Carotenes are precursors of vitamin A and function as powerful antioxidants, playing a crucial role in protecting cells against oxidative damage caused by free radicals³. In the context of male fertility, it is well established that oxidative stress impairs sperm function, leading to reduced motility, DNA damage and poor sperm quality⁴. Studies have shown a positive association between β-carotene intake and sperm concentration as well as progressive motility^5,6. The antioxidant properties of β-carotene protect spermatozoa from oxidative stress during spermatogenesis, thus ensuring sperm structural integrity and motility. Moreover, β-carotene has been shown to influence sperm maturation and their ability to fertilize an egg, with studies suggesting that its protective effects against reactive oxygen species (ROS) could be particularly important in improving fertilization rates in ICSI cycles, especially in men with documented sperm quality abnormalities⁷. Studies have also shown that vitamin A deficiency can interrupt spermatogenesis and lead to germ cell degradation, with recovery generally observed after supplementation⁸. This underlines the importance of maintaining adequate levels of this nutrient for optimal fertility.

Coenzyme Q10 (CoQ10) is an essential component of the mitochondrial electron transport chain, responsible for cellular energy production⁹. It is also a powerful antioxidant, reducing oxidative stress by neutralizing free radicals⁹. This dual role is particularly beneficial for spermatozoa, which require high levels of energy for motility and are highly vulnerable to oxidative damage¹⁰. Research has consistently shown that CoQ10 supplementation leads to significant improvements in sperm parameters, particularly in men suffering from idiopathic infertility ¹⁰. A systematic review concluded that CoQ10 supplementation improves sperm motility, concentration and overall sperm quality, making it an essential nutrient for men with asthenozoospermia (low sperm motility)¹⁰. CoQ10 has also been shown to increase antioxidant enzyme activity in seminal plasma, reducing lipid peroxidation and DNA damage to sperm cells, while improving their function¹¹. This protective effect is crucial for maintaining sperm integrity and ensuring their ability to fertilize an egg. In addition, CoQ10 supplementation can improve sperm mitochondrial function, increasing energy production, a critical factor for sperm motility¹¹.

Lycopene is a natural compound found in tomatoes and other red fruits, and is the most effective of all carotenoids at neutralizing harmful oxygen molecules¹². Its powerful antioxidant properties make it an important element in protecting spermatozoa from damage¹². Studies have shown that lycopene supplementation can significantly improve sperm motility and DNA integrity, reduce markers of oxidative stress in seminal plasma, and decrease lipid peroxidation and DNA damage¹². In addition, lycopene has been shown to reduce DNA damage in spermatozoa, increasing the chances of successful oocyte fertilization and promoting better embryonic development¹².

Several studies have revealed that men with low vitamin D levels are more likelyto have reduced sperm motility and lower testosterone levels, both of which are essential to male fertility¹³. Vitamin D supplementation has been shown to improve motility by increasing the influx of calcium into sperm cells, which is crucial for their proper function¹⁴. Vitamin D also helps regulate hormonal balance, promoting testosterone production and improving overall reproductive health¹⁴. Research also suggests that vitamin D may have anti-inflammatoryand antioxidant effects, helping to protect sperm cells from oxidative damage and improve their motility¹⁵. This is particularly important for maintaining sperm DNA integrity and reducing the risk of DNA fragmentation, which can impair fertility¹⁵. By improving sperm motility, increasing testosterone levels and protecting sperm from oxidative stress, vitamin D plays a crucial role in optimizing male fertility outcomes.