“I’m strong to the finish, ‘cause I eats me spinach…”
These iconic words from Popeye summed up the classic cartoon sailor’s love for spinach. After eating just one can, Popeye would transform into a muscle-bound strongman, rescuing his girlfriend Olive Oyl from the evil villains.
Recent research suggests that Popeye might have been right to eat spinach for improved muscular health. Leafy vegetables such as spinach and lettuce are full of inorganic nitrates, which are used by the body to produce nitric oxide (NO). Nitric oxide delivers oxygen to the blood and is a powerful anti-inflammatory. It’s also involved in blood pressure regulation and cell metabolism, making it a vital substance.
In one small study, researchers looked at the relationship between nitrates and mitochondrial performance. Mitochondria are the “power houses” of the cells and are responsible for supplying energy to the body. The participants were given 200-300mg equivalents of spinach in the form of a nitrate supplement. After completing a cycling exercise, tissue samples were taken from the participants. When compared with similar tissue from the same participants when they were taking a placebo (table salt) supplement, the results were significant.
Researchers found that daily spinach supplementation, combined with intense exercise, improves mitochondrial performance. The mitochondria consumed less oxygen and produced more of the energy-rich substance ATP, which resulted in better overall health and improved muscle gains.
"The mitochondria play a key role in cellular metabolism," says Professor Eddie Weitzberg, who headed the study with Professor Jon Lundberg. "Improved mitochondrial function probably has many positive effects on the body, and could explain some of the health benefits of vegetables."
A later study, published in The Journal of Sports Medicine and Physical Fitness, produced similar results. Participants were given either a spinach or placebo supplement daily for 14 days before running. These participants were well-trained athletes and ran 21.1 km (about 13 miles).
After analyzing several markers of muscle damage and oxidative stress, researchers found that the group who took spinach supplements had lower levels of stress markers and muscle damage than the placebo group. The study suggests that daily supplementation of spinach has an alleviating affect on exercise-induced muscle stress.
Although eating spinach and lettuce won’t cause a transformation like Popeye’s, it’s still a good idea to include plenty of nitrate-rich vegetables as part of a balanced diet. For vegetables rich in nitrates, consider recipes including spinach, arugula, butter leaf lettuce or beets.