Statins reduce your ‘good’ brown fat

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Statins reduce beneficial brown adipose tissue, according to new research. But this is no reason to demonize these drugs, the researchers insist.

A certain proportion of the adult population has not only white adipose (or fatty) tissue, but also brown fat. This brown adipose tissue helps to convert sugar and fat into heat. People with brown adipose tissue are better at regulating their body temperature in the winter, and are less likely to suffer from excess weight or diabetes.

Doctors prescribe statins as a way to reduce the risk of a heart attack since they reduce cholesterol levels in the blood. They are among the most commonly prescribed drugs worldwide.

Connecting the dots

The researchers have been studying brown fat for some time. Previously, they looked into the question of how “bad” white fat cells, which form the layer of fat under our skin, become “good” brown fat cells. Having conducted cell culture experiments, they found out that the biochemical pathway responsible for producing cholesterol plays a central role in this transformation. They also discovered that the key molecule regulating the transformation is the metabolite geranylgeranyl pyrophosphate.

Earlier studies showed that the cholesterol biochemical pathway is also central to the functioning of statins; one of their effects is to reduce the production of geranylgeranyl pyrophosphate. This is why the researchers wanted to know whether statins also affect the formation of brown adipose tissue. And indeed they do, as the scientists have now shown in studies on mice and humans.

The researchers studied positron emission tomography scans of 8,500 patients at the University Hospital Zurich, which allowed them to determine whether the person had brown adipose tissue. They also knew whether these patients were taking statins. Evaluating the scans showed that 6 percent of those not taking the medication had brown adipose tissue, but this tissue type was present in only a little over 1 percent of those who were taking statins.

The researchers conducted a separate clinical study of 16 people at the University Hospitals of Basel and Zurich to demonstrate that statins reduce the activity of brown adipose tissue.

Don’t dismiss statins, though

Although the study demonstrates that statins have a negative impact, Christian Wolfrum, professor for translational nutritional biology at ETH Zurich, warns against talking them down.

“We also have to consider that statins are incredibly important as a way to prevent cardiovascular disease. They save millions of lives around the world, and they are prescribed for a very good reason,” he says.

However, statins also have another negative effect: in high doses, they slightly increase some people’s risk of developing diabetes—as has been shown in other studies.

“It’s possible that these two effects—the reduction in brown adipose tissue and the slightly increased risk of diabetes—are related,” Wolfrum says, adding that this question requires further research.

But Wolfrum stresses that even if such a link were established, that would be no reason to demonize statins. Rather, it would become imperative to conduct further research into the mechanisms behind this and find out which patients are affected. It might then be possible to take a personalized medicine approach and continue to recommend statins to most people, while proposing alternative therapies for a small group of patients.

The research appears in Cell Metabolism.

Source: ETH Zurich