The connection between diet and fertility is well-established. The Harvard Nurses' Health Study, which followed over 18,000 women for eight years, found that specific dietary patterns were associated with significantly higher rates of ovulatory fertility. Here's what that and subsequent research tells us.
Key Nutrients for Fertility
Folate (not just folic acid)
Critical before and during early pregnancy for neural tube development. Found in leafy greens, lentils, and beans. Consider methylfolate if you have an MTHFR gene variant.
CoQ10
Supports mitochondrial function in eggs — egg quality declines with age partly due to mitochondrial changes. Supplements are common for women over 35.
Vitamin D
Low vitamin D is common and linked to PCOS, endometriosis, and implantation failure. Get your levels tested — deficiency is correctable.
Zinc & Selenium
Both support egg development and thyroid function. Found in seafood, nuts, seeds, and meat.
Omega-3 fatty acids
Anti-inflammatory and important for egg quality and embryo development. Oily fish, walnuts, and flaxseeds are good sources.
Iron
Adequate iron intake (particularly plant-based iron with vitamin C) was associated with better ovulatory function in the Harvard study.
Foods to Eat More Of
The research-backed "fertility diet" pattern emphasises:
- Full-fat dairy — the Harvard study found a surprising association between full-fat dairy (not low-fat) and better ovulatory function. One serving per day was associated with lower risk of ovulatory infertility.
- Plant-based protein — beans, lentils, and tofu associated with better fertility outcomes than the same amount of animal protein (particularly processed red meat)
- Slow-digesting carbohydrates — whole grains, legumes, and vegetables rather than white bread, white rice, and sugary foods. Rapid blood sugar spikes affect insulin and androgen levels.
- Antioxidant-rich vegetables and fruits — particularly leafy greens, berries, and colourful vegetables that protect eggs from oxidative stress
- Healthy fats — olive oil, avocado, nuts, and oily fish rather than trans fats (which are directly associated with poorer fertility outcomes)
Foods to Limit or Avoid
- Trans fats — found in some processed foods and fried fast food; associated with ovulatory infertility even in small amounts
- High-glycaemic foods — white bread, sugary drinks, and sweets that spike blood sugar, disrupting insulin and hormone balance
- Processed red meat — associated with poorer fertility in some studies; unprocessed lean red meat in moderation is fine
- Excess alcohol — reduces fertility in both men and women; most guidelines recommend no alcohol while TTC
- Excess caffeine — over 200mg/day (roughly 2 cups of coffee) may affect fertility; stay under this threshold
Multiple studies have found that women following a Mediterranean-style diet (high in vegetables, legumes, whole grains, olive oil, and fish; low in processed foods and red meat) have significantly better IVF outcomes and natural conception rates. It's not a single magic food — it's the overall pattern that matters.
Supplements Worth Considering
Beyond a prenatal vitamin, the supplements with the most evidence for female fertility are:
- Methylfolate (400–800mcg) — start at least 3 months before trying to conceive
- Vitamin D3 — dose based on your tested level; many people need 2,000–4,000 IU daily
- CoQ10 (ubiquinol form) — 200–600mg daily; especially for women over 35 or with diminished ovarian reserve
- Omega-3 (fish oil or algae-based) — 1,000–2,000mg EPA/DHA daily
- Inositol (myo-inositol) — strong evidence for improving ovulation and egg quality in PCOS; typically 2–4g daily
Always talk to your doctor before starting supplements, especially if you have any medical conditions or are taking medications.
What About My Partner?
Sperm quality is equally important — roughly half of all fertility challenges are related to male factors. The same dietary principles apply: Mediterranean-style eating, antioxidants (vitamins C and E, zinc, selenium), and avoiding processed foods and excess alcohol all support sperm quality. CoQ10 also has good evidence for male fertility.
Track Every Step of Your TTC Journey
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