Infertility affects approximately 15-20% of couples trying to conceive. The causes are numerous and often unrelated to diet. However, preconception nutrition has a documented impact on egg quality, sperm quality, hormonal cycle regularity, and uterine health. For both partners, a 3-6 month period of nutritional preparation before attempting conception is among the most evidence-based recommendations in reproductive medicine.

Folate and folic acid: the absolute priority for women

Folates (vitamin B9 in natural forms) and folic acid (synthetic supplemental form) are essential for cell division and neural tube formation. Folic acid supplementation (400-800 mcg daily) starting at least 4 weeks before conception through the end of the first trimester reduces the risk of neural tube defects (spina bifida, anencephaly) by 50-70%: one of the most effective preventive interventions in perinatal medicine. Food sources of folates: leafy greens (spinach, arugula, broccoli), legumes, asparagus, avocado, eggs. The 5-MTHF form (methyltetrahydrofolate) is the active form of folate: preferable for women with MTHFR mutations that reduce the ability to convert folic acid into its active form.

Iron, vitamin D, omega-3: the trinity of female fertility

Iron: iron deficiency reduces egg quality and uterine receptivity. Women with heavy periods often have low ferritin. Check ferritin before conception and correct any deficiencies. Vitamin D: vitamin D receptors are present in ovarian cells and the endometrium. Studies show that women with adequate vitamin D levels have higher pregnancy rates both with natural conception and IVF. Omega-3 DHA: a structural component of egg cell membranes. A diet low in omega-3 is associated with reduced egg quality. 2-3 servings of fatty fish per week (or algae-based supplement) during the preconception phase is recommended.

Male fertility: nutrients for spermatogenesis

Spermatogenesis takes approximately 74 days: this means dietary changes take about three months to influence sperm quality. The nutrition plan for male fertility should begin 3-4 months before conception attempts. Zinc: essential for sperm maturation and protection of sperm DNA. Zinc deficiency reduces motility and increases morphological abnormalities. Selenium: a component of selenoprotein P that protects sperm from oxidation. Selenium supplementation improves sperm motility in deficient men. Coenzyme Q10 (CoQ10): a mitochondrial antioxidant that improves sperm motility. Numerous clinical studies show improvement in concentration and motility with CoQ10 200-300 mg daily for 3-6 months. Antioxidants (vitamin C, vitamin E, lycopene): protect sperm DNA from oxidative stress. Excessive heat (saunas, tight underwear, laptops on the lap) damages sperm: avoid it.

The Mediterranean diet and fertility: the evidence

Epidemiological studies on women undergoing IVF treatment show that greater adherence to the Mediterranean diet is associated with higher clinical pregnancy rates. An analysis of 244 couples undergoing IVF treatment (Chavarro et al., 2018, Human Reproduction) found that women in the highest tertile of Mediterranean diet adherence were 66% more likely to become pregnant and 68% more likely to have live births compared to those in the lowest tertile. The Mediterranean diet simultaneously provides all the critical nutrients for fertility: folates from leafy greens, omega-3 from fish, antioxidants from fruits and vegetables, zinc and selenium from fish and legumes.

What to reduce or avoid for fertility

Alcohol in both partners: reduces sperm quality, interferes with ovulation, increases miscarriage risk even in early weeks. There is no safe threshold: it's best to avoid it during the preconception phase. Excessive caffeine: above 200 mg daily (about 2 coffees) is associated with reduced female fertility and increased miscarriage risk. Smoking: reduces ovarian reserve in women (accelerates egg loss), reduces sperm quality in men. Plastic and xenoestrogens: as described in the andropause article, reducing exposure to endocrine disruptors makes sense during the preconception phase for both partners.

The 3-month preconception protocol

For her: folic acid 400-800 mcg daily (or 5-MTHF if MTHFR mutated), vitamin D (check levels, supplement if below 30 ng/ml), omega-3 DHA 200-300 mg daily (fish or algae), normal iron and ferritin (check, supplement if deficient), Mediterranean diet as foundation. For him: zinc (pumpkin seeds, oysters, lean meat), selenium (two Brazil nuts daily), CoQ10 200 mg daily, vitamin E (seeds, nuts, extra virgin olive oil), lycopene (cooked tomatoes), omega-3. For both: no alcohol, reduce caffeine to max 1 coffee daily, quit smoking, reduce stress (cortisol suppresses reproductive hormones in both sexes).

PCOS and fertility: the specific nutritional approach

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility in women. Insulin resistance is central to PCOS. A low glycemic load diet (whole grains, legumes, vegetables, adequate protein, reduced refined sugars) improves insulin resistance, reduces androgen levels, and can restore ovulation in many women. Inositol (myo-inositol and D-chiro-inositol, naturally present in citrus fruits, legumes, whole grains) has clinical evidence of improving ovulation in PCOS. Consult a gynecologist specialized in PCOS for an integrated plan.

When to see a gynecologist or andrologist: the right timing

After 12 months of trying without success (or 6 months if the woman is over 35): consult a gynecologist for ovarian reserve assessment (AMH, follicular ultrasound) and a physician for your partner's semen analysis. Don't wait 2 years: ovarian reserve decreases with age and time has a biological cost. The 3-month nutritional preparation period is ideal to do simultaneously with medical evaluation, not sequentially.