Quercetin halts loss of bone density caused by obesity in rats

Last year Florida State University researchers identified a new syndrome called “osteosarcopenic obesity” that links the deterioration of bone density and muscle mass with obesity, supporting earlier observations of this connection. The syndrome, outlined in the May issue of Aging Research Reviews, explains that abdominal fat (which is more toxic than fat found in other places in the body) has a more negative impact on bone and muscle strength and can also boost inflammation.

Now a research team in China tested whether quercetin supplementation can effectively improve bone quality and promote losing body weight in a mouse model of obesity.

50 male mice (C57BL/6) were randomly divided into groups: normal diet, high fat diet (HFD) and HFD + 0.4% quercetin. They also created a division for the obesity groups into the two kinds of weight phenotypes: diet-induced obesity and obesity-resistant. Analyses and conclusions were made after 15 weeks of diets.

Liver D1 level (used as indicator for abnormal liver development), femoral bone and oxidative stress biomarkers were examined. The bone markers included bone formation related gene expression and osteoclast differentiation related gene expression.

The researchers found that the body weight of mice fed HFD + quercetin was 12.5% lower than HFD alone. They speculated that quercetin reduced HFD fed mice body weight by increasing thyroid hormone depending energy consumption. Compared with the control group, femoral bone mineral content, bone strength, ash content, calcium content in HFD only mice were significantly lower than that of the control group. However the HFD + quercetin fed groups femoral bone mineral content, bone strength, ash content, bone length was significantly higher than that of the HFD only group. Quercetin likely improved femoral bone by alleviating oxidative stress and regulating col1a1, BMP-2, RANKL/OPG expression which impact bone health.

The study did not have more details about dosing than the “HFD + 0.4% quercetin”. So this calculation is speculative but creates some perspective. The average daily consumption of feed for an adult 25 g mouse is 3-5g. If we use the 5g value then 0.4% quercetin would mean 20mg of quercetin. In dosing terms that becomes 4g/kg/day. Now we can we calculate the Human Equivalent Dose (HED). The FDA has specified guidelines for this conversion to Human Equivalent Dose (HED). Using this guideline 4g/kg dosing in mice translates into a HED of approx. 320mg/kg. Or into approximately 17.6gram daily quercetin dose for a person weighing 70kg. That is a high amount and it would have been useful the researchers would have done the same study using lower supplementation amounts. Quercetin is typically sold in 0.5g servings and has been used at high dosing.

In conclusion this study suggest that oral supplementation with quercetin may improve bone quality and promote loss of body weight. Given the discussion around dosing amounts with quercetin is would be great for some testing results with humans to come out. In the mean time this adds to the potential health benefits of quercetin supplementation.

You can the research paper here.

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