PERSPECTIVES: Dr ALAN BARCLAY
IT TAKES TWO TO TANGO
It is generally well accepted that a key factor in the health and wellbeing of both the mother and new-born infant is an optimal food and nutrient intake before and during pregnancy. Of course, the nutritional status of prospective fathers is also an important factor in at the very least conception, but it is often overlooked, however.
Indeed, male infertility is on the rise around the globe, and sub-optimal food and nutrient intake may be part of the problem. Infertility is defined as the failure to achieve a successful pregnancy after 12 months or more of regular unprotected intercourse.
In recent decades, infertility has been recognized by the World Health Organisation as a global public health issue, affecting 15% of all reproductive age couples. In real terms this means that worldwide, 70 million couples experience subfertility or infertility.
Male factors, including decreased semen quality, are thought to be responsible for ~25% of cases of infertility. Some studies suggest that human semen quality has declined in certain geographic regions of the world in recent decades (e.g. Europe and USA). Environmental factors such as air pollution, smoking, stress, chemicals and other toxic agents have all been considered as possibly responsible.
Accumulating evidence from human, animal and in vitro studies indicates that male obesity and some components of the diet may play a pivotal role in modulating spermatogenesis, sperm maturation and fertilizing ability. For example, male obesity has been related to impaired reproductivity because of its effect on the molecular and physical structure of sperm. Diets high in energy (kilojoules/calories), trans-fatty acids, saturated fats and/or cholesterol have been associated with testicular disruption, involving impairments in spermatogenesis potentially affecting male fertility and the offspring.
A recent systematic review and meta-analysis of randomized controlled trials that included 2,900 men aged 18 to 52 years from 11 countries (Australia, England, Germany, Iran, Italy, Kuwait, Netherlands, Saudi Arabia, Scotland, Spain, and the USA) found that supplementation with the following nutrients improved sperm quality and quantity:
- Selenium (100–300 μg per day for 3–11 months)
– Increases sperm concentrations, motility (ability to swim) and improves morphology (shape, which affects sperms ability to fertilize eggs).
– Selenium is found in seafood, poultry and eggs and, to a lesser extent, muscle meats.
- Zinc (66–500 mg per day for 3–6 months)
– Increases sperm concentrations and sperm motility.
– Meats, fish and poultry are the major contributors to the diet, but cereals and dairy foods also contribute substantial amounts.
- Omega-3 fatty acids (1000 mg per day for 2–8 months)
– Increase sperm concentrations, sperm counts, motility and improve sperm morphology.
– Long-chain omega-3 fatty acids are found predominantly in oily fish such as mackerel, herrings, sardines, salmon, tuna and other seafood.
- Co-enzyme Q10 (200–300 mg per day for 3–6 months)
– Increases sperm concentrations, sperm counts and improves sperm morphology.
– Co-enzyme Q10 is found in many foods but in particular cold-water fish, like tuna, salmon, mackerel, and sardines, vegetable oils and organ meats.
There is also some evidence from observational studies that provide some additional clues as to what an optimal dietary pattern for male reproductive health may look like. A recent systematic review of observational studies included ~13,000 men aged 18 to 80 years from 18 countries (Argentine, Brazil, Canada, Denmark, Estonia, Finland, France, Germany, Greece, Iran, Italy, Lithuania, the Netherlands, Norway, Poland, Spain, Sweden and the USA). It found that a higher consumption of these foods is associated with improved sperm quality:
- Fruits, vegetables and cereals
– Many are rich in antioxidant vitamins (e.g., vitamin C, A, β-carotene and polyphenols), some minerals with antioxidant properties (e.g., potassium and magnesium), folate and fibre.
- Lower fat dairy products
– Low-fat and skimmed milk consumption is associated with higher circulating levels of insulin-like growth factor 1 and insulin and this may increase sperm motility and concentration.
- Fish, shellfish and seafood – Are rich sources of omega-3 fats.
On the other hand, it found that a higher consumption of these foods is associated with decreased sperm quality:
– Most varieties have a high GI and insulinemic response and this has been associated with oxidative stress which has an important effect on semen quality.
- Sugar-sweetened beverages
– Excess consumption of sugar-sweetened beverages (high glycemic load) is associated with weight gain and insulin resistance which could negatively influence semen quality via increased oxidative stress.
- Meat and processed meats
– Some meats are low in omega 3 fatty acids but high in saturated fatty acids, trans-fatty acids and/or cholesterol which are related to decreased fertility parameters in men.
These nutrients can be obtained from dietary patterns that are in-line with current dietary guidelines for adults. It takes two to tango – optimal nutritional status is also important for men to facilitate conception of healthy children.
- The Effect of Nutrients and Dietary Supplements on Sperm Quality Parameters: A Systematic Review and Meta-Analysis of Randomized Clinical Trials
- Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies
Alan Barclay, PhD is a consultant dietitian and chef (Cert III). He worked for Diabetes Australia (NSW) from 1998–2014 . He is author/co-author of more than 30 scientific publications, and author/co-author of The good Carbs Cookbook (Murdoch Books), Reversing Diabetes (Murdoch Books), The Low GI Diet: Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment, New York).
Contact: You can follow him on Twitter or check out his website.