Dietary interventions and fertility outcomes have been a point of interest for many years. New research, published on 30 January 2018 in the Human Reproduction journal (a monthly publication of the European Society of Human Reproduction and Embryology / ESHRE) (1) looks at the association again and finds that women who adopt a Mediterranean diet at least 6 months prior to an IVF (or assisted reproductive) treatment appear to have a greater chance of achieving pregnancy, and giving birth to a healthy new bundle of joy… more so than women who have alternate eating habits.
ESHRE, published by Oxford Journals (a division of Oxford University Press), is regarded as one of the top journals for those who specialise in reproductive biology, gynaecology and obstetrics across the globe.
The latest study, creating a little bit of buzz at the moment, appears to have focussed more on dietary patterns than specific nutrients, foodstuffs or food groups. The general findings appear to show that a diet that is plentiful of whole grains, fresh fruit and vegetables, olive oil, fish and legumes … basically, the Mediterranean diet, contributes to a 65% - 68% pregnancy and birth success rate.
This study is just one of many that have been conducted along similar lines, reaching much the same conclusion. One example is an observational prospective study conducted in 2010 which looked at the associations between dietary patterns (before assisted reproductive treatment) and the outcomes of IVF or ICSI (intracytoplasmic sperm injection) in 161 couples. For women, one of the dietary patterns which showed a high adherence rate boosting the odds of pregnancy success was the MedDiet. Overall, this study concluded that a preconception Mediterranean diet adopted by both partners could contribute to a better chance of fertility treatment success. (2)
What is the Mediterranean diet?
The diet varies slightly from one country or region to the next, but the general dietary patterns incorporate the traditional munching habits of populations bordering the Mediterranean Sea – Italy, Spain, France and Greece.
The diet is traditionally high in legumes, nuts, beans, whole grains, cereals, fresh fruit and vegetables, fish, chicken and olive oil. Intake of red meat and dairy is typically low. Processed foods and refined sugars are also consumed at lower intake ratios than those found in other parts of the world. The odd glass of wine does not go amiss with this diet either and is largely consumed in moderation (often with a meal).
This unique combination of food types makes the diet one that is regarded as highly ‘heart healthy’ with benefits that extend throughout the body. Risk factors for conditions like diabetes, heart disease, renal or kidney disease and breast cancer are considered to be low in individuals who follow it.
Whole, plant-based foods are generally healthier choices to include in any diet, with many of these foods having antioxidant and anti-inflammatory properties – ingredients which are crucial to lowering disease development risk factors. Many would argue that the Mediterranean diet is so healthy, it’s a sure-fire way to extend your lifespan. It’s not entirely a low-fat diet but it does seem to tick the boxes when it comes to keeping cholesterol levels within a healthy range and contributes to maintaining a good weight.
Healthy helpings of fresh fruit and vegetables are key to this diet. The more colourful the better. Leafy greens, and lots of red, orange and yellow fruits and veggies ensure that the body receives plenty phytochemicals and other essential nutrients.
When it comes to fats, the healthier varieties are encouraged in the correct proportions (swopping out butter and margarine for olive oil), and the same goes for starches. If you’re going to tuck into a pasta dish, whole grain varieties are the preferred option.
Lean proteins, eggs, cheese and plain yoghurt also feature, all washed down with plenty of water. The Mediterranean diet is basically fresh and wholesome with foodstuffs that can essentially be prepared in as close to their natural form as possible.
Those that swear by the diet will also most likely advocate ‘the lifestyle’ that goes along with it – when eating, sit down at a table with good company. Social interaction and exercise activity are also aspects of ‘the lifestyle’. All in all, the Mediterranean diet seems to offer the whole package when it comes to healthy eating, and by extension, a healthy lifestyle.
What does the latest research in relation to IVF success show?
The research team assessed 244 women (aged between 22 and 41, who were not classified as obese) and their dietary habits prior to IVF (in vitro fertilisation) treatment with the use of a questionnaire looking at food frequency. Each female participant was enrolled at the Assisted Conception Unity, prior to receiving their initial IVF treatment in Athens, Greece.
The food-frequency questionnaire was filled in upon enrolment and focussed on the past 6 months, asking questions which related to the various foods eaten and their frequency during that time period. Answers were then measured showing adherence scores (0 - 55). Each woman thus received a MedDiet Score once each answer was logged. The higher the scores, the greater the adherence to a Mediterranean-style diet.
