Having a healthy body mass index (BMI) is important for fertility. Although it is currently not recommended that you try for a baby due to the coronavirus outbreak, you can use this time to get all the information you need and make positive steps to improve your fertility health for the future when the pandemic comes to an end.
Angela Attwood is a Nutritional Therapist specialising in nutrition for hormonal health, fertility and pregnancy. Up until the recent shutdown, Angela had been providing sessions at Bourn Hall’s Wickford clinic, advising people about how their diet might be affecting their fertility.
She is often asked in these sessions about how to reduce body mass index (BMI) to help conception, so in this guest blog she answers some of the frequently asked questions about nutrition and fertility.
What is BMI and how does it affect fertility?
A woman’s fertility can be directly affected by her Body Mass Index (BMI) – so if you are trying to get pregnant naturally this is one of the first things you should investigate.
BMI is calculated by dividing an adult’s weight by the square of their height; to make this easier the NHS website has an easy-to-use BMI calculator.
The NHS regards a ‘healthy BMI’ for adults as being between 18.5 and 24.9.
To maximise the chance of natural conception and a healthy pregnancy it is recommended by the National Institute for Health and Care Excellence (NICE) that couples have a BMI of 19-30, so this is the ‘magic number’ if you are wanting to be referred by NHS funded IVF (if you are funding your own treatment you may be accepted with a slightly higher BMI).
The good news is that we have found that losing weight can help to stimulate ovulation (egg production) for many women with a previously high BMI and irregular or no periods.
For some this can result in a natural pregnancy and for others it improves the chances of success with ovulation induction (OI) or IVF treatment.
As a nation we have become heavier, and forty five per cent of Bourn Hall patients now have a BMI of more than 25. Encouraging, however, is recent research at Bourn Hall that has shown that IVF success rates can be improved for women with a BMI of 25-30 through a personalised approach and careful selection of most appropriate drug regime.
I have been advised to reduce my BMI to improve fertility. Can you offer a few tips that seem to work for the people you speak to?
Certain medical conditions can make it more difficult for some women to lose weight than others. For example, insulin resistance affects a person’s metabolism and is linked to a number of health disorders such as diabetes, heart disease, obesity and polycystic ovary syndrome (PCOS).
Specialist dieticians and nutritionalists can give personalised advice, but as a general rule the most effective way of reducing BMI is to ensure that you have a healthy intake of protein and whole unprocessed foods that are high in fibre and healthy fats.
These foods will help to balance blood sugar, so reduce the amount of insulin required. It also helps to reduce cravings for higher calorie foods.
Some other tips are:
- Reducing intake at meal times by using a smaller plate is an easy way to reduce calorie intake without feeling deprived.
- Ensuring a 12 hour overnight fast and allowing 4-5 hours between meals is also a great way to reduce calorie intake.
- Keeping well hydrated can also really help to reduce cravings as well as having many other health benefits.
- Exercise is also key to reducing BMI and doesn’t have to be high impact – walking is one of the most beneficial forms of exercise you can do.
These tips also have the added health benefits of improving sleep and digestive system health, and reducing stress and anxiety, which may improve hormone balance – all really useful benefits for someone preparing for IVF.
However, our relationship with food is complex, and often there are emotional issues associated with weight, so as a Nutritional Therapist I also take the individual into consideration and work with them to reduce their BMI in a way that is going to work for them.
Is there any evidence that good nutrition boosts sperm quality?
Most research on sperm quality focuses on individual nutrients, of which many, such as zinc, vitamin D and vitamin E, amongst others, have been suggested as important in improving sperm quality.
Can people get the vitamins and minerals they need from their diet and when do you think nutritional supplement have their place?
Nutrition has a lot to offer any couple encountering fertility issues, whether it is to address any underlying health issues or to ensure you have covered off every aspect of your health that is under your control to give yourself the best chance of conceiving naturally or via IVF. Dietary changes can have a huge impact and often people have an imbalance in their macronutrient intake (good fats, carbohydrates, protein and water) which really affects their health, and these have to be included in our diet.
Nutritional supplements have their place – for instance if a patient has a vitamin D deficiency. Antioxidants as supplements may be indicated in men with sperm DNA damage and omega 3 fatty acids also have a significant role in fertility as well as general health since we have to get them from the diet and many individuals do not eat oily fish or sufficient oily fish. It really isn’t one size fits all, but about individual nutritional needs, and this will be affected by people’s lifestyle, any medication they may be on and any hormonal or health issues they have such as endometriosis, PCOS or digestive issues.