So, what can we tell our patients?
Having trouble conceiving a child is a relatively common problem experienced by one in every six couples.
Factors that affect fertility may be genetic, environmental or behavioural. There are a variety of medical treatments that increase fertility and assist in conception but these can be invasive and expensive. In many cases, focusing on food and nutrition is a simple and effective approach to increase the fertility of men and women.
When giving advice about fertility, diet, body weight and lifestyle, it is important to remember that these may be very sensitive topics for men and women.
Your patients want clear, consistent and non-judgmental advice from someone who they trust. It is important to clarify that no single food or diet has been proven to guarantee pregnancy. However, there are a few dietary approaches that have been shown to be of benefit.
Advice for men: What nutrients are important for fertility?
Food and nutrition affects sperm quality in men. Sperm quality governs how well sperm swim and how readily they are able to fertilise an egg. Spermatogenesis, the 90 day process of developing sperm and increasing sperm count, is affected by nutrition. What a man eats today will determine his sperm quality and quantity in 90 days. Therefore, it is important for men to eat a healthy diet for many months before trying for a baby.
Two nutrients that are essential for healthy and abundant sperm are zinc and folate. Zinc is required for spermatogenesis and sperm motility. Good sources of zinc include oysters and lean red meat as well as nuts, sesame seeds, beans and whole grains. Folate is required for the synthesis of genetic information, or DNA, that is found in sperm. Good sources of folate include fruits and vegetables, particularly green leafy vegetables, and cereal products.
Sperm also need to be protected once they are formed. They are easily damaged by free-radicals that circulate around the body and damage cells. Antioxidants are molecules that can protect against this damage by neutralising the free-radicals. Antioxidants include nutrients such as vitamin C, vitamin E and selenium and a large number of other compounds found in fruits, vegetables and whole grains.
Researchers in the United States found that men who consume higher amounts of folate, zinc and antioxidants (vitamin C and E) from food and supplements produce sperm with less DNA damage. These findings were most pronounced in older men.
Researchers in the Netherlands found that a combined zinc and folate supplement taken under medical supervision increased the sperm count in men. Due to lack of sufficient evidence (i.e. studies with relatively small samples, and/or potential bias that has not been addressed), these findings are yet to be translated into specific recommendations that can be made by health professionals.
So what can we advise men?
Men may enhance their fertility by consuming a balanced diet that includes a variety of fresh foods that contain folate, zinc, and antioxidants.
These foods include lean meat, fruit, vegetables and wholegrain cereals. Preventing cell damage by free-radicals is also important. Heavy-hitters (free-radicals) include cigarettes, substance use, excessive alcohol consumption, pollutants, excess weight and infections.
Advice for women: What nutrients are important for fertility?
Women of a healthy weight have higher fertility rates than those who are underweight or overweight. Significant weight-loss can disrupt the menstrual cycle while excess weight-gain can affect the hormones that regulate ovulation and pregnancy. Therefore, it is recommended that women achieve a healthy weight before they fall pregnant.
In Australia, the Royal Australian and New Zealand College of Obstetrics and Gynaecologists (RANZCOG) recommend that women achieve and maintain a healthy, balanced diet prior to conception. This not only assists with weight management, but with optimal nutrition.
A balanced diet includes a variety of fresh foods such as wholegrain cereals, fruit, vegetables, good sources of protein from lean meat and vegetables, and calcium-rich foods.
Researchers from the Harvard School of Public Health suggest that a well-balanced diet that includes low-GI carbohydrates, monounsaturated fats and protein from predominantly plant sources may increase fertility. Their findings do not guarantee pregnancy but the healthy eating messages can be applied safely and at a low cost.
Women are also advised to take prenatal supplements prior to conception. Recommendations vary between countries.
In Australia, it is recommended that women take at least a 400μg dose of folate at least one month prior to conception and throughout the first trimester for the prevention of neural tube defects (NTDs). A150μg dose of iodine throughout pregnancy and breastfeeding is recommended to prevent hypothyroidism in pregnancy and optimise brain and nervous system development in the foetus.
Additional supplementation may be required in cases of nutritional deficiency, some population sub-groups and restricted diets (more about this next week).
Prenatal supplements will not guarantee pregnancy but they will assist in optimising the nutritional status of women if they do become pregnant.
So, what can we advise women?
Women may enhance their fertility by achieving a healthy weight and consuming a balanced diet that consists of a variety of fresh foods. Prenatal supplements are also important for women considering pregnancy.
Food choices may not solve all fertility problems but it provides a very good start.
Take home messages…
Both men and women can use food and nutrition to increase their fertility.
Men are advised to focus on diet quality as this affects their sperm quality – even months before conception. Foods rich in antioxidants can also protect against sperm damage.
Women are advised to achieve a healthy weight prior to conception in order to regulate the hormones associated with ovulation and pregnancy. A balanced diet will assist with this, as well as optimising nutritional status.
© Monash University 2019. CRICOS No. 00008C