Not many articles speak about male fertility since more importance is given to the reproductive health of women of childbearing age. However, recent studies show that lifestyle factors can have an adverse effect on reproductive health, in males as well as females. They can even go as far as affecting the health of their offsprings.
To get an overall picture of this new disease, let’s first begin to understand what studies say about obesity and male infertility, and then moving on to other lifestyle factors.
Obesity in men is associated with impaired semen quality, decreased libido and erectile dysfunction (ED). This originates from multiple factors including reduced levels of reproductive hormones, elevated levels of inflammatory substances called cytokines, altered androgen-to-estrogen ratios, insulin resistance and sleep apnea. Obesity is also associated with cardiovascular risk factors which can cause ED.
The relation between obesity and sperm parameters is complicated by various factors such as the percentage of body fat, waist circumference, and waist-to-hip circumference, the outcomes of which could impair sperm motility and result in low sperm count.
Male obesity is associated with lower total testosterone levels. It is known that in obese men both estrone and estradiol are increased due to increased peripheral aromatization of androgens (the same effect that is seen with excess alcohol consumption). Increased circulating estrogens may have a direct deleterious effect on sperm production.
Sleep apnea affects testosterone levels negatively in obese men. Total testosterone is reduced proportionally to the severity of the sleep apnea. The combination of both factors may result in a compounding effect on male fertility.
Obesity was also shown to be associated with high homocysteine and low vitamin D levels. Both are suspected to affect semen parameters. Vitamin D has a role in sperm production and survival.
Type 2 Diabetes
The effect of Type 2 diabetes (frequently associated with obesity) on male fertility is increasingly being accepted. Insulin resistance seen in Type 2 diabetes can increase the inflammatory cytokines as mentioned above. It can also lower the sex hormone-binding globulin levels which control maintenance of the sex hormones in the blood. The Endocrine Society now recommends that men with Type 2 diabetes should be screened for low testosterone levels.
Environment and Lifestyle
Additionally, some environmental toxins such as alcohol, and endocrine disruptors such as organochlorines usually found in pesticides possess estrogenic properties that can affect male fertility. Some of these toxins are fat soluble and tend to accumulate in fatty tissue.
Sedentary life, prolonged sitting and fat deposition in the lower abdomen can reduce male fertility, likely through increased testicular temperature, an effect also seen with working on the laptop placed on the thigh.
Effect On The Offspring
Children of obese fathers are more likely to be diagnosed with autism spectrum disorders, according to a study published in the April edition of the journal Pediatrics. There was a five- to seven-fold increased risk of higher blood pressure in children of obese fathers.
Studies show that men who start smoking before the age of 11 risk having sons who are overweight. Similarly, fathers who use recreational drugs increase the risk of cancer in their children.
Increase In Paternal Age
While the increase in maternal age at childbirth has received much attention, an upwards shift in paternal age at childbirth is also taking place. Many reasons may account for the trend towards postponement of fatherhood, including economic pressures, late marriage or just personal choice.
Some studies suggest that male fertility and sperm DNA quality start to decline after approximately 35 years of age. Such a decline leads to an increased risk of spontaneous gene mutations, which when passed on to the offspring, increase the child’s risk for both schizophrenia and autism.
Increasing paternal age also means longer duration of exposure to environmental toxins as listed above. Much has been spoken about diets in pregnancy, studies now show that even the father’s dietary habits may affect the offspring, for example, a recent animal study found that a paternal diet rich in carbohydrates was associated with adverse lipid profiles in the offspring.
What should one do?
Effective therapeutic interventions for male infertility are needed that require dietary changes coupled with exercise. Regular exercise and daily intake of omega-3’s, folic acid supplements and reduced intake of fat and sugar, should be integrated into any comprehensive approach to maximizing male fertility. This increases nitric oxide production and can improve erectile dysfunction.
Studies have reported the effect of weight loss programs (especially weight training) on outcomes of male fertility such as the increased testosterone, reduction in estrogen levels and improved sperm parameters.
In the presence of sleep apnea, those that lost weight have shown improvements not only related to sleep apnea but also an increase in testosterone levels.
Men who use hormones for bodybuilding should do so with caution as side effects include decreased sperm production and heart disease. Recovery of normal sperm production after discontinuation of exogenous testosterone is necessary.
Stop smoking and cut down the alcohol intake. Working late nights can increase your risk for obesity besides reaching out for stimulants such as cigarettes/caffeine. Adequate rest is needed for stress reduction and repair. Disruption of the circadian rhythm as seen in those working night shifts is related to an increased risk for some cancers too.
In men with severe obesity, a semen analysis and a hormonal profile consisting of serum estradiol, total and free testosterone, FSH, LH, prolactin, thyroid-stimulating hormone and SHBG should be obtained. The evaluation should also include screening for diabetes (fasting glucose, glycosylated hemoglobin), high blood pressure, sleep apnea and the lipid panel.