Potatoes: Nutrients, What Research Shows and Safety

The potato (Solanum tuberosum) is the underground tuber of a plant in the nightshade family (Solanaceae). The tuber is the part eaten, usually cooked. People eat potatoes as an everyday starchy staple that also supplies potassium, vitamin C and vitamin B6. This page keeps the whole food apart from supplements and from hype, and it separates how a potato is cooked from the potato itself. It is information, not a plan for what to eat.

Read this first

• Green or sprouting potatoes: the World Health Organization (WHO) says potatoes make natural toxins called solanines, and levels are higher in sprouts, the bitter peel and green parts. Do not eat green or sprouting parts, and store potatoes in a dark, cool, dry place. [5]
• Kidney disease and some blood pressure medicines: potatoes are a good potassium source. MedlinePlus says too much potassium in the blood can cause dangerous heart rhythms, that poor kidney function is a common cause, and that ACE inhibitors, ARBs and potassium-sparing diuretics can raise levels. Ask your care team if this applies to you. [4]
• Allergy: any food can cause an allergic reaction. For trouble breathing or swelling of the face or throat, call 911. See food allergy basics and emergency signs.
• 5 A DAY: in the UK, the NHS does not count potatoes toward the 5 A DAY because they are a starchy food. [2]
• Evidence in one line: how a potato is cooked seems to matter more than the potato. In large observational studies, french fries are linked with higher diabetes risk, while baked, boiled or mashed potatoes are not clearly linked. Observation cannot prove cause. [10][11]

What is in it (USDA values)

Source: USDA FoodData Central, potatoes, flesh and skin, raw (SR Legacy, item 170026). [1] % Daily Value uses the FDA 2016 Daily Values; values vary with variety, ripeness and storage. Per-serving figures are our arithmetic from the USDA per-100 g values. These are raw values; boiling, baking or frying changes them, and adding oil, butter or salt changes the food again.

The main plant compound we can source here is starch. Some starch resists digestion in the small intestine and is called resistant starch; the amount in a food depends heavily on how it is prepared. [17] A 2026 trial measured total phenolic compounds in cooked potato in the lab, but we did not read a human trial showing a health effect of potato phenolics, so we make no claim about them. [18]

What research says

Eaten as food vs taken as a supplement or extract. The findings above are about potatoes eaten as food. Resistant potato starch is also sold as a powder. In one randomized trial in 70 healthy adults, 3.5 g a day for four weeks changed some gut bacteria and stool measures compared with placebo. [19] That is a concentrated starch, not a potato, and a result for the powder does not tell us what eating potatoes does. We do not cover potato supplements.

How much is a normal serving

• NHS: 80 g of fresh, canned or frozen fruit or vegetables is one portion of the 5 A DAY, but potatoes do not count because they are a starchy food. Sweet potatoes, parsnips and turnips do count. [2] See sweet potatoes, carrots and orange vegetables.
• WHO: at least 400 g of fruits and vegetables a day for people older than 10 (fact sheet date 26 January 2026). [3] The WHO figure is about fruits and vegetables in general; we did not read whether WHO counts potatoes in it, so we make no claim.
• The USDA household portions are 0.5 cup diced (75 g), 1 small potato (170 g), 1 medium (213 g) and 1 large (369 g), all raw. [1]
• These are official figures, information only, not a prescription.
• Cooking: a 2022 review says boiling and long cooking in water can lower water-soluble nutrients such as vitamin C and folate, while steaming or microwaving may keep more. [20] It notes that findings are inconsistent for some nutrients. We did not find potato-specific numbers we could verify.

Safety, allergy and medicines

• Green and sprouted potatoes (solanine): WHO says solanines and chaconine are natural glycoalkaloids in potatoes and other nightshades, usually at low levels but higher in sprouts, the bitter peel and green parts. They form when the plant is stressed, for example by bruising, light or microbes. WHO advises storing potatoes in a dark, cool, dry place and not eating green or sprouting parts. [5] A case report describes that acute poisoning from green or sprouted potatoes mainly causes vomiting, diarrhea and stomach pain, with fever, fast pulse, low blood pressure and nerve symptoms at higher doses, and calls poisoning rare. [6] A 2026 review notes that glycoalkaloids are toxic above a certain level and that agricultural and storage conditions can raise them. [8] The WHO page does not say whether peeling or cooking removes them, so we make no claim. Seek medical care for severe symptoms.
• Potassium, kidney disease and medicines: one medium raw potato has 905 mg potassium (19% of the Daily Value). [1] MedlinePlus says people with kidney problems, especially on dialysis, may need to limit high-potassium foods, and that ACE inhibitors, ARBs and potassium-sparing diuretics (spironolactone, triamterene, amiloride) can raise blood potassium. A care team can say whether a limit is needed. [4] See foods, kidney disease, potassium and oxalates and foods and medicine interactions.
• Acrylamide in fried and baked potato foods: the US National Cancer Institute says acrylamide forms when foods with the amino acid asparagine, such as potatoes, are heated to high temperatures with certain sugars, and that french fries and potato chips are major dietary sources. [9] It adds that many human studies have not found consistent evidence that dietary acrylamide is linked to any type of cancer, that estimating intake is hard, and that rodent studies have linked acrylamide to cancers; the US National Toxicology Program considers it reasonably anticipated to be a human carcinogen. [9] The FDA says acrylamide forms during frying, roasting and baking. [23] NCI lists shorter cooking time, blanching before frying and avoiding refrigeration of raw potatoes as ways to lower levels. [9] Note that WHO's storage advice (cool, dark, dry) and the acrylamide note on refrigeration are different questions; neither source gives a single fridge temperature. [5][9]
• French fries, chips and sodium: the cohort studies above link french fries with higher type 2 diabetes risk and fried potatoes with higher hypertension risk. [10][13] A cohort in which fries and chips were eaten also found higher fasting glucose and insulin. [16] This is observational; fries differ from boiled potatoes in oil, salt and portion size as well as in cooking method. We did not read a source separating those factors.
• Diabetes and blood sugar: the evidence above is mixed; people with diabetes who take insulin or other medicines should ask their team how potatoes fit their meals. See foods for blood sugar control.
• Allergy: any food can cause an allergic reaction. For trouble breathing or swelling of the face or throat, call 911. We did not read a source on how common potato allergy is, so we make no claim.
• Pregnancy: Proper evidence not found in the sources we read on potatoes in pregnancy. See foods in pregnancy.
• Pesticide residues: we did not read a source on potato residues, so we make no claim.

Choosing, storing and food safety

• Pick potatoes without bruises or damage, and cut away bruised areas, as the FDA advises for produce. [22] WHO links bruising to solanine formation, so avoid green or sprouting parts. [5]
• Rinse produce under running water, including produce you will peel; do not use soap or produce wash. Washing lowers bacteria but does not remove them. Scrub firm produce with a clean brush. [22]
• Store in a dark, cool, dry place (WHO). [5]
• Cooked leftovers: see food storage, leftovers and food safety basics.

Related pages

• Resistant starch foods
• Foods for blood sugar control
• Foods, kidney disease, potassium and oxalates
• Foods for blood pressure
• Sweet potatoes, carrots and orange vegetables
• Parsnips