Dipartimento della Donna, del Neonato e del Bambino, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 12, 20122, Milan, Italy.
Reproductive Sciences Laboratory, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy.
Nutr J. 2017 Jun 24;16(1):37. doi: 10.1186/s12937-017-0257-2.
Semen quality, a predictor of male fertility, has been suggested declining worldwide. Among other life style factors, male coffee/caffeine consumption was hypothesized to influence semen parameters, but also sperm DNA integrity. To summarize available evidence, we performed a systematic review of observational studies on the relation between coffee/caffeine intake and parameters of male fertility including sperm ploidy, sperm DNA integrity, semen quality and time to pregnancy.
A systematic literature search was performed up to November 2016 (MEDLINE and EMBASE). We included all observational papers that reported the relation between male coffee/caffeine intake and reproductive outcomes: 1. semen parameters, 2. sperm DNA characteristics, 3. fecundability. All pertinent reports were retrieved and the relative reference lists were systematically searched in order to identify any potential additional studies that could be included.
We retrieved 28 papers reporting observational information on coffee/caffeine intake and reproductive outcomes. Overall, they included 19,967 men. 1. Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration. 2. As regards sperm DNA defects, caffeine intake seemed associated with aneuploidy and DNA breaks, but not with other markers of DNA damage. 3. Finally, male coffee drinking was associated to prolonged time to pregnancy in some, but not all, studies.
The literature suggests that caffeine intake, possibly through sperm DNA damage, may negatively affect male reproductive function. Evidence from epidemiological studies on semen parameters and fertility is however inconsistent and inconclusive. Well-designed studies with predefined criteria for semen analysis, subject selection, and life style habits definition, are essential to reach a consistent evidence on the effect of caffeine on semen parameters and male fertility.
精液质量是男性生育力的预测指标，据报道全球范围内精液质量呈下降趋势。在其他生活方式因素中，男性咖啡/咖啡因的摄入被认为会影响精液参数，也会影响精子 DNA 的完整性。为了总结现有证据，我们对观察性研究进行了系统评价，这些研究评估了咖啡/咖啡因摄入与男性生育力参数（包括精子倍性、精子 DNA 完整性、精液质量和妊娠时间）之间的关系。
我们进行了系统的文献检索，截至 2016 年 11 月（MEDLINE 和 EMBASE）。我们纳入了所有报告男性咖啡/咖啡因摄入与生殖结局之间关系的观察性论文：1. 精液参数，2. 精子 DNA 特征，3. 生育能力。检索到所有相关报告，并系统地搜索了相关的参考文献列表，以确定任何可能纳入的潜在额外研究。
我们检索到 28 篇报告了咖啡/咖啡因摄入与生殖结局关系的观察性信息的论文，共纳入 19967 名男性。1. 精液参数似乎不受咖啡因摄入的影响，至少来自咖啡、茶和可可饮料的咖啡因不会影响，在大多数研究中。相反，其他研究表明，含可乐的饮料和含咖啡因的软饮料会对精液量、计数和浓度产生负面影响。2. 就精子 DNA 缺陷而言，咖啡因摄入似乎与非整倍体和 DNA 断裂有关，但与其他 DNA 损伤标志物无关。3. 最后，一些研究表明，男性喝咖啡与妊娠时间延长有关，但并非所有研究都如此。
文献表明，咖啡因摄入可能通过精子 DNA 损伤，对男性生殖功能产生负面影响。然而，关于精液参数和生育力的流行病学研究证据不一致且没有定论。对于咖啡/咖啡因对精液参数和男性生育力的影响，需要进行设计良好的研究，具有明确的精液分析、受试者选择和生活方式习惯定义的标准，才能得出一致的证据。
