What blueberries can do, cherries can do too. Researchers at the University of Michigan published a study in which rats that had been fattened with a high-fat diet developed more muscle and less fat mass when they were given a supplement of anthocyanins derived from cherries.
Scientists like to experiment with anthocyanins, the phenols present in grapes, berries, cherries, raspberries and strawberries. Animal studies have shown that they inhibit the formation of fat reserves, probably by making muscle cells more sensitive to insulin, and thereby increasing nutrient uptake.
One of these pieces of research was published in 2009 in the Journal of Medicinal Food. The publication describes an experiment with Zucker rats that were given food with extra fat and sugar for 90 days [CON]. Half of the rats got the same food, but with an additional 1 percent cherry extract containing anthocyanins [CHE]. The human equivalent of this dose is approximately 8-12 g/day.
The table below gives the composition of the extract.
The structural formulas of two cherry-anthocyanins are shown below: on the left cyanidin-3-glucoside, on the right cyanidin-3-rutoside.
Supplementation reduced the increase in fat mass and stimulated the growth of lean muscle mass. But the cherry extract did not prevent the rats from gaining weight.
In the rats that had been given the supplement, the fat cells produced fewer inflammatory factors such as Interleukine-6 and Tumor Necrosis Factor-alpha. At the same time the supplementation also boosted the production of PPAR proteins, with which cells detect fat.
So the anthocyanins make fat tissue healthier by inhibiting inflammatory reactions. Probably as a result of this the fat cells absorb more nutrients. The effect on the body composition, however, makes one suspect that a similar process also takes place in the muscle cells, but then even more so. Whether that is indeed the case the researchers did not look into.
Regular tart cherry intake alters abdominal adiposity, adipose gene transcription, and inflammation in obesity-prone rats fed a high fat diet.
Obesity, systemic inflammation, and hyperlipidemia are among the components of metabolic syndrome, a spectrum of phenotypes that can precede the development of type 2 diabetes and cardiovascular disease. Animal studies show that intake of anthocyanin-rich extracts can affect these phenotypes. Anthocyanins can alter the activity of tissue peroxisome proliferator-activated receptors (PPARs), which affect energy substrate metabolism and inflammation. However, it is unknown if physiologically relevant, anthocyanin-containing whole foods confer similar effects to concentrated, anthocyanin extracts. The effect of anthocyanin-rich tart cherries was tested in the Zucker fatty rat model of obesity and metabolic syndrome. For 90 days, rats were pair-fed a higher fat diet supplemented with either 1% (wt/wt) freeze-dried, whole tart cherry powder or with a calorie- and macronutrient-matched control diet. Tart cherry intake was associated with reduced hyperlipidemia, percentage fat mass, abdominal fat (retroperitoneal) weight, retroperitoneal interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) expression, and plasma IL-6 and TNF-alpha. Tart cherry diet also increased retroperitoneal fat PPAR-alpha and PPAR-gamma mRNA (P = .12), decreased IL-6 and TNF-alpha mRNA, and decreased nuclear factor kappaB activity. In conclusion, in at-risk obese rats fed a high fat diet, physiologically relevant tart cherry consumption reduced several phenotypes of metabolic syndrome and reduced both systemic and local inflammation. Tart cherries may reduce the degree or trajectory of metabolic syndrome, thereby reducing risk for the development of type 2 diabetes and heart disease.
PMID: 19857054 [PubMed – indexed for MEDLINE]