Potatoes are stuffed with phytonutrients, which are organic components of plants that are thought to promote health, according to the USDA. Phytonutrients in potatoes include carotenoids, flavonoids and caffeic acid. The vitamin C in potatoes acts as an antioxidant. These substances may prevent or delay some types of cell damage, according to the National Institutes of Health. They may also help with digestion, heart health, blood pressure and even cancer prevention.
Purple potatoes are especially good sources of phytonutrients and antioxidants. A 2012 study published in the Journal of Agriculture and Food Chemistry found that six to eight small purple potatoes twice a day helped lower blood pressure and risk of heart disease and stroke among people who were overweight and suffering from hypertension. Despite the carbohydrates in purple potatoes, the participants did not gain weight.
Potatoes may help lower blood pressure for several reasons. Jarzabkowski said that the fiber found in potatoes could help lower cholesterol by binding with cholesterol in the blood. “After it binds, we excrete it.”
Potatoes are also a good source of potassium. “All potatoes are potassium rich,” Jarzabkowski said. “They have even more potassium than a banana, and a lot of it is found in the [potato’s] skin.” She noted that the outer potato peel also contains a good deal of fiber. Potassium is a mineral that helps lower blood pressure, according to the U.S. Food and Drug Administration.
Potassium, too, can help lower blood pressure through its actions as a vasodilator (blood vessel widener). Scientists at the Institute for Food Research have discovered that potatoes contain chemicals called kukoamines, which are associated with lowering blood pressure.
Brain functioning and nervous system health
The B6 vitamins in potatoes are critical to maintaining neurological health. Vitamin B6 helps create useful brain chemicals, including serotonin, dopamine and norepinephrine. This means that eating potatoes may help with depression, stress and even perhaps attention deficit hyperactivity disorder (ADHD).
Potatoes’ high level of carbohydrates may have some advantages, including helping maintain good levels of glucose in the blood, which is necessary to proper brain functioning. A 1995 study published in the American Journal of Clinical Nutrition found that modest increases in glucose could help enhance learning and memory. Potassium, which encourages the widening of blood vessels, also helps ensure your brain gets enough blood.
Vitamin C can help prevent everything from scurvy to the common cold, and potatoes are full of this nutrient, with about 45 percent of the recommended daily intake per medium baked potato, according to the Washington State Potato Commission.
Some people think potatoes and other members of the nightshade family — such as eggplants, tomatoes and peppers — trigger arthritis flares. However, there is limited scientific evidence to support this hypothesis, according to the Arthritis Foundation. The organization suggests that people with arthritis try cutting nightshade vegetables from their diets for two weeks to see if symptoms improve.
Some studies suggest these vegetables may actually help reduce arthritis symptoms, the foundation said. For example, a 2011 study published in the Journal of Nutrition found that potatoes might reduce inflammation.
The largest health benefit offered by potatoes is how they can help with digestion due to their high fiber content, Jarzabkowski said. Potatoes’ high level of carbohydrates makes them easy to digest, while their fiber-filled skin can help keep you regular.
Potatoes give your heart plenty of reasons to swoon, due to the fiber content. Jarzabkowski said fiber is associated with clearing cholesterol from blood vessels; vitamins C and B6 help reduce free radicals; and carotenoids help maintain proper heart functioning.
Additionally, B6 plays a crucial role in the methylation process, which, among other things, changes the potentially dangerous molecule homocysteine into methionine, a component in new proteins, according to Harvard. Too much homocysteine can damage blood vessel walls, and high levels of it are associated with increased risk of heart attack and stroke.
Jarzabkowski described how potatoes could be a win for athletes. “Potatoes can help restore electrolyte balance,” she said. “Sodium and potassium, which are found in potato peels, are two important electrolytes, and athletes lose them in sweat.” Electrolytes are necessary for optimum body function, and having too few can cause cramps, as many athletes know.
