Fructose damages the heart

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MunichFor a long time, fructose was touted as "healthy fruit sugar". Now there are increasing indications that the sweetener is rather detrimental to health. Especially people with high blood pressure should consume as little of it as possible - because fructose seems to promote the enlargement of the heart muscle in them. One possible consequence: heart failure.

When blood pressure rises, the heart needs more strength to pump blood around the body. The result: the heart muscle strengthens and grows. In order to work effectively, it then not only needs more energy, but also more oxygen. And when that is scarce, the heart cells can no longer obtain their energy from fatty acids, but only from sugars - and this is where fructose comes into play.

Vicious cycle without a brake

At this point in the metabolism there is a molecular mechanism that Peter Mirtschink from ETH Zurich and his colleagues recently discovered: The lack of oxygen in the heart stimulates the production of a certain enzyme, ketohexokinase-C (KHK-C). It is the central worker in the breakdown of fructose. The energy from the fructose makes the heart muscle cells continue to grow, but then they need even more oxygen and their need for fructose continues to increase. A vicious cycle because there is no brake on this mechanism.

In an experiment with mice, the researchers were able to show that rodents with high blood pressure produced increased levels of CHD-C. When the scientists inhibited the enzyme, heart muscle growth also stopped. Mirtschink and his team also found large amounts of CHD-C in the heart tissue of patients with enlarged heart muscles.

Apple and Co. are allowed

Nevertheless, nobody has to and should not do without fresh fruit. "In addition to fructose, fruits contain numerous important trace elements, vitamins and fiber," explains Mirtschink. However, finished products, fruit juices or soft drinks, some of which contain considerable amounts of fructose, are problematic. Sometimes also hidden - as sucrose or corn syrup. "In patients with high blood pressure, this excess alone can help set the mechanism we have described in motion," emphasizes Mirtschink. (away)

Source: Mirtschink et al .: HIF-driven SF3B1 induces KHK-C to enforce fructolysis and heart disease, Nature, 2015.

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