Consumption of a single serving of red raspberries per day reduces metabolic syndrome parameters in high-fat fed mice

Abstract

Using an animal model for diet-induced metabolic disease, we have shown previously that the addition of raspberry juice concentrate (RJC) and raspberry puree concentrate (RPC) at a level of 10% of kcal, equivalent to four servings per day, to an obesogenic high-fat, western-style diet (HF) significantly reduced body weight gain, serum resistin levels, and altered the expression of hepatic genes related to lipid metabolism and oxidative stress. This study was designed to examine the effect of a lower level of RJC or RPC consumption, at a level representing a single serving of food per day (2.5% of kcal). For ten weeks, four groups of C57BL/6J mice (n = 8 ea.) were fed: low fat (LF), HF, HF + RJC, or HF + RPC diets. Intake of RJC and RPC decreased final body weight. Hepatic lipid accumulation was significantly decreased in HF + RPC- and HF + RJC-fed mice, compared to HF-fed mice. Further, the relative expression of hepatic genes including Heme oxygenase 1 (Hmox1) and Hormone sensitive lipase (Lipe), were altered by RPC or RJC consumption. In this mouse model of diet-induced metabolic disease, consumption of the equivalent of a single daily serving of either RPC or RJC improved metabolism in mice fed HF diet. We hypothesize that the phytochemicals contained in raspberries, and/or their subsequent metabolites, may be acting to influence gene expression and other regulatory pathways, to produce the metabolic improvements observed in this study.

Red Raspberry Polyphenols Attenuate High‐Fat Diet–Driven Activation of NLRP3 Inflammasome and its Paracrine Suppression of Adipogenesis via Histone Modifications

“…bioactive molecules that induce metabolic improvement [31]. Recently, Zhao et al reported metabolic benefits of consuming RR by supplementing with a freeze-dried powder of whole RR fruits containing ~1% of polyphenols in gallic acid equivalent (GAE).…”

Effects of Dietary Red Raspberry Consumption on Pre-Diabetes and Type 2 Diabetes Mellitus Parameters

“…Of the identified animal studies utilizing whole RR as a treatment for the consequences of a HFD, three studies assessed markers of hepatic steatosis (Table 2). A HFD diet induced ectopic lipid accumulation in the liver of WT mice [35,37], whereas RR produced a significant decrease in hepatic lipid droplets but not total TG in liver tissue, while RPC and RJC decreased liver lipid levels, although not to levels expressed by mice fed a LFD [35,37]. RPC and RJC significantly increased hepatic gene expression of TG catabolism and RJC alone showed increased expression of genes protective against oxidative stress in the liver [37].…”

“…Insulin resistance promoted by a HFD was improved with RR supplementation, albeit only partial restoration of insulin signaling in IngWAT was seen [36]. Raspberry juice concentrate (RJC) was effective in lowering insulin levels raised due to a HFD, but not in lowering elevated fasting glucose levels [37]. Wild type (WT) mice fed a standard chow diet benefited from RR supplementation through induced insulin signaling [35].…”

“…While Zhao et al (2018) and Xing et al (2018) found increased mitochondrial biogenesis in skeletal muscle and IngWAT, respectively, with RR treatment, Zhu et al (2018) reported a decrease in liver mitochondrial biogenesis without any changes in respiratory exchange ratio (RER) compared to HFD alone, suggesting that lipids remained the preferred fuel source [33,35,36]. Supplementation of a HFD with RR was shown to prevent excess weight gain, decreased fat accumulation in skeletal muscle, and decreased WAT mass in different rodent models [33,34,36,37]. Conversely, Zhu et al showed only a decreasing trend in excess body weight in WT mice fed a HFD supplemented with RR and Noratto et al (2017) found no change in body weight, BMI, body fat mass, or organ weight in obesity-prone mice fed a standard diet supplemented with RR [35,38].…”

“…Of the RCTs with human participants (Table 1), only one study measured serum adipokines in adults with symptoms of MetSy [46]. A daily treatment of 300 g of combined whole strawberries, raspberries, and cloudberries (SRC) increased serum leptin levels over time, with no change in resistin levels compared to a control group with restricted berry consumption, suggesting that combined berry intake may suppress appetite and regulate excess energy consumption [37]. Weight loss due to reduced energy consumption has been shown to ameliorate MetSy and therefore has the potential to prevent progression to conditions such as T2DM and CVD [5].…”