woman preparing mashed potatoes with butter and cream

Americans love potatoes. In fact, the average American eats 142 pounds of potatoes a year, and potatoes represent the second most frequently consumed food in the United States — behind only dairy products (via the North Carolina Potato Association). Potatoes are also an important staple for hundreds of millions of people around the globe. This humble root vegetable plays such a key part in mankind’s diet that the Food and Agriculture Organization (FAO) of the United Nations (UN) designated 2008 the International Year of the Potato to highlight its importance.

Although many dismiss potatoes as a high-calorie comfort food with little nutritional value, potatoes are relatively low in calories and packed with micronutrients (via Healthline). Of course, there are a million ways to eat a potato, and their nutritional mileage may vary considerably based on how they’re prepared and what other ingredients get involved. Unfortunately, Americans tend to gravitate toward less healthy preparations. According to a 2017 survey conducted by National Today and reported on by The Food Channel, 16% of Americans said french fries were their preferred way to eat potatoes. Other top options included mashed potatoes (15%), baked (12%), and hash browns (11%).

If you’re like most Americans, you’re probably already eating potatoes every day in one form or another. But what effects — positive and negative — are all those spuds having on your body?

Your blood sugar spikes

basket of potatoes

Potatoes are a carb-heavy food. In fact, according to Healthline, they’re roughly 66-90% carbohydrate by dry weight. Their hefty carb content means that potatoes are considered a high-glycemic food. The glycemic index (GI) measures how quickly the carbs in a food are converted to glucose, and thus how quickly a food can cause an increase in blood glucose levels. Straight glucose is used as a reference point for the GI and has a score of 100.

A food that scores 70 or higher is considered a high-GI food, while a food that scores 55 or lower is a low-GI food. Glycemic load (GL) is similar to GI but takes into account how much of a particular food a person is likely to eat at one sitting. A high-GI food may not be a big deal if it has a low GL (in other words, if the serving size is small). A GL of 20 or more is considered high, while a GL of less than 10 is low (via WebMD).

Unfortunately for spud lovers, potatoes score high on both scales. Baked potatoes have a GI of 111 and a GL of 33. Boiled and instant mashed potatoes aren’t significantly lower, with the former having a GI of 82 and a GL of 21 and the latter having a GI of 87 and GL of 17 (via Oregon State University).

You won’t get much protein

tray of roasted potato wedges

Potatoes don’t contain a lot of protein. They’re only about 8-9% protein by dry weight and a 3.5-ounce serving of boiled potatoes contains less than 2 grams of protein. They contain less protein per serving than other starchy foods like rice, corn, and wheat (via Healthline). But what potatoes lack in quantity they make up for in quality.

According to a 2020 book about the nutritional benefits of potatoes, these root vegetables contain a form of plant protein that is easily digested and used by the body, making it more bioavailable than the protein found in soy, beans, and other plant foods. The authors noted that potato protein was 90-100% digestible. By contrast, the protein from soy is only about 84% bioavailable, while legume protein is even lower (73%).

We all know protein is essential for building and maintaining muscle, but it serves many other important functions as well. In an interview with Harvard Medical School, registered dietitian Nancy Rodriguez explained that protein is vital for making hair, blood, connective tissue, antibodies, and enzymes. The recommended dietary allowance (RDA) for protein is expressed as a formula: 0.8 grams per kilogram of body weight. But Rodriguez and many other health professionals suggest that getting up to twice the RDA is a "safe and good range to aim for."

The potassium is beneficial

bowl of mashed potatoes

Although bananas have become the poster child for high-potassium foods, potatoes are actually a richer source of this important mineral. A medium baked potato (skin off) contains 610 milligrams of potassium — 13% of your daily intake. A medium banana, on the other hand, has only 422 milligrams, which is 9% (via the National Institutes of Health). Because Americans love potatoes so much, they’re actually one of the top dietary sources of potassium for both adults and children in the United States. But when you consider the fact that most Americans don’t consume the recommended amount of potassium (3,400 milligrams for adult men and 2,600 milligrams for adult women who aren’t pregnant or breastfeeding), you may want to double down on these potassium-rich tubers.

Potassium is an important electrolyte that works with sodium to maintain fluid balance in the body. Potassium is essential for proper signaling of nerves, muscle contractions (including the muscles of the heart), and kidney function. Having low levels of potassium may increase your risk for high blood pressure and stroke. Getting plenty of potassium may reduce your risk for kidney stones and appears to improve bone mineral density. Potassium may also play a role in helping to regulate blood glucose levels.

