Egg Quality and Nutrition After 35: What the Research Actually Says

When Dorothy turned 40 and we were deep into trying to conceive, the supplement aisle was overwhelming.

CoQ10. Myo-inositol. DHEA. Vitamin D. Folate versus folic acid. Everyone seemed to have a strong opinion. Most of it came without sources.

We are still on this journey. We built FertiNutrition because we needed it ourselves: a tool that told us what to eat and when, based on where we were in the cycle.

This article is what we found when we went looking for real evidence. Not conclusions, the actual research behind them.

Why egg quality changes after 35

Women are born with all the eggs they will ever have, roughly 1 to 2 million at birth. By puberty, that number has already dropped to around 300,000 to 500,000. After 35, both the quantity and the quality of remaining eggs decline more noticeably.

What does "egg quality" actually mean? It refers to whether an egg has the correct number of chromosomes and whether it has enough cellular energy to fertilise, implant, and develop into a healthy embryo.

The cellular energy part is where nutrition comes in.

Each egg contains more mitochondria, the energy-producing structures in cells, than almost any other cell in the body. That's because egg development and the first days of embryo growth require enormous amounts of energy. As we age, mitochondrial function naturally declines. Nutrition cannot reverse this process, but research suggests it can support it.

Why the 90-day window matters

Here's something that changed how we thought about eating: an egg takes approximately 90 days to fully mature before ovulation.

This means the food you eat today is influencing eggs that won't be released for three months.

A 2025 article published by Dame Health summarised it clearly: improving egg quality is not about overnight fixes. It is about consistent, nutrient-rich support over at least three ovulatory cycles, which is roughly 90 days.

This is why we built FertiNutrition around a 90-day journey. Not because 90 days is a magic number, but because that's how long egg maturation actually takes.

The nutrients that have the most research behind them

Folate

Folate, and its synthetic form folic acid, is the most well-established fertility nutrient. Beyond its well-known role in preventing neural tube defects, folate supports DNA synthesis and cell division, both critical for healthy egg development.

Dark leafy greens, asparagus, lentils, and avocado are among the richest food sources. If you are trying to conceive, most European health authorities recommend a supplement of 400mcg daily.

CoQ10 (Coenzyme Q10)

CoQ10 is a naturally occurring antioxidant found in nearly every cell. It plays a central role in mitochondrial energy production, which, as we explained above, matters a great deal for eggs.

The research on CoQ10 for egg quality is promising but not definitive. A 2023 review published in the journal Human Fertility found that CoQ10 supplementation could improve fertilisation rates and markers of egg quality in women aged 31 and over. A 2024 narrative review in Reproductive BioMedicine Online noted positive signals for ovarian response in women with lower ovarian reserve, while acknowledging that more large randomised trials are still needed.

The honest summary: CoQ10 is not a guarantee, and it does not create new eggs. But the evidence suggests it may support the function of the eggs you have, particularly after 35. Typical doses studied are 200 to 600mg daily, started at least 8 to 12 weeks before trying to conceive.

Food sources of CoQ10 include fatty fish, organ meats, spinach, and broccoli, though food alone is unlikely to provide therapeutic doses.

Omega-3 fatty acids

Omega-3s are essential fats with two important roles for fertility: they help maintain the structural integrity of egg cell membranes, and they have anti-inflammatory properties that create a more favourable hormonal environment.

Research links higher omega-3 levels to better ovarian reserve. The most bioavailable forms, EPA and DHA, are found in fatty fish like salmon, sardines, and mackerel. Plant sources like walnuts, chia seeds, and flaxseeds provide ALA, which the body can partially convert to EPA and DHA.

Iron

Iron deficiency is common in women of reproductive age, particularly during and after menstruation. Low iron is associated with ovulatory dysfunction.

Good dietary sources include red meat, lentils, spinach, pumpkin seeds, and fortified cereals. Combining plant-based iron sources with vitamin C improves absorption significantly.

Zinc

Zinc is involved in follicle development and the maturation process of eggs. Oysters are exceptionally high in zinc, more than any other food. Other good sources include pumpkin seeds, eggs, legumes, and meat.

