1.
Sugar-sweetened beverages, urate, gout and genetic interaction.
Merriman, TR, Dalbeth, N, Johnson, RJ
Pacific health dialog. 2014;(1):31-8
Abstract
The clinical manifestations of gout occur as a result of immune responses to monosodium urate crystals. Elevated serum levels of urate (hyperuricemia) are a prerequisite for the development of gout with reduced fractional renal excretion of uric acid (FEUA) an important cause. In New Zealand, Mãori and Pacific Island people have inherently raised urate levels with one consequence a higher prevalence of more severe gout. One characteristic metabolic effect of fructose, present in sugar-sweetened beverages (SSB), is raised urate from hepatic processing of fructose. Here we discuss, and place in a biological context evidence, linking consumption of SSB with hyperuricemia and gout, including the first review of recent ecological and clinical studies of the impact of fructose and SSB exposure in Pacific Island people. Both increased serum urate and increased FEUA are observed in clinical studies examining the effects of an acute fructose load. In contrast, chronic exposure to increased fructose in the diet also leads to increased serum urate concentrations, but reduced FEUA. Epidemiological studies have consistently associated SSB consumption with increased serum urate levels and increased risk of gout. Non-additive interaction of SSB consumption with a genetic variant of a uric acid transporter in serum urate levels and gout risk emphasizes the causality of SSB in gout. Taken together these data demonstrate the hyperuricemic effect of SSB and fructose, with biochemical pathways reasonably well understood. The evidence that dietary fructose increases urate is strong. The evidence summarized here is of sufficient weight to recommend reduction of SSB consumption, particularly in Pacific Island and Mãori people, to reduce the burden of gout.
2.
Regular consumption of concord grape juice benefits human immunity.
Rowe, CA, Nantz, MP, Nieves, C, West, RL, Percival, SS
Journal of medicinal food. 2011;(1-2):69-78
Abstract
γδ T cells are important immune surveillance cells residing in epithelial layers lining the intestine, lung, and reproductive tract. The main objective of this study was to test the hypothesis that consumption of dietary compounds from grapes would modify γδ T-cell function. Other factors related to immune function after grape juice consumption were also tested. A randomized, double-blind, placebo-controlled, parallel intervention was conducted: 100% grape juice made from Concord grapes or a placebo beverage was consumed by 85 individuals daily for 9 weeks. Subjects were asked not to consume other red, blue, and purple fruits during the study. Blood samples, taken at the beginning and the end, were analyzed for γδ T-cell numbers and proliferation, vitamin C, antioxidant capacity, and the ability to protect DNA from strand breaks. Those consuming the grape juice had significantly greater numbers of circulating γδ T cells and higher serum vitamin C levels compared to the placebo by two-way repeated-measure analysis of variance (P < .05). Individuals consuming the placebo had lower serum antioxidant activity, less γδ T-cell proliferation, and increased DNA strand breaks when challenged with H(2)O(2). Analysis of the data by structural equation modeling confirmed that 61% of the variance in biological functions at 9 weeks was due to grape juice consumption. Based on conventional statistical analyses, as well as on sophisticated modeling techniques, regular consumption of purple grape juice in the absence of other red, blue, or purple fruits benefited immunity in healthy, middle-aged human subjects.
3.
Immune-modulating efficacy of a polyphenol-rich beverage on symptoms associated with the common cold: a double-blind, randomised, placebo-controlled, multi-centric clinical study.
Schütz, K, Sass, M, de With, A, Graubaum, HJ, Grünwald, J
The British journal of nutrition. 2010;(8):1156-64
Abstract
In the present study, the immune-modulating efficacy of a polyphenol-rich beverage on symptoms associated with the common cold was evaluated. For this purpose, ninety-eight patients reporting common cold symptoms that began no longer than 24 h before the study intervention were randomly assigned to consume either the test beverage or placebo twice per d for 10 d. The severity of the disease was expressed as the total score of the five cold symptoms 'general feeling of sickness', 'headache and/or joint aches', 'sore throat and/or difficulty swallowing', 'hoarseness and/or cough' and 'stuffy nose/sniffle'. Consequently, the decrease from 10.2 (sd 3.1) points at the beginning to 2.1 (sd 2.7) points by the end of the study in the verum group demonstrated a clear improvement, whereas in the placebo group only a reduction from 10.5 (sd 3.0) to 6.3 (sd 3.8) points could be observed. The mean difference between the groups (primary efficacy criterion) of 3.9 points was highly significant (P < 0.01). At the end of the study there were highly significantly (P < 0.01) more patients in the verum group complaint free than in the placebo group (secondary efficacy criterion). In addition to these self-reported values, several local findings of the physical examination were also significantly improved in the verum group.