Popeye’s secret is out: spinach may improve muscle strength, say researchers in Sweden. After seven days of drinking water spiked with nitrate – a chemical found in high doses in the leafy vegetable – mice developed stronger muscles. Why the robust rodents? The nitrate increased their levels of two proteins that play 
a role in muscle contraction. Try to eat about 1½ cups of cooked spinach a day. Try these delicious recipes: Polenta, Spinach and Eggs and Egg Drop Soup with Edamame and Spinach.