Eating potatoes at least four times a week increases the risk of high blood pressure, scientists have found.
According to research, boiled, mashed or baked potatoes are nearly as likely to raise blood pressure as fried potatoes such as chips from the chip shop, or French fries, research has revealed.
Researchers at the Harvard Medical School believe that it is the polysaccharide ‘starch‘ – which makes up most of a potato tuber – is to blame.
Blood Pressure and Glycemic Index
Potatoes have a high glycemic index value. These underground stems quickly break down into monosaccharide sugars, which increases blood sugar levels. Over time, this may cause blood sugar problems.
The Glycemic Index is a ranking of carbohydrates in foods according to how they affect blood glucose levels. Carbohydrates with a low glycemic index value (55 or less) are digested slowly, causing a lower elevation in blood sugar. That means insulin levels will not rise and cause problems like type 2 diabetes.
The Harvard scientists analysed data from 187,000 individuals and tracked three large US projects over a 20 year period. The results suggest that women who eat potatoes regularly may be at a slightly higher risk of high blood pressure than men.
Overall, the scientists found that men or women who ate four or more servings of baked, boiled, or mashed potatoes each week had an 11 per cent increased risk of high blood pressure compared to people who ate potatoes less than once a month.
Those who ate fried potatoes like chips four or more times each week had a 17 per cent higher risk of high blood pressure.
Replacing one serving a day of potatoes with a serving of non-starchy vegetables led to a 7 per cent decrease in the risk of high blood pressure.
Corn, peas, parsnips, potatoes, pumpkin, squash, zucchini and yams are examples of starchy vegetables.
Non-starchy vegetables are lettuce, asparagus, broccoli, cauliflower, cucumber, spinach, mushrooms, onions, peppers and tomatoes.
Eating potato crisps amazingly has no effect on the elevation of blood pressure, the scientists discovered, even when the team took the weight of participants into account. Now this is some good news about potatoes at last for a change!
In the end though, this type of study can only show an ‘association’ – not cause and effect. As Victoria Taylor, senior dietician at the British Heart Foundation says:
“Although a higher consumption of potatoes, such as chips and mash is associated with high blood pressure, it is still possible that other things being eaten, or lifestyles are affecting results.
“In the UK, white potatoes are not included in the five-a-day recommendations for fruit and vegetable consumption.
“A third of British adults suffer from high blood pressure, so it is crucial that we understand the condition and its causes.”
It is clear that we do not.