Potatoes 101: Nutrition Facts and Health Effects

Cooked potatoes with the skin are a good source of many vitamins and minerals, such as potassium and vitamin C.

Aside from being high in water when fresh, potatoes are primarily composed of carbs and contain moderate amounts of protein and fiber — but almost no fat.

The nutrients found in 2/3 cup (100 grams) of boiled potatoes — cooked with the skin but without salt — are (1):

• Calories: 87
• Water: 77%
• Protein: 1.9 grams
• Carbs: 20.1 grams
• Sugar: 0.9 grams
• Fiber: 1.8 grams
• Fat: 0.1 grams

Carbs

Potatoes are mainly composed of carbs, primarily in the form of starch. The carb content ranges from 60–80% of dry weight (2).

Simple sugars — such as sucrose, glucose, and fructose — are also present in small amounts (1).

Potatoes usually have a high glycemic index (GI), making them unsuitable for people with diabetes. The GI measures how foods affect your rise in blood sugar after a meal. However, some potatoes may be in the medium range — depending on the variety and cooking methods (3, 4).

Cooling potatoes after cooking may lessen their effect on blood sugar and lower their GI by 25–26% (4, 5).

Fibers

Even though potatoes are not a high fiber food, they may provide a significant source of fiber for those who eat them regularly.

The level of fiber is highest in the skin, which makes up 1–2% of the potato. In fact, dried skins are about 52% fiber (6).

Potato fibers — such as pectin, cellulose, and hemicellulose — are mainly insoluble (7). They also contain varying amounts of resistant starch, a type of fiber that feeds the friendly bacteria in your gut and improves digestive health (8).

Resistant starch can also improve blood sugar control, moderating your rise in blood sugar after meals (9, 10). Compared with hot potatoes, cooled ones offer higher amounts of resistant starch (4).

Protein

Potatoes are low in protein, ranging from 1–2% when fresh and 8–9% by dry weight (1, 11).

In fact, compared with other common food crops — such as wheat, rice, and corn — potatoes have the lowest amount of protein. However, the protein quality of potatoes is very high for a plant — higher than that of soybeans and other legumes (12).

The main protein in potatoes is called patatin, which may cause allergies in some people (13).

SUMMARY

Carbs are the main dietary component of potatoes. Cooling potatoes after boiling may increase the amount of resistant starch, which can improve gut health. Potatoes also contain small amounts of high quality protein.

Potatoes are a good source of several vitamins and minerals, particularly potassium and vitamin C.

The levels of some vitamins and minerals drop during cooking, but this reduction can be minimized by baking or boiling them with the skin on.

• Potassium. The predominant mineral in potatoes, potassium is concentrated in the skin and may benefit heart health (2, 14).
• Vitamin C. The main vitamin found in potatoes, vitamin C is significantly reduced with cooking — but leaving the skin on appears to reduce this loss (2).
• Folate. Concentrated in the peel, folate is mostly found in potatoes with colored flesh (15, 16).
• Vitamin B6. A class of B vitamins involved in red blood cell formation, B6 is found in most foods. Deficiency is rare.

SUMMARY

Potatoes are a good source of several vitamins and minerals, including potassium, folate, and vitamins C and B6.

Potatoes are rich in bioactive plant compounds, which are mostly concentrated in the skin.

Varieties with purple or red skin and flesh contain the highest amounts of polyphenols, a type of antioxidant (17).

• Chlorogenic acid. This is the main polyphenol in potatoes (17).
• Catechin. An antioxidant that accounts for about 1/3 of total polyphenol content, catechin is highest in purple potatoes (18).
• Lutein. Found in potatoes with yellow flesh, lutein is a carotenoid antioxidant that may boost eye health (19, 20).
• Glycoalkaloids. A class of toxic phytonutrients produced by potatoes as a natural defense against insects and other threats, glycoalkaloids may have harmful effects in large amounts (21).

SUMMARY

Potatoes harbor some healthy antioxidants that are responsible for many of their health benefits and mostly concentrated in the skin.

Potatoes with skin may offer a number of health benefits.

