How can nutrition help combat infertility?

Did you know that, worldwide, around 1 in 6 people have suffered from infertility at some point in their lives? (1) 

But what exactly is infertility? According to the World Health Organization (WHO), infertility is the inability to conceive after at least one year of unprotected sexual intercourse. (2) 

Infertility can be primary or secondary. Primary infertility occurs when a couple has never achieved pregnancy, and secondary infertility occurs when there has been at least one previous pregnancy. (2) 

Causes of infertility: (3)  

Causes of male infertility: (3)  

Causes of female infertility: 

Female fertility begins to decline from the age of 25-30, due to the progressive reduction in ovarian reserve and oocyte quality. In addition to age, several lifestyle factors have a significant influence on female fertility: (3,4)  

Factors affecting fertility: (4,5,6)  

Unbalanced diets, whether restrictive or excessive in calories, negatively affect ovarian function. Body mass index (BMI) below 19 or above 25 kg/m² is associated with lower conception rates and a higher risk of pregnancy complications. Obesity, in particular, compromises ovulation and increases rates of spontaneous abortion. 

Eating disorders such as anorexia and bulimia can lead to amenorrhea and infertility, as malnutrition directly interferes with oocyte maturation and hormonal cycles. 

Obesity is strongly associated with insulin resistance, which in turn induces hyperandrogenism and ovulatory dysfunction. PCOS, which affects up to 20% of women of reproductive age, is characterised by anovulation, hyperandrogenism, and polycystic ovaries. Insulin resistance plays a central role in the pathophysiology of PCOS, and its treatment involves strategies such as weight loss, metformin, and low-carbohydrate diets. 

Metabolic syndrome (MS) combines obesity, dyslipidaemia, hypertension, and insulin resistance, negatively impacting the reproductive hormonal axis. Women with MS have changes in LH and FSH pulses and a higher risk of amenorrhea and anovulation. Therapeutic strategies aimed at normalising insulin homeostasis, such as lifestyle changes and bariatric surgery, have been shown to be effective in restoring fertility.   

Smoking negatively affects fertility in both sexes, reducing ovarian reserve and the success rate of medically assisted reproduction, in addition to compromising male sperm quality. A meta-analysis involving more than 30,000 women showed that women who smoke have a significantly higher risk of infertility compared to non-smokers. In addition, women who smoke tend to enter menopause 1 to 4 years earlier, which indicates an acceleration in follicular depletion. Smoking is also associated with an increased risk of miscarriage, both in natural pregnancies and in assisted reproduction cycles.  

Excessive alcohol consumption is associated with nutritional disorders and possible pregnancy loss, although the direct effects on female fertility are not yet fully understood. Caffeine, on the other hand, has a dose-dependent relationship with increased time to conception and risk of miscarriage. 

The most common toxins are pesticides and industrial compounds. These toxins act as endocrine disruptors, negatively impacting the endocrine and reproductive systems. Prolonged exposure to heavy metals and pesticides can affect fertility and increase the risk of recurrent miscarriages.  

High levels of stress have been linked to infertility, especially when accompanied by anxiety and depression. Some studies show that stress management can significantly improve fertility treatment outcomes. 

The relative risk of infertility increasing with the use of illegal substances is 40%.  

There are also medications and treatments, such as chemotherapy, that can affect fertility. 

Importance of diet 

Studies indicate that dietary patterns, when considered as a whole and not just in terms of isolated nutrients, have a major influence on the development of fertility disorders. The Mediterranean diet appears to offer the most benefits in terms of improving fertility. (7) 

To improve sperm quality, there are some foods that should be prioritised and others that should be avoided: (8)  

It is also known that supplementation with certain nutrients (zinc, coenzyme Q10, omega-3, selenium, L-carnitine and L-acetyl-carnitine) can help improve sperm quality, although the need for and dosage of these supplements should be assessed by a healthcare professional specialized in this area. (9) 

In the case of women, to optimise ovulation, it is recommended to:  

Conclusion   

Infertility is a multifactorial challenge that affects millions of people worldwide, but the good news is that some of the factors that influence it are directly linked to lifestyle and, in particular, diet.   

A balanced eating pattern, such as the Mediterranean diet, can play a key role in hormone regulation, ovulation and sperm quality. Adopting a conscious diet, combined with reducing toxins, managing stress and regular physical exercise, represents a powerful approach to promoting fertility in both men and women. In addition, when assisted fertilisation is necessary, optimising nutrition can significantly improve results. 

Incorporating practical, healthy, and nutrient-rich snacks is an excellent strategy for those who want to take care of their reproductive health in a simple way on a daily basis. Here are some suggestions for snacks that can be good allies in this process: 

Bibliography: 

Author:

Sofia Silva 5784N