Optimising Nutrition to Improve Fertility
Almost every function in the human body is affected by diet and nutritional intake, and both female and male fertility are no different.
It can be hard to find specific advice based on medical science, so we collected some of the top tips for both male and female fertility in this blog post to help.
With a team specialised in prenatal and postnatal personal training, we have the experience and expertise to help work on your fitness for pregnancy.
Further Reading & Research
How nutrition affects fertility for Women
Metabolic & Hormonal Spikes
One of the key goals of a fertility diet is to avoid spikes in blood glucose, also known as blood sugar. The level of blood glucose in your body is regulated and erratic increases or decreases which are known as spikes could act to disrupt hormones and compromise egg quality.
When pregnant the American Diabetes Association recommends that before a meal the blood glucose level should be less than 95 mg/dL, within one hour following a meal it should be less than 140 mg/dL and after two hours it should be 120mg/l.
So where exactly does blood sugar come from? Well it all starts with carbohydrates, your body breaks down the starches in carbohydrates that you eat like bread, pasta and rice and converts them into glucose which are then absorbed and trigger increases in the level of blood glucose.
The speed with which this absorption happens depends on how easy it to convert the starches into glucose, simple carbohydrates make it extremely easy for your body to quickly convert and absorb the glucose whilst complex carbohydrates make it a more difficult and longer process which leads to a more steady increase and decrease.
When blood sugar levels increase, the body sends a signal to the pancreas to release insulin. Insulin is a hormone that is released to modulate the levels of blood glucose and induses glucose storage in the liver, muscles and adipose (fat) tissue. The body does this because elevated levels of blood glucose levels can have severely detrimental effects for health.
Excess glucose damages cells in a variety of ways, triggering the production of free radicals and causing mitochondria to break apart or malfunction.
Preventing this requires the glucose to be safely stored away inside muscles or converted into fat cells, insulin is the chemical messenger that instructs the body to start this process.
The higher the blood glucose level, the more insulin is released. Over time, if insulin is too high too often the cells develop something called insulin resistance, they stop reacting to the insulin level increase and the body stops soaking up the excess glucose as effectively.
When the blood glucose levels remain too high for too long, the body reacts by overcompensating with increased insulin production.
Sugar and Insulin
Sugar and insulin is a big problem for female fertility, high glucose levels directly compromise egg quality while insulin disrupts the balance of other hormones that are responsible for regulating the reproductive system.
It is important to note that this damage is not limited to the medical definition of insulin resistance, it also occurs when blood sugar and insulin levels are simply elevated but within the medically accepted range considered normal.
One of the major factors that causes these higher than average blood sugar levels is the type of carbohydrates consumed.
When you eat highly processed carbohydrates, such as those made with refined flour, the starch molecules in the food are broken down much easier by the digestive enzymes so they are broken down much faster leading to larger spikes in blood glucose levels.
By contrast, more natural carbohydrate-rich foods such as nuts, seeds and unrefined grains often take much longer to break down.
The starches in these foods are packed up tightly and are less accessible to digestive enzymes and so the glucose molecules are released gradually over time.
The blood sugar response after eating whole unrefined foods is therefore slower and less erratic. Instead of a sudden spike, there is a slow and steady climb in glucose levels.
A study conducted published in the European Journal of Clinical Nutrition which tracked thousands of women over a period of years found that those who had followed the advice and emphasized the slow release carbohydrates had a much lower rate of infertility due to ovulation, ovulatory infertility is often influenced by hormonal imbalances.
By modifying your diet to choose more slow carbohydrates you are more likely to maintain steady blood sugar and insulin levels, in any case monitoring your blood sugar levels prior to meals and one hour and two hours after a meal is a good practice to understand how your meals are influencing these problems.
Blood sugar monitors are available from most pharmacies in the UAE, and you can even find them for under 200AED online at retailers such as amazon.ae.
Maintaining a steady blood sugar and insulin level in the body helps keep hormone levels normal in the ovaries.
Fertility Diet
When blood sugar is very high, a chemical reaction occurs between glucose and either proteins or lipids within our cells.
This reaction creates damaged proteins and lipids called "advanced glycosylation end products" or AGEs. These damaged molecules accumulate in the body over time as a result of high blood sugar levels.
