Italian scientists decided to investigate the impact of nutrition on female fertility, which includes the ability to conceive and the effectiveness of assisted reproductive technologies, including in vitro fertilization (IVF). The research findings were published in the journal Reproductive Toxicology.
The Link Between Nutrition and Infertility Risk
According to the World Health Organization (WHO), infertility is defined as the inability to achieve pregnancy after 12 months of unprotected sexual intercourses. An estimated 15-20% of couples worldwide experience this problem.
Researchers have identified diet as an additional modified risk factor that can affect fertility. Abnormal low or high body weight can significantly impact fertility, underscoring the importance of balanced and healthy eating habits. The potential impact of certain dietary patterns, such as the Mediterranean and Western diets, as well as specific foods on infertility, has also been extensively studied.
To consolidate modern knowledge on this issue, scientists have analyzed three main classes of macromolecules: carbohydrates, proteins, and fatty acids.
Carbohydrates
Consuming whole grains instead of refined and sugary products has been linked to a higher frequency of pregnancies and live births. Similarly, a higher intake of vegetables has been shown to improve embryo quality after intracytoplasmic sperm injection (ICSI).
Carbohydrate consumption and metabolism also play a role in regulating ovarian function. Women who consume more carbohydrates are at a greater risk of ovulatory infertility compared to those who consume them moderately.
A diet that contains less than 45% of total energy intake from carbohydrates can help improve the symptoms of polycystic ovary syndrome (PCOS). This is due to its ability to increase follicle-stimulating hormone (FSH) and sex hormone-binding globulin while decreasing testosterone and insulin levels. This correlates with weight loss in patients with PCOS who are overweight or obese.
Similarly, a low-calorie diet where half of the daily calorie intake comes from carbohydrates is beneficial. Infertile women became pregnant more frequently, and the ICSI procedure was more effective in women with obesity and infertility.
Proteins
High intake of animal protein can interfere with ovulation more than plant protein. Replacing just 5% of animal protein with plant protein can significantly reduce the risk of ovulatory disorders by over 50%.
Furthermore, consuming dairy products and soy can improve outcomes during in vitro fertilization (IVF). This may be attributed to the presence of phytoestrogens in soy, which are a type of isoflavone with a structure similar to that of estrogen.
There is fair evidence that animal-based proteins affect female fertility as opposed to those plant-based, suggesting that proteins source may represent an important determinant of reproductive success.
Maria Cristina Budani and Gian Mario Tiboni, “G. Bernabeo” General Hospital, Ortona, Chieti, Italy
Fats
Omega-3 polyunsaturated fatty acids and omega-6 are present in a variety of foods. Omega-3 is commonly found in fish, such as salmon, mackerel, sardines, and tuna, as well as in nuts, seeds, and vegetable oils. Conversely, omega-6, also present in nuts, seeds, and oils, is often found in poultry, fish, and eggs.
There is currently no conclusive evidence on how these fats impact IVF results. However, Omega-3 acids are known to increase the likelihood of pregnancy.
It’s worth noting that consuming fish may lead to higher exposure to persistent organic pollutants, such as methylmercury and dioxins. Likewise, consuming fruits and vegetables may increase the risk of pesticide exposure.
However, the risk associated with the presence of toxic compounds may vary based on several factors. They include the amount of food consumed, the origin month, and the hormonal status of the woman.
Nutrition and fertility – next steps
The risk associated with the presence of these toxicologically active compounds might depend on several factors. Among them are the amount of food consumed, the patients’ ethnicity and hormonal status.
Maria Cristina Budani and Gian Mario Tiboni, also a corresponding author at the Department of Medical, Oral and Biotechnological Sciences, University “G. d′Annunzio” Chieti-Pescara, Italy
Further research is necessary to ascertain the relationship between diet and the influence of chemical substances that disrupt the endocrine system. Moreover, investigations are currently underway to pinpoint the specific targets of the toxic effects. The aim is to gain a better understanding of their impact on reproductive function.
For more information on achieving a balanced diet preparing for pregnancy, please refer to the accompanying material.
