Eating potatoes or chips increases the risk of high blood pressure, research suggests.
Four or more servings a week of baked, boiled, or mashed potatoes is linked to an 11% increased risk of high blood pressure compared with less than one serving a month in women, researchers found.
They also found that men and women who ate four or more servings a week of French fries had a 17% higher risk of high blood pressure.
But eating crisps had no effect, the study, which was published in the British Medical Journal, found.
The researchers also noted that replacing one serving a day of potatoes with one serving of non-starchy vegetables led to a 7% drop in the risk of high blood pressure.
The team, from the Brigham and Women’s Hospital and Harvard Medical School in Boston, Massachusetts, suggested the high glycaemic index (GI) of potatoes could be to blame.
High-GI foods release energy more quickly and therefore raise blood sugar more quickly.
The team said high-GI meals had been associated with dysfunction of cells in the body, oxidative stress, and inflammation, “all potentially important mechanisms in the development of hypertension [high blood pressure]”.
The team took account of factors such as the weight of people in the study, but the results still held true.
Overall, the experts analysed data from more than 187,000 men and women from three large US studies over 20 years.
In January, a separate study found that women who enjoy potatoes may be at increased risk of suffering diabetes in pregnancy.
Those who eat two to four servings of potatoes a week may be around 27% more likely to suffer diabetes in pregnancy, even when taking into account their weight, it said.
Even one serving a week appeared to increase the risk by 20% compared with women eating less than one serving a week, once body mass index (BMI) was taken into account.
Those eating more than five servings a week had a 50% increased risk.
When women substituted two servings a week with other vegetables, pulses such as beans, lentils, and peas, and whole grain foods, they had a 9% to 12% lower risk.
Commenting on the study, Victoria Taylor, senior dietitian at the British Heart Foundation, said: “This type of study can only show an association, not cause and effect. We cannot therefore conclude that potatoes cause high blood pressure and we cannot explain the cause of the effects seen in the study among higher consumers of potatoes.
“Although a higher consumption of potatoes, such as mashed potatoes or French fries, was associated with high blood pressure, it is still possible that other factors in the diet or lifestyle are also affecting the results, especially as both the blood pressure and food frequency were self-reported.”
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