Do Green Vegetables Aid Heart Health?
A trio of recent studies suggest that the chemical nitrate found in green vegetables such as spinach, lettuce, and celery may aid heart health and help decrease the risk of diabetes and obesity.
The studies, conducted by researchers from the University of Cambridge and the University of Southampton, used various methods to reach similar conclusions.
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In the first study, for instance, researchers found that eating more of the vegetables rich in nitrate can reduce production of erythropoietin, a hormone made by the liver and kidneys that regulates the body’s number of red blood cells. According to investigators from the University of Cambridge, the body is subject to a shortage of oxygen at high altitudes or in cardiovascular diseases. In these cases, erythropoietin increases the production of blood cells as a way to circulate more oxygen throughout the body. The authors caution, however, that high numbers of blood cells can cause the blood to become too thick, which effectively starves the body’s organs and tissues of oxygen.
Nevertheless, the findings suggest that eating more vegetables that are rich in nitrate could thin the blood by lowering the number of red blood cells produced.
In a second study, researchers exposed rats to high altitudes, in order to initiate greater production of red blood cells. The team found that putting rats on a diet with nitrate, which is similar to humans eating slightly more green vegetables, gave the rats more protection against various heart and circulatory conditions, in comparison to rats on a nitrate-free diet. This finding, the authors noted, is a result of nitrate’s increased production of a compound that widens the blood vessels, and subsequently improves blood flow.
A third study, led by Lee Roberts, PhD, an Elsie Widdowson Fellow at the Medical Research Council, Human Nutrition Research Unit and a Research Fellow at Wolfson College, University of Cambridge, found that nitrate subjects “bad” white fat cells to a process known as browning, which converts them into beige cells.
These beige cells are similar to the “good” brown fat cells that burn fat in order to generate heat, the authors explained, adding that increased levels of brown fat have been linked to lower risk of obesity and diabetes. As such, the team hypothesized that including nitrate into diet can help guard against such conditions.
While describing the findings as “promising,” Roberts notes that “it is important to realize that we are still at an early stage of research.
“However,” he adds, “when primary care physicians are recommending dietary and behavioral lifestyle changes to patients, especially those at risk of diabetes and obesity, it is worth considering specifically mentioning green leafy vegetables as part of a healthy balanced diet.”
—Mark McGraw
Reference
Ashmore T, Fernandez B, et al. Suppression of erythropoiesis by dietary nitrate. The FASEB Journal. 2014.
Ashmore T, Fernandez B, et al. Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart. J Physiol. 2014.
Roberts L, Ashmore T, et al. Inorganic nitrate promotes the browning of white adipose tissue through the nitrate-nitrite-nitric oxide pathway. Diabetes. 2014.