How diet and dietary supplements during preconception may impact fertility

Women are having children later in life, which can pose some challenges when it comes to conception. For example, in 2021, women between the ages of 30 and 34 had a higher birth rate than those aged 25-29 years, with 97.6 births per 1000 women, compared to 93 births per 1000 women, respectively.¹ Overall the mean ages of mothers at first birth in 2021 was 27.3 years, which increased from 24.9 years in 1968. Conceiving can be challenging once women reach their mid-to-late 30s because they’re born with a limited amount of eggs, and these eggs are not as easily fertilized as one gets older.² While some women deal with more severe complication and may need medical interventions to aid in conception, diet also plays a role in a women’s ability to conceive, opening up the potential for the use of specialty diets and nutritional supplements in supporting the physiological conditions for conception.

"Our consumer research at Kerry tells us that women of reproductive age are interested in hormonal tracking and fertility-focused wellness. Functional ingredients within this space remain focused on pre-natal vitamins and omega-3s, but have expanded to target concerns of overall wellness, including oxidative stress and microbial dysbiosis coupled with a targeted approach to optimize hormonal regulation, ovulation and oocyte health," notes Amy B Smith, PhD, medical affairs director, ProActive Health at Kerry. "The industry is evolving to highlight the overall impact of total health on fertility among women during this reproductive life stage."

Role of Diet in Preconception

How diet impacts fertility is still being investigated but there are some diets that are associated with a higher rate of conceptions. The Mediterranean diet, for example, is characterized by a high consumption of vegetables, pulses, fruits, olive oil, unrefined carbohydrates, low fat dairy, poultry, and oil fish, as well as a lower consumption of red meat and simple sugars. This diet is known to support metabolic health, and reduce the risk of obesity, which are important in the context of fertility, but research does find a higher association between adherence to the Mediterranean diet and fertility.³

There is even a pro-fertility diet that is similar to the Mediterranean diet that has been associated with a lower risk of infertility caused by ovulation disorders. That diet is characterized by lower consumption of trans-fatty acids and higher consumption of monounsaturated fatty acids, plant protein, and a decreased consumption of animal protein, low-glycemic index foods, high-fiber foods, and high-fat dairy. Women following this diet consume more nonheme iron, and take multivitamins and B vitamins such as folic acid more frequently.³ The Mediterranean diet, for its part, has been correlated with red blood cell folate and serum vitamin B₆. Research has even shown that women adhering to the Mediterranean diet while undergoing in vitro fertilization had an increased probability of pregnancy.

Folic acid, vitamin B₁₂, and vitamin B₆ may impact fertility because of their role in homocysteine metabolism.³ For example, hyperhomocysteinemia (abnormally high levels of homocysteine in the blood) combined with a low concentration of folic acid constitutes a risk factor for recurrent miscarriage. One cohort study even found that 259 women who were regularly menstruating and not using hormonal contraceptives or dietary supplements had higher homocysteine concentrations and therefore an increased risk of a lack of ovulation by 33%.³ Additionally, a higher folic acid to homocycteine ratio decreased the risk of anovulation by 10%.

The types of fats associated with the Mediterranean diet are also very important for supporting conception, mostly due to their anti-inflammatory properties. Omega-3s, for example, support the growth and maturation of oocytes, which are eggs prior to maturation, decrease the risk of anovulation and also support embryo morphology.³ It can be difficult to get enough from the diet, therefore supplementation is crucial. Antioxidants such as CoQ10 and ubiquinol may also play an important role of supporting fertility. For example, supplementation with CoQ10 was found in a study to enhance clinical pregnancy rate in women undergoing assisted reproductive technology procedures.⁴ It may also support oocyte quality. Oxidative stress and mitochondrial dysfunction could hinder oocyte maturation, and the development of eggs requires significant amounts of ATP (adenosine triphosphate). Because CoQ10 is a crucial component of the mitochondrial transport chain, facilitating ATP production and enhancing mitochondrial function, supplementation with CoQ10 may therefore aid in restoring mitochondrial function and improve energy metabolism of oocytes in older women or those experiencing ovarian dysfunction.⁵

