London - Tucking into potatoes at least four times a week increases the risk of high blood pressure, experts have found.
Surprisingly, mashed, boiled or baked potatoes are nearly as likely to raise blood pressure as chips, the research revealed.
The Harvard Medical School researchers said they suspected the starch in potatoes was to blame.
Because potatoes have a high glycaemic index, these starchy carbohydrates rapidly transform into sugars in the body, triggering a sharp rise in blood sugar levels. Over time, this may cause blood sugar problems.
The experts, whose work was published in the British Medical Journal, analysed data from 187 000 men and women tracked in three large US projects for 20 years. The results suggest that women who regularly eat potatoes may be at a slightly higher risk of high blood pressure than men.
Overall, however, they found that men or women who ate four or more servings of baked, boiled, or mashed potatoes a week had an 11 percent increased risk of high blood pressure compared to those who ate potatoes less than once a month.
Those who ate chips four or more times a week had a 17 percent higher risk of high blood pressure.
Replacing one serving a day of potatoes with one serving of non-starchy vegetables led to a seven percent drop in the risk of high blood pressure, they found. Eating crisps had no effect, the experts found. The researchers said potatoes should no longer be included as “vegetables” when governments issued health advice.
Victoria Taylor, senior dietitian at the British Heart Foundation, said: “This type of study can only show an association, not cause and effect.
“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.”
She added: “In the UK, white potatoes are not included in the five-a-day recommendations for fruit and vegetable consumption.
“Nearly 30 percent of adults in the UK have high blood pressure so it is key that we understand the condition and its causes as much as possible.” Professor Tom Sanders of King’s College London, added: “Being overweight, a high intake of salt and alcohol and a low intake of potassium are well known to increase blood pressure but the effects of individual foods are less certain.
“Generally, fruit and vegetables are associated with lower blood pressure, with the exception of pickled vegetables.
“However, potatoes, especially chips, are often consumed with added salt which may be part of the explanation for this association with raised blood pressure.
“I don’t think this study should be used to discourage people from eating potatoes. In the UK, potatoes are more widely consumed than in the US and make an important contribution to the intake of vitamin C and potassium.”
Daily Mail