Plenty of vitamin C

potato casserole

When you think about foods high in vitamin C, oranges and other citrus fruits are probably the first thing that come to mind. And while these are excellent sources of vitamin C, potatoes are no slouch in this department. One medium baked potato contains 17 milligrams (19%) of your daily vitamin C needs (via the National Institutes of Health). In fact, potatoes represent a significant source of dietary vitamin C for many Americans. Vitamin C is a water-soluble vitamin that plays a number of important roles in the body.

It’s essential for the production of collagen, a protein that gives skin and connective tissues their structure. Vitamin C is also needed to produce certain neurotransmitters, metabolize the protein you eat, and absorb iron from plant foods. As a powerful antioxidant, vitamin C fights free radical damage in the body. It may even have the power to "regenerate" other antioxidants in the body. Adequate vitamin C is also needed for proper immune function.

While true vitamin C deficiency is rare today, 38.9% of American adults don’t meet the estimated average requirement (EAR) for vitamin C (via Oregon State University). Severe vitamin C deficiency causes scurvy, a condition marked by bleeding gums and tooth loss, bleeding under the skin, extreme weakness, and mood changes. If untreated, scurvy can lead to delirium, organ failure, coma, and death (via Healthline).

You’ll stock up on B vitamins

baked potatoes

Potatoes are also a powerhouse when it comes to many of the B vitamins. One large potato contains about 46% of your daily vitamin B6 needs, as well as 21% of your folate (vitamin B9) and niacin (vitamin B3) and 13% of your thiamin (vitamin B1) requirements (via NutritionData). Collectively, the B vitamins perform a number of critical tasks. As the Harvard School of Public Health explained, "These vitamins help a variety of enzymes do their jobs, ranging from releasing energy from carbohydrates and fat to breaking down amino acids and transporting oxygen and energy-containing nutrients around the body."

Vitamin B6, also known as pyridoxine, assists with more than 100 functions in the body. Most of these center around turning dietary protein into energy, but B6 is also involved in the production of neurotransmitters, white blood cells, and hemoglobin (the protein that allows red blood cells to carry oxygen throughout the body). It also helps maintain normal concentrations of homocysteine, an amino acid that can cause damage to arteries if levels get too high (via the National Institutes of Health). Folate is necessary for the replication of DNA and RNA, as well as cell division.

Because of these roles, folate is particularly important during pregnancy. Babies whose mothers don’t get enough folate during pregnancy are at increased risk for preterm birth, low birthweight, and neural tube defects (via the National Institutes of Health).

Load up on antioxidants

collection of colorful potatoes

While regular ol’ white potatoes aren’t known for being rich in antioxidants, these important micronutrients can be found in more colorful varieties. According to a 2007 study published in the American Journal of Potato Research, purple-flesh potatoes contain the highest amount of antioxidants (including polyphenols), followed by red and yellow potatoes. Chlorogenic acid is the chief polyphenol found in these potatoes, making up 50–70% of total polyphenol content. Other important potato polyphenols include gallic acid, catechin, and caffeic acid.

But what exactly are polyphenols? According to WebMD, polyphenols are a large group of more than 8,000 substances found naturally in plants. Polyphenols are a type of antioxidant, which means they prevent or even reverse damage done to cells as a result of aging, environmental conditions, and the food you eat. A diet rich in polyphenols has also been associated with decreased risk for a number of diseases, including heart disease, diabetes, and certain types of cancer.

Polyphenols also boost the immune system. Individuals who consume more than 650 milligrams of polyphenols daily have an overall lower risk of death than those who eat a diet lacking in polyphenols. While red wine, berries, and cocoa powder are probably the best-known sources of polyphenols, you should also make room at the table for brightly colored potatoes.

You’ll feel full longer

roasted potato on the end of a fork

Adding potatoes to your breakfast or lunch may mean you can skip snacks later in the day. That’s because potatoes are incredibly filling. In a study published in the European Journal of Clinical Nutrition, researchers gave participants 240-calorie servings of 38 common foods and then tracked how satiated individuals felt. The researchers ranked the foods, using white bread as a reference point with a score of 100. Boiled potatoes topped the list, scoring an impressive 323%. Although arguably not that healthy, even french fries ranked well, scoring 116%.

Another study, published in Nutrients in 2018, compared the "full factor" of potatoes, rice, and pasta when eaten as part of a meal. The researchers noted that participants "felt fuller, more satisfied, and wanted to eat less" after eating the meal that included potatoes compared to the other two starch options.

