The study – published in the Journal of Agricultural and Food Chemistry – reports to be the first of its kind to investigate the effects of potato consumption on blood pressure. The research team, led by Dr Joe Vinson from the University of Scranton, USA, found that two small helpings of purple potatoes (Purple Majesty) a day decreases blood pressure by about 4 percent in obese people – without causing weight gain.
Vinson and his colleagues said that the decrease, although seemingly small, is sufficient to potentially reduce the risk of several forms of heart disease.
“The null effect of four weeks of Purple Majesty [PM] supplementation on weight and biochemical parameters other than blood pressure is important in that it proves that an increased consumption of PM did not deleteriously effect cardiovascular and diabetes risk factors but in fact lowered the blood pressure and thus lowered the risk of cardiovascular disease,” wrote Vinson and his colleagues.
Vinson and his team pointed out that the majority of people eat more potatoes than any other vegetable.
Speaking about his research previously at the National Meeting & Exposition of the American Chemical Society (ACS) last year, Vinson said “the potato, more than perhaps any other vegetable, has an undeserved bad reputation that has led many health-conscious people to ban them from their diet.”
The team added that purple-skinned potatoes, are noted for having high levels of beneficial antioxidant compounds, including phenolic acids, anthocyanins, and carotenoids.
In Korea, purple potatoes are renowned in folk medicine as a way to lose weight, they added.
The researchers investigated the effects of eating 6-8 small microwaved purple potatoes twice a day on 18 volunteers – most of whom were overweight with high blood pressure (hypertension).
Volunteers ate potatoes or no potatoes for four weeks, and then switched to the opposite regimen for another four weeks while researchers monitored systolic and diastolic blood pressure, body weight and other health indicators.
Diastolic blood pressure was reported to drop by an average of 4.3%, whilst systolic pressure decreased by an average of 3.5&, they reported.
Vinson and his team added that none of the study participants gained weight, and noted that the majority of subjects took anti-hypertensive drugs and still had a reduction in blood pressure.
Vinson said that other studies have identified substances in potatoes with effects in the body similar to those of the well-known ACE-inhibitor medications. However added that he suspects the effects may be due to other substances in potatoes.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, doi: 10.1021/jf2045262
“High antioxidant potatoes: Acute in vivo antioxidant source and hypotensive agent in humans after supplementation to hypertensive subjects”
Authors: J.A. Vinson, C.A. Demkosksy, D.A. Navarre, M.A. Smyda