Vitamin D

Low vitamin D levels have been associated with poorer fertility outcomes in multiple studies. Most people in Northern Europe are deficient, particularly in winter. Sources include fatty fish, egg yolks, and sunlight, though supplementation is often necessary at northern latitudes.

The Mediterranean diet and fertility

Beyond individual nutrients, there is strong evidence for an overall dietary pattern: the Mediterranean diet.

A systematic review published in the European Journal of Public Health in 2025, covering studies from 2010 to 2024, evaluated the relationship between Mediterranean diet adherence and assisted reproductive outcomes. The findings were encouraging. Women who followed the diet more closely tended to have better fertilisation rates and more embryos.

A 2024 study published in Frontiers in Nutrition found that women following a high Mediterranean diet had a significantly higher blastocyst formation rate compared to those with low adherence.

What does the Mediterranean diet look like in practice? Plenty of vegetables and fruit, whole grains, legumes, fish, olive oil, and nuts. Limited red meat, processed foods, and sugar.

This is not a radical diet. It is close to what most of us already know to be healthy eating, but with a particular emphasis on the foods that support hormonal health and reduce oxidative stress.

What we actually ate

We want to be clear: we are not nutritionists or doctors. What follows is our personal experience, not medical advice.

During the months we were trying to conceive, we focused on:

• Salmon or sardines at least three times per week for omega-3 and vitamin D
• Leafy greens every day, spinach, kale, rocket, for folate and iron
• Lentils or chickpeas several times per week as a plant-based source of iron and folate
• Pumpkin seeds as a daily snack for zinc and magnesium
• Whole grains instead of refined carbohydrates to support stable blood sugar
• Berries regularly for antioxidants
• Limiting alcohol and processed foods, not eliminating entirely, just reducing

We also took folate supplements throughout. Dorothy took CoQ10, ubiquinol form, for the 90 days before her most successful cycle.

These changes did not happen overnight. They happened because we built a system: a daily meal plan synced to Dorothy's cycle, so the right foods appeared at the right time without having to think about it every day.

That system became FertiNutrition.

What nutrition cannot do

We want to be honest about limits.

Nutrition cannot reverse the biological effects of age on egg quantity. It cannot guarantee a pregnancy. It cannot replace medical care.

If you have been trying to conceive for 12 months, or 6 months if you are over 35, the most important step is to see a fertility specialist. Nutrition is supportive. It is not a substitute for medical investigation.

What nutrition can do is give your eggs the best possible cellular environment during the time they are maturing. It can reduce oxidative stress. It can support hormonal balance. And it can give you a sense of agency during a process that often feels entirely out of your control.

That, more than anything, is why we think it matters.

References

1. Dame Health. Eat Smart, Conceive Strong: 10 Nutrient-Rich Foods for Egg Health. May 2025. damehealth.com
2. Ben-Meir A, et al. Coenzyme Q10 and female fertility: a narrative review. Reproductive BioMedicine Online. 2024;48:103407. doi:10.1016/j.rbmo.2023.103407
3. Human Fertility (UK). CoQ10 supplementation and oocyte quality in women aged 31+. 2023 review.
4. Phytaphix. Fertility After 35 and 40: The Best Evidence-Based Vitamins and Supplements for Egg Quality. March 2026. phytaphix.com
5. European Journal of Public Health. Associations between adherence to a Mediterranean diet and assisted reproductive techniques outcomes: a systematic review. 2025. doi:10.1093/eurpub/ckaf100
6. Chen H, et al. Mediterranean diet improves blastocyst formation in women previously infected with COVID-19: a prospective cohort study. Frontiers in Nutrition. 2024;11:1371077. doi:10.3389/fnut.2024.1371077
7. Conceive Health. Can a Mediterranean Diet Improve Your Fertility? September 2024. conceivehealth.com
8. European Food Safety Authority (EFSA). Dietary Reference Values. efsa.europa.eu

FertiNutrition is a nutrition tool, not a medical product. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider or fertility specialist for personalised guidance.