The Fertility Diet: How What You Eat Affects Your Chances of Conceiving

Nutrition is one of the most modifiable factors affecting human fertility. While genetics, age, and medical conditions certainly play a role, the quality of your diet can meaningfully improve or diminish your reproductive potential—and there's now a solid body of clinical research to support specific dietary recommendations for both men and women trying to conceive. Understanding the fertility diet and what to eat—and what to avoid—when trying for a baby is not about perfection. It's about making consistent choices that support your hormonal health, egg quality, sperm quality, and the environment your future embryo will develop in.

This guide covers the scientific evidence on diet and fertility, the nutrients that matter most, which foods to prioritise, and practical strategies for building a fertility-supportive eating pattern—whether you're in Hong Kong or anywhere else in the world.

What the Research Says About Diet and Fertility

The most influential study in this area is the Nurses' Health Study from Harvard, which tracked more than 17,000 women over eight years and identified a cluster of dietary habits associated with significantly lower rates of ovulatory infertility. Women following what the researchers called the "Fertility Diet" were 66% less likely to experience ovulatory infertility than those at the opposite dietary extreme.

The key features of this fertility-protective dietary pattern included:

• High intake of monounsaturated fats (olive oil, avocado, nuts) rather than trans fats
• Preference for plant protein over animal protein
• High-fat dairy in modest quantities rather than low-fat dairy
• Low glycaemic carbohydrates rather than refined carbohydrates
• High intake of iron from plant sources
• Multivitamin use including folic acid

For male fertility, prospective cohort studies from Massachusetts General Hospital (part of the EARTH study) show consistent associations between diet quality and semen parameters. Men eating more fish, whole grains, vegetables, and fruits have significantly better sperm motility and morphology than those eating processed foods, red meat, and alcohol.

Importantly, diet affects fertility through multiple pathways: hormonal balance, antioxidant protection (particularly for sperm, which are highly vulnerable to oxidative damage), inflammation, insulin sensitivity, and the basic supply of micronutrients required for cell division during spermatogenesis and folliculogenesis.

The Most Important Nutrients for Fertility

A fertility-supportive diet must provide adequate amounts of the following key nutrients:

Folate (not just folic acid)

Folate—or its synthetic form, folic acid—is the most critical preconception nutrient. It is required for DNA synthesis, cell division, and the closure of the neural tube in early embryo development. The standard recommendation is 400–800 mcg of folic acid daily for three months before and throughout the first trimester of pregnancy. However, some women carry MTHFR gene variants that reduce their ability to convert folic acid to its active form (5-MTHF). For these women, methylated folate (5-methyltetrahydrofolate) is more appropriate. Dietary folate sources include leafy greens, legumes, and fortified foods.

Iron

Iron deficiency is the world's most common nutritional deficiency and is associated with anovulatory infertility in the Nurses' Health Study. Interestingly, the fertility-protective effect was stronger for plant-based iron (non-haem iron from legumes, tofu, leafy greens) than for haem iron from red meat. Iron is essential for oogenesis and the early stages of embryo development. Women with menorrhagia (heavy periods) are at particular risk of deficiency.

Omega-3 Fatty Acids

Long-chain omega-3 fatty acids—EPA and DHA from oily fish—are incorporated into cell membranes throughout the body, including egg cells and sperm. For women, omega-3s reduce inflammation, support progesterone production, and may improve ovarian reserve markers. For men, DHA is highly concentrated in the sperm head, and multiple studies link higher omega-3 intake with better sperm morphology and motility. The best dietary sources are oily fish (salmon, mackerel, sardines, herring); plant sources (flaxseed, chia, walnuts) provide ALA, which requires conversion to EPA/DHA and is less efficient.

Zinc

Zinc is critical for both male and female fertility. In women, zinc is required for follicle development, oocyte maturation, and fertilisation. In men, it's the dominant mineral in seminal plasma and is directly linked to sperm count, motility, and DNA integrity. Both red meat and seafood are excellent zinc sources; plant-based zinc from legumes and grains is less bioavailable due to phytates.

Vitamin D

Vitamin D receptors are found in the ovaries, uterus, and sperm cells. Deficiency is strongly associated with reduced fertility in both sexes—lower egg quality, reduced sperm motility, worse IVF outcomes. Vitamin D synthesis from sunlight is limited at latitudes far from the equator and varies considerably by season, skin tone, and sun exposure habits. Supplementation (1,000–2,000 IU/day) is appropriate for many people, particularly in regions with limited year-round sunlight.

CoQ10 (Coenzyme Q10)

CoQ10 is an antioxidant and essential component of the mitochondrial electron transport chain—the energy production system in every cell. In fertility, it's relevant in two ways: egg cells require enormous amounts of mitochondrial energy for maturation and early embryo development, and CoQ10 is concentrated in the sperm midpiece, powering the flagellum. CoQ10 levels naturally decline with age. Clinical trials show improvements in egg quality, ovarian response (in IVF), and sperm motility with CoQ10 supplementation. Dietary sources are limited (organ meats, oily fish, beef), making supplementation practical for fertility support.

