Are zinc and folic acid useful for increasing male fertility?

Dietary supplements containing zinc and folic acid, marketed as a treatment for male infertility, do not appear to improve pregnancy rates, according to a study by the National Institute of Child Health and Human Development (NICHD), which is part of the National Institutes of Health  . , the number of sperm or their motility.

Infertility, defined as a couple’s inability to conceive after at least 12 months of regular, unprotected intercourse, affects approximately 15% of couples worldwide. Numerous factors can lead to male and female infertility

In males, for example, infertility has also been linked to low levels of antioxidants in their seminal fluid. This puts them at an increased risk of ROS (chemically reactive oxygen-containing species), which can damage sperm cells.

These reactive oxygen species, which account for the majority of free radicals, are naturally involved in various processes essential for normal reproduction. Uncontrolled and excessive levels of ROS cause cell damage (“ oxidative stress ”). This can affect the health of the seminal fluid, damaging sperm DNA and lead to the onset of male infertility.

Can supplements improve sperm health?

Antioxidants have long been used to manage male infertility as they can help reduce the harmful role of ROS.

There are studies that have shown favorable effects with supplementation, but with unreliable results due to the high variability of conditions, formulations of antioxidants and dosages.

Some studies have reported beneficial effects of antioxidants (such as vitamins E) on the fertilizing capacity of sperm.

There is some research suggesting that six months of supplementation with vitamin E and selenium can increase sperm motility and the percentage of healthy, viable sperm, as well as pregnancy rates. Other studies have found improvements in sperm count, DNA, and pregnancy rate following treatment with l-carnitine (an amino acid), coenzyme Q10, and zinc supplements .

In particular, the benefits of using zinc and folic acid were based on a 2017 meta-analysis   which concluded that these two nutrients were beneficial in sub-fertile men.

However, there appear to be an equal number of studies that show no improvements in sperm motility, concentration, size or shape,   or other parameters.

As a result, the inconsistency in results and the general desire to improve fertility rates have led some companies to create their own specific nutrient “cocktails”, the effectiveness of which remains dubious and probably subjective.

Zinc and folic acid supplements? No thank you

The study in question , published in January 2020, aimed to understand whether zinc and folic acid are useful for male fertility since most of the so-called fertility supplements include them among the main ingredients.

Zinc is an essential mineral for sperm formation, and folate, the natural form of folic acid, depends on zinc to help form DNA in sperm.

The researchers enrolled 2,370 couples who were due to undergo infertility treatments.

The men were randomly assigned: one party received a placebo and another a daily supplement containing 5 milligrams of folic acid and 30 milligrams of zinc.

It was seen that there were no significant differences, in terms of live births, between the two groups: 34% of full-term pregnancies in the group with the supplement and 35% of full-term pregnancies in the placebo group.

Likewise, no differences were found between the two groups with regard to the parameters analyzed in semen: no significant differences were found in terms of mobility, shape and number of sperm.

However, the percentage of sperm DNA fragmentation (sperm DNA fragmentation is a condition linked to male infertility) was found to be higher in the group taking the supplement (29.7%) than in the placebo group ( 27.2%).

Men in the supplement group also had a higher proportion of gastrointestinal symptoms than in the placebo group: abdominal discomfort (6% vs 3%), nausea (4% vs 2%) and vomiting (3% vs 1%).

Enrique Schisterman, who led the study said: “ Our study is one of the first randomized, placebo-controlled trials to evaluate whether folic acid and zinc supplements help improve male fertility. Our findings suggest that these dietary supplements have no effect on fertility and may even cause mild gastrointestinal symptoms.”

The best investment?

Before stocking up on antioxidants and supplements,  take a look at your lifestyle.

Sperm health can be negatively affected by unhealthy habits such as poor diet, alcohol consumption, cigarette smoking and stress.
Eat a healthy diet, avoid excessive alcohol consumption, engage in regular physical activity and quit smoking. All of these things can go a long way when it comes to improving sperm health.

As far as supplements go, there is still a lot of research that needs to be done before we can confidently state that they are a worthwhile investment.