Optimising fertility with a plant-based diet
Does eating a vegan diet benefit those trying for a baby? By Lisa Simon
Infertility has been defined by the World Health Organisation as 'a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular, unprotected sexual intercourse.'
Infertility affects up to one-in-seven couples in the UK, with 50 per cent of cases now due to male infertility, 40 per cent of which is thought to be attributed to diet and lifestyle factors. It is for this reason that it is vital to include men in the conversation, and to highlight that positive diet and lifestyle changes can help to optimise sperm health and chances of conception.
The process of developing sperm and increasing sperm count takes around ninety days, and the process of egg maturation is comparable. Therefore, it is important for both sexes to make diet and lifestyle changes at least three months prior to trying to conceive.
There are specific nutrients in a plant-based diet which are important for both egg and sperm health. Zinc plays a role in hormone balance and ovulation in women, and is needed in the process of spermatogenesis (making new sperm) and for sperm motility.
Men's zinc requirements are slightly higher than women's as they lose zinc in each ejaculation. A useful way to increase zinc intake is by including a portion of mixed seeds daily, for example sprinkled over breakfast, added to a smoothie, or as a crunchy topping to a pasta dish.
Folate is important for oocyte (the immature egg) quality and maturation as it lowers levels of a common amino acid in the blood, mainly derived from meat, that is associated with stress and inflammation.
Acute inflammation is a normal process that occurs in our bodies, for example, in response to injury, infection and during a woman's menstrual cycle. However, when inflammation goes beyond the acute stage and becomes chronic, it can affect ovulation, hormone production, and egg and sperm quality.
Folate is important for men as it is needed to synthesis DNA in sperm, however, unlike women who should take a folic acid supplement in addition to dietary folate, men should be encouraged to increase their dietary intake rather than take a supplement. Rich sources include leafy green vegetables, whole grains and legumes (Review: Human Reproduction Update).
Once the sperm has been formed, it can be easily damaged and needs protecting. This can be achieved by eating a diet rich in antioxidants such as vitamin C and E, carotenoids (lycopene, beta carotene) and the mineral, selenium. Vitamin C and carotenoids are found in fruits and vegetables, especially those with red, yellow and orange pigments such as sweet potato, carrots, tomatoes and peppers, as well as in dark green leafy vegetables.
Just one-two Brazil nuts daily will enable you to meet your selenium requirements, and this is also an important nutrient in terms of female fertility and aiding implantation. Vitamin E can be found in foods such as avocadoes, olive oil and almonds.
Animal fats and processed foods
Western diets high in animal and highly processed foods, as well as sugary drinks, are high in advanced glycation end products (AGEs). These promote chronic inflammation and may exacerbate polycystic ovarian syndrome (PCOS), affect fertility and even prevent a fertilised egg from implanting due to inflammation in the uterus (Journal of Obstetric, Gynecologic and Neonatal Nursing).
They can also induce early ovarian aging if they accumulate around the ovarian follicle. Plant-based diets, however, are generally low in dietary AGEs, and also contain nutrients shown to support implantation, specifically vitamins C, E and B6, and selenium. These nutrients can be found in foods such as whole grains, avocados, nuts, soya, and beetroot.
A large study which followed 116,000 women showed that higher rates of fertility are associated with diets rich in unsaturated fats from foods such as avocados, nuts and olive oil, vegetable protein rather than animal protein, and wholegrains, such as quinoa, whole wheat pasta and brown rice.
In men, saturated fats, predominantly found in animal products but also in coconut and palm oil, negatively affect sperm quality. However, polyunsaturated fats from foods such as sunflower seeds, walnuts and flaxseeds improve sperm quality, quantity and production.
The same data suggests that women who eat larger amounts of non-haem iron (vegetarian sources) are at decreased risk of ovulatory infertility (American Journal of Obstetric Gynecology) and this is likely due to the inflammatory effect of haem iron (animal sources). Some examples of non-haem iron include tofu (comparable to red meat), nuts, seeds, beans, lentils, chickpeas and dried fruit.
It is important to consume vitamin C alongside these foods to help your body absorb the iron and to avoid drinking tea, coffee, cocoa and red wine with meals as these reduce absorption. Calcium supplements, if prescribed by a Dr, should be avoided around mealtimes.
Aiming to maintain a healthy weight is important for individuals and couples, as being under or overweight can affect fertility (nhs.uk). Plant-based diets have been shown to aid weight loss and maintenance, and improve blood fat levels, among other health benefits.
Reasons for this include a reduction in saturated fat and total energy intake and an increase in dietary fibre which helps regulate appetite and prevents overeating. In addition, the fibre in plants binds with both cholesterol and excess hormones in the intestines and helps remove them from the body, thus helping to maintain hormonal balance.
For those trying to gain weight healthfully, a plant-based diet contains a wide range of foods high in predominantly unsaturated fats which can be increased to offer useful calories. Some ways in which to incorporate these foods includes adding ground flax/hemp, and/or whole chia seeds to overnight oats/porridge/smoothies, drizzling tahini or extra virgin olive oil over roasted veg, including a portion of mixed nuts as a snack, or stuffing dates with nut butter and walnut halves.
In summary, a plant-based diet provides a wide range of nutrients important for both partners sexual health. There are certain nutrients, including iodine, B12 and vitamin D which will need to be supplemented, however this is not just exclusive to those following a vegan diet. Each individual and couple are different and tailored advice is vital, and of course there are other considerations, including environmental factors, stress, sleep and exercise. If you are struggling to conceive and would like advice and support you can contact me via our website in my bio.