Phloem fortification in rye bread elevates serum enterolactone level.
OBJECTIVE
To analyse the lignan content of phloem powder enriched rye bread and to study the dose-response relationship of the effect of dietary plant lignans derived from phloem on intestinal production of enterolactone by measuring enterolactone concentration in serum.


METHODS
A randomized double-blind supplementation trial.


METHODS
Seventy-five non-smoking men recruited by newspaper advertisements.


METHODS
Subjects were randomized to three study groups receiving either rye bread high in phloem (HP, 14% of rye flour substituted with phloem powder), rye bread low in phloem (LP, 7% of rye flour substituted with phloem powder) or placebo rye bread. Participants consumed 70 g of study bread daily for 4 weeks and provided serum samples for enterolactone analysis at baseline and at the end of the intervention.


RESULTS
There was a significant increase in serum enterolactone concentration in the LP and HP groups compared with the placebo group (P=0.009 and P=0.003, respectively). Considerable interindividual differences were observed in the response to dietary lignans within the study groups.


CONCLUSIONS
Our results indicate that plant lignans attached to insoluble fibre layer in phloem can be further metabolized and converted to enterolactone presumably by the bacteria present in the colon. Phloem powder is useful source of lignans for functional foods aimed to elevate serum enterolactone levels.


BACKGROUND
Phloem powder and the study breads were provided by Finnpettu Oy and Linkosuo Oy, respectively. The clinical study work was sponsored in part by Oy Jurilab Ltd.
Vanharanta
M
M
The Research Institute of Public Health, University of Kuopio, Kuopio, Finland.
Mursu
J
J
Nurmi
T
T
Voutilainen
S
S
Rissanen
T H
TH
Salonen
R
R
Adlercreutz
H
H
Salonen
J T
JT
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000097:blood*; D000328:Adult; D000368:Aged; D001939:Bread; D003106:Colon / Q000382:microbiology*; D004043:Dietary Fiber / Q000008:administration & dosage / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005285:Fermentation; D005527:Food, Fortified; D006801:Humans; D017705:Lignans / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D012434:Secale; D012995:Solubility
D004043:Dietary Fiber; D017705:Lignans; D015107:4-Butyrolactone; C029497:2,3-bis(3'-hydroxybenzyl)butyrolactone