Fertility and diet: What has research found to be the best way to eat?
With a plethora of information about fertility diets available, we have to look a little deeper. This post will answer some of the commonly asked questions, addressing those perceived fertility diet ‘supervillains’ - sugar, gluten and dairy, as well as outline where current research has landed in terms of the ideal way to eat for fertility.
So…. What are your thoughts on dessert?
No one asks directly if they should give up sugar, its more of a subtle “can I have dessert” type scenario.
What’s the big deal?
When we’re talking sugar, we’re really talking about simple carbohydrates. Simple carbohydrates are short chains of glucose joined together. They are broken down easily and quickly. We can compare these to complex carbohydrates which are slower to be broken down and utilised.
When we eat a simple carbohydrate, that carbohydrate is quickly broken down resulting in a rapid increase of glucose in our blood. This glucose spike causes the pancreas to release a hormone called insulin. Insulin encourages the glucose to move out of the blood stream where is damaging to our health, and into our muscles cells to be used as energy, or to be stored as fat to be used at a later point.
The boy who cried wolf
The more glucose spikes we have, the less reactive our response becomes. Our cells start to stop reacting to insulin. This leads to increased sugar in our blood, and further insulin resistance. High blood sugar levels are detrimental on many health fronts – including fertility.
Impaired fertility
Ovulatory dysfunction: As part of the Nurses Health Study, researchers found that women with fertility challenges due to ovulation dysfunction were more likely to eat a diet high in simple carbohydrates than women who didn’t have ovulatory dysfunction. Importantly, quantity of carbohydrate didn’t appear to play a role, the important factor was the type.
Egg quality: Research is quite clear that egg quality is likely to be impacted by high sugar diets. There is plenty of research to support a low sugar diet leading into IVF, findings we can take and apply to conception outside the IVF setting.
Sperm: There appears to a correction between sugar intake and sperm quality. A study from 2012 demonstrated poorer progressive motility was directly correlated with sugar intake in the form of sugary soda drinks, regardless of BMI.
Do I need to give up dairy?
Definitely maybe. The jury is out, and research would suggest the decision to keep or refuse dairy should be made on a case by case basis.
The last almost 3 decades have provided mixed results in terms of fertility and dairy, with some research finding a positive impact and others finding the opposite. This holds true in different conditions.
PCOS: A direct correlation between milk intake and increase risk of PCOS has been determined.
Endometriosis: Studies have found women with higher dairy intake were less likely to have endometriosis.
Sperm health
More conflicting research. High fat dairy products appear to have a negative effect on sperm motility and morpholgy, where as low fat dairy appears to be correlated to higher sperm concentration and motility.
What to do with the problem with dairy?
With up to 75% of the population unable to break down lactose beyond infancy, we need to consider dairy on a case by case basis.
Should I stay away from gluten?
Possibly… probably.
Gluten is a protein found in barely, wheat and rye which acts as a glue to help hold food together.
Coeliac disease and non celiac gluten sensitivity
The evidence is quite clear that the reproductive health of women with coeliac disease is compromised most likely due to nutrient deficiencies, or inflammation. What is not evident is whether these same effects exist for women with non celiac gluten sensitivity, those women who respond to gluten, but don’t suffer the same intestinal damage. Thats not to say that it isn’t damaging in some way, just that at the moment, research doesn’t show a link.
Natural Killer Cells
If you're looking down the barrel of intralipid therapy for NK cells, it might be worth adopting a gluten free diet leading up to the IVF cycle, or concurrently. Research from 2014 found that mice exposed to gluten had an increase in NK cells in terms of presence, toxicity and activity.
Should I leave it?
There doesn’t appear to be any research that gluten is beneficial for fertility for anyone, but certainly damage for certain people. If you are considering dropping gluten it is very important to consider what nutrients you might be missing when you do so.
What does research say I should be eating?
Enter, the Mediterranean diet. Research demonstrates women eating a diet high in fish, vegetables, unsaturated fats and low in sugar, gluten and dairy not only had a lower incidence of requiring help for fertility support, but also a significantly increased chance of IVF success.
How strict do I need to be?
This kind of depends on the circumstance. For the most part, if you’re in the general preconception care space, a little leeway is generally fine. If you’re working toward an IVF round, you have an end date in sight and it might be worth lifting your bar slightly.
Special occasion? Celebrating is good for your soul and a little indulgence is generally fine (FYI - unfortunately, Friday, Saturday and Sunday aren’t special occasions). 100% adherence all the time is just not sustainable and realistically, not fun.
Need more help? Before dropping a food group or making huge dietary changes, it might be worth meeting with a nutritionist to make sure you’re reaching all your nutrition needs.