Researchers at Sweden’s Karolinska Institute are backing Popeye’s diet after finding spinach and some other vegetables significantly improved the strength of muscles in mice. The team identified two proteins in the body that are stimulated by the intake of nitrate, which is present in many leafy vegetables, but is particularly prevalent in spinach and beetroot.
The mice were split into two groups, with one receiving the equivalent amount of nitrate in their drinking water as a human would get from eating around three beetroots a day or 200-300 grams of spinach.
“The study found that mice supplied with nitrate in their drinking water developed significantly stronger muscles – and this at doses obtainable from a normal diet,” the Karolinska Institute said in a news release. “The mice that had been on consistent nitrate had much stronger muscles.”
When testing the muscles a week later, the researchers also found a higher concentration of CASQ1 and DHPR proteins in the mice that were given the nitrate-enriched water.
“From a nutritional perspective, our study is interesting because the amount of nitrate that affected muscle strength in mice was relatively low,” said Dr Andrés Hernández, researcher at the Karolinska Department of Physiology and Pharmacology.
“Translated to humans, it means that we can obtain the equivalent volume by eating more of a vegetarian diet, as nitrate is found naturally in several leafy vegetables, especially in beetroot juice, for example. There are currently no dietary supplements containing nitrate,” he added.