Heart health

Hypertension, a harmful condition characterized by abnormally high blood pressure, is one of the main risk factors for heart disease.

Potatoes contain a number of minerals and plant compounds that may help lower blood pressure. The high potassium content of potatoes is particularly noteworthy.

Several observational studies and randomized controlled trials link high potassium intake to a reduced risk of high blood pressure and heart disease (22, 23, 24).

Other substances in potatoes that may promote lower blood pressure include chlorogenic acid and possibly kukoamines (25).

Fullness and weight management

Foods that are very filling may support weight management, prolonging the feeling of fullness after meals and reducing food and calorie intake (26).

Relative to other carb-rich foods, potatoes are particularly filling. One older study of 40 common foods found potatoes to be the most filling (27).

Another older trial in 11 men showed that eating boiled potatoes as a side with pork steak led to less calorie intake during the meal when compared to pasta or white rice (28).

Thus, potatoes may aid weight management by helping you reduce overall intake. Studies indicate that proteinase inhibitor 2 (PI2), a potato protein, may suppress appetite (29).

Even though PI2 may suppress appetite when taken in its pure form, it is unclear whether the trace amounts present in potatoes have any effect.

SUMMARY

Potatoes are relatively filling. For this reason, they may be useful as a part of a weight management plan.

Eating potatoes is generally healthy and safe. However, in some cases, people need to limit their consumption — or avoid them altogether.

Potato allergies

Food allergies are a common condition, characterized by an immune reaction to proteins in certain foods.

A potato allergy is relatively rare, but some people may have an allergy to patatin, one of the main proteins in potatoes (30, 31, 32).

Those with a latex allergy may be sensitive to patatin as well due to a phenomenon known as allergic cross-reactivity (33).

Potato toxins

Plants of the nightshade family, such as potatoes, contain a class of toxic phytonutrients known as glycoalkaloids. The two main glycoalkaloids in potatoes are solanine and chaconine.

Glycoalkaloid poisoning after eating potatoes has been reported in both people and animals (21). However, reports of toxicity are rare, and the condition may go undiagnosed in many cases. In low doses, glycoalkaloids usually cause mild symptoms, such as headache, stomach pain, diarrhea, nausea, and vomiting (21).

In more serious cases, the symptoms include neurological disorders, rapid breathing, fast heartbeat, low blood pressure, fever, and even death (21, 34).

Some animal studies indicate that the low levels of glycoalkaloids likely found in the human diet may exacerbate inflammatory bowel disease (IBD) (35).

Normally, potatoes contain only trace amounts of glycoalkaloids. A 154-pound (70-kg) individual would have to eat over 13 cups (2 kg) of potatoes (with the skin) in one day to get a lethal dose (34). That said, lower amounts may still cause adverse symptoms.

The levels of glycoalkaloids are higher in the peel and sprouts than in other parts of the potato. It’s best to avoid eating potato sprouts (36).

Potatoes rich in glycoalkaloids have a bitter taste and cause a burning sensation in your mouth, an effect that may be a warning sign of potential toxicity (37).

Potato varieties containing high amounts of glycoalkaloids — over 25 mg per cup (200 mg per kg) — cannot be marketed commercially, and some varieties have been banned (38).

Acrylamides

Acrylamides are contaminants formed in carb-rich foods when they’re cooked at very high temperatures, such as during frying, baking, and roasting (39).

They are found in fried, baked, or roasted potatoes, but not fresh, boiled, or steamed ones (40, 41, 42). The amount of acrylamides increases with higher frying temperatures and longer cooking times (42). Compared to other foods, french fries and potato chips are very high in acrylamides (42).

These compounds are used as industrial chemicals, and acrylamide toxicity has been reported in people exposed to them in the workplace (43).

Although the amount of acrylamides in foods is generally low, long-term exposure may be harmful. Animal studies indicate that acrylamides may increase cancer risk and harm the brain and nervous system (44, 45, 46, 47).

In humans, acrylamides have been classified as a possible risk factor for cancer (48).

