Efficient muscles do come from eating spinach
Vegetables like spinach that are rich in nitrates improve muscle efficiency. Scientists now know nitrates in green leafy vegetables, beets and spinach improve function of mitochondria in cells that in turn adds to muscle power.
In a study, healthy participants who took a small dose of inorganic nitrate for three days used less oxygen when riding an exercise bike. Rather than taking a supplement, the scientists suggest eating fruits and vegetables to keep muscles working efficiently.
"We're talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach," said Eddie Weitzberg of the Karolinska Institutet in Sweden. "We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven't been clear. This shows inorganic nitrate as a candidate to explain those benefits."
Until recently nitrates found in vegetables like spinach, watermelon, kale, collards and beets were thought to be toxic. Beets have been studied for their role in boosting athletic performance and improving blood pressure, but only when consumed. The interaction between vegetables and saliva releases nitric oxide and improves blood flow.
Now the scientists have discovered another way nitrates and the nitric oxides improve muscle efficiency. They say normally mitochondria in the cells are "leaky" from protein. Eating the likes of spinach and other vegetables comes from lower protein.
"Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes," the researchers concluded. "However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects."
The researchers note eating vegetables like spinach, beets and green leafy varieties can have an immediate effect, but they are unclear if consuming large amounts over long periods of time would be harmful. They say the next step is to see how nitrates in fruits and vegetables affect diabetics and patients with heart disease who have mitochondrial dysfunction.
They also speculate powerful mouthwashes could interfere with the benefits of eating fruits and vegetables because of the way mouth bacteria help convert nitrates into nitric oxide.
The study shows muscle efficiency improves from eating spinach and other vegetables and fruits. The effect is from improved mitochondrial function that the scientists say is normally inefficient. The researchers say more studies are needed to better understand all of the benefits of green leafy vegetables like spinach.
Cell Metabolism: doi:10.1016/j.cmet.2011.01.004
"Dietary Inorganic Nitrate Improves Mitochondrial Efficiency in Humans: