Potato consumption linked to high blood pressure

A new study in the British Medical Journal has found an association between potato consumption and hypertension in a large group of men and women in the U.S. But studying dietary patterns may be more useful than focusing on just one food, says an accompanying editorial.

Higher intakes of boiled, baked, mashed or fried potatoes may increase your chance of hypertension

Potatoes are a popular staple with Canadians, but new research says eating too many spuds may increase the risk of high blood pressure. (Yfat Yossifor/Bay City Times/Associated Press)

Whether it's boiled, baked, mashed or deep-fried, the potato is associated with an increased risk of developing high blood pressure, says a new study published in the BMJ today.

Researchers based at Brigham and Women's Hospital and Harvard Medical School followed over 187,000 American men and women for more than 20 years. Participants returned a questionnaire with updates on their health every two years, and another about their eating habits, including potato consumption, every four years.

"We found that participants who consumed four or more than four servings a week of baked, boiled or mashed potatoes, had an 11 per cent higher risk of developing hypertension," says lead author Dr. Lea Borgi. That's compared with participants who consumed one or less than one serving a month. But Borgi and her team noticed a higher risk only in women, and not in men. 

Whether it's boiled, baked, mashed or deep-fried, the potato is associated with an increased risk of developing high blood pressure 1:51

She told CBC News that result was quite unexpected. "We would expect it to be the same for men and women." The author points out that the study does have limitations. Participants self-reported a diagnosis of hypertension, and questionnaires tend to be an imperfect way of tracking trends over a long period of time.

And finally, potatoes are often eaten with salt and butter. Increased sodium could explain hypertension.

"Definitely, more research is needed," says Borgi.

Comfort food

But what can be confirmed is the popularity of one of the world's most commonly eaten comfort foods. It may be described as the lowly potato, but in Canada, it's the most valuable vegetable crop.

"I like them in their skin, I like them fried," says Beryl Haines, 85, while having her twice monthly dinner at P.J. O'Brien's, a popular Irish pub in Toronto. Her dining companion, Bob Clark, clearly shows the same enthusiasm for the root vegetable. "If I had a choice," he says, "I think mashed potatoes, with lots of butter and milk."

Mashed potatoes and Irish stew with potatoes are tasty fare at the P.J. O'Brien Pub & Restaurant in Toronto. (Kas Roussy/CBC)

"You can have potatoes once in a while, but they are not an especially healthy food," says Toronto cardiologist Christopher Labos. But they're not an especially dangerous food either, he says.  

Potatoes are high in potassium, and that's a good thing. But Labos says the starch in the potato delivers a high sugar load, which can increase your chance of obesity, and that in turn can increase the risk of high blood pressure.

It's all about moderation, says Labos.

"You can't look at one food and ask, is it good or is it bad for you. It's more important to look at your overall diet," he says.

Beryl Haines, 85, saves her potatoes for last. She says she eats them three times a week. (Kas Roussy/CBC)

An editorial attached to the BMJ study questions whether there are bad foods, or just bad diets.

Back at the Irish pub, the kitchen is busy dishing out the favourite fares, beef and Guinness stew, with roast potatoes, shepherd's pie with creamed potatoes.  

Anne Quinn, who helps run the family-owned restaurant, says studies with their conflicting health messages come and go.  

"Potatoes," she says with her Irish lilt, "are still around." 

About the Author

Kas Roussy

Senior Reporter

Kas Roussy is a senior reporter with the Health unit at CBC News. In her more than 30 years with CBC, Kas’s reporting has taken her around the globe to cover news in countries including Pakistan and Afghanistan, Chile, Haiti and China, where she was the bureau producer.

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