24/10/2023 - 4 min read
Can nutrition influence IVF outcome?
It is well known that some of the poorest parts of the world, where nutritional levels are low, also have very high birth rates. By contrast, the majority of IVF cycles take place in countries with a much higher per capita income and which could be assumed to have much better nutrition. There is a bewildering array of dietary theories around today and the pronouncements of ‘experts’ seem to change on an almost daily basis.
Take eggs for example. I remember the ‘Go to work on an egg’ campaign which portrayed eggs as the perfect breakfast food: high in protein and low in calories. Then eggs were found to be full of ‘dangerous cholesterol’ and people were told they could only eat the white but not the yolk (the tasty bit!). Now eggs are back in foodie fashion again!
Some nutritionists take the view that all food is just basically fuel and whether the calories come from protein, fat or carbohydrate doesn’t really matter so long as the total number (2000kcal a day for an average active young woman) isn’t exceeded.
But some interesting research in America suggests that for IVF patients at least, it really might matter where the calories come from!
A clinic in California identified a group of IVF patients who weren’t doing as well as expected. They were young, normal BMI and normal ovarian reserve but this group didn’t respond so well to the drugs; got fewer eggs, lower numbers of top quality embryos and fewer positive pregnancy tests. Those that did get pregnant had a higher miscarriage rate. So what was going wrong? The team asked them to keep a ‘food diary’ and found that although they were having the right number of calories per day (about 2000kcals is perfect for active young women), almost all their calories were coming from carbohydrates. They would have cereal and toast for breakfast, a sandwich for lunch, pasta for supper and their favourite snacks were crisps and biscuits. Over 75% of their daily calories were Carbs!
The ‘food diaries’ of the ‘normally’ successful group were very different: they had more protein and lots of leafy vegetables and fruit. Their live birth rates were almost double those of the ‘high carb’ patients.
When PCOS patients (who may need help with weight loss) have followed a ‘low-carb’ plan they often found that the ‘low carb’ eating plan assisted their efforts to shed those stubborn pounds. This is not too surprising as part of the problem that PCOS women face (and the reason why they are five times more likely to develop Type 2 Diabetes) is that they don’t handle sugar properly. We then started recommending it for all patients (and encouraged their partners to join in as over-weight and obesity has been shown to reduce sperm quality too).
The ‘sperm cycle’ is about 70 days so it takes over 2 months to see the benefit of lifestyle changes on the chaps’ sperm function. In just the same way, dietary and nutritional changes for women need to be started 2-3 months before a treatment cycle as the eggs we will be collecting for IVF or ICSI actually started developing 3 months before she even starts her treatment cycle drugs.
This sort of Fertility Nutrition plan we have been advocating has now been given a huge boost by the publication of a paper in Human Reproduction, one of the world’s leading fertility journals, which claims that a ‘Mediterranean diet’ may help young women receiving IVF to boost their chances of achieving successful pregnancies.
The researchers, from a University in Athens, Greece, asked women about their diet before they underwent an IVF treatment and found that those who ate more fresh vegetables, fruit, whole grains, legumes, fish and olive oil and less red meat and simple carbohydrates had an almost doubled live birth rate compared to young women who ate the ‘poorest’ diet. The effect was not so clear for women aged over 35 years where other factors can influence IVF outcome.
Half of all women in the UK having IVF are 35 or under so wider knowledge about the role of good nutrition for fertility is absolutely vital.