However, numerous observational studies have investigated the effect of eating acrylamide-rich foods on cancer risk in humans, and most did not detect any significant adverse effects (49, 50, 51, 52, 53).

High intake of acrylamides may have adverse health effects over time, but the extent of these effects is unclear, and further studies are required.

For optimal health, it seems sensible to limit your consumption of french fries and potato chips.

French fries and potato chips

Potatoes have been blamed for contributing to obesity, cardiovascular disease, and diabetes.

The main reason for this is that potatoes are widely consumed as french fries and potato chips — high fat foods that harbor a number of unhealthy compounds. French fries are also frequently associated with fast food.

Observational studies link the consumption of fried potatoes and potato chips to weight gain (54, 55).

Fried potatoes and potato chips may also contain acrylamides and high amounts of salt, which may be harmful over time (42, 56, 57).

For this reason, high consumption of fried potatoes — especially french fries and chips — should be avoided.

Who should avoid potatoes?

Anyone with an allergy to potatoes or any of the compounds in potatoes should avoid eating them.

Some believe potatoes and other vegetables in the nightshade family exacerbate autoimmune conditions like IBS (58). However, more research is needed to know for sure whether individuals with autoimmune conditions should avoid potatoes.

Potatoes can be part of a nutrient-dense diet. However, fried potatoes, like french fries and potato chips, should be limited, especially in people who are trying to manage their weight or who have an increased risk of cardiovascular disease or diabetes.

SUMMARY

Potatoes may contain a number of unhealthy compounds — particularly when fried. Limit your consumption of french fries and chips, and remove potato sprouts when preparing potatoes.

There are many ways to prepare potatoes. Different preparation methods result in different flavor and texture characteristics and also can greatly affect the nutrition content of the potatoes.

Here is a rundown of the most common ways to prepare potatoes and how these preparation methods affect nutrition content:

Boiling

Boiling potatoes causes water-soluble nutrients, such as vitamin C and potassium, to leach out (2). This results in slightly less nutritious potatoes.

The longer you boil, the more nutrients are lost. Boiling potatoes in their skin helps to retain some of the water-soluble nutrients.

Frying

Fried potatoes are cooked in hot oil and include french fries and potato chips.

While the fast cooking time of frying helps preserve some of the nutrients, frying in oil significantly increases the fat content of potatoes, sometimes including trans fats, an unsaturated fat associated with a number of negative health effects (2).

Limiting your consumption of fried foods, like french fries or potato chips, is one of the best ways to lower your intake of trans fats. Frying potatoes also increases the formation of potentially harmful chemicals like acrylamides.

Baking

Perhaps the simplest way to prepare potatoes, baking requires only scrubbing the skin clean, pricking the skin with a fork to allow steam to escape, and baking the potatoes for about an hour at 425°F (218°C).

Baked potatoes retain more of the nutrients when compared with boiling or frying. They also offer more fiber, particularly if you eat the skin.

Keep in mind that typical toppings, like sour cream, cheese, or butter, can significantly change the nutrition profile of your potato, adding additional fat, calories, and sodium.

Roasting

Roasting is similar to baking — some use the terms interchangeably. Typically, baked potatoes are cooked whole, whereas roasted potatoes are frequently chopped and tossed with oil and seasonings. Both are nutritious ways to prepare potatoes.

Here is an easy, healthy recipe for perfect roasted potatoes.

Microwaving

Microwaving potatoes is one of the most nutritious and fastest ways to prepare potatoes. Microwaving potatoes preserves many of the nutrients lost through other cooking methods (2).

SUMMARY

How you prepare potatoes affects their nutrient composition. Baking, roasting, or microwaving potatoes with their skin on retains most of the nutrients. Boiled potatoes contain fewer water-soluble nutrients. Frying increases the formation of potentially harmful chemicals.

Potatoes are a popular high carb food that provides several healthy vitamins, minerals, and plant compounds. What’s more, they may aid weight management and help prevent heart disease.

However, this does not apply to fried potatoes — such as french fries and chips — that have been soaked in oil and cooked under high heat. For optimal health, it’s best to limit or avoid these products altogether.