You may first think of protein when it comes to building strong muscles, but compelling evidence from a new study suggests that if you’re trying to get gains on your lower body, reaching for a cup of greens could be an important part of your strength routine to include.
The study followed people over a 12-year time span who focused on eating a diet high in leafy vegetables—specifically rich in nitrates such as spinach, lettuce, or kale—which accounted for serious gains in lower limb strength. Participants who ate the most of these nitrate-rich green vegetables were 11% stronger and could walk 4% faster than those who ate the least of these vegetables.
Around 81% of the nitrate consumed by these individuals was vegetable-derived, around 52-83 mg per day. The study built upon existing knowledge that nitrate is essential to vascular function and nitrate supplements are helpful for blood vessel health, but it was unknown if consumption of nitrate-rich foods could help in a similar way.
You may be wondering why nitrates are being described as healthy, when most of us have heard nitrates, like the ones in processed meats, are carcinogenic. Surprisingly, despite our avoidance of nitrates, only 6% of the nitrates we eat come from cured meats, and the rest (up to 85%) comes from vegetables.
The vegetables get their nitrate content from the soils they’re grown in as they come in contact with mineral deposits and microorganisms. The concern comes from nitrites (ending in -ites rather than -ates) because these nitrites are converted to nitrates in our mouths due to the bacteria in our saliva. On their own, these newly converted nitrates aren’t harmful, but when it reaches the stomach and combines with the acids, they form nitrosamines. These nitrosamines have been linked to gastrointestinal cancers.
Nitrosamines can also be created by cooking cured meats at a high temperature, such as frying bacon. Vegetable-derived nitrates can provide the body with nitric oxide, which is an important component of good cardiovascular health because it relaxes blood vessels and improves flow. Still, there isn’t enough evidence to suggest that nitrates should be something you’re actively seeking; it’s just a bonus to the rest of the goodness found in vegetables.
Instead, maintaining a balanced diet full of leafy greens while you’re working on lower limb strength appears to be a good strategy based on this current information.
Marc Sim, Lauren C Blekkenhorst, Nicola P Bondonno, et al. Dietary Nitrate Intake Is Positively Associated with Muscle Function in Men and Women Independent of Physical Activity Levels. The Journal of Nutrition, 2021; DOI: 10.1093/jn/nxaa415