Based on the score range of the women, the research team from the Department of Nutrition and Dietetics at Harokopio University of Athens created three groupings. The first batch of women consisted of scores ranging between 18 and 30. The others had scores between 31 and 35, and between 36 and 47 respectively.
The group which scored the highest consisted of 86 women and the lowest, 79. Following IVF treatment, the higher scoring ladies appeared to have better pregnancy success rates by approximately 50%. The lower scoring groups achieved a 29% pregnancy success. Live births also faired better among the higher scoring group – 48.8% compared to 26.6%.
About 93.9% (229) of the women participating in the study achieved at least 1 embryo transfer in the uterus during an IVF procedure. Of those 56% (138 women) achieved a successful implantation. Of those, 42.6% (104 women) experienced a clinically successful pregnancy which was confirmed with an ultrasound scan. A total of 40.5% (99 women) carried to term and achieved a successful live birth.
As was to be expected, the research team also found that the younger the participant (i.e. under the age of 35), the higher the likelihood of a successful pregnancy and birth. The team noted that for every 5-point improvement in the MedDiet scores of younger women, the likelihood of pregnancy and birth success increased 2.7-fold.
That said, the research team did not seem to be able to determine a distinctive link between what was eaten and success rates among women in the older age group (over 35). They concluded what most in the field of fertility would attribute this to fewer available and viable eggs and hormonal fluctuations / changes.
Associate Professor Nikos Yiannakouris, who led the study concludes this regarding their research, “The important message from our study is that women attempting fertility should be encouraged to eat a healthy diet, such as the Mediterranean diet, because greater adherence to this healthy dietary pattern may help to increase the chances of a successful pregnancy and delivering a live baby.”
The research team believes that healthy eating increasing fertility and the odds of conception would apply to every woman wishing to achieve pregnancy success, no matter their age. The team has also suggested that further research is required to delve a little more into diet adherence and success rates, factoring in older women and those suffering from obesity. All in all, the team feels that their research demonstrated that improved IVF outcomes can be linked to a Mediterranean-style diet.
Being an observational study, the team does state that further research and intervention studies could provide more detail on the role of diet as it relates to fertility, particularly with regard to assisted reproduction. Other populations within the Mediterranean region and further afield can also be considered for study in order to gain more detailed insight. If this can be achieved, it is possible that findings may reveal underlying mechanisms of dietary factors which could be highly useful for the development of more specific nutritional guidelines for women receiving fertility treatment. Such guidelines could then aid in improving success rates – a highly desirable goal.
Surely diet is as important for men as it is for women hoping to conceive?
Previous research suggests yes. Research has also focussed on the MedDiet where men and their sperm quality are concerned. More recent studies conducted by the same research team in this area have asked a similar question, ‘Is adherence to a Mediterranean diet associated with better sperm quality?’ (3)
This 2016 cross-sectional study assessed males and concluded much the same as it did in their female counterparts. Yes, higher MedDiet scores (which were allocated using a food-frequency questionnaire) show improved adherence levels to a Mediterranean diet and display increased sperm concentration, total sperm count and better sperm motility.
The study enrolled 225 men (aged 26 to 55) who had a female partner at a fertility clinic in Athens. Habitual dietary intake and overall lifestyle were assessed and compared to fertility outcomes. The study took place between November 2013 and May 2016, with findings published in the Human Reproductive journal on 16 December 2016.
The semen quality of each participant was assessed according to the World Health Organisation’s 2010 guidelines, and a multiple logistic regression analysis helped to determine associations between three allocated groupings and the likelihood of abnormal semen parameters.
The study suggested a greater adherence to the MedDiet was linked to improved sperm quality, and that the findings appeared to be consistent with other research studies conducted previously. Basically, it concluded that a diet laden with fresh fruit and vegetables, whole grains and legumes does have some influence on the quality of sperm, and thereby fertility success rates.
The research team feels that the two studies conducted show that dietary influences are important when it comes to fertility in both men and women. Their findings do appear to support a favourable role for the MedDiet in the success rates of assisted reproduction.
So, is the MedDiet really the secret to success?
