Can a Plant-based Diet Support Fertility Alone?

By Chloe Dymond Young - BANT Registered Nutritional Therapist, IBCLC and ex-Midwife (17 years).

Nutrition in Vegetarian and Vegan Diets: Implications for Fertility and Pregnancy:

Following a vegetarian or vegan diet offers many health benefits and aligns with ethical and environmental values. However, these diets may put individuals at risk for certain nutritional deficiencies that are crucial during preconception, fertility, and pregnancy. Understanding these risks, especially in the context of genetic variations, can help ensure both maternal and baby health.

In this blog, we’ll explore common nutrient gaps in plant-based diets, how they relate to fertility and pregnancy outcomes, the influence of genetics and evidence-based strategies to optimise nutrition.

Common Nutrients to Watch on a Plant-Based Diet

Even a healthy, well-balanced plant-based diet can sometimes fall short in certain nutrients that are crucial for conception and a healthy pregnancy. Here’s a look at which nutrients are commonly depleted:

1. Vitamin B12 – Found mainly in animal products. It’s essential for healthy eggs and baby’s brain and spine development. A deficiency can lead to tiredness, low mood, and poor fertility outcomes. Supplementation is usually needed on a vegan diet.

2. Iron – Plant-based iron isn’t absorbed as well as iron from meat. Low iron can affect ovulation, energy, and increases the risk of complications like preterm birth. Adding vitamin C-rich foods to meals can help with absorption.

3. Zinc – Important for hormone health and egg and sperm development. Found in nuts, seeds, and legumes, but absorption can be reduced due to natural compounds called phytates in these foods.

4. Omega-3 Fats (DHA & EPA) – These healthy fats support baby’s brain and fertility. The plant form (ALA) found in chia or flax isn’t converted very efficiently, so a vegan DHA supplement (from algae) is often a good idea.

5. Vitamin D – Made from sunlight, but often low in the UK and other cooler climates. Low levels have been linked to poor fertility, low mood, and weaker bones.

6. Calcium – Needed for bone strength and baby’s development. Found in leafy greens, fortified plant milks and tofu - absorption varies.

7. Iodine – Needed for healthy thyroid function, which affects fertility and baby’s brain development. It’s low in most plant foods unless the soil is rich in iodine. Seaweed (in small amounts) can help.

8. Vitamin A – Found in plant foods as beta-carotene, which the body converts into active vitamin A. Some people convert it less efficiently, so it’s important to include colourful veggies daily and consider your intake if planning a pregnancy.

Research:

• A 2020 review in Nutrients highlights the increased risk of B12 and iron deficiency in vegetarians and vegans, recommending supplementation for women of reproductive age.

• The NIPPER trial emphasises the role of early nutritional optimisation, linking micronutrient status with improved fertility outcomes.

• Genetic studies underscore the importance of personalised nutrition approaches, particularly for folate, iron, and omega-3 metabolism.

  The NIPPER Trial and Plant-Based Nutrition:

  The NIPPER trial (Nutritional Intervention Preconception and Pregnancy to Improve Outcomes) investigated the impact of preconception nutrition on fertility and pregnancy outcomes. Among its findings:

  • Women with optimised micronutrient status prior to conception had improved fertility and reduced pregnancy complications.

  • Plant-based eaters particularly benefited from targeted supplementation (B12, iron, omega-3s) alongside dietary counselling.

  • The study supports early intervention before conception to address nutrient gaps for better maternal and fetal health.

    Genetics:

Individual genetic variants can further influence nutrient status in plant-based eaters:

• MTHFR C677T: affects folate metabolism; plant-based folate is abundant but may require methylated supplementation.

• TMPRSS6: alters iron absorption efficiency.

• FADS1 and FADS2: influence conversion of ALA to EPA/DHA, impacting omega-3 status.

• CYP2R1: affects vitamin D activation.

• TCN2: impacts vitamin B12 transport and utilisation.

• BCO1: reduces conversion efficiency of beta-carotene to active vitamin A, affecting vitamin A status.

• FUT2 (Secretor Status): determines secretion of blood group antigens in bodily fluids and influences gut microbiota composition. Secretor status has been linked to variations in vitamin B12 absorption because gut bacteria affect the availability and uptake of B12. Non-secretors may have altered microbiomes that reduce B12 bioavailability, increasing deficiency risk even with adequate intake.

  Protein on a Plant-Based Diet: What You Need to Know

  Protein provides our body with the building blocks for hormone production, egg and sperm quality, and baby’s development, making it vital during fertility and pregnancy. A complete protein is made up of twenty amino acids - nine of which are essential (the others can be made from the essential amino acids). Consuming the full range can be a challenge for people following a plant-based diet and while it is absolutely possible to meet protein needs, it may require a bit of extra attention to ensure all essential amino acids are covered.

  Unlike animal proteins, most plant sources are considered "incomplete" - meaning they don’t contain all nine essential amino acids in one food. But by combining a variety of sources (like beans with grains, or nuts with legumes) across the day, you can get everything you need.

  Great plant-based protein sources include:
  ✓ Lentils, chickpeas, black beans
  ✓ Tofu, tempeh, edamame (contain all nine essential amino acids)
  ✓ Quinoa (contain all nine essential amino acids)
  ✓ Nuts, seeds, whole grains
  ✓ Protein powders

  Aim for at least 1.1g of protein per kg of body weight daily preconception and during early pregnancy and more as pregnancy progresses.

  Simple Tips for Staying Nourished on a Plant-Based Diet:

• Get your B12, iron, vitamin D, and folate levels tested before pregnancy.

• Take a good-quality prenatal supplement tailored to vegetarian or vegan needs.

• Use vitamin C-rich foods to boost iron absorption (e.g. add lemon juice to lentils).

• Soak, sprout, or ferment grains and legumes to improve mineral uptake.

• Have tea and coffee between meals, not with them, to avoid blocking iron and zinc.

• Include a variety of nuts, seeds, pulses, tofu, leafy greens, and fortified foods daily.

• Consider a vegan DHA supplement for omega-3 support.

• Include a protein source at every meal and snack for balance and sustained energy.

• Work with a practitioner who understands plant-based nutrition and fertility to tailor your plan.

Finally:

You can thrive on a plant-based diet while preparing for pregnancy - it just takes a little extra planning. With the right nutrients in place, you're giving both yourself and your future baby the very best start.

If you’d like a plan tailored to your needs BOOK A FREE DISCOVERY CALL to find out more. My signature Maternity Nutrition and DNA programmes are ideal for those following a plant-based diet.