Aim:
The aim of this study was to evaluate the bioavailability of selected carotenoids and vitamins from a fruit and vegetable juice powder concentrate (FV) and their impact on antioxidant status, homocysteine, plasma lipids, and insulin resistance in men.
Methods:
Thirty-two healthy men between the ages of 18 and 50 completed the randomized, double-blind, placebo-controlled, crossover clinical trial. Forty percent of them were smokers. Participants took either an encapsulated fruit and vegetable juice powder concentrate (Juice Plus+®, 2 capsules of the Fruit Blend and 2 capsules of the Vegetable Blend) or placebo for 6 weeks, followed by a 3-week wash-out phase. For the next 6 weeks, the groups switched. Blood samples were collected at baseline, day 21, and after 6 weeks of each intervention period. Coronary heart disease risk was assessed by measuring concentrations of homocysteine, lipids, lipoproteins, glucose, and insulin.
Results:
Compared to placebo, FV increased the concentrations of antioxidants in the blood significantly. Levels of β-carotene rose 4-fold, while concentrations of vitamin C and vitamin E (alpha tocopherol) increased 32% and 9% respectively. In addition, blood levels of folate rose by 79% and homocysteine levels decreased by 8%. There was a positive association between plasma levels of vitamin C and resistance of LDL to oxidation. Plasma glucose, insulin, and lipid concentrations were unaffected. Results were similar among smokers and non-smokers.
Conclusion:
In conclusion, supplementation with a mixed fruit and vegetable concentrate increases plasma ascorbic acid, β-carotene and folate, and lowers plasma homocysteine.
PubMed link:
https://pubmed.ncbi.nlm.nih.gov/12840177/