Nutrition for Fertility: Optimising Your Health Before Pregnancy

Written By Finola Power RD

Why Preconception Nutrition Matters

What you eat before pregnancy plays a crucial role in fertility and pregnancy outcomes. A well-balanced diet supports egg and sperm health, hormone balance, and a healthy pregnancy. Since nutrient needs change during pregnancy, laying a strong nutritional foundation beforehand can improve conception chances and reduce the risk of complications.

The Role of Micronutrients in Fertility

Micronutrients are essential vitamins and minerals that the body requires in small amounts for optimal function. While they do not directly provide energy, they play a critical role in hormonal balance, reproductive health, and overall metabolism.

When it comes to fertility, micronutrient status is a key modifiable factor that can influence both male and female reproductive health. Adequate levels of essential vitamins and minerals support:
✔ Egg and sperm quality
✔ Ovulation and hormone regulation
✔ Fertilisation and implantation

Lets explore the key micronutrients that play a role in fertility, their food sources, and how they can support your journey to conception.

1. Folate & Neural Tube Defects (NTDs)

  • Why folate matters: Essential for DNA synthesis and cell division, and is crucial in early pregnancy for preventing neural tube defects (NTDs).

  • For women: Women trying to conceive or those in the first 12 weeks of pregnancy should supplement with 400mcg of folic acid daily.

  • For men: Folate also supports sperm health and DNA integrity.

  • Top sources: Leafy greens, legumes, citrus fruits, fortified grains.

2. Iron

  • Why iron matters: Iron deficiency is the most widespread nutritional deficiency globally, with women of reproductive age at higher risk due to menstrual blood loss, inadequate iron intake, or multiple past pregnancies. Both excess and deficiency of iron can negatively affect fertility.

  • For women: Non-haem iron (from plant-based sources) has been linked to better ovulation outcomes than .

  • Top sources:

    • Haem-iron: Red meat

    • Non-haem iron: Lentils, beans, spinach.

3. Omega-3 Fatty Acids

  • Why omega-3 matters: Reduces inflammation, supports egg & sperm health, and helps fetal brain development.

  • Top sources: Fatty fish (salmon, sardines), flaxseeds, chia seeds, walnuts.

  • Caution: Some fish contain high mercury levels, which can effect fetal development — limit intake of shark, swordfish, and king mackerel. Uncooked fish, such as sashimi, should also be avoided during pregnancy due to the risk of foodborne illness this poses.

4. Vitamin D & Reproductive Health

  • Why vitamin D matters: Influences fertility and is linked to better reproductive success. Deficiency has been associated with gynaecological disorders.

  • For men: Supports semen quality and androgen (testosterone) levels.

  • Top sources: Sunlight, fatty fish, egg yolks, fortified dairy.

5. Zinc & Fertility

  • Why zinc matters: Plays a role in hormone balance, ovulation, and sperm health.

  • For men: Essential for sperm production and motility.

  • For women: Supports egg quality and hormone regulation.

  • Top sources: Meat, shellfish, dairy, nuts, seeds, whole grains.

6. Iodine & Thyroid Function

  • Why iodine matters: Iodine is critical for thyroid health, which plays a major role in ovulation, menstrual cycle regulation, and fetal brain development.

  • Deficiency: Mild to moderate iodine deficiency is common among women of reproductive age worldwide. Both low and excessive iodine levels can impact semen quality and egg maturation.

  • Top sources: Dairy, fish, eggs, iodised salt, seaweed.

7. Antioxidants & Fertility

  • Why antioxidants matter: Oxidative stress can damage egg and sperm cells, contributing to infertility. Antioxidants help protect reproductive cells from damage.

  • For women: Some evidence suggests that antioxidant supplementation may benefit women experiencing infertility, though more research is needed.

  • Key antioxidants:

    • Vitamin C: Supports sperm health and protects against DNA damage.

    • Vitamin E: May improve egg and sperm quality.

    • Vitamin A: Plays a role in cell development and reproductive health.

  • Top sources: A diet rich in fruits, vegetables, nuts, seeds, legumes, whole grains, and herbs provides a wide variety of natural antioxidants.

