There is so much misinformation out there about how to optimise fertility, which at best can be confusing, and at worst can negatively affect your chances of conceiving.
But evidence-based information is available that can help both men and women optimise egg and sperm quality, as well as helping to increase endometrial tissue thickness and the chance of implantation (where a fertilised egg attaches to the wall of the uterus at the start of pregnancy).
Making positive diet and lifestyle changes during the preconception period – ideally a minimum of three months before you try to conceive – is so important as there are many things that can negatively and positively affect fertility.
Nutrition is key too. Here’s what you need to know about how diet and fertility are interlinked.
1. Eating lots of meat may impact fertility
Certain components of animal products can negatively impact fertility. These include haem (animal-based) iron, saturated and trans fats, and advanced glycation end products (AGEs).
These negative effects result from them inducing oxidative stress, which can damage sperm and egg cells as well as the DNA within the cells.
They also result from the inflammation caused by AGEs attaching to receptors throughout the reproductive tract, which can affect implantation by preventing the embryo from burying into the lining.
The most impactful dietary change that can be made to improve both male and female fertility is to minimise consumption of animal products, especially meat, and increase intake of plant foods.
But if you do it’s important to supplement B12 and iodine, two important micronutrients for fertility and general health.
Some simple meat swaps you might want to try include:
- Substituting mince in spaghetti bolognese and cottage pie for lentils, and in swapping it in a chilli for mixed beans.
- Swapping ham in a sandwich for thinly cut slices of smoked tofu and adding crispy lettuce and tomatoes.
- Using tofu rather than chicken in a stir fry and packing it full of a variety of different coloured vegetables.
If you’re not quite ready to eliminate meat entirely, changing your cooking method can significantly decrease the amount of AGEs that form.
This means introducing moisture to cooking to prevent the brown layer from forming on the meat – so techniques like slow cooking, casseroling or poaching.
Changing the acidity can also help and this can be achieved by marinading in lemon juice or vinegar.
Clinical studies have shown that adopting such strategies is associated with up to a 50% reduction in the AGEs content of the diet.
2. A colourful plant-based diet can aid fertility (and general health)
This type of diet provides a range of phytonutrients, including polyphenols found in foods such as herbs and spices, fruits, vegetables and soya.
These exert anti-inflammatory, anti-microbial and anti-oxidant effects on our cells which is beneficial to fertility and also to general health.
Aim for 30 different plant foods (30 plant points) a week – this is so easily achievable if you are aiming for vegetables with every meal, choosing fruit as a regular snack choice, including legumes weekly and ensuring each meal contains a carbohydrate source with preference given to whole grains.
You can also rack up your plant points by using a variety of herbs and spices, but remember that each tsp of herbs and spices equates to ¼ of a plant point rather than a whole one.
3. Some micronutrients can help improve egg and sperm quality
There are many micronutrients that are important for improving egg and sperm quality and these include vitamin C and E, zinc, selenium and non-haem (plant-based) iron.
It is important to aim for a diverse plant-based diet, ensuring daily intakes of fruits, vegetables, legumes, whole grains and minimally-processed protein sources. Regarding the latter, soya products such as tofu and edamame beans are an excellent choice.
Soya is often feared by those trying to conceive and by men who fear it will reduce testosterone levels. The science clearly shows this is not the case and studies have found positive associations between soya intake and improved fertility and fertility treatment outcomes.
4. A diet high in nitrate-rich fruits and vegetables can reduce the risk of sexual dysfunction
For both men and women, a diet high in nitrate-rich fruits and vegetables is important as these are a source of nitric oxide (NO), which plays a role in the relaxation and erection of the smooth muscle tissue in the penis and also helps to dilate blood vessels.
This reduces the risk of high blood pressure and enables good blood flow to organs, including the penis and vagina. So nitrate-rich foods can reduce the risk of sexual dysfunction.
To add more of these foods into the diet, blueberries and pomegranate seeds can be added onto breakfast cereal/oats, eaten as a snack, or sprinkled over peanut butter on toast.
Leafy greens such as kale, spinach, broccoli and cauliflower are also a rich source so including a variety of these in the diet is important.
It is also a good idea to include walnuts regularly in the diet and these are also a source of omega 3. Walnuts can be crunched on top of breakfast cereals/oats, used as an alternative to pine nuts in a homemade pesto or sprinkled over a pasta dish to add some crunch.
They can also be used to make an incredible curry, and are great as a snack – simply cut a date in half lengthways and stuff with a little nut butter and a walnut half.
5. A high fibre diet can help manage hormone-driven conditions like PCOS and endometriosis
Fibre binds with excess hormones that are filtered out of the body by the liver and enables them to be removed in the faeces. This helps to manage hormone imbalances.
Fibre can also help prevent spikes in blood glucose levels and insulin which is especially important for those with PCOS, as there is an increased risk of insulin resistance and type 2 diabetes.
Finally, fibre helps with fullness and satisfaction after a meal which can help manage weight.
Here are some great ways to add in more fibre to the diet:
- Choose oats for breakfast – these can be eaten as hot porridge during the winter months and as overnight oats during the summer months. You can add an array of toppings to boost the nutritional profile of your breakfast. These can include nuts, seeds, nut butters, tahini and mixed fruits.
- Make a homemade smoothie – unlike juices where the fibre is removed from the fruit and vegetables, smoothies retain the fibre.
- Favour whole grains. Refined sources of carbohydrates should not be demonised but choosing whole grains for the majority of your meals will really pack that fibre in. These include brown, red or black rice and whole wheat pasta, as well as quinoa and buckwheat.
6. Dietary fats are beneficial for fertility
For men, polyunsaturated fatty acids (PUFAs) are important and these are most commonly known as omega fatty acids.
Sperm is predominantly made up of PUFAs so it makes sense to ensure good dietary intake. Studies have shown PUFAs may improve sperm count, concentration, motility, structure and reduce DNA damage.
Dietary sources include chia, flax and hemp seeds, walnuts and soya foods but it may also be beneficial to take a daily omega 3 algae supplement of around 450mg.
If you eat fish, this can be achieved by eating one portion of oily fish a week and one non-oily fish. However, it is important to note that fish get their omega 3s from algae, so an algae supplement is going straight to the original source.
For women, monounsaturated (MUFAs) fatty acids are important for improving ovulatory infertility and reducing the risk of pre-term delivery. Food sources include avocados, nuts and seeds and vegetable oils.
Lisa Simon is a registered dietician and author of The Plant-Based Dietitian’s Guide to Fertility. She splits her time working in the NHS as dietetic lead in child and adolescent mental health, and at Plant Based Health Online, where she runs individual and group consultations and delivers educational webinars.