Eating too many white potatoes on a regular basis has been linked to high blood pressure in a new study.
Researchers recommend replacing one serving of boiled, baked, or mashed potatoes a day with one serving of a non-starchy vegetable.
This, they believe, can lower the risk of high blood pressure (or hypertension).
Potatoes are one of the world’s most commonly consumed foods. But the association of potato intake with high blood pressure has not been studied before.
They followed the dietary intake of over 187,000 men and women from three large US studies for more than 20 years.
High blood pressure was reported by participants based on diagnosis by a health professional.
The researchers found that four or more servings a week of baked, boiled, or mashed potatoes was associated with an increased risk of high blood pressure.
Higher consumption of French fries was also associated with an increased risk of hypertension in both women and men.
However, consumption of crisps was associated with no increased risk.
Researchers suggest that replacing one potato serving a day with non-starchy vegetables is the best way to reduce risk of high blood pressure.
They said that potatoes have a high glycaemic index compared with other vegetables, so can trigger a sharp rise in blood sugar levels, which could explain the findings.
They added that the study has its limitations and said no firm conclusions can be drawn about cause and effect.
Nevertheless, they said 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".
In a linked editorial, researchers at the University of New South Wales argued that, although diet has an important part to play in prevention and early management of hypertension, dietary behaviour and patterns of consumption are complex and difficult to measure.
They said: "We will continue to rely on prospective cohort studies, but those that examine associations between various dietary patterns and risk of disease provide more useful insights for both policy makers and practitioners than does a focus on individual foods or nutrients."
The study was published in The BMJ.