BACKGROUND: A significant body of research demonstrates that intake of berries and berry phytochemicals favorably influence metabolism via a number of different biological mechanisms. However, raspberries and select phytochemicals present in raspberries have been less studied than several other berry fruits. OBJECTIVE:The current study tested the relative effect of whole raspberry products or raspberry phytochemicals using the C57BL/6J mouse fed a high-fat, high-sucrose diet as a model for the obesigenic Western diet. The development of obesity and related metabolic complications were measured. METHODS: C57BL/6J mice were fed experimental diets for ten weeks. Diets were formulated to include a typical dietary level of whole raspberry food products, or for the case of ellagic acid (EA) and raspberry ketone (RK), levels that could be reasonably achieved with typical dietary supplement use. In week nine, a glucose tolerance test was conducted. After ten weeks, animals were sacrificed, serum collected, and liver tissue saved for histology and lipid accumulation measurements. RESULTS: Addition of raspberry food products and phytochemicals to high-fat diet reduced body weight gain significantly when raspberry juice and puree concentrates (RJC and RPC), and the EA+RK combination were added. Food efficiency values reflected these weight changes, with the same three groups having food efficiencies similar to normal-weighted lowfat fed mice. Serum insulin and resistin levels were measured and resistin levels were reduced in the two groups fed high fat diets with RPC or RJC added. A histological evaluation of liver tissue was completed and some differences were impacted by diet. CONCLUSIONS: When added to a high-fat diet, raspberry juice and puree concentrates and the combination of EA+RK decreased weight gain and food efficiency obesity associated with consumption of the obesigenic high-fat, high-calorie diet. Future studies are required to determine mechanisms that may be responsible for these changes.

Genistein and daidzein decrease mice food intake, ameliorate symptoms of metabolic syndrome, including decreasing body weight gain, and improving glucose metabolism, and appear to produce differential effects, possibly via the regulation of LXR-mediated pathways.

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.