While soy is praised for its high protein content and heart-healthy benefits, some studies suggest that its effects on reproductive health warrant closer scrutiny.

The primary concern centres around phytoestrogens, plant compounds found in soy that mimic the hormone oestrogen in the body. These compounds, particularly isoflavones (found in fruits, vegetables, chocolate, wine, and tea), have been studied for their potential to influence hormonal balance.

Some research suggests that high levels of phytoestrogens could interfere with natural oestrogen and testosterone levels, potentially affecting fertility in both men and women.

In women, the consumption of soy products has been linked to changes in menstrual cycle length and hormone levels.

For example, a study published in the Journal of Nutrition found that a high intake of soy isoflavones was associated with longer menstrual cycles and reduced levels of luteinising hormone, which plays a crucial role in ovulation. However, these effects are typically mild and vary widely among individuals.

Many men are worried about the effects of soy on their testosterone levels and sperm quality. Some studies on animals have indicated that high doses of soy isoflavones might reduce sperm count and motility. However, human studies have produced mixed results.

A review published in Fertility and Sterility found that regular intake of soy isoflavones through diet does not significantly impact testosterone levels or semen quality in men.

It is important to note that most studies indicate that moderate soy consumption does not adversely affect fertility. The key appears to be moderation and individual sensitivity. For most people, including soy as part of a balanced diet is unlikely to pose significant reproductive risks.

For those planning to conceive, it might be beneficial to diversify protein sources and maintain a well-rounded diet to support overall reproductive health.