AGEs are known to contribute to cosmetic aging by damaging collagen in the skin as well as cardiovascular aging by causing cholesterol to clump together into plaques. Research shows they also contribute to ovarian aging.
Studies have shown that women with higher levels of AGEs before starting IVF tend to have fewer eggs retrieved, fewer eggs fertilised and fewer good-quality embryos.
The pregnancy rate is also very different: 23% in women with normal levels, compared to just 3% in women with higher levels of glucose-induced damage.
What are Mitochondria?
Mitochondria are the tiny generators of energy within each cell in the body, producing the cellular energy required for egg development.
Any disruption in the function of the mitochondria can often compromise the ability to separate the copies of chromosomes properly and lead to genetically abnormal eggs and embryos.
Research shows that high blood sugar levels impair mitochondrial function.
We would therefore expect an increase in the rate of chromosomal abnormalities which is exactly what has been found in animal studies. Eggs from diabetic mice are much more likely to have an incorrect number of chromosomes.
This could explain part of the link between insulin resistance and the risk of miscarriage. More than a decade ago scientists revealed that in women with recurrent pregnancy loss the rate of insulin resistance was nearly three times higher than normal.(9)
Controlling Blood Sugar
Achieving steady even blood sugar levels does not require a strict low carbohydrate diet. Instead, there are a variety of small shifts and strategies that you can use to help prevent blood sugar spikes, by focusing on either the amount, type or timing of the carbohydrates you eat.
Reduce Consumption in Amount of Carbohydrates
The first strategy is to reduce your reliance on high carbohydrate foods, while increasing fat, fiber and protein. This appears to have a powerful impact on IVF success rates, even in women without noticeable insulin or blood sugar problems.
In one study researchers asked women with previous failed IVF cycles to eat fewer carbohydrates and more protein. After two months the women undertook another IVF cycle with impressive results.
The greatest impact was on the percentage of eggs that made it to the 5 day embryo stage. When the women followed their normal diet, 19% of eggs developed into blastocysts, but after two months of a lower carbohydrate and higher protein diet, 45% of eggs survived to the blastocyst stage. Ten out of the twelve women also became pregnant.
Importantly, this study indicates that you do not need to drastically cut carbohydrates to improve egg and embryo quality. A good ratio appears to be around 40% of the calories from carbohydrates, 30% from protein and 30% from fat.
This represents a healthy balanced diet and many people can easily reach these ratios by just changing one meal per day, such as having yogurt or eggs for breakfast rather than toast or cereal, or reducing a portion of rice or pasta at dinner while adding more protein or vegetables and this is not a huge price to pay for reducing the risk of infertility.
Impact of being Overweight on Fertility
Overweight and obesity significantly impact fertility in both women and men, with numerous medical studies and published research underscoring the complex relationship between body weight and reproductive health.
Overweight and obese women can experience heightened risk of a range of reproductive issues primarily due to hormonal imbalances. Excess body fat is associated with an increased production of estrogen, which can disrupt the regularity of menstrual cycles and ovulation, a key factor in fertility.
A study published in "Obesity Reviews" (2017) highlighted that obesity is linked to a higher prevalence of ovulatory infertility. Research has shown that overweight and obese women often experience a longer time to conceive compared to those with a normal body weight.
Polycystic ovary syndrome (PCOS), a common cause of infertility, is also closely linked to obesity. PCOS is characterized by insulin resistance, which can be exacerbated by excess weight.
A study in "The Journal of Clinical Endocrinology & Metabolism" (2013) indicated that weight loss interventions in obese women with PCOS significantly improved the frequency of ovulation, thereby enhancing fertility.
In men, obesity has been found to negatively affect sperm quality and quantity, which are crucial parameters of male fertility.
Excess body weight can lead to hormonal changes, including reduced testosterone levels and increased estrogen, impacting sperm production. A study in "Human Reproduction" (2012) noted a direct correlation between increased body mass index (BMI) and reduced sperm concentration and motility. Additionally, obesity in men is often associated with erectile dysfunction, further complicating fertility issues.
