Male obesity is associated with impaired reproductive health. One potential mechanism common to multiple causes of subfertility is oxidative stress in sperm. Dietary supplementation with antioxidants reduces sperm oxidative stress in normal weight men. However, the effects of dietary micronutrient supplementation in obese males on sperm quality and function have not been investigated to date.
We used a mouse model of diet induced obesity (i.e. a high fat diet; HFD) to examine the effects of dietary micronutrient supplements with anti-oxidative properties on sperm quality and function for a duration that spans two rounds of spermatogenesis (10 weeks). Sperm measures of motility, concentration, morphology, intracellular reactive oxygen species (ROS), oxidative DNA damage, capacitation, binding and fertilisation rates were examined. In addition, body composition, glucose and insulin tolerance; serum metabolites, testosterone and C-Reactive Protein (CRP) concentrations were also examined.
Mice fed a HFD supplemented with micronutrients had reduced total adipose tissue mass with no changes in serum metabolites, testosterone, CRP or glucose and insulin tolerance compared to mice fed a non-fortified HFD. Micronutrient supplementation of a HFD improved normal sperm morphology, reduced sperm intracellular ROS and reduced 8-hydroxyguanosine (8-OHdG) fluorescence, a biomarker for oxidative DNA damage, with no effect on sperm motility or concentration. Furthermore, sperm capacitation, binding and fertilisation were also improved when mice consumed a HFD supplemented with micronutrients, which are normally compromised by the HFD regime.
This study demonstrates that impaired sperm quality and function resulting from male diet induced obesity can be improved by micronutrient supplementation for 10 weeks, without a change of diet. Moreover, given that obesity is often linked with a lack of basic nutrients including essential vitamins and minerals, our findings suggest that micronutrient supplementation may attenuate obesity associated nutrient deficiencies ultimately improving spermatogenesis and sperm quality and function.