The retrospective cohort study involved 900 men with varicocele—a common cause of infertility that impairs sperm production by disrupting testicular function and increasing oxidative stress, damaging sperm through lipid peroxidation, mitochondrial dysfunction and DNA fragmentation.
The researchers in China aimed to evaluate the effects of dietary antioxidants and micronutrient status on oxidative stress and semen quality in patients with varicocele.
“Men with varicocele demonstrated impaired sperm quality and reduced fertility potential, which appeared to be associated with increased oxidative stress and alterations in antioxidant status,” the researchers wrote in Frontiers in Nutrition. “The findings also suggest that lifestyle and dietary antioxidant intake may play a contributory role in modulating these effects.”
Dietary antioxidants may help improve sperm health
Male infertility contributes to around half of all infertility cases, with varicocele affecting between 15 and 20% of the male population and up to 40% of infertile men.
Dietary antioxidants and micronutrients—including vitamins, trace elements, amino acids and other bioactive compounds—can counteract oxidative stress by scavenging free radicals and supporting endogenous antioxidant enzymes.
Studies have shown that antioxidant supplementation can improve semen quality and reduce sperm DNA fragmentation in subfertile men, suggesting that increasing antioxidant availability may mitigate reactive oxygen species (ROS) -induced reproductive damage.
In men with varicocele, increased scrotal temperature and poor blood flow can also promote oxidative stress, leading to reduced sperm movement, impaired mitochondrial function and DNA damage.
Poor nutrition and oxidative stress to male infertility
The researchers conducted the study between 2021 and 2023 using the medical records of men aged 20 to 45 years with clinically and Doppler-confirmed varicocele. Participants were classified into Grade I, II and III severity groups.
They included infertile men with complete clinical information and excluded those with genetic infertility, systemic diseases affecting fertility, incomplete records or other conditions that could influence reproductive outcomes. Semen quality was assessed according to World Health Organization 2021 guidelines, including sperm concentration, motility, morphology, viability and DNA integrity.
The researchers collected demographic, lifestyle, dietary, biochemical, hormonal, semen, oxidative stress and reproductive outcome data from existing medical records. They then analyzed treatment outcomes, including conservative management, antioxidant therapy, varicocelectomy, and assisted reproductive technology (ART).
Results showed that nutrition was strongly associated with varicocele severity and sperm quality. Men with more severe varicocele had lower intake of important nutrients, including protein, omega-3 fatty acids, vitamins A, C, D and E, zinc, selenium, magnesium, iron, fiber, as well as antioxidant-rich foods such as fruits and vegetables.
Blood results also showed that Grade III patients had lower levels of zinc, selenium, magnesium, iron and antioxidant markers. They also had increased oxidative stress, with higher ROS levels and reduced protective antioxidants such as total antioxidant capacity, glutathione and superoxide dismutase.
Higher antioxidant intake, particularly zinc, vitamin C and vitamin E, was linked to better sperm concentration and motility. In contrast, lower antioxidant intake and increased oxidative stress were associated with poorer semen quality, greater sperm DNA damage and reduced chances of natural conception.
“We have expanded on previous work through finding that there exists a correlation between the level of severity and malnutrition,” the researchers concluded. “It can be stated that varicocele negatively influences male fertility via the oxidative, endocrine, and nutritional pathways.
“Decreased antioxidant and nutritional parameters contributed to lower reproductive success, whereas logistic regression analysis revealed that both varicocele degree and oxidative stress were significant predictors for sperm quality.”
They added that future long-term studies are needed to determine whether improving antioxidant intake or using targeted antioxidant treatments can improve fertility outcomes.
Source: Frontiers in Nutrition; doi: 10.3389/fnut.2026.1832900; “Dietary antioxidants and micronutrient status in varicocele-associated male infertility: oxidative stress-mediated effects on semen quality.” Authors: B. Fang, et al.