Overweight and obese couples may experience a longer duration to achieve pregnancy. According to research published in "The Lancet" (2007), every BMI unit increase above 29 in either partner significantly reduced the probability of conception within a year.
Achieving and maintaining a healthy weight is a key strategy for improving fertility. The "American Society for Reproductive Medicine" emphasizes that even a modest weight loss of 5-10% can significantly improve fertility outcomes in overweight individuals.
Choose Slow Carbohydrates
From a fertility standpoint, the best carbohydrates are those which are digested slowly, preventing sudden bursts of insulin.
Researching your own options are always the best way to go, but for general advice some best bets would be beans, lentils, nuts seeds and most vegetables, any grains should be whole grains which are minimally processed like quinoa, wild rice, brown rice, oats etc.
Choosing wholemeal bread and wholemeal pasta would provide you with more fibre and protein, there are even types of pasta made from chickpeas and lentils. Increasing your intake of these foods in proportion will help balance blood sugar and provide steady energy levels.
Choosing slow release carbohydrates also means reducing sugar in all its forms. There is clear evidence that eating too much sugar compromises fertility.
Replacing standard sugar is with natural forms such as honey and dates is likely no better. Sweeteners often contain a combination of glucose, fructose or sucrose, all of which cause similar rises in blood sugar and insulin.
Fruit also contains a significant amount of sugar, but it is likely fine to include in moderation. The sugar in whole fruit is packed together with fiber, which slows absorption and to some extent lessens the impact on blood sugar levels.
Even so, it is better to have fruit after a meal that includes protein and vegetables to further slow the release of sugars. If you find yourself needing a sweet treat, dark chocolate is a good choice. Also keep in mind that long term daily habits matter most. The occasional indulgence is not worth feeling guilty about.
The benefits of eating Fibre and protein before Carbohydrates
Studies have found that you can significantly reduce blood sugar spikes by simply eating foods in the right order, specifically by eating high carbohydrate foods after vegetables or protein. That could mean starting your meals with a salad and saving bread or pasta for the end of the meal.
A salad can lessen the impact on blood sugar even further if you add a vinegar based dressing. That's because the acetic acid in vinegar not only inhibits the enzymes that break starch into sugar but it also prompts cells to soak up and utilize the glucose.
Studies have shown that one tablespoon of vinegar before a meal can reduce the glucose spike of that meal by up to 30%. In one study in Japan, adding a tablespoon of apple cider vinegar per day was found to improve hormone balance and restore ovulation in some women with polycystic ovary syndrome.
Exercising after Eating
Adding physical activity after eating is a great way to reduce blood sugar spikes. Whether going for a short walk or doing housework or light resistance exercises, even ten minutes of activity can significantly reduce spikes in blood sugar.
When your muscles are active, they soak up glucose from the bloodstream, preventing glucose and insulin spikes that can disrupt hormones and cause oxidative stress.
Fertility Diet
It is quite commonly agreed that one of the best diets to follow for healthy pregnancy is a mediterranean diet, the most studied diets being based on Greek, Spanish and southern Italy, which all emphasise the consumption of fish, olive oil, nuts, legumes and antioxidant rich vegetables.
This type of diet has been shown to improve life expectancy, reduce inflammation and reduce the risk of heart disease, cancer and diabetes.
A growing body of evidence has emerged that ties inflammation to infertility and miscarriage, researchers have also specifically found that eating this type of diet can boost IVF success rates. In 2018 researchers demonstrated that women who followed a Mediterranean diet for six months before IVF were much more likely to become pregnant.
The foods with the strongest links to improved success rates were vegetables, fruit whole grains, legumes, fish and olive oil. This follows on from an earlier study on diet and IVF success frates which surveyed 161 couples at an IVF clinic in the Netherlands.
The researchers found that women who more closely followed a Mediterranean diet before IVF cycle had a 40% higher chance of becoming pregnant. These women typically had a higher intake of vegetables, vegetable oil, fish and legumes.
The researchers suggested two ways in which these foods could improve pregnancy rates so dramatically, the first is a higher level of specific vitamins such as folate, B6 and B12.
