Safety assessment of common foods enriched with natural nonesterified plant sterols.
OBJECTIVE
To assess safety during a diet based on low-fat foods enriched with nonesterified wood-derived plant sterols and mineral nutrients related to serum phytosterol, sex hormone and fat-soluble vitamin metabolism.


METHODS
Seventy-one study participants (52 women, 19 men) with mild-to-moderate hypercholesterolemia completed the double-blind, placebo-controlled feeding trial lasting for 15 weeks. The subjects were randomly allocated to the sterol group receiving food items enriched with mineral nutrients as well as with a total of 1.25, 2.5 and 5.0 g per day of plant sterols during the first, second and third 5-week periods, respectively, or to the placebo group receiving similar food items without plant sterols. This outpatient clinical trial with free-living subjects was carried out at two hospital clinics.


RESULTS
Two significant findings were observed. Serum sitosterol concentrations increased from 2.84 to 5.35 mg l(-1) (P<0.004 vs placebo) but those of serum total plant sterols did not because of compensatory changes in other phytosterols. The highest plant sterol levels did not exceed 0.6% of total serum sterols. Serum alpha-tocopherol concentrations decreased in the sterol group by 10% (P<0.0002), but the between-group difference disappeared after adjusting for the change in the carrier (LDL cholesterol).


CONCLUSIONS
Fifteen-week consumption of natural nonesterified plant sterol-enriched food does not cause any serious adverse effects during such a period. However, serum alpha-tocopherol levels were somewhat reduced in the sterol group suggesting that long-term effects of plant sterols on serum fat-soluble vitamin concentrations should be further explored, especially in relation to very low-fat diets.
Tuomilehto
J
J
Department of Health Promotion and Chronic Disease Prevention, Division of Biochemistry, National Public Health Institute, University of Helsinki, Finland.
Tikkanen
M J
MJ
Högström
P
P
Keinänen-Kiukaanniemi
S
S
Piironen
V
V
Toivo
J
J
Salonen
J T
JT
Nyyssönen
K
K
Stenman
U-H
UH
Alfthan
H
H
Karppanen
H
H
D000328:Adult; D000368:Aged; D008078:Cholesterol, LDL / Q000097:blood; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D005387:Finland; D005527:Food, Fortified; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D006937:Hypercholesterolemia / Q000188:drug therapy; D000960:Hypolipidemic Agents / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010840:Phytosterols / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D012855:Sitosterols / Q000097:blood*; D014815:Vitamins / Q000097:blood; D024502:alpha-Tocopherol / Q000097:blood
D008078:Cholesterol, LDL; D012739:Gonadal Steroid Hormones; D000960:Hypolipidemic Agents; D010840:Phytosterols; D012855:Sitosterols; D014815:Vitamins; C025473:gamma-sitosterol; D024502:alpha-Tocopherol