Saturated fat has a scientifically validated, though moderate, link to the health and function of the testes, primarily through its influence on testosterone production. Several studies have shown that dietary fat, particularly saturated fat, can affect serum testosterone levels in men. Testosterone, the primary male sex hormone, is synthesized in the Leydig cells of the testes from cholesterol, a process that relies on an adequate supply of dietary lipids. Research published in journals such as Lipids and Journal of Clinical Endocrinology and Metabolism indicates that diets higher in total and saturated fat are associated with higher circulating testosterone levels compared to low-fat diets. However, the magnitude of this effect is modest, and other lifestyle or dietary factors also play significant roles.

It is important to note that while saturated fat can support normal testosterone synthesis, excessive intake is linked to adverse cardiovascular and metabolic health outcomes. Current dietary guidelines do not recommend increasing saturated fat intake for the explicit purpose of supporting testicular or hormonal health. Instead, a balanced intake of healthy fats, including monounsaturated and polyunsaturated fats, is generally advised. In summary, there is moderate scientific evidence supporting a role for saturated fat in testicular hormone production, but this does not translate into a recommendation for high saturated fat diets for testicular health.