Nutritional Requirements Throughout the Life Cycle: Fertility

The role of nutrition in fertility has been the subject of a limited body of research focusing particularly on the role of antioxidants, other micronutrients, and alcohol. However, while nutritional and lifestyle factors may affect fertility directly, they also influence risk for several diseases that impair fertility, including polycystic ovarian syndrome, endometriosis, and uterine fibroids (see relevant chapters).

In females, some studies suggest a potential role for high–dose (750 mg/day) vitamin C and combinations of antioxidants, iron, and arginine supplements in achieving pregnancy.²¹ Celiac disease, an immune–mediated condition triggered by gluten, can also impair fertility in women by causing amenorrhea, inducing malabsorption of nutrients needed for organogenesis, and resulting in spontaneous abortion. In affected individuals, fertility may be improved by a gluten–free diet.²²

In males, infertility may occur by disruption of the normal equilibrium between the production of reactive oxygen species by semen and oxygen–radical scavengers. This may occur through smoking, infection of the reproductive tract, varicocele,²³ and perhaps through poor diet as well. The result is oxidative damage to sperm. Controlled studies of high–dose combinations of supplementary antioxidants (vitamins C, >200 mg/day; vitamin E, 200–600 IU/day; selenium, 100–200 μg/day) improved sperm motility and morphology and increased pregnancy rates, particularly in former smokers.²³

Carnitine is concentrated within the epididymis and contributes directly to the energy supply required by sperm for maturation and motility.²⁴ Treatment with carnitine or acetylcarnitine (1.0–2.0 g/day) increases the number and motility of sperm, and the number of spontaneous pregnancies.^23,24

Alcohol consumption is associated with decreased fertility in both women²⁵ and men.²⁶ In males, alcohol consumption contributes to impotence and also to a reduction of blood testosterone concentrations and impairment of Sertoli cell function and sperm maturation.²⁶