Nutrient-Wise Genetic Predispositions Affecting Menstrual Regularity

1. Vitamin D — VDR Gene Polymorphisms

• Vitamin D regulates insulin signaling through the VDR in ovarian granulosa cells, modulating follicle-stimulating hormone (FSH) sensitivity and folliculogenesis.
• Women with PCOS (the most common cause of oligomenorrhea) consistently show higher rates of vitamin D deficiency (~67–85%) compared to controls.
• VDR polymorphisms amplify the ovarian dysregulation seen in vitamin D-deficient states — disrupting AMH signaling, androgen excess, and anovulation.
• Two 2024–2025 RCTs (PMID 39014475 and PMID 40219003) showed that vitamin D3 supplementation improved menstrual frequency, insulin sensitivity, and androgen profiles in women with PCOS.

2. Iron — HFE Gene (Hereditary Hemochromatosis / Iron Deficiency Risk)

• HFE gene mutations (C282Y, H63D) → hereditary hemochromatosis → iron overload → disruption of the hypothalamic-pituitary-gonadal (HPG) axis → hypogonadotropic amenorrhea.
• TMPRSS6 (Matriptase-2) gene variants → reduced hepcidin suppression → functional iron restriction → higher susceptibility to iron-deficiency anemia (IDA).

• Severe IDA causes hypothalamic GnRH pulsatility disruption, suppressing LH/FSH surges needed for ovulation.
• Iron is a cofactor for thyroid peroxidase; iron deficiency → subclinical hypothyroidism → anovulation and cycle irregularity.
• Adolescents and reproductive-age women with these variants are disproportionately vulnerable during high menstrual blood loss.

3. Folate / B12 — MTHFR C677T & A1298C Polymorphisms

• Impaired methylation → elevated homocysteine → oxidative stress → endothelial dysfunction in the endometrium and ovarian microvasculature.
• Disrupted one-carbon metabolism interferes with estrogen metabolism: catechol estrogens must be methylated (via COMT enzyme) for excretion; MTHFR variants impair this, leading to estrogen excess or cycling imbalance.
• MTHFR C677T homozygotes show elevated rates of anovulatory infertility, dysmenorrhea, and endometriosis-associated cycle disruption.
• B12 deficiency (common with MTHFR, vegans) compounds the effect by blocking the methionine cycle.

4. Magnesium — SLC41A1 and TRPM6/7 Variants

• Magnesium is required for insulin receptor tyrosine kinase activity; deficiency → insulin resistance → hyperandrogenism → PCOS-like anovulation.
• Magnesium modulates prostaglandin synthesis; low levels → increased PGF2α → dysmenorrhea and uterine spasm.
• It also regulates progesterone receptor sensitivity in the luteal phase.
• Women with PCOS show ~19% lower erythrocyte magnesium than controls.

5. Zinc — SLC30A8 and Metallothionein Gene Variants

• Zinc is essential for FSH receptor signaling, LH biosynthesis, and progesterone production by corpus luteum cells.
• Zinc deficiency → reduced aromatase activity → impaired estradiol synthesis → follicular arrest.
• Women with PCOS have significantly lower serum zinc; zinc supplementation improves hirsutism scores and menstrual frequency.
• Thyroid function (TSH synthesis requires zinc) is also impaired, further disrupting ovulation.

6. Omega-3 Fatty Acids — FADS1/FADS2 Gene Variants

• EPA/DHA modulate prostaglandin balance (PGE2 vs. PGF2α) regulating uterine contractility and cycle length.
• Low DHA → pro-inflammatory prostaglandin dominance → heavy, irregular, or painful periods.
• FADS2 variants also alter arachidonic acid metabolism, driving estrogen-receptor sensitivity changes in endometrial tissue.

7. PCOS as the Primary Genetically Predisposed Menstrual Irregularity Condition

• Insulin signaling (IRS1, INSR, HMGA2) → respond to low-GI diet, inositol (myo-inositol/D-chiro-inositol ratio 40:1), chromium, berberine
• Gonadotropin regulation (FSHB, LHB, GNRHR) → respond to zinc, vitamin D
• Androgen metabolism (CYP11A1, AR) → respond to spearmint, zinc, saw palmetto (limited evidence)
• Metabolic risk (FTO, TCF7L2) → respond to low-carbohydrate diet, magnesium, omega-3

Summary Table