Low follicular oestrogen levels in New Zealand women consuming high fibre diets: a risk factor for osteopenia?
OBJECTIVE
To study effects of anthropometry, diet and exercise on plasma 17 beta-oestradiol concentrations in healthy premenopausal women.


METHODS
Fifty-five healthy female volunteers aged 19-29 (Mean (SD) = 22.2 (2.6) years) were studied. Anthropometric measurements were made, food intakes were estimated using a food frequency questionnaire, physical activity was assessed, menstrual histories were taken and blood 17 beta-oestradiol values were measured in the follicular and luteal phases of the menstrual cycle.


RESULTS
Adiposity and dietary fat intake did not influence circulating plasma 17 beta-oestradiol but dietary fibre intake was negatively correlated with both follicular (r = -0.43, p < 0.001) and luteal (r = -0.28, p < 0.05) 17 beta-oestradiol concentrations. Follicular oestradiol values were abnormally low in 53% of the population. Subjects with high fibre intakes (> or = 25 g fibre daily) had significantly lower concentrations of 17 beta-oestradiol in the follicular phase of the menstrual cycle (p < 0.01). Physical activity was similar in groups consuming high and low fibre diets. Subjects with oligomenorrhoea or amenorrhoea (n = 7) had higher fibre intakes/energy (p < 0.05) than subjects with eumenorrhoea (n = 48).


CONCLUSIONS
Our study suggests that healthy New Zealand women of premenopausal age have lower 17 beta-oestradiol levels on high fibre diets than on low fibre diets. Because hypoestrogenism is a known risk factor for osteoporosis we propose that high fibre intakes may influence bone mass adversely and be a risk factor for osteoporosis. The effects of high fibre intakes on bone mass warrant further investigation.
Feng
W
W
Department of Human Nutrition, Otago School of Medicine, University of Otago, Dunedin.
Marshall
R
R
Lewis-Barned
N J
NJ
Goulding
A
A
D000328:Adult; D000568:Amenorrhea / Q000097:blood / Q000209:etiology; D000886:Anthropometry; D001851:Bone Diseases, Metabolic / Q000209:etiology; D004041:Dietary Fats / Q000008:administration & dosage / Q000009:adverse effects; D004043:Dietary Fiber; D002149:Energy Intake; D004958:Estradiol / Q000097:blood*; D005260:Female; D005498:Follicular Phase / Q000097:blood*; D006801:Humans; D008183:Luteal Phase / Q000097:blood*; D009520:New Zealand; D009839:Oligomenorrhea / Q000097:blood / Q000209:etiology; D017697:Premenopause / Q000097:blood*; D012307:Risk Factors
D004041:Dietary Fats; D004043:Dietary Fiber; D004958:Estradiol