These vitamins are likely to improve egg and embryo quality by lowering homocysteine. Vitamin B6 alone could have a major impact on boosting fertility in women, with one study finding that the chances of conception increased by 40% with B6 supplementation and decreased early miscarriage by 30%. This type of diet also increases the levels of important fatty acids.
Fertility Dietary Fat Intake
A wave of high quality studies have demonstrated the fats and oils found in foods like fish, nuts and olive oil have beneficial impact on fertility.
Theyimprove egg and embryo quality in IVF and reduce the time it takes to get pregnant. In 2017 Harvard researchers found that women with above average levels of omega-3 fats in their blood had a much higher chance of conceiving through IVF.
The omega 3 fatty acids found in fish were the ones found to be linked to these improved fertility, and not the ones found in plant sources such as flaxseed oil for example, which did not have the same impact.
Outside the context of IVF, a study of 2,000 women also reported that those with sufficient omega-3 intake conceived sooner than those with a lower intake.
The researchers noted that this was likely because omega-3 fats reduce inflammation, support progesterone production and increase uterine blood flow.
These mechanisms may also be responsible for the link between higher omega-3 consumption and a lower risk of pregnancy complications and loss.
One interesting pattern to emerge in these recent studies is that above a certain level of omega-3 intake, consuming more does not confer any additional benefit.
The threshold for improved fertility appears to be eating omega-3 rich fish approximately two times a week.
The fish with the highest omega-3 levels and negligible mercury include free range (not factory farmed) salmon, sardines and Atlantic mackerel.
If these fish are part of your regular diet there is likely no benefit in supplementing with additional omega-3.
If you do not eat seafood regularly, or only eat types of fish with much lower omega 3 fatty acids it may make sense to add a low dose fish oil supplement.
A recent study found that women fish oil supplements and trying to conceive naturally have a significantly higher chance of getting pregnant each cycle.
In men, fish oil supplements have been shown to improve semen quality. A reasonable dose is approximately 500 milligrams per day of omega-3. It is best to take omega-3 supplements with a meal containing some fat in order to allow for proper absorption.
Olive oil is also not only rich in antioxidants but also contains a type of monounsaturated fats that is likely important for egg development known as oleic acid.
Another study found that women with higher levels of oleic acid had more mature eggs retrieved before IVF. Oleic acid accounts for around 70% of the total fat found in olive oil and it is also the primary type of fat found in avocados and avocado oil.
Other fats found in olive oil, avocados, nuts and seeds have been found the likely to improved fertility . In contrast saturated fats which are typically found in coconut oil, butter and red meat appear to negatively affect egg development, this does not mean you should avoid red meat but it is worth choosing leaner cuts of meat.
Taken as a whole research indicates that we can significantly improve fertility by aiming for a higher intake of fish, olive oil, nuts, seeds and somewhat lower intake of saturated fats from coconut oil, butter and red meat.
Rebalancing fat intake in this way may be particularly important for those with variants in folate metabolism genes such as MTHFR because a greater consumption of fish and a higher ratio of monounsaturated fats to saturated fat results in lower homocysteine levels.
Alcoholic beverage intake & Fertility
In 1998 a small but highly publicised study found that consuming just one to five alcoholic drinks per week could significantly reduce the odds of conceiving.
When it comes to IVF, even moderate alcoholic consumption has been shown in a 2011 study with 2,000 couples to be problematic.
The study found that compared to women reporting fewer than four alcoholic drinks per week, women drinking more than this amount had a 16% lower chance of a live birth.
More recent studies found an impact on IVF success rates when alcohol consumption exceeded six drinks per week, however since these are self reported number of drinks per week it is highly advisable to forego alcohol altogether in order to maximise fertility and prospects for a healthy pregnancy.
Caffeine Intake and Fertility
Caffeine intake is another factor that should be considered when trying to get pregnant. When considering a fertility diet for both men and women, the amount of caffeine intake per day needs to be monitored.
The risk was not as pronounced for women drinking fewer coffees each day, but even a lower intake still raised the risk of miscarriage.
The finding is consistent with prior studies which reported that the miscarriage risk begins to rise at 100mg to 150mg of caffeine intake per day during pregnancy. Translating that into real-world terms, the amount of caffeine in a single cup of coffee is typically between 100-200mg.
