Potato consumption linked to high blood pressure

Increased consumption of potatoes — whether boiled, baked, mashed or as French fries — has been linked to an increased risk of developing high blood pressure (hypertension), according to a study published by The BMJ.

Researchers based at Brigham and Women’s Hospital and Harvard Medical School followed over 187,000 men and women from three large US studies for more than 20 years. Dietary intake, including frequency of potato consumption, was assessed using a questionnaire.

After taking account of several other risk factors for hypertension, the researchers found that four or more servings a week of baked, boiled or mashed potatoes was associated with an increased risk of hypertension compared with less than one serving a month in women, but not in men.

Higher consumption of French fries was associated with an increased risk of hypertension in both women and men. However, no increased risk was found from consumption of potato chips (crisps).

The researchers suggest that replacing one serving a day of boiled, baked or mashed potatoes with one serving of a non-starchy vegetable is associated with a lower risk of developing hypertension. They point out that potatoes have a high glycaemic index compared with other vegetables and so can trigger a sharp rise in blood sugar levels, and that this could be one explanation for the findings.

They also acknowledge some study limitations and say that, as with any observational study, no firm conclusions can be drawn about cause and effect.

Nevertheless, they say their findings “have potentially important public health ramifications, as they do not support a potential benefit from the inclusion of potatoes as vegetables in government food programs but instead support a harmful effect that is consistent with adverse effects of high carbohydrate intakes seen in controlled feeding studies”.

But a linked editorial, by researchers at the University of New South Wales, argues that studying overall dietary patterns and risk of disease is more useful than a focus on individual foods or nutrients. It emphasises that although diet has an important part to play in the prevention and early management of hypertension, dietary behaviour and patterns of consumption are complex and difficult to measure.

“Potatoes, when consumed in healthier ways such as cooked in potato salads, baked, boiled, mashed with milk and extra virgin olive oil [and] going easy on the salt, are a good food to be included as part of a healthy, balanced diet,” said Dr Rebecca Reynolds, lecturer in nutrition at the University of New South Wales.