Antioxidants: Vitamins C and E, Selenium

Oxidative stress—an imbalance between free radical production and antioxidant defence—is a major mechanism of both egg and sperm damage. Vitamin C protects sperm DNA from fragmentation and supports ovarian function. Vitamin E protects cell membranes from lipid peroxidation. Selenium is an essential component of glutathione peroxidase, the primary antioxidant enzyme in the testes. A diet rich in colourful vegetables, citrus fruits, nuts, and seeds provides a broad spectrum of antioxidants.

Foods to Prioritise on a Fertility Diet

Building a fertility-supportive diet doesn't require exotic ingredients or restrictive rules. The evidence consistently points to a pattern of eating that broadly resembles the Mediterranean diet:

Vegetables and Leafy Greens

Aim for at least 5–7 servings daily. Leafy greens (spinach, kale, bok choy, broccoli) provide folate, iron, and antioxidants. Deeply coloured vegetables—orange, red, and purple—deliver carotenoids and other antioxidants that protect gametes from oxidative damage.

Legumes

Lentils, chickpeas, black beans, and edamame provide plant protein, non-haem iron, folate, and fibre. The Nurses' Health Study showed that replacing one serving of animal protein with plant protein was associated with reduced ovulatory infertility risk.

Oily Fish

Two to three servings of oily fish per week (salmon, mackerel, sardines, herring) delivers EPA and DHA omega-3s that support both egg and sperm quality. Avoid high-mercury fish (shark, swordfish, marlin, king mackerel) which are associated with impaired neurological development in foetuses.

Nuts and Seeds

A daily handful of mixed nuts—particularly walnuts, Brazil nuts (for selenium), and pumpkin seeds (for zinc)—delivers a concentrated dose of fertility-relevant minerals and healthy fats. A randomised trial showed that adding 75g of walnuts daily to the diet significantly improved sperm morphology, motility, and vitality in young men.

Whole Grains

Oats, brown rice, quinoa, and wholemeal bread have a lower glycaemic index than their refined counterparts, meaning they raise blood glucose more slowly and produce a more moderate insulin response. Better insulin sensitivity is associated with better hormonal balance in both sexes.

Full-Fat Dairy (in Moderation)

The Nurses' Health Study found that high-fat dairy (full-fat milk, cheese, yoghurt) was associated with lower ovulatory infertility risk, while low-fat dairy was associated with higher risk. The hypothesis is that fat-soluble reproductive hormones present in full-fat dairy may support fertility, and that the hormones are removed or changed during fat skimming. One to two servings of full-fat dairy daily appears beneficial.

Berries and Citrus

Blueberries, strawberries, raspberries, and citrus fruits are rich in vitamin C, flavonoids, and antioxidants that protect against oxidative stress. Daily consumption contributes meaningfully to antioxidant intake.

Avocado and Olive Oil

Both provide monounsaturated fats associated with better fertility outcomes. Avocado also delivers vitamin E, folate, and potassium. Use olive oil as your primary cooking fat.

Foods and Substances to Limit When Trying to Conceive

Just as certain foods support fertility, others appear to be counterproductive. The evidence here is generally less strong than for beneficial foods (observational rather than interventional), but the following are worth reducing or eliminating:

Trans Fats

Partially hydrogenated vegetable oils (found in some margarines, pastries, and processed snack foods) are associated with increased ovulatory infertility risk. Replace with natural fats from olive oil, avocado, nuts, and oily fish.

Refined Carbohydrates and Sugar

High-glycaemic foods cause rapid blood glucose rises and exaggerated insulin responses. Chronic hyperinsulinaemia promotes androgen overproduction in women (particularly relevant for PCOS) and is associated with poorer semen parameters in men.

Processed Meats

Multiple studies link processed meat consumption (sausages, bacon, hot dogs, deli meats) to poorer sperm morphology. Replacing processed meat with fish, poultry, or legumes is a straightforward improvement.

Alcohol

Evidence shows that even moderate regular alcohol consumption—more than 5 units per week for women trying to conceive—is associated with reduced fertility. For men, heavy drinking reduces testosterone, increases oestrogen, and impairs sperm production. While occasional light drinking hasn't been definitively proven harmful, abstinence or strict moderation (no more than 1–2 units occasionally) is the precautionary recommendation when trying to conceive.

Caffeine

The evidence on caffeine and fertility is mixed, but most fertility specialists recommend limiting caffeine to fewer than 200 mg per day (approximately one strong cup of coffee or two smaller cups). Very high caffeine intake (>500 mg/day) is associated with reduced fertility and modestly elevated miscarriage risk.

High-Mercury Fish

Shark, swordfish, marlin, tilefish, and king mackerel accumulate mercury to levels that can damage the developing nervous system. Limit these to no more than one small serving per month and avoid entirely during pregnancy.