It’s actually a little surprising that potatoes are as satiating as they are. According to the Cooper Institute, how full you feel after eating something depends on the macronutrient content of that meal. While food that takes up a lot of space in your stomach may trigger signals to stop eating, protein and fiber have the biggest role to play in controlling when you’ll be hungry again. Potatoes contain relatively small amounts of both (via Healthline).

Manage your weight

potatoes

Although potatoes are often considered a "fear food" among dieters, they’re actually quite low in calories. A 3.5-ounce serving of boiled skin-on potatoes contains just 87 calories (via Healthline). Potatoes also contain a compound known as protease inhibitor II (PI2) that can have an effect on how many total calories a person consumes and therefore can help manage weight. According to a 2017 study published in Food & Function, individuals who consumed PI2 during a meal reported greater feelings of fullness afterward and less desire to continue eating than those in the control group. These individuals ate fewer calories overall.

Based on the energy-balance model of weight control, losing weight is a matter of consuming fewer calories than you burn (via WebMD). So if potatoes cause you to eat fewer calories throughout the day, they can certainly aid in weight loss.

While potatoes may be a helpful addition to your weight-loss journey, you can definitely take things too far. One popular fad diet, aptly named the potato diet, requires followers to eat nothing but plain, cooked potatoes for three to five days. Although individuals may see some short-term weight loss due to the extremely restrictive and low-calorie nature of their potato-only meal plan, the weight is likely to come back. This simply isn’t a sustainable diet; although nutritious, potatoes lack protein, fat, and many micronutrients needed for good health (via Healthline).

A healthy gut will thank you

bowl of new potatoes

Potatoes aren’t considered a high-fiber food (via Healthline), but they’re a rich source of another important but undigestible nutrient: resistant starch. According to Clean Eating magazine, resistant starch is a type of fermentable fiber that has properties of both insoluble and soluble fiber. It passes undigested from the small intestine to the large intestine, but once there it becomes food for the beneficial bacteria that live in your colon.

The bacteria produce butyric acid as they metabolize the resistant starch, and the cells lining your colon use this butyric acid as their main energy source. So the resistant starch provides food for your gut bacteria, which in turn provide the fuel your intestinal cells need to stay healthy and well-functioning.

In addition to potatoes, resistant starch is present in foods like oats, lentils, and unripe bananas. Cooking potatoes and then allowing them to cool before eating increases their resistant starch content. Some individuals add raw potato starch to smoothies, oatmeal, or yogurt to sneak more resistant starch into their diet. Potato starch — a white flour-like powder similar to cornstarch — is about 80% resistant starch. While it’s not as tasty as eating an actual potato, you’ll only need one or two tablespoons a day to keep your friendly bacteria happy (via Healthline).

Your blood pressure may or may not spike

tater tots with ketchup

The jury’s still out on the connection between potatoes and blood pressure. WebMD reported on a 2016 study that found that those who ate baked, boiled, or mashed potatoes four or more times a week were 11% more likely to have high blood pressure compared to those who ate these foods less than once a month. Individuals who ate fried potatoes four or more times per week had a 17% greater risk for high blood pressure.

But clinical nutritionist Samantha Heller pointed out that Americans usually eat their potatoes loaded with salt and saturated fat (in the forms of butter, sour cream, cheese, bacon, and frying oil), and it’s these additions — not the potatoes themselves — that are likely responsible for spiking blood pressure.

In fact, some research suggests that potatoes may actually lower blood pressure. In 2021, News Medical reported on a study published in Nutrients that found the high potassium content of potatoes may decrease systolic blood pressure (the pressure in the arteries when the heart is contracting). Dr. Connie Weaver, head researcher on the study, told News Medical: "While significant emphasis is often placed on reducing dietary sodium intakes to better control for blood pressure and cardiovascular disease risk, that’s only half of the story. Potassium plays just as an important role." Weaver noted that eating potassium-rich potatoes caused study participants to retain less sodium than simply taking a potassium supplement.

Healthier brain

loaded baked potatoes

Potatoes are a solid source of choline — a nutrient you’ve probably never heard of but which plays an important role in brain health. According to the Harvard Medical School, choline assists with the creation and release of a protein called acetylcholine. Acetylcholine conducts signals between neurons and plays an important role in cognition and memory. In fact, individuals with Alzheimer’s disease have lower levels of acetylcholine in their brains, and medications to treat the early stages of the condition work by blocking the enzyme that breaks down acetylcholine.

