Effects of one week juice fasting on lipid metabolism: a cohort study in healthy subjects.
OBJECTIVE
We investigated the effects of a popular modified juice fasting program on lipid metabolism.


METHODS
5 healthy, nonobese, male volunteers fasted for 8 days. Daily energy intake was limited to 150-300 kcal/d solely as carbohydrates (vegetable and fruit drinks). Physical activity was maintained as before. At baseline, on days 2, 3, and 8 during fasting, and on days 2 and 8 after fasting, serum lipids, lipoproteins, and insulin were investigated.


RESULTS
Juice fasting resulted in bi-phasic changes: Until day 2 and 3 triacylglycerols (TG), very low-density lipoprotein apolipoprotein B (VLDL apo B), and insulin decreased by 52, 51, and 65% respectively, while nonesterified fatty acids (NEFA), low-density lipoprotein (LDL) apo B, and LDL cholesterol increased by 363, 38, and 35%. Between day 3 and 8 NEFA increased; TG and insulin increased as well, but remained below baseline values, and LDL cholesterol normalized. After 8 days juice fasting significant changes (p < 0.05) compared to the baseline were found only for free cholesterol (-10%), phospholipids (-14%), apo AI (-9%), apo AII (-11%), insulin (-42%), C-peptide (-57%), and NEFA (+535%, p = 0.0001). Total cholesterol decreased by 9% (n.s.) after 8 days. One week after the ending of fasting all parameters returned to normal.


CONCLUSIONS
Contrary to total fasting and fasting with limited physical activity, 8 days juice fasting without limitation of physical activity results in a decrease of free cholesterol and an only initial increase of LDL cholesterol. After 8 days insulin, TG, and VLDL are still lower than at baseline, however, they have increased compared to the initial phase, probably counterregulatory to a further increase of NEFA.
Huber
R
R
Ambulanz für Naturheilverfahren/Abteilung Innere Medizin II, Universitätsklinik Freiburg. rhuber@med1.ukl.uni-freiburg.de
Nauck
M
M
Lüdtke
R
R
Scharnagl
H
H
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D001628:Beverages; D002784:Cholesterol / Q000097:blood; D015243:Cholesterol, VLDL / Q000097:blood; D015331:Cohort Studies; D002149:Energy Intake; D015444:Exercise; D005215:Fasting / Q000097:blood / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005638:Fruit; D006801:Humans; D007328:Insulin / Q000097:blood; D007657:Ketone Bodies / Q000652:urine; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D014280:Triglycerides / Q000097:blood; D014675:Vegetables
D001053:Apolipoproteins; D015243:Cholesterol, VLDL; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007657:Ketone Bodies; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol