Polyunsaturated fatty acids in male and female reproduction.
In Westernized societies, average consumption of n-6 polyunsaturated fatty acids (PUFAs) far exceeds nutritional requirements. The ratio of n-6 to n-3 PUFAs is generally >10:1 whereas on a primitive human diet it was closer to 1:1. Diets fed to intensively farmed livestock have followed a similar trend. Both n-6 and n-3 PUFAs can influence reproductive processes through a variety of mechanisms. They provide the precursors for prostaglandin synthesis and can modulate the expression patterns of many key enzymes involved in both prostaglandin and steroid metabolism. They are essential components of all cell membranes. The proportions of different PUFAs in tissues of the reproductive tract reflect dietary consumption. PUFA supplements (particularly n-3 PUFAs in fish oil) are promoted for general health reasons. Fish oils may also benefit fertility in cattle and reduce the risk of preterm labor in women, but in both cases current evidence to support this is inconclusive. Gamma-linolenic acid containing oils can alter the types of prostaglandins produced by cells in vitro, but published data to support claims relating to effects on reproductive health are lacking. Spermatozoa require a high PUFA content to provide the plasma membrane with the fluidity essential at fertilization. However, this makes spermatozoa particularly vulnerable to attack by reactive oxygen species, and lifestyle factors promoting oxidative stress have clear associations with reduced fertility. Adequately powered trials that control for the ratios of different PUFAs consumed are required to determine the extent to which this aspect of our diets does influence our fertility.
Wathes
D Claire
DC
Department of Veterinary Basic Sciences, Royal Veterinary College, North Mymms, Hatfield, Herts, AL9 7TA, United Kingdom. dcwathes@rvc.ac.uk
Abayasekara
D Robert E
DR
Aitken
R John
RJ
D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D005260:Female; D005298:Fertility; D006801:Humans; D008297:Male; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011453:Prostaglandins / Q000502:physiology; D012098:Reproduction / Q000502:physiology*; D013256:Steroids / Q000096:biosynthesis; D014157:Transcription Factors; D014599:Uterus / Q000502:physiology
D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D011453:Prostaglandins; D013256:Steroids; D014157:Transcription Factors