Practical Meal Planning for Fertility

Translating the evidence into daily eating doesn't require elaborate meal preparation. Here's a practical framework:

Breakfast: Whole grain porridge (oats) with berries and a spoonful of nut butter; or eggs with sautéed leafy greens and wholegrain toast; or full-fat Greek yoghurt with mixed berries and pumpkin seeds.

Lunch: Large salad with leafy greens, chickpeas, avocado, mixed vegetables, olive oil and lemon dressing; or wholegrain wrap with grilled salmon, cucumber, and tahini.

Dinner: Grilled mackerel with roasted vegetables and brown rice; or lentil and vegetable curry with wholegrain roti; or stir-fried tofu with bok choy and edamame over soba noodles.

Snacks: A handful of walnuts and a piece of fruit; hummus with vegetable sticks; or a Brazil nut (for selenium) with a few pumpkin seeds.

Drinks: Water, herbal teas, and moderate green tea. Limit alcohol and coffee.

Should I Take Supplements on a Fertility Diet?

Even a well-designed fertility diet may not provide all nutrients at the therapeutic doses associated with fertility benefits in clinical research. Several nutrients—particularly folate (to prevent neural tube defects), vitamin D (especially in less sunny climates or with indoor lifestyles), CoQ10, and omega-3s—are difficult to obtain in sufficient amounts from food alone.

A quality preconception supplement—for both partners—is a sensible addition to dietary changes. For women, Conceive Plus Women's Fertility Support provides folate, CoQ10, inositol, vitamin D, and comprehensive micronutrient support. For men, Conceive Plus Men's Fertility Support delivers zinc, selenium, CoQ10, and antioxidant vitamins that complement a fertility-supportive diet.

Frequently Asked Questions About the Fertility Diet

Does diet really affect fertility?

Yes. Multiple large prospective cohort studies, including Harvard's Nurses' Health Study, have identified clear associations between dietary patterns and fertility outcomes. Randomised controlled trials have also shown that specific nutrients and dietary changes measurably improve semen parameters, hormonal profiles, and conception rates.

What are the best foods to eat when trying to conceive?

Leafy greens, legumes, oily fish, whole grains, nuts and seeds (especially walnuts and Brazil nuts), berries, citrus fruits, avocado, olive oil, and full-fat dairy in moderation. These foods collectively provide the folate, omega-3s, zinc, antioxidants, and healthy fats most strongly associated with fertility support.

Is a Mediterranean diet good for fertility?

Yes. Multiple studies have found associations between Mediterranean diet adherence and better semen parameters in men, better IVF outcomes in women, and reduced risk of ovulatory infertility. The Mediterranean diet is characterised by high vegetable, legume, whole grain, fish, and olive oil intake—which aligns closely with the specific dietary factors associated with fertility benefit.

Should both partners change their diet?

Absolutely. Male factor infertility contributes to approximately half of all fertility challenges. Diet significantly affects sperm count, motility, morphology, and DNA integrity. Both partners benefit from a fertility-supportive diet, and doing it together makes adherence easier.

How long does it take for diet to affect fertility?

For women, hormonal changes and ovarian function can begin to improve within a few months of dietary changes. For men, improvements in semen parameters require at least 2–3 months because of the 74-day spermatogenesis cycle. Starting dietary improvements at least 3 months before planned conception is recommended for both partners.

Is organic food necessary for fertility?

The evidence is not strong enough to make organic food a strict requirement. However, some pesticide residues are endocrine-disrupting, and higher pesticide intake from conventional produce has been associated with worse semen quality in some studies. If budget allows, prioritising organic for the "Dirty Dozen" (high-pesticide crops including strawberries, apples, spinach) is a reasonable precaution.

What should I not eat when trying to get pregnant?

Limit: trans fats (processed snack foods, some margarines), refined carbohydrates and sugar, processed meats, alcohol, and high-mercury fish. These are associated with poorer fertility outcomes in observational research. Eliminating them is not necessary for occasional consumption, but regular intake of several of these simultaneously creates a meaningful nutritional burden on reproductive health.

Does caffeine affect fertility?

High caffeine intake (>500 mg/day) is associated with reduced fertility. Most fertility specialists recommend limiting intake to fewer than 200 mg/day (roughly one strong coffee). Moderate consumption is unlikely to significantly impair fertility, but reducing intake is a low-risk precaution when trying to conceive.

Can a fertility diet help with IVF success?

Yes. A prospective study from the EARTH cohort found that women with higher Mediterranean diet scores had significantly better IVF outcomes, including higher fertilisation rates and live birth rates. Similarly, men's dietary patterns affect sperm quality used in IVF. Starting fertility-supportive eating at least 3 months before IVF gives both partners' reproductive cells the best nutritional foundation.

Does Conceive Plus offer fertility supplements to complement a fertility diet?

Yes. Conceive Plus offers targeted fertility supplements for both men and women, designed to complement a fertility-supportive diet with nutrients that are difficult to obtain in therapeutic amounts from food alone. Available in Hong Kong at conceiveplus.hk.