The lack of effect of isoflavones on high-density lipoprotein cholesterol concentrations in adolescent boys: a 6-week randomised trial.
BACKGROUND
A substantial fall in high-density lipoprotein cholesterol (HDL-C) during puberty in boys, but not girls, has been reported in Western populations. The fall in boys is believed to be due to hormonal changes--androgens have been shown to be associated with lower HDL-C, whereas oestrogens are associated with higher HDL-C. The fall in HDL-C during puberty was not observed, however, in a study of Moslem boys in Israel, nor in a group of Japanese boys. A diet high in phyto-oestrogens may account for the lack of a fall in HDL-C in these populations.


OBJECTIVE
To examine the effect of dietary supplementation with phyto-oestrogens on the HDL-C concentration of adolescent boys from a Western population. We hypothesised that dietary supplementation of 50 mg of the isoflavones daidzein and genistein would produce a 12% higher HDL-C concentration than in controls at the end of a 6-week intervention period.


METHODS
A randomised controlled trial.


METHODS
Hellyer College in Burnie (Tasmania, Australia).


METHODS
Adolescent boys (aged 16-18 years) were recruited through a letter sent to parents. A total of 132 eligible participants enrolled and five subjects withdrew from the trial.


RESULTS
No significant increase in HDL-C was observed in the treatment group (-0.02 mmol l(-1), standard error (SE)=0.03, P = 0.53) or the placebo group (0.05 mmol l(-1), SE = 0.03, P = 0.11).


CONCLUSIONS
Factors other than isolated dietary isoflavones may be responsible for the lack of fall in HDL-C during puberty in Japanese and Moslem boys.
Dwyer
Terence
T
Menzies Research Institute, University of Tasmania, Private Bag 23, Hobart, Tasmania 7001, Australia.
Hynes
Kristen L
KL
Fryer
Jayne L
JL
Blizzard
C Leigh
CL
Dalais
Fabien S
FS
D000293:Adolescent / Q000502:physiology; D017195:Adolescent Nutritional Physiological Phenomena / Q000502:physiology*; D001315:Australia; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D008076:Cholesterol, HDL / Q000097:blood*; D003431:Cross-Cultural Comparison; D004045:Dietary Services; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D007557:Israel; D007564:Japan; D008297:Male; D048789:Phytoestrogens / Q000494:pharmacology*; D011627:Puberty / Q000097:blood*; D013648:Tasmania; D016896:Treatment Outcome
D008076:Cholesterol, HDL; D007529:Isoflavones; D048789:Phytoestrogens