fluctuations.

• Reduce caffeine and alcohol to support liver clearance and sleep.

• Hydration and potassium-rich foods (e.g., bananas, sweet potatoes) to help with fluid retention.

Evidence

Low magnesium levels may be associated with more severe PMS symptoms (Posadzki et al., 2013). Fibre intake supports oestrogen clearance via the gut-liver axis (Tomova et al., 2019,). Progesterone promotes GABA activity, which may improve sleep and reduce anxiety (Backstrom et al., 2003).

When Hormone Imbalance May Be at Play

A hormone imbalance doesn’t always mean something is “wrong” but it suggests that something in the system (e.g. nutrient intake, stress levels, thyroid function, gut health) may need additional attention.

Signs of Possible Imbalance Include:

• Irregular or absent cycles (longer than 35 days or shorter than 21).

• Painful, heavy, or very light bleeding.

• Persistent PMS, anxiety, mood swings.

• Acne, hair thinning, or unwanted hair growth.

• Cyclical migraines or digestive issues.

Potential drivers may include stress, undereating, PCOS, thyroid dysfunction, or perimenopause. Individual hormone testing or a nutrition and lifestyle assessment may help identify root causes.

Final Thoughts: Supporting Your Cycle, Your Way

We are all unique - our genetics, lifestyle, stress levels, and nutritional needs all influence how smoothly we move through the menstrual cycle.

If you're experiencing symptoms that feel disruptive, there’s no need to accept them as "normal." Supporting hormonal health with evidence-based nutrition, lifestyle strategies, and personalised care may make a significant difference.

If you're ready to get to the root cause and support your cycle more effectively, get in touch. I offer personalised guidance rooted in science, because your hormones deserve clarity, not guesswork.

References:

1. Smith, R.P., 2007. Prostaglandins and uterine contractility. Obstetrical & Gynecological Survey, 62(8), pp.527-533.

2. Backstrom, T., Bixo, M., Johansson, M., Nyberg, S., Osby, U., Magnusson, A., Andreen, L. and Timby, E., 2003. Allopregnanolone and mood disorders. Progress in Neurobiology, 71(1), pp.1-17.

3. Barth, C., Villringer, A. and Sacher, J., 2015. Sex hormones affect neurotransmitters and shape the adult female brain during hormonal transition periods. Frontiers in Neuroscience, 9, p.37.

4. Espey, L.L., 1994. Current status of the hypothesis that mammalian ovulation is comparable to an inflammatory reaction. Biology of Reproduction, 50(2), pp.233-238.

5. Jaafari, N., Dehghan, F., Heidari, A. and Malekzadeh, S., 2020. Curcumin for the treatment of primary dysmenorrhea: A double-blind, randomized clinical trial. Complementary Therapies in Clinical Practice, 39, p.101132.

6. Milman, N., 2011. Anemia—still a major health problem in many parts of the world! Annals of Hematology, 90(4), pp.369-377.

7. Oteiza, P.I., Fraga, C.G. and Mills, D.A., 2021. Zinc deficiency, oxidative stress and inflammation. Nutrients, 13(2), p.446.

8. Posadzki, P., Alotaibi, A. and Ernst, E., 2013. Magnesium and PMS: A systematic review. BMC Complementary and Alternative Medicine, 13(1), pp.1-8.

9. Schindler, A.E., 2004. Vitamin B6 in premenstrual syndrome. Gynecological Endocrinology, 19(7), pp.385-389.

10. Schmidt, P.J., Nieman, L.K., Danaceau, M.A., Adams, L.F. and Rubinow, D.R., 1998. Differential behavioral effects of gonadal steroids in women with and in those without premenstrual syndrome. New England Journal of Medicine, 338(4), pp.209-216.

11. Seow, A., Yuan, J.M., Sun, C.L., Van Den Berg, D., Lee, H.P. and Yu, M.C., 2021. Dietary glucosinolate intake and cancer risk: A review of the evidence from epidemiological studies. Molecular Nutrition & Food Research, 65(7), p.2000898.

12. Smith, R.P., 2007. Prostaglandins and uterine contractility. Obstetrical & Gynecological Survey, 62(8), pp.527-533.

13. Tomova, A., Bukovsky, I., Rembert, E., Yonas, W., Alwarith, J., Barnard, N.D. and Kahleova, H., 2019. The effects of vegetarian and vegan diets on gut microbiota. Frontiers in Nutrition, 6, p.47.

14. Zhu, B.T., Conney, A.H. and Li, X., 2022. Metabolism of estrogens and their implications in breast cancer: A review. Endocrine Reviews, 43(2), pp.157-195.