Are there any supplements or dietary changes that might improve my fertility?
This is a huge topic that has been widely studied and debated, so I’ll present a digestible summary of the most recent research.
Malnutrition is associated with delayed menarche (onset of periods) while obesity is associated with an early menarche. Weights on either side of the standard 'healthy' range (BMI less than 18 or greater than 25) are both, through differing mechanisms, associated with ovulatory dysfunction (OD) and infertility.
Diet Composition (What you eat)
The following foods and nutrients have been found to affect fertility in clinical trials:
- Polyunsaturated fats appear to have a beneficial effect on fertility, while trans fats are associated with OD, because they increase insulin resistance, which is damaging to fertility.[i]
- Low GI carbohydrates are better for ovulatory function than High GI, but the total amount of carbohydrates eaten should be low.
- Increased dietary protein with no calorie restriction has been shown to improve weight loss and glucose metabolism, both of which are associated with good ovulatory function.
- The type of protein consumed also appears to be significant. Studies have shown that diets rich in animal protein are associated with OD, and that by switching as little as 5% of an individual's diet from animal-based foods to plant-based foods, OD related infertility can be reduced by 50%[ii].
- The dairy content of diets has also been studied, but data remains inconsistent. However there is a general agreement within the literature that low fat dairy products are associated with OD.
- Folate deficiency also seems to negatively affect fertility, and folate supplementation has been linked to improved egg quality and numbers in IVF treatment cycles.
"The Fertility Diet"
By taking this kind of information and applying it to a large group of women, investigators have come up with what has been termed “The Fertility Diet”. The key study in this area[iii] showed that the following dietary features were associated with a 69% reduction in OD related fertility:
- Higher protein consumption
- More plant (rather than animal) protein
- Higher monounsaturated fats
- Lower trans fats
- Higher full fat dairy and reduced low fat dairy
- An overall low carb (particularly sugar) intake
These findings have been supported by similar findings looking at other cohorts of women, and the evidence is generally regarded as strong.
What does this diet look like in practice?
- Very brown bread such as soy and linseed bread (low GI and rich in monounsaturated fats)
- Olive oil
- Fish and poultry instead of beef (healthier protein source)
- Full fat milk
- More vegetables than you’re used to, particularly avocado (rich in folic acid)
- Nuts (rich source of plant protein).
Things to avoid:
- Fast food
- Refined carbohydrates
- Excessive (more than the recommended daily intake) Vitamin A.
[i] It is interesting to note that the FDA (Food and Drug Administration) in the USA have recently moved to ban trans fats completely – hopefully Australia won’t be far behind!
[ii] It is suspected that the mechanism for this effect could be related to hormone residues in beef, as cattle are treated with anabolic steroids for the last 60-90 days before slaughter to increase their size in Australia, New Zealand and the USA, a practice that is banned in the EU.
[iii] This study, known as The Nurse’s Health Study, analysed the diets of 116,000 female American nurses who were enrolled in the study. This has so far been the most important study of its kind, with most of those studies that followed merely supporting the claims that had already been made.