The Mediterranean diet is always popping up in the news. Most recently, a 2023 study in the Journal of the American Medical Association Internal Medicine, found that 119,315 people who followed the Mediterranean diet over 30+ years had lower rates of dying from heart disease, lung disease, and cancer.1 If it prevents cancer and heart and lung disease, then can it help improve fertility?
What is a Mediterranean Diet?
Let’s dive into what you eat on a Mediterranean diet. The Mediterranean diet is all about fruits, vegetables, whole grains, lentils, fish, nuts, lean meats, and olive oil. These foods are known to provide:
- Higher fiber (from whole grains, lentils, and eating more fruit and vegetables) which can support healthy hormonal balance and lower blood sugar and inflammation levels.
- Higher levels of antioxidants (from eating more fruits and vegetables) which can reduce inflammation and thus protect sperm and eggs from damage as they grow.
- Higher monounsaturated fats (from nuts, seeds, olive oil, and fish) which also helps lower inflammation and support good blood flow to the uterus, ovaries, and testicle.
- Higher lean protein intake (from lean meats, lentils, and fish) provides the protein building blocks needed to make hormones without the saturated fat that can be more inflammatory and again damage precious eggs and sperm.
According to some great studies, eating this way is more beneficial in those trying to conceive. One of the 1st studies to look at the effects of a Mediterranean diet in those dealing with infertility was in the journal Fertility and Sterility back in 2010. In this study they asked people planning an IVF to fill out a questionnaire of what they ate for 4wks before their egg retrieval. They grouped people into either a “health conscious-low processed” diet (where people ate more fruits, vegetables, fish, and whole grains and ate less snacks, meats, and mayonnaise) or “Mediterranean” diet (where people ate more vegetable oils, vegetables, fish, and legumes and less snacks).
Both groups had their eggs removed and fertilized by the sperm being put into the egg (also known as ICSI). 3 days after the retrieval, both groups had either 1 or 2 embryos transferred back into the uterus. When the pregnancy rates from the fresh transfer were compared for the 2 groups, the odds of getting pregnant was 40% higher in those who followed the Mediterranean diet for 1 mo before the retrieval. Both groups had good red blood cell folate levels (important for DNA repair and thus egg quality) and similar blood Vitamin B12 and homocysteine levels. Only those who ate more Mediterranean diet foods showed better Vitamin B6 in both the blood and fluid around the eggs.
Although there was a lot of overlap in the diet, the authors thought one big reason for the increased likelihood to get pregnant in the Mediterranean diet group was thanks to the higher vegetable oil intake.2 Vegetable oils are the base for a group of chemicals in the body called prostaglandins. Prostaglandins play a role in supporting blood flow to the uterus and maintaining receptivity of the uterus. They also thought the higher Vitamin B6 levels could have reduced the risk of losing the baby.
Can a Mediterranean Diet Help During IVF?
The next year a study came out comparing women who went through IVF and followed the Mediterranean diet more and those who followed it less. They didn’t note how long the women ate that way or exact details on what they ate. They found that regardless of how much they adhered to the diet they had roughly the same pregnancy rates with fresh transfers, but the women who ate more Mediterranean diet items had more eggs that fertilized and had more embryos.
The authors thought those eating a greater amount of Mediterranean diet foods, specifically more fruit and vegetables, could have better folate levels and antioxidant levels and that could have resulted in better egg quality and thus a slight bump in the number of embryos.3
In addition to these IVF specific studies, there are a number of studies looking at how sperm might benefit from a Mediterranean diet. In 2017, the journal Human Reproduction found that when less Mediterranean Diet foods were eaten there was 2.6% increase in the likelihood for the sperm to be abnormally shaped, move less, and to see a lower number of sperm. In that study they concluded that the greater the intake of, specifically, vegetables, legumes, fruits, nuts, whole grains, and fish the more likely we are to find healthier sperm. These foods are beneficial because they can lower inflammation and oxidative stress meaning less damage done to sperm as they develop. 4
One critique to these studies would be not comparing those following a Mediterranean diets against individuals eating:
- higher saturated meats (such as beef and pork)
- more sugary and processed foods
- drinking more coffee
- drinking more alcohol
- not eating many fruits or vegetables
- eating large amounts of dairy
If researchers did a study comparing those 2 diets, then we might see even better odds of the Mediterranean diet leading to a greater number of eggs retrieved, a greater number of eggs being fertilized, more embryos created, a higher amount of quality sperm, more pregnancies, and more babies being born.