Nutrients like folic acid, omega-3s and CoQ10 have been found to be helpful for women dealing with polycystic ovary syndrome (PCOS), which is a hormonal disorder that can impact a woman’s ability to get pregnant. Folic acid is even recommended for women with PCOS, since it presents with homocysteine metabolism disorder.³ Another ingredient, called Caronisitol Fertility (from Kerry; Tralee, Ireland), which is a patented combination of Myo-inositol and D-chiro inositol (3.6:1 ratio), has been shown in research to support the quality of oocytes and even pregnancy and live birth rate in women with PCOS undergoing in vitro fertilization.^6,7 Kerry's Smith says that approximately 12% of the population has PCOS and most cases go undiagnosed, meaning there is a potential gap in the market. Women with PCOS suffer from a number of symptoms that Caronositol may help address.

"Kerry also offers Caronositol, a purified D-chiro-inositol, for women with PCOS who are suffering from the effects of PCOS with symptoms of hyperinsulinemia and hormonal imbalance, including mood swings, acne and hair growth in unwanted places," explains Smith. "The Caronositol product addresses the deficiency of D-chiro-inositol in women with PCOS and helps to balance hormone levels and regulate menstrual cycles , which does provide support outside of fertility for these women."

The process of trying to get pregnant can be a challenging and emotional one as women get older, but nutritional changes through diet and supplementation may give women the tools to succeed. Even when medical intervention is necessary, dietary supplements may offer the necessary nutritional support to improve the odds.

References

1. Dilmaghani, D.; Ainsworth, A.J.; Nath, K.A.; Garovic, V.D. Decreasing Fertility Rate in the United States: Demographics, Challenges, and Consequences. Mayo Clin Proc. 2024, 99 (11), 1693-1697. DOI: 10.1016/j.mayocp.2024.09.004
2. Pregnancies after 35: Healthy pregnancies, healthy babies. Mayo Clinic. June 7, 2025. https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/pregnancy/art-20045756 (Accessed 2025-11-17).
3. Skoracka, K.; Ratajczak, A.E.; Rychter, A.M.; Dobrowolska, A.; Krela-Kazmierczak, I. Female Fertility and the Nutritional Approach: The Most Essential Aspects. Adv Nutr. 2021, 12 (6), 2372-2386. DOI: 10.1093/advances/nmab068
4. Florou, P.; Anagnostis, P.; Theocharis, P.; Chourdakis, M.; Goulis, D.G. Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? A systematic review and meta-analysis of randomized-controlled trials. J Assist Repod Genet. 2020, 37 (1), 2377-2387. DOI: 10.1007/s10815-020-01906-3
5. Jiang, Y.; Han, Y.; Qiao, P.; Ren, F. Exploring the protective effects of coenzyme Q10 on female fertility. Front Cell Biol. 2025, 13. DOI: 10.3389/fcell.2025.1633166
6. Mendoza,N.; Galan, M.I.; Molina, C.; Mendoza-Tesarik, R.; Conde, C.; Mazheika, M.; Diaz-Ropera, M.P.; Fonolla, J.; et al. High dose of d-chiro-inositol improves oocyte quality in women with polycystic ovary syndrome undergoing ICSI: a randomized controlled trial. Gynecological Endocrinology. 2020, 36 (5), 398–401. DOI: 10.1080/09513590.2019.1681959
7. Mendoza, N.; Diaz-Ropera, M.P.; Aragon, M.; Maldonado, V.; Llaneza, P.; Lorente, J.; Mendoza-Terarik, R.; Maldonado-Lobon, J.; et al. Comparison of the effect of two combinations of myo-inositol and D-chiro-inositol in women with polycystic ovary syndrome undergoing ICSI: a randomized controlled trial. Gynecological Endocrinology. 2019, 35 (8), 695–700. DOI: 10.1080/09513590.2019.1576620