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Study under review: Effect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial.
Infertility, which is defined as the inability to conceive after one year of regular, unprotected sex, affects around 9% of couples of reproductive age, globally. It is estimated that male infertility contributes to approximately half of all infertility cases, and affects about one in 20 adult men younger than 40 years of age.
Although the pathogenesis of male infertility is still poorly understood, several genetic, environmental, and lifestyle factors like nutrition are implicated. Healthy, balanced diets rich in omega-3 fatty acids, antioxidants, and vitamins are associated with improved semen quality and male fertility.
Two micronutrients that have received a lot of attention in recent years due to their potential for improving male fertility are folate and zinc. Folate is involved in DNA synthesis, which is critical for the production of sperm, and folic acid, the synthetic form of folate, is an antioxidant, which means that it may minimize the toxic effects of oxidative stress in male sperm cells. Zinc is the second most abundant trace metal in the body after iron, and is found in the testicles and semen in extremely high concentrations relative to other body fluids and tissues. As a cofactor for more than 80 metalloenzymes involved in DNA transcription and protein synthesis, and due to its anti-apoptotic and antioxidant properties, it seems to be essential in the development of the testicles, and in the production and motility of sperm.
Despite the biologically plausible effects of folate and zinc on sperm production and improved semen quality, trials in humans have generally employed small sample sizes and produced conflicting results. Although a recent meta-analysis found that folate and zinc supplementation improved some sperm characteristics in infertile men, there was large heterogeneity between the included trials, and the main outcome of interest to most couples, live birth, was not examined. The study under review was the first large-scale randomized trial to assess the effect of combined folic acid and zinc supplementation on semen quality and live birth in couples seeking infertility treatment.
Male infertility affects about one in 20 adult men under 40, and contributes to approximately half of all infertility cases in couples trying to conceive. While folate and zinc have received a lot of attention in recent years due to their potential for improving male fertility, the evidence is currently limited to small trials with conflicting results. Moreover, the main outcome of interest, live birth, has not been sufficiently examined. The study under review was the first large-scale randomized trial to assess the effect of combined folic acid and zinc supplementation on semen quality and live birth.
Other Articles in Issue #64 (February 2020)
A higher protein diet for 48 hours can create a negative energy balance
Swapping carbs for protein may help people with obesity and prediabetes keep the weight off.
Deep Dive: Does early exposure reduce food allergies in infants?
Most early exposure studies to date looked at the effects of early exposure to a single potential allergen. Here, we cover a secondary analysis of a study that used six potentially allergenic foods.
Pomegranate’s possible UV-B(enefits)
Pomegranate contains compounds that could help skin become more resistant to UV-B radiation. How well does it actually work, though?
Interview: Matt Stranberg, MS, RDN, LDN, CSSD, CSCS
Dietitian and exercise scientist Matt Stranberg covers the ins and outs of disordered eating and problematic physical activity in this detailed interview.
Omega-3s may make mild cognitive impairment a little bit milder
This meta-analysis found a small impact of omega-3 supplementation on a measure of cognition in people with mild cognitive impairment.
Deeper Dive: Elevated protein intake can benefit lean mass
People who resistance train got the biggest bang for the buck, but the benefit is less clear in other populations.
Nulls: November–December 2019
Welcome to the first installment of NERD Nulls — a rapid-fire roundup of some nutritional studies that didn’t find a clear effect!