According to Organic Facts, vitamin C, vitamin B6, potassium, magnesium, zinc and phosphorous can all help keep skin as smooth and creamy as, well, mashed potatoes. These nutrients are all present in potatoes.
A 2017 study published by the Journal of Nutritional Biochemistry found that consuming purple potatoes might reduce the risk of colon cancer. Purple potatoes are high in antioxidants and anti-inflammatory properties that can reduce levels of interleukin-6 or IL-6, a protein linked to cancer cell growth within the colon. The study looked at groups of pigs on three different diets, one of which was supplemented with purple potatoes. At the end of the study, pigs that ate purple potatoes had levels of IL-6 six times lower than the other groups. While the study has not yet been replicated on humans, researchers anticipate that the results will transfer because a pig’s digestive system is similar to a human’s.
In 2017, an Australian man named Andrew Flinders Taylor appeared in the headlines for having eaten almost nothing but potatoes for a year and losing around 110 lbs., according to Australian Popular Science. This sparked public interest in the potato diet. Dieticians, however, do not recommend such a diet because it is almost impossible to get all 20 essential amino acids and 30 vitamins and minerals from one food. A mix of white and sweet potatoes would, however, get you closer than most foods. Nevertheless, your health would suffer from eating nothing but potatoes, said Jarzabkowski.
Potatoes are fat free, but they are also starchy carbohydrates with little protein. According to Harvard, the carbs in potatoes are the kind that the body digests rapidly and have a high glycemic load (or glycemic index). That is, they cause blood sugar and insulin to surge and then dip. This effect can make people feel hungry again soon after eating, which may lead to overeating. The rapid rise in blood sugar can also lead to increased insulin production. Jarzabkowski said, “The last thing I’d recommend to a diabetic is a potato.”
On the other hand, potatoes are also a great source of fiber, Jarzabkowski said, and the fiber content helps you feel fuller longer.
Jarzabkowski recommended that when planning meals, people should remember potatoes’ carb content. “Potatoes should take the place of a grain on the plate. Use it as a carb rather than as your only vegetable,” she said.
Even when prepared in a healthy way, potatoes can present health problems to individuals with obesity or diabetes. They are high in simple carbohydrates, which can lead to weight gain. Jarzabkowski likened the vegetables in this way to white bread.
The Harvard School of Public Health tracked the diet and lifestyle of 120,000 men and women for about 20 years and found that people who increased their consumption of French fries and baked or mashed potatoes gained more weight over time — as much as 3.4 lbs. every four years.
The risk held for women who ate baked, boiled, mashed or fried potatoes and for men who ate fried potatoes. Men who ate the equivalent amount of potato chips, however, did not see their risk for higher blood pressure increase. This study further indicates that potatoes may contribute to different health outcomes in different people, perhaps depending on their unique glycemic index reactions. It also emphasizes the importance of potato preparation.
Healthiest ways to cook potatoes
You can probably guess that smothering your potato in sour cream and bacon isn’t the healthiest way to enjoy it, but what is? Which is more nutritious — baked, boiled or steamed potatoes?
Jarzabkowski emphasized the importance of preparation in potato consumption. “The best way to eat a potato is in its whole, unprocessed form,” she said. Baking a potato is the best way to prepare it, as baking, or microwaving, a potato causes the lowest amount of nutrients to be lost, she said.
The next-healthiest way to cook a potato is through steaming, which causes less nutrient loss than boiling. Cooking a peeled potato in this way results in significant nutrient loss, as the water-soluble nutrients leach out into the water.
In a potato, those water-soluble nutrients include B-complex vitamins, vitamin C, potassium and calcium. As much as 80 percent of a potato’s vitamin C may go down the drain if you boil the vegetable. The same thing can happen with peeled potatoes that are left to soak, a method used to stop darkening. If you use the water from the potato boil as stock, however, you’ll still get some of the nutrients.
However you cook a potato, try to eat the skin. Ounce for ounce, the skin contains more nutrients — including the majority of the vegetable’s fiber — than the rest of the potato, Jarzabkowski said.