Understanding the facts about fertility

Understanding the facts about fertility

Conception problems are not unusual in our modern world, and there are a variety of factors that can contribute. And so here, Jenny Carson, Nutritionist and Technical Services Manager at Viridian Nutrition, gives the lowdown on what you need to know.

Although it may appear that conception comes easily, there are several factors that may make it a little harder.

Firstly, diet plays a role, and it is not just the diet of the mother-to-be. In fact, the World Health Organization acknowledges that the diet and lifestyle of both the father- and mother-to-be in the 12 months preceding conception can play a role in the ease of conception and health of the foetus.

At birth, women are born with approximately 400,000 immature follicles. Each follicle can produce an egg, however, at each menstruation, hundreds of follicles are recruited to produce a few good quality eggs. Subsequently, as women age, there are fewer and fewer follicles that can mature into eggs. In addition, testosterone in men starts to decline around the age of 40 years by approximately one per cent per year, alongside the deterioration of the genetic quality of the sperm.

The stressed state triggers a series of hormonal responses that are known to decrease fertility. It is known that both men and women produce less sex hormones when long-term stress is apparent.

Health barriers

Female specific health conditions of the ovaries reduce the success rate for conception, which include polycystic ovary syndrome (PCOS), fibroids, pelvic inflammatory disease (PID) and endometriosis.

  • PCOS is a common disorder that is characterised by a dominance of testosterone and poor blood glucose management, which results in cysts on the ovaries. Often, eggs are of poor quality and menstruation occurs less frequently, therefore, conception can be difficult.
  • Fibroids are tissue growths in the lining of the uterus, which can stop the implantation of the fertilised egg. Often, fibroids are asymptomatic, however, they can be related to a heavy period flow.
  • PID can be a result of a chlamydia or gonorrhoea, post-infection inflammation and secondary infections can occur in the fallopian tubes. In these circumstances, the tube may become blocked or damaged and affect fertility.
  • Endometriosis is a health condition whereby womb-like tissue grows in other physical locations, for example, in the ovaries or fallopian tubes. The condition commonly causes pain in the lower stomach or lower back regions, which is exacerbated during menstruation. Similarly, pain can be experienced during or after sex or when using the toilet. The resulting scarring and tissue distortion can affect the quantity and quality of eggs.

Similarly, there are male health conditions of the testes that affect fertility that include varicocele, infection, retrograde ejaculation, autoimmunity whereby antibodies attack sperm and low testosterone.

  • Varicocele is an enlargement of the veins in the scrotum, similar to varicose veins in the legs. The veins cause swelling and drain the testicle of blood, which can lead to a reduce sperm count and quality.
  • Infections can leave scarring and inflammation in the testes and tubules that transport the sperm and so issues lie in the ejaculation of the sperm.
  • Retrograde ejaculation is when the sperm is deposited in the bladder and therefore cannot fertilise an egg.  This is associated with diabetes, spinal injuries or surgery of the bladder, urethra or prostate.
  • Lowered testosterone affects the production and quality of the sperm, whereby a low sperm count is produced and lowered sperm motility.

Another hormone that plays an indirect effect on male and female fertility is thyroid hormone and thyroid function. Underactive or overactive thyroid impacts the production of sex hormones and affects the necessary roles of egg fertilisation, implantation and the maintenance of the pregnancy.

And in terms of lifestyle, smoking has been shown to stop the egg from properly detaching from the fallopian tube to travel to the womb after fertilisation. Furthermore, smoking has been shown to decrease the blood flow to the womb, which may limit the growth of the foetus, and in men, smoking can affect the quality of the sperm, primarily damaging the DNA.

Nutritional focus

Nutrition and lifestyle play an important role in fertility, for example, a diet that is predominantly processed foods, although convenient, often provide low levels of nutrition, are laden in salt, provide added sugars and hydrogenated fats. This combination of compounds is considered to exert an inflammatory effect, while not providing enough nutrition to quell the inflammation, which may impact the chances of a successful conception.

Obesity as a condition of hypercaloric intake but malnourishment through eating in excess and processed foods may permanently alter egg maturation. It is reported that 20-25 per cent of obese women are treated for infertility and, if conception occurs, are at greater risk of gestational diabetes and generating obese children. Typically in men, sperm formation is affected via poor nutrient provision.