A cup of green tea typically contains around 25mg of caffeine whereas black tea can have around 50mg per cup. The studies therefore indicate that miscarriage risk begins to rise slightly with just one cup of tea or less than half a cup of coffee per day.
In addition, even though most studies have found no impact on fertility, some research does suggest caffeine can make it more difficult to get pregnant.
A Yale study revealed that women who used to drink tea or coffee in the past but stopped prior to fertility treatment had a higher pregnancy and live birth rate than current tea and coffee drinkers.
Another study found a correlation between caffeine intake and a decrease in the number of good quality embryos during IVF.
To be cautious, it would be advisable to reduce consumption of caffeine to the equivalent of one cup of tea or half a cup of coffee per day, while gradually switching to decaffeinated tea and coffee to be completely safe.
Folic Acid Supplements
Folic acid, a form of vitamin B9, is increasingly recognized for its significant role in enhancing female fertility and contributing to a healthy pregnancy.
Its importance is underscored in various dietary guidelines aimed at women of childbearing age, especially those trying to get pregnant.
Folic acid plays a vital role in DNA synthesis and repair, crucial for rapid cell division and growth during pregnancy.
This synthesis is essential not only for maternal health but also for the fetus's development, particularly for the formation of the neural tube, reducing the risk of neural tube defects.
Studies, including those published in journals like Obstetrics & Gynecology, have highlighted the impact of folic acid on improving ovulation, a key aspect of female fertility.
These studies indicate that a higher folate intake, often through folic acid supplements, is associated with a reduced risk of ovulatory infertility.
Folic acid's role in metabolizing and reducing homocysteine levels, an amino acid linked to reproductive problems, is crucial.
Elevated homocysteine levels have been associated with a higher risk of miscarriage, and reducing these levels through folic acid supplementation may improve pregnancy outcomes.
Folic acid's influence extends to male fertility as well. Some research suggests that folic acid can enhance semen quality, thereby impacting overall reproductive health for couples.
This highlights the significance of a balanced diet, incorporating elements like healthy fats, whole grains, and a variety of proteins, both animal and plant-based, for both male and female fertility.
Diets high in trans fats, on the other hand, like those often found in processed meat and high-fat dairy products, have been shown to negatively affect fertility.
For women, especially those overweight or obese, maintaining a healthy weight through diet and lifestyle changes is crucial. Weight loss interventions that include a fertility diet rich in nutrients like folic acid, monounsaturated fats, found in foods like olive oil, and omega-3 fatty acids can aid in managing conditions like insulin resistance and polycystic ovary syndrome, both of which can impact fertility. Conversely, excessive caffeine intake and a high intake of alcoholic beverages are often discouraged in fertility diets due to their potential to negatively affect fertility.
The relationship between dietary fat intake and reproductive health is complex. While low-fat dairy products are often recommended for general health, some studies, such as those examining the Mediterranean diet, suggest that full-fat dairy foods might be beneficial for those trying to conceive. This is particularly relevant in the context of assisted reproductive technologies like in vitro fertilization, where dietary patterns can influence outcomes.
Folic acid supplementation is a key component of a fertility-enhancing diet. Its benefits, backed by medical research, underscore the importance of a varied and healthy diet for reproductive health. For women at reproductive age, consuming iron supplements, prenatal vitamins, and maintaining a diet rich in essential nutrients, including folic acid, can pave the way for improved fertility and a successful clinical pregnancy.
Should Gluten & Dairy foods intake be avoided?
For people with Celia disease, the risks of gluten intake for infertility and risk of miscarriage are clear, however for everyone else the question of whether to avoid gluten and dairy is quite commonly asked. The typical advice is to avoid dairy while trying to concieve is often based on a concern that the hormones present in milk may compromise fertility. Studies have so far not found a clear and direct link, in fact one study from the Nurses' Health Study found that a higher intake of full fat dairy foods was actually associated with a lower risk of ovulation disorder. In a more recent study of IVF outcomes, women with the highest dairy intake had the highest chance of a live birth (20). Perhaps the best option would be to eliminate each one from your diet for a period of time like two weeks and see how your body responds.