The National Institutes of Health (NIH) recommends adult men get 550 milligrams of choline a day, while nonpregnant women need 425 milligrams. While liver is the best dietary source of choline, potatoes are another (more appealing) option. One large baked red potato (eaten with the skin) contains 57 milligrams of choline. Although a small amount of choline can be synthesized in the liver, this is only supplemental — it’s not enough to fully meet an individual’s needs. That’s why getting enough choline from food is so important. The NIH reported that most Americans don’t consume the recommended amount of choline. Average daily intake is just 402 milligrams for men and 278 milligrams for women. Choline deficiency can cause muscle damage, liver damage, and nonalcoholic fatty liver disease.

Eating them fried could lead to problems

woman eating fries

While potatoes in their natural form are quite nutritious, it’s a whole different ball game when it comes to french fries, tater tots, chips, and other deep-fried potatoes. According to WebMD, fried foods have been linked to increased risk of type 2 diabetes and heart disease. Dr. Leah Cahill, assistant professor at Dalhousie University, explained, "Fried foods may influence risk of these diseases through several key risk factors: obesity, high blood pressure, and high cholesterol. The process of frying is known to alter the quality and increase the caloric content of food." High-temperature frying also produces acrylamide, a chemical formed when the amino acid asparagine reacts with sugars. Acrylamide has been found to cause cancer in animals.

The Food and Drug Administration (FDA) offers several suggestions for reducing acrylamide formation in potatoes. Roasting and baking produce less acrylamide than frying, but boiling and microwaving potatoes don’t churn out any acrylamide — which makes them the best cooking options. In addition, soaking raw potatoes in water for 15–30 minutes prior to frying can reduce acrylamide content. Storing raw potatoes in the fridge may increase their acrylamide content, so be sure to store them in a pantry or other cool, dark place. If you really can’t give up frying your potatoes, try to limit the time they spend at high heat.

Sprouted potatoes might make you ill

sprouted potatoes

You’ve probably heard that eating green or sprouted potatoes can make you sick, but is there any truth to that or is it just an old wives’ tale? According to Poison Control, potatoes contain solanine and chaconine, two toxic substances known as glycoalkaloids. These "cause toxicity through cell disruption leading to gastrointestinal symptoms such as vomiting, abdominal pain, and diarrhea. Some people may also experience headache, flushing, confusion, and fever." Although it’s rare, some people have even died from consuming large amounts of these toxic glycoalkaloids.

Exposure to light increases both the chlorophyll and glycoalkaloid content of potatoes. The large amounts of chlorophyll turn the potato’s skin green. While chlorophyll is harmless, a green potato means glycoalkaloid content is also elevated. The "eyes" and sprouts of a potato contain concentrated amounts of solanine and chaconine. So it’s best to toss green or sprouted potatoes.

But just how much of these glycoalkaloids can you eat before becoming sick? According to Smithsonian Magazine, "Studies have recorded illnesses caused by a range of 30 to 50 milligrams of solanine per 100 grams of potato, but symptoms vary depending on the ratio of body weight of the toxin and the individual’s tolerance of the alkaloid." Death from solanine poisoning is rare and commercially-grown potatoes are screened for high glycoalkaloid content before being sold (though, as mentioned above, these toxins can build up naturally over time, especially when potatoes are exposed to light).

They can trigger an allergic reaction

hand refusing French fries

Although rare, it’s possible to be allergic to potatoes. There are four proteins that can cause allergic reactions, with patatin being the main culprit. It’s also possible to have pollen-food allergy syndrome or latex food syndrome, in which an allergy to certain types of plants or to latex can cause a cross-reaction with potatoes and other foods. This is because (chemically) the patatin protein in potatoes is very similar to the allergens in latex and various trees and grasses.

While eating cooked potatoes usually isn’t a problem, peeling and cutting raw potatoes can trigger an allergic reaction because the body mistakes the patatin for the allergens in latex or plants (via Allergy Resources).

Potatoes are part of a plant family known as nightshades, which also includes tomatoes, eggplants, bell peppers, paprika, and cayenne pepper. Some people have a nightshade intolerance, meaning they have difficulty digesting these foods. Symptoms of a nightshade intolerance include skin rashes, bloating, and nausea. While there’s no test to definitively diagnose a nightshade intolerance, keeping a food and symptom diary or trying an elimination diet can help individuals pinpoint whether or not potatoes and other nightshades are at the root of their digestive distress. Individuals with an intolerance should avoid nightshades (via Patient).