The Role of Macronutrients in Fertility

While micronutrients are essential in small amounts, macronutrients, carbohydrates, proteins, and fats form the foundation of a fertility-supporting diet. These nutrients provide the energy and building blocks needed for hormone production, egg and sperm development, and overall reproductive health. Balancing quality sources of macronutrients is key to regulating blood sugar, supporting ovulation, and optimising your chances of conception.

1. Protein

  • Why protein matters: Protein plays a fundamental role in fertility, serving as the building block for hormones, enzymes, and reproductive cells. Adequate protein intake supports egg and sperm quality, hormone regulation, and overall reproductive function.

  • Plant v animal protein: A study of 22,786 participants found that increasing plant-based protein while reducing animal protein, especially from processed meats, may help lower the risk of ovulatory infertility. While poorly planned vegetarian or vegan diets can lead to nutrient deficiencies, a well-balanced plant-based diet that includes sufficient protein, iron, and other essential nutrients is considered safe for both maternal and fetal health.

  • Top sources:

    • Plant: Lentils, beans, chickpeas, tofu, nuts, seeds.

    • Animal: Eggs, fish, lean poultry, full-fat dairy.

2. Carbohydrates

  • Why carbohydrates matter: Carbohydrates are an important part of a healthy, balanced diet, particularly when it comes to supporting fertility. However, both the quantity and quality of carbohydrates matter. Research has shown that diets with a high glycaemic load may be associated with an increased risk of infertility due to anovulation. These findings support a growing body of evidence linking insulin and glucose metabolism to reproductive health. While more studies are needed to confirm these associations, reducing intake of refined carbohydrates such as white bread, sugary snacks, and sweetened drinks is a sensible approach, as it may support fertility while also reducing the risk of chronic disease. For the general population of women trying to conceive, a moderate intake of high-quality carbohydrates remains the most evidence-based approach to supporting fertility.

  • Fibre: Opting for high-fibre, low-glycemic foods such as whole grains, legumes, and vegetables can support hormonal balance and ovulation, particularly for women trying to conceive.

  • Top sources: Whole grains (brown rice, quinoa, oats), legumes, vegetables, and fibre-rich foods.

  • Limit: Refined carbs, sugary snacks, and sodas, as they may negatively impact fertility and hormone balance.

3. Dietary Fats & Fertility

  • Why fats matter: Diets consisting of monounsaturated fatty acids (found in foods like avocados, nuts, and olive oil) and full-fat dairy have been linked to improved fertility and lower rates of ovulatory infertility.

  • Low-fat dairy: Some research suggests that low-fat dairy products may negatively impact fertility, but the evidence is inconclusive. Dietary choices should be considered within the broader context of overall health e.g., an individual with high LDL-cholesterol that is trying to conceive may still be better off consuming low-fat dairy products.

  • For men: Omega-3 fatty acids, known for their anti-inflammatory properties, have been shown to improve sperm quality, motility, and overall reproductive health. In contrast, high intakes of saturated and trans fats (commonly found in processed foods and fried items) may negatively affect sperm function.

  • Top sources:

    • Monounsaturated fats: Olive oil, avocados, nuts, seeds

    • Omega-3s: Fatty fish, flaxseeds, walnuts

    • Full-fat dairy: Greek yogurt, full-fat milk, cheese

Final Thoughts

A balanced diet is the best source of essential vitamins and minerals, but when trying to conceive, prenatal vitamins can help fill any nutrient gaps e.g., folate and vitamin D. Always consult with a healthcare provider before adding supplements to your routine. Be cautious of self-proclaimed 'experts' promoting expensive fertility supplements with bold, unproven claims. Always ensure that any supplementation is evidence-based and necessary for your health

References

  • PMID: 34139003

  • PMID: 28595290

  • PMID: 18226626

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  • PMID: 24522025

  • PMID: 19567449

  • PMID: 30196940

  • PMID: 17882137

  • NICE Clinical Guideline [CG156]

Finola Power RD

Hi, I’m Finola Power, a registered dietitian with a passion for helping individuals make informed and sustainable food choices. I focus on providing personalised nutrition advice grounded in science. I’m committed to guiding you towards healthier habits that work for your unique lifestyle, ensuring you feel your best while enjoying a balanced approach to food.

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