donderdag 23 mei 2013

Lycium barbarum overzicht onderzoek

Meta-analysis of the Clinical Effects of Goji Juice Consumption on General Well-being 
Hsu C-H (P), Nance DM, Amagase H. A meta-analysis of clinical improvements of general well-being by a standardized Lycium barbarum. J Med Food. November 2012;15(11):1006-1014.

Goji (Lycium barbarum) fruit, used traditionally in Asia, is viewed as a "superfood" or a food with multiple beneficial properties to support health; however, there are not many clinical trials that have specifically investigated this claim. Also, standardization of goji juice is not widespread. The authors' previous clinical trials reported elevated parameters of general health, including energy expenditure, immune system, gastrointestinal health, and general well-being, in those supplemented with goji for between 14 to 30 days. This meta-analysis of the authors' previous randomized, placebo-controlled, blinded clinical trials analyzed whether goji juice consumption resulted in an increase of well-being in healthy subjects.

A MEDLINE search yielded only the 4 studies previously completed by the authors. The goji product used was GoChi® (FreeLife International; Phoenix, Arizona). GoChi was standardized to the amount of goji polysaccharides (LBPs) in 150 g of the fresh fruit. [Note: The exact amount of LBPs is not specified.] The placebo was designed to be the same color, flavor, and taste as GoChi and contained artificial fruit flavoring, citric acid, and caramel color. Included subjects were healthy; over 18 years of age; without organ diseases; had no allergy to goji or other fruit juice; were not pregnant or breastfeeding; were not undergoing therapy for immune, liver, or kidney problems; and were not taking warfarin.

Subjects (n=161) were randomly assigned to either the treatment group (n=80) or the placebo group (n=81). Dropouts were due to deviation from the study protocol, moving, or other "personal" reasons, but it is not specified how many subjects left the study. The diet of the participants was kept consistent through the use of a food diary. No differences between soda, coffee, tea, alcohol, or tobacco usage were noted between the groups.

The studies consisted of a washout period ranging from 2 weeks to 2 months with no goji consumption prior to the study period. After randomization, subjects underwent an exam, and weight, body mass index, body fat, blood pressure, and heart rate were measured. Participants received a questionnaire covering fatigue and associated symptoms like weakness, short-term memory, and mental functioning. Subjects were asked to assess these parameters, ranging from 0 (better) to 5 (worse), at the baselines and endpoints of the studies. Goji juice (120 ml) was administered after breakfast each morning for a time period ranging from 14 to 30 days. Compliance was ensured by daily observation. Physical parameters were also measured at the endpoints of the studies. Changes in questionnaire scores were the primary outcome, and tests for heterogeneity determined the statistical analysis.

A total of 161 subjects were analyzed in this study. Heterogeneity was found in calmness, energy, procrastination, and shoulder stiffness parameters in 3 of the studies. A random effects model was used for these analyses, and no significant changes were observed in these parameters in the treatment group. For those parameters without heterogeneity, a fixed effects model was used, and significant improvement was seen in fatigue (P=0.0103), weakness (P=0.0049), depression (P=0.0287), stress (P=0.005), mental acuity (P=0.0142), shortness of breath (P=0.0219), focus (P=0.0026), circulation (P=0.0486), sleep (P=0.0050), daydreaming (P=0.0054), and general well-being (P=0.0021). When only analyzing improvement or lack thereof, significant improvement was observed in fatigue, dizziness, and sleep, according to both fixed and random effects models.
This meta-analysis showed positive effects of supplementation with goji juice on multiple parameters of health and stress, despite small sample sizes in the individual studies. It is mentioned that the dosage used was estimated from the apparent amount used in traditional medicine. Future studies are necessary to assess more robust physical parameters and elucidate mechanisms associated with the results reported here.

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