The Connection Between Protein Intake and Fertility: What You Need to Know

Why Protein Matters for Fertility

Fertility isn’t just determined by age or hormone levels—what you eat, especially your protein intake, matters more than most of us realize. Protein is a vital building block for every cell in the body, helping repair tissues, balance hormones, and support the healthy development of eggs and sperm. Yet, there’s still a lot of confusion: Is animal protein better than plant-based? How much is too much? And are there hidden risks with our modern diets?

Let’s take a gentle, practical look at the science, the stories, and the balanced ways you can approach protein on your path to conception.

How Protein Supports Reproductive Health

Protein is made up of amino acids, which the body uses for everything—from building hormones like FSH and LH that regulate menstrual cycles, to constructing the very DNA inside eggs and sperm. In the context of fertility, protein supports:

• Hormonal balance: Proteins help the body make and transport reproductive hormones.
• Egg and sperm quality: Amino acids are crucial for cell division and the healthy growth of eggs and sperm cells.
• Healthy cycles: Adequate protein intake helps maintain stable cycles and ovulation.
• Uterine and placental health: Protein is essential for preparing the uterine lining and, eventually, for the developing placenta.

What Does the Research Say?

Questions about the role of protein in fertility have been asked for decades. Some of the largest clues come from nutritional epidemiology—the study of how whole patterns of eating relate to reproductive health:

• The Nurses’ Health Study: This long-term study of over 18,000 women found that replacing just some animal protein with plant sources (like beans, lentils, and nuts) was linked to a lower risk of ovulatory infertility (Chavarro et al., Harvard School of Public Health, 2008). Women eating more plant-based protein were more likely to have regular ovulation and shorter time to conception, regardless of their age or weight.
• Animal vs. Plant Protein: Although both animal and plant proteins provide essential amino acids, studies suggest that moderating animal protein—especially red and processed meats—may help reproductive hormone balance and ovarian health (Fertility and Sterility, 2015).
• Protein Quantity: Too little protein can signal stress to the body and disrupt cycles, but excessive intake (especially above 120g/day for women) may increase nitrogen metabolites and oxidative stress, which are not ideal for early conception (Repro BioMedicine Online, 2017).

How Much Protein Is Optimal When Trying to Conceive?

Official guidelines suggest that most women need about 0.8 grams of protein per kilogram of body weight daily. For a 150-pound (68-kg) woman, that’s roughly 55 grams per day. During preconception and pregnancy, some experts recommend increasing this slightly, aiming for 1–1.2 grams/kg, especially if you are very active or under stress (American College of Obstetricians and Gynecologists, 2023).

But beyond numbers, it’s about balance and listening to your body. If you’re active, vegan or vegetarian, or have a history of food sensitivities, your needs may be unique.

A simple way to gauge: Include a quality protein source at each main meal. You’ll likely reach an optimal intake naturally.

Choosing Fertility-Friendly Sources of Protein

• Plant-Based Proteins: Lentils, chickpeas, quinoa, tofu, tempeh, edamame, nuts, seeds. These foods are high in fiber, vitamins, and usually lower in saturated fat. Studies show they help balance blood sugar, which is key to hormonal balance.
• Quality Animal Protein: Eggs, wild-caught fish (like salmon and sardines, low in mercury), organic poultry, and dairy provide complete amino acids and nutrients like choline, zinc, and B12. Limit finished red meats and processed meats, which have been linked to higher rates of inflammation and, in some studies, poorer egg quality.
• Mix it up: Combining different sources gives you a broad spectrum of amino acids, micronutrients, and antioxidants.

Protein and Male Fertility: Not Just a Women’s Issue

Protein is equally vital for sperm health. Amino acids—especially L-carnitine and L-arginine—play a direct role in sperm motility and DNA integrity. Research published in Andrology (2018) found diets rich in fish, poultry, eggs, legumes, and nuts were associated with higher sperm counts and motility compared to those heavy in processed meats.

Zinc and selenium, often found in protein-rich foods, are also essential for healthy testosterone and sperm development.

Common Pitfalls: Too Much or Too Little?

• Excess protein from animal sources—especially processed meats and some commercial dairy—may contribute to higher levels of inflammation and exposure to environmental toxins, which can negatively affect fertility in both men and women. The World Health Organization classifies processed meats as a Group 1 carcinogen, and several large studies point to lower fertility rates and higher miscarriage rates in populations with high processed meat consumption (British Medical Journal, 2018).
• Very low protein intake (below 40g per day for women) may result in irregular cycles, fragile uterine lining, and lower egg quality. Traditional societies typically consumed a moderate protein intake, favoring whole food sources from both plants and animals.

How to Build a Fertility-Friendly Plate

Creating meals that support fertility doesn’t have to be overwhelming. Here’s a simple framework:

1. Start with protein: Every meal contains at least one protein serving (about the size of your palm).
2. Balance your plate: Fill half with a rainbow of vegetables, a quarter with whole grains or starchy roots, and a quarter with protein.
3. Include healthy fats: Add a drizzle of olive oil, a handful of seeds, or half an avocado to help your body absorb fat-soluble vitamins essential for hormonal health.
4. Eat mindfully: Slowing down helps you digest and absorb those important amino acids and nutrients.

Listening to Your Body & Staying Motivated

Sometimes, when trying to conceive, changes in appetite and digestion can occur—either from stress, treatments, or hormones. If you find yourself struggling with protein-rich foods, know that it’s okay to adapt. Try incorporating proteins into soups, smoothies, or gentle cooked meals. Remember, there’s no “perfect” diet—what matters most is the overall pattern and consistency over time.

When in doubt, choosing mostly whole, minimally processed protein sources—guided by your taste, comfort, and culture—is a compassionate way to fuel your fertility journey.

Looking Ahead: Finding a Protein Pattern That Fits

Fertility is built day by day, meal by meal—not through one food or magic number, but through balance, curiosity, and kindness toward yourself. Protein is a quiet ally in this process, supporting hormones, eggs, sperm, and every hopeful step forward.

If you’re ever unsure about the right amount or type of protein for your personal needs, seeking guidance from a registered dietitian or holistic nutritionist can offer perspective tailored to your full story. For now, let’s celebrate the small ways mindful eating can nurture every part of the fertility journey.

Sources consulted: Harvard T.H. Chan School of Public Health, Fertility and Sterility Journal, American College of Obstetricians and Gynecologists, British Medical Journal, Andrology Journal, Reproductive BioMedicine Online.