Following on from previous posts in this blog, such as the effects of exercise and nutrition on male fertility, this post will explore the ways in which neglecting these major aspects can affect male fertility, both directly and indirectly. A balanced diet and regular exercise are recommended in order to optimize sperm production.
Body fat is essential in males in order for the body to successfully regulate temperature, as an emergency fuel source and to protect the vital internal organs. Upon consumption of calories greater than the amount utilized by the body, body fat, or adipose tissue, is created as a store for this fuel in times of starvation.
There are two types of body fat, essential fats, which cannot be lost without compromising regular bodily functions (membranes, tissues, and bones) and storage fats, which pose the well-known health threats. Obesity is continuing to become a major threat to the health and well-being of men of all ages. Body fat percentage is a better measure than body mass index to determine obesity as body mass index doesn’t take into account for muscle mass.
So what body fat percentage is ideal? To an extent, this is down to personal preference and the relevant fitness and health goals for the individual. However, for men aged 20-39, 25% body fat or above is considered obese. On the other hand, a BFP of below 6% in non-athletes can also have a detrimental effect on men’s health, particularly with normal sperm production and hormone synthesis. The image below outlines a generalized diagram of the different body fat percentages for reference.
(Image sourced from http://www.builtlean.com/2012/09/24/body-fat-percentage-men-women/)
Excess storage fat can decrease a man’s fertility in many ways. Obesity can cause hormonal changes, which directly affect the production of sperm and therefore the quality of the sperm ejaculated. Excess fat tissue converts the male hormone, testosterone, into the female hormone, oestrogen, thus directly affecting the quality and quantity of the sperm produced. Excessive leptin, a hormone produced by fat cells, may have a direct effect on sperm cells and the cells involved in spermatogenesis. Excess abdominal body fat directly applies heat and pressure to the testes, the effects of which were explored in my very first blog post.
On the other hand, however, an excessively low body fat can have adverse effects on sperm quality. Low levels of leptin trigger a chain of hormonal responses in the brain, which result in less testosterone being produced, and therefore resulting in a lower sex drive, possibly impotence, and much fewer sperm. As a consequence of these low leptin and testosterone levels, the reproductive system undergoes a temporary shut-down event (known as hypogonadotropic hypogonadism) as the body focuses on survival rather than reproduction.
In conclusion, as with many other aspects explored in previous blog posts, moderation is key in promoting healthy sperm production. A happy medium in body fat allows for optimum sperm production in non-athletes.