Swedish researchers confirm: spinach makes you strong
Who didn't hear as a child that spinach makes big and strong? In a comprehensive study, Swedish researchers have now confirmed what has long been known in the vernacular: The nitrates contained in spinach and other leafy greens improve muscle performance.
Comic hero Popeye already knew the strengthening effects of spinach. Swedish researchers have now found out where this comes from. In the course of their study, the scientists were able to prove that nitrates contained in vegetables improve muscle efficiency, which enables the muscles to perform the same performance with less oxygen. Accordingly, spinach actually makes you strong. The researchers around Filip Larsen from the Karolinska Institute in Stockholm have published their study results in the current issue of the journal "Cell Metabolism".
Nitrates have many positive health effects As part of their study, the Swedish researchers took a closer look at the health effects of nitrate intake and found that the nitrates contained in leafy greens sometimes have a bad reputation. The researchers from the Karolinska Institute subjected 14 volunteers to a three-day nitrate cure. Before and after, volunteers had their thigh muscles removed and a performance test performed on a bicycle ergometer. The Swedish researchers found that the nitrates, which are considered harmful or even carcinogenic, apparently also have a number of positive effects on health. However, the condition for this is a healthy oral flora, because to process nitrate, humans need bacteria that live in saliva, according to the Swedish scientists
Cancer-causing nitrosamines responsible for the bad reputation When eating, part of the nitrate in the oral cavity is converted into nitrite by the bacteria, which then gets into the gastrointestinal tract when swallowed. There, the nitrite is then converted into nitrogen monoxide (NO), which the body uses as an important messenger substance, or the so-called nitrosamines, which are considered carcinogenic, are produced. The nitrosamines are one of the main reasons why nitrates have a relatively bad reputation today with regard to the health consequences. Various studies have also observed numerous positive effects of nitrate intake, report Larsen and colleagues. For example, the NO dilates the blood vessels and can thereby lower blood pressure. In addition, there are apparently positive effects on blood sugar levels and the body is armed against the negative effects of a local lack of oxygen, the Swedish scientists explained.
Nitrates increase muscle efficiency According to the participants in their study, after the three-day nitrate cure - with an amount that corresponded to about two to three beetroot balls or a large portion of spinach - there was a significant improvement in muscle efficiency Researchers at the Karolinska Institute. After the nitrate cure, the test subjects had consumed significantly less oxygen with the same muscle performance when measuring performance on a bicycle ergometer, the scientists continued. The additional tissue samples taken from the thigh muscle also indicated increased muscle efficiency, explained Larsen and colleagues. According to the researchers, the increased performance of the muscles is presumably due to the nitrate's improved efficiency of the mitochondria in the muscle cells. When examining the tissue samples, there would have been signs that the nitrates closed a kind of leak in the tiny cell power plants and the mitochondria could thus generate more energy per oxygen unit. In the opinion of the Swedish scientists, the quick effect of the nitrate treatment in the context of their study was also impressive. Larsen and his team explain that the performance-enhancing effects are triggered immediately after the consumption of nitrate-containing foods. Like Popeye, after a can of spinach.
Further studies necessary However, the Swedish researchers also point out that some questions remain unanswered. Because the negative effects of nitrosamines remain. According to the scientists, further investigations should, for example, clarify what amount of nitrate is optimal, whether regular, permanent nitrate intake also has predominantly positive effects and whether chronically ill people can also benefit from the nitrates. Overall, however, nitrates are wrongly wrong, Larsen and colleagues judged.
How healthy is spinach? Spinach not only contains a particularly large amount of nitrates, which increase muscle efficiency, but also a large number of other minerals and vitamins such as carotenoids, vitamin C, vitamin E, calcium, and magnesium. Spinach also contains iron and a high protein content. All in all, nutritionists describe spinach as extremely healthy, although it should be eaten fresh, as the nitrate contained is bacterially converted to nitrite and then to the carcinogenic nitrosamines. In addition, it should be borne in mind that spinach can not only absorb a particularly large number of nutrients, but possibly also a particularly large number of pollutants from the cultivated soil. As with all types of vegetables, the type of cultivation has a significant impact on the desired health-promoting effect of spinach. (fp)
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