Potatoes have been maligned in nutritional circles for decades, with links to obesity, type 2 diabetes, and cardiovascular disease. But they are also very satisfying and provide many essential nutrients.
So are potatoes good for you or not?
"Potatoes have gotten a bad rap because of the way they have been eaten and processed in the modern food system," says Charles Mueller, Ph.D., associate clinical professor in the University's Department of Nutrition and Food Studies. from New York. .
Uncultivated potatoes are healthy, says Mueller: They provide a good mix of nutrients. It's when people fry them in oil or smother them in butter, sour cream, or salt that French fries turn into food scraps.
A cooked medium white potato (about 6 ounces) with skin has 159 calories, 36 grams of carbohydrates, and almost 4 grams of fiber. Potatoes also contain a healthy mix of vitamins and minerals such as magnesium, potassium, and vitamins B6 and C. One medium potato, for example, supplies about 15 percent of your daily need for magnesium; and about 20 percent of your daily need for potassium.
"Most people don't get enough potassium," says Ellen Klosz, a nutritionist for Consumer Reports. "It is very important to help control blood pressure."
And few Americans get the recommended daily allowance for fiber, which has a number of health benefits, from helping to control cholesterol, protect against diabetes, control weight, and even lower the risk of colorectal cancer. Dietary recommendations say that most adults need about 25 to 30 grams of fiber per day. If you eat a medium potato with skin, you will get about 4 grams. If you eat one without it, you will only get about 3 grams. "It's always good to eat potatoes with the skin on," says Mueller, "because you pick up some fiber."
Still, many diet experts advise going easy on potatoes due to their high glycemic index. Carbohydrates in a high-GI food are digested quickly, leading to a rapid rise and then a drop in blood sugar and insulin levels. These effects can cause people to overeat and can increase the risk of obesity, type 2 diabetes, and heart disease.
But Mueller says you can greatly minimize the spike in blood sugar from potatoes by eating them as part of a healthy meal that includes protein.
Another way to minimize the GI effect of potatoes is to chill them after cooking and eat them cold (like in a potato salad) or reheat them. This alters the chemical structure of the potato's carbohydrates and forms resistant starch, a type of fermentable fiber that can lower blood sugar levels after a meal and have other health benefits.
Plus, Klosz says, when potatoes are compared to other high-GI staples, like white rice, they're actually much lower in calories and carbohydrates, and provide more fiber.
For most people, having potatoes a few times a week can be part of a healthy diet, Mueller says. But only if you look at your serving size and what you put on them.
"Potatoes are among the most popular vegetables in the American diet," says Klosz. “But most are consumed in their processed form, like potato chips and potato chips. Only 26 percent of the potatoes we eat are fresh or unprocessed. " And even when eaten fresh, drizzling them with butter or cream can negate their health benefits.
That could at least partially explain the findings of some observational studies, such as those of Harvard researchers, who found that eating potatoes frequently can increase the risk of high blood pressure, type 2 diabetes and weight gain.
In one of the studies, people who ate potatoes two to four times a week had a modest increase in their risk of type 2 diabetes, 7 percent, compared to those who ate them less than once a week. However, those who had 7 servings a week had a 33 percent increased risk. While all forms of baked, boiled, fried, and mashed potatoes were linked to the disease, French fries were more of a problem.
That was also the case in the other Harvard studies. For example, people who ate four or more servings of baked, boiled, or mashed potatoes had an 11 percent increased risk of high blood pressure compared to those who ate less than once a month. For French fries, the risk was 17 percent higher.
People often make the mistake of counting potatoes as a vegetable in their meals. "While it is a tuber and is in the vegetable family," says Mueller, "it is a starch, and should be considered equivalent to eating pasta, whole wheat pasta, whole wheat bread or brown rice." Harvard studies suggest that replacing potatoes with non-starchy vegetables or whole grains in your meals helps protect against chronic health problems.
A range of colors
In addition to white potatoes, you can find yellow, purple, and red meat varieties. The colors come from compounds in plants called phytochemicals, such as anthocyanins, carotenoids, and flavonoids, which have antioxidant properties and can protect against cardiovascular disease, cancer, and other chronic diseases. Red and purple potatoes have almost twice as many flavonoids as white ones.
What about sweet potatoes? Technically, they are not really potatoes, they are not part of the same plant family, and they may be a bit healthier. A medium sweet potato is only slightly lower in calories and carbohydrates (147 calories, 35 grams carbs) than a white version of the same size, but has about one more gram of fiber. And it provides enough carotenoids to supply more than five times your RDA of vitamin A. Purple sweet potatoes offer the highest levels of anthocyanins, a type of flavonoid linked to heart and liver benefits, compared to white, yellow. and orange types.
How to prepare potatoes in a healthy way
It's pretty simple - go easy on the potato ingredients and add-ons. Just one tablespoon of butter and two tablespoons of sour cream add about 100 calories and 9 grams of fat. "When you add a lot of cream, butter and salt," says Mueller, "you can increase the caloric value of them and you are more likely to overeat." Why? Because they taste good.
The same goes for sweet potatoes. Adding marshmallows, butter, and brown sugar significantly increases the fat and sugar load. There are 14 grams of sugars and 9 grams of fat in a half cup of sweet potato casserole, compared to about 7 grams of sugars and no fat in a medium sweet potato. Avoid varieties canned in heavy syrup.
Fortunately, potatoes, whether sweet or regular, don't take much to make them tasty. Cut them into cubes and cover with a little rosemary, olive oil and salt and pepper; or boil or microwave them whole. When eating them baked or pureed, keep seasonings to a minimum.
By Julia Calderone
Original article (in English)