With the MedDiet in relation to fertility having been researched numerous times, surely then, it must be a dietary pattern with some relevance? Perhaps the reason behind such interest in more recent studies is that previous research conclusions have stated that this diet is capable of improving pregnancy success rates by as much as 40%. (4) This is relatively consistent with the current research conclusions which also saw an overall pregnancy and live birth success percentage in the 40s.
As much as has been studied in relation to fertility, it does still appear that there are many more questions to be answered. It is generally agreed that certain nutrients are beneficial to both men and women, but specifically which ones and for how long they would need to be ingested prior to conception requires more extensive research.
The MedDiet itself has also been studied multiple times in relation to overall health, and not just as to how it can potentially influence fertility. As a nutritional model (i.e. a diet that is adhered to correctly), the MedDiet is regarded as one that enhances both the quality and safety of foodstuffs which are key to the diet. The high consumption of wholegrains, fresh fruits and vegetables, legumes, fish and eggs versus moderate intakes of lean meat, oils and wine has been shown to improve overall health, and especially so when committed to in conjunction with an active lifestyle. (5)
When adopted correctly the MedDiet has been shown to contribute to marked improvements in cardiovascular health, and specifically the prevention of heart related complications. PREDIMED, a large cohort study is one example showing the considerable preventative benefit in over 19 000 British individuals following this diet (that is rich in heart healthy antioxidants, flavonoids and polyphenols). (6)
Cognitive health has also featured in the mix. A MedDiet that is followed with adequate amounts of calcium and dairy may also significantly improve cognitive function, and especially so in populations who are most at risk of developing cognitive diseases such as dementia. A diet that is rich in flavanols and various polyphenols is beneficial to cognitive functions such as processing speed and memory. Improved overall cognitive function has also been seen in older adults with milder dysfunction. (7)
It is thus not so surprising that a dietary pattern with such proven potential to both prevent and be adopted as part of an effective treatment plan when it comes to various chronic diseases and overall healthy function be considered for research when it comes to the creation of new life. If its primary composition of nutrients is so beneficial, surely it can influence the chances of healthier conception, even if this process assisted?
What studies in relation to this question have seemingly shown, is that there is some potential. The MedDiet ticks many boxes when it comes to healthier eating patterns. It’s certainly not the worst eating pattern you can adopt. It can benefit those at risk of serious chronic illness and help turn around an ill state of health by adopting better eating habits during a treatment process. Now, it also appears to have some relevance in boosting chances of assisted conception for couples.
More extensive research into this dietary pattern which has been long associated with overall health, and now fertility too, will likely produce the specific information needed to determine a more conclusive understanding of its benefits and how they pertain to both men and women wishing to conceive via fertility treatment.
References:
1. Human Reproduction Journal. 30 January 2018. Adherence to the Mediterranean diet and IVF success rate among non-obese women attempting fertility: https://academic.oup.com/humrep/advance-article/doi/10.1093/humrep/dey003/4828066 [Accessed 01.02.2018]
2. US National Library of Medicine National Institutes of Health. November 2010. The preconception Mediterranean dietary pattern in couples undergoing in vitro fertilization/intracytoplasmic sperm injection treatment increases the chance of pregnancy: https://www.ncbi.nlm.nih.gov/pubmed/20189169 [Accessed 01.02.2018]
3. Human Reproduction Journal. 16 December 2016. Association between adherence to the Mediterranean diet and semen quality parameters in male partners of couples attempting fertility: https://academic.oup.com/humrep/article/32/1/215/2513723 [Accessed 01.02.2018]
4. US National Library of Medicine National Institutes of Health. November 2014. A randomised controlled trial of a preconceptional dietary intervention in women undergoing IVF treatment (PREPARE trial): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4289275/ [Accessed 01.02.2018]
5. US National Library of Medicine National Institutes of Health. 2013. The Mediterranean Diet: A History of Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3684452/ [Accessed 01.02.2018]
6. US National Library of Medicine National Institutes of Health. 2016. Benefits of the Mediterranean diet beyond the Mediterranean Sea and beyond food patterns: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064779/ [Accessed 01.02.2018]
7. US National Library of Medicine National Institutes of Health. February 2017. A Mediterranean Diet to Improve Cardiovascular and Cognitive Health: Protocol for a Randomised Controlled Intervention Study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331576/ [Accessed 01.02.2018]