In 2020, a research paper published by Professor Jack E James of Reykjavik University concluded that mothers-to-be who consumed 300mg or more of caffeine were at a greater risk of low birthweight babies. This led to the advice of a maximum of 200mg of caffeine daily during pregnancy. However, caffeine is present in several foods and drinks, in addition to coffee. For example, tea and coffee provide 75-277mg of caffeine per serving, chocolate approximately 50mg, some soft drinks around 80mg and medications such as Anadin Extra approximately 45mg. Therefore, the total caffeine intake should be considered.

Stress in working women has been suggested to contribute to infertility, besides anxiety and depression, which have been described more frequently in infertile than in fertile women.

Heavy alcohol consumption has been reported to affect fertility when combined with poor nutritional intake and secondary health conditions.

Advanced glycation end products are produced when food is cooked at extremely high temperatures or charred, such as chargrilled foods, barbecue, crackers and bread. These compounds promote the cross linkage of proteins and sugars, which stops the protein from fulfilling its role. AGEs can affect the tissues of the womb and ovaries, as well as the testes to damage reproductive capacity. The best alternatives are to steam, poach and slow cook on low temperatures, while avoiding added sugars to avoid the formation of AGEs.

Ideally, the parents to be would adopt a diet that is rich in brightly coloured whole foods, which are foods in their natural state as opposed to processed, are nutrient dense and would contribute to providing the nutrients that are known to support reproductive health.

Several nutritional studies have confirmed that the dietary pattern of the Mediterranean diet alongside regular physical activity in overweight women significantly improves conception rate and the success rate of assisted reproductive technology programmes. The Mediterranean diet is characterised by the consumption of oily fish, green leafy vegetables, fermented foods, brightly coloured fruit and vegetables, olives, nuts and seeds and sustainably farmed eggs, dairy and meats. This style of eating naturally eliminates processed foods, flour-based products and added sugar.

Nutrient top-up

All vitamins, minerals and trace elements should be provided through a balanced whole foods diet, however, there are specific nutrient deficiencies that are associated with poorer fertility outcomes.

  • B vitamin family – B vitamins, especially folic acid, B6 and B12, are well known for their role in the reduction of the aggressive molecule homocysteine, a known marker of increased risk of cardiovascular outcomes. In addition, it is well known that folic acid supplementation in the peri-conceptional and conceptional period reduces the risk of neural tube defects.
  • Vitamin D – vitamin D receptors are distributed throughout the ovaries, placenta and womb besides the testicles and sperm. A meta-analysis, which is an accumulation of high-quality research, concluded that adequate blood levels of vitamin D were related to more positive pregnancies and live births in women undergoing artificial reproductive technology. Plausibly, in men, suboptimal vitamin D has been shown to be related to lowered testosterone and poor semen quality.
  • Zinc – zinc is highly important in both male and female reproduction. In fact, the ovaries and testes are domains of high zinc density. In men, it contributes to sperm production and in women, in hormone regulation and ovulation.
  • Vitamin C – vitamin C consumption is considered to support collagen production and placental tissues. Subsequently, women with frequent spontaneous miscarriage had lower blood levels of vitamin C.
  • Omega 3 essential fatty acids – the typical UK diet is dominant in omega 6 essential fatty acids, and it is considered that the omega-6 to omega-3 ratio could be as high as 20:1. Although omega 6 is important in the diet, it is imperative that the ratio of omega 6 to omega 3 is around 3:1. Omega 3 plays an important role in quelling inflammation, but are also used structurally in the cell membrane to produce a flexible membrane that easily accepts nutrients and emits waste. Sources of omega 3 include oily fish, algae, flaxseed, perilla seed, almonds and walnuts. These foods also provide some omega 6 but if processed oils and foods are removed from the diet this would naturally improve the 6:3 balance.
  • Iron – iron deficiency is the most common nutritional deficiency worldwide. Women especially are at risk due to menstruation. However, certain diets are also low in iron such as the vegan and vegetarian dietary patterns. It is advised that iron status is tested when planning a pregnancy for both partners as a combined lowered iron status can contribute to issues around fertility that may include poor sperm production, lowered libido and ovarian insufficiency.

The B vitamins and magnesium play a multifunctional role in the body to support the stress response, energy production and hormone production besides normal DNA production, maintenance and repair.

Mothers-to-be following a vegan diet may benefit from the amino acid, carnitine, iodine and iron.

There are gender specific requirements for reproduction. Male priorities would include nutrients that promote vasodilation, this helps ensure a normal blood supply to the reproductive organs, such as arginine and coenzyme Q10.

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