Another issue is that it was not clear in these studies how much emphasis was placed specifically on monounsaturated fat intake from olive oil. In non-fertility Mediterranean diet studies olive oil has been a key component of the diet’s success. The 2010 Fertility and Sterility study suggested the higher vegetable oil intake in the Mediterranean diet group was a reason for increased pregnancy rates, but even they didn’t go into details on if it was specifically olive oil or the amount.
We also might see more benefits from the Mediterranean diet if the people in the studies were given examples of Mediterranean foods to eat, told to eat those foods over 3mo for sperm support or 4mo for egg support, and met regularly with a nutritionist over those timelines to ensure they were eating the targets per each food group.
Ensuring people understand what specific foods to eat, how often and how much to eat in each food group, and knowing to eat that way over the window of time it takes for sperm and eggs to grow is a big focus of our work at Conceive Health.
Is the Mediterranean Right for You?
The Mediterranean diet is a good starting place for individuals who are looking at ways to increase their odds of conceiving. That being said, our bodies are all different. Working with a professional who knows what diet is best for your body or tweaking the Mediterranean diet to fit your needs is going to be even more effective.
For example with patients with endometriosis, a Naturopathic Doctor would use similar building blocks as the Mediterranean diet. We’d just work harder on avoiding butter, saturated fats, soy, red meats, and possibly gluten.5 Likely, we would all benefit from eating the items listed in the Mediterranean diet and even more if we work with a knowledgeable practitioner who can provide us with additional diet advice that is specific to our needs.
References
- Shan, Z., Wang, F., Li, Y., Baden, M. Y., Bhupathiraju, S. N., Wang, D. D., Sun, Q., Rexrode, K. M., Rimm, E. B., Qi, L., Tabung, F. K., Giovannucci, E. L., Willett, W. C., Manson, J. E., Qi, Q., & Hu, F. B. (2023). Healthy Eating Patterns and Risk of Total and Cause-Specific Mortality. JAMA internal medicine, 10.1001/jamainternmed.2022.6117. Advance online publication. https://doi.org/10.1001/jamainternmed.2022.6117
- Vujkovic, M., de Vries, J. H., Lindemans, J., Macklon, N. S., van der Spek, P. J., Steegers, E. A., & Steegers-Theunissen, R. P. (2010). The preconception Mediterranean dietary pattern in couples undergoing in vitro fertilization/intracytoplasmic sperm injection treatment increases the chance of pregnancy. Fertility and sterility, 94(6), 2096–2101. https://doi.org/10.1016/j.fertnstert.2009.12.079
- Toledo, E., Lopez-del Burgo, C., Ruiz-Zambrana, A., Donazar, M., Navarro-Blasco, I., Martínez-González, M. A., & de Irala, J. (2011). Dietary patterns and difficulty conceiving: a nested case-control study. Fertility and sterility, 96(5), 1149–1153. https://doi.org/10.1016/j.fertnstert.2011.08.034
- Karayiannis, D., Kontogianni, M. D., Mendorou, C., Douka, L., Mastrominas, M., & Yiannakouris, N. (2017). Association between adherence to the Mediterranean diet and semen quality parameters in male partners of couples attempting fertility. Human reproduction (Oxford, England), 32(1), 215–222. https://doi.org/10.1093/humrep/dew288
- Arab, A., Karimi, E., Vingrys, K., Kelishadi, M. R., Mehrabani, S., & Askari, G. (2022). Food groups and nutrients consumption and risk of endometriosis: a systematic review and meta-analysis of observational studies. Nutrition journal, 21(1), 58. https://doi.org/10.1186/s12937-022-00812-x
