If you've ever popped a piece of raw potato in your mouth while you were chopping some up for a soup or stew, you know they have an interesting flavor when uncooked.
Although potatoes are a rich source of nutrients that provide energy and boost your health, no matter how you eat them, you should be careful about eating potatoes raw — especially if the flesh has a green hue.
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Although there are some health benefits to eating raw potatoes, the presence of lectins and the potential presence of solanine, a toxic compound, outweigh those benefits.
Benefits of Eating Raw Potatoes
It moves through your digestive system mostly unchanged, pushing food along and aiding regularity.
Fiber can also help reduce the absorption of cholesterol into your bloodstream, which can reduce your total cholesterol levels for better heart health, according to the Harvard T. H. Chan School of Public Health. Americans only get about 15 grams of fiber per day but should aim for between 20 and 30 grams daily.
2. Vitamin C
Potatoes also contain vitamin C, crucial for a healthy immune system and wound healing, per the National Institutes of Health (NIH). The 3.5-ounce serving of skin-on raw potatoes offers 11.4 milligrams of vitamin C — or 15 percent of the daily value (DV) for women and nearly 13 percent DV for men.
However, vitamin C is water-soluble and temperature-sensitive, according to a December 2018 study in Food Science and Biotechnology, which found that boiling and blanching can destroy nearly all vitamin C content. Microwaving and steaming had less of an effect on vitamin C content.
3. Vitamin B6
Raw potato also contains 18 percent of the DV of vitamin B6, which plays a role in brain function, hemoglobin formation and immune function, per the NIH.
Raw potatoes are a good source of certain minerals, too, with each serving providing around 18 percent of the DV of iron, which supports muscle and brain health, per the NIH.
4. Resistant Starch in Raw Potatoes
Potato starch is 70 percent to 80 percent the resistant starch amylopectin, according to a July 2020 study published in the American Journal of Plant Sciences. Resistant starch is a type of carbohydrate that, as the name suggests, resists digestion — much like fiber.
Instead of moving through the small intestine, resistant starch ferments in the large intestine, where it acts as a prebiotic that feeds the helpful bacteria in the gut, according to Johns Hopkins Medicine.
And because the starch isn't digested, it doesn't break down into glucose. This can lower post-meal blood sugar levels, which can help managee diabetes and prevent the fatigue and mood changes that can result from post-meal blood sugar spikes, according to a February 2017 study in Nutrition Journal.
The American Journal of Plant Sciences study reviewed the starch content of eight types of potatoes and found that total starch, including resistant starch, decreased across all varieties when the potatoes were cooked. A November 2018 study in Nutrients confirmed that cooking affects the starch content, but data is limited because tubers are nearly always cooked before they're eaten.
Both the temperature at which the potato is cooked and the length of cooking time has an effect on the final amount of resistant starch, with baking being preferred over microwaving or boiling.
Risks of Eating Raw Potatoes
Although the micronutrients and resistant starch content of raw potatoes are great, it doesn't necessarily mean you should gobbling down uncooked tubers.
1. Lectins in Raw Potatoes
All raw plants — including raw potatoes — contain the anti-nutrient lectin, a protein that binds to carbohydrates.
When consumed in large amounts, lectins can lead to severe reactions such as nausea, vomiting, stomach upset and diarrhea as well as interfere with the absorption of certain minerals, according to the Harvard T.H. Chan School of Public Health.
However, lectins are water-soluble, which means that cooking the lectin-containing plants completely denatures it, according to the Mayo Clinic. Therefore, while lectins in raw potatoes can be considered toxic, especially when eaten in large amounts, eating cooked potatoes is safe.
2. Solanine in Green Potatoes
Potatoes, as well as other vegetables in the nightshade family, can produce the alkaloid compound solanine if they've been exposed to light, especially fluorescent light, or too hot or too cold temperatures for a long period of time.
You'll know if your potatoes have produced solanine because they'll take on a green hue.
Even in small doses, solanine is toxic and can cause headaches, diarrhea, nausea, vomiting and central nervous system paralysis, and in rare cases, death, according to Colorado State University.
Although removing the skin of a green potato can decrease its solanine content, cooking the potato doesn't eliminate the risk, per the National Capital Poison Center. When in doubt, it's better to toss that potato out.
- National Institutes of Health Office of Dietary Supplements: "Vitamin C"
- Harvard T. H. Chan School of Public Health: "Fiber"
- Nutrition Journal: "Resistant Starch Lowers Postprandial Glucose and Leptin in Overweight Adults Consuming a Moderate-to-High-Fat Diet: A Randomized-Controlled Trial"
- Critical Reviews in Food Science and Nutrition: Resistant starch and energy balance: impact on weight loss and maintenance
- USDA FoodData Central: "Potatoes, Raw, Skin"
- National Institutes of Health Office of Dietary Supplements: "Vitamin B6"
- National Institutes of Health Office of Dietary Supplements: "Iron"
- Food Source Information-Colorado State University: "Potatoes"
- Food Science and Biotechnology: "Effect of Different Cooking Methods on the Content of Vitamins and True Retention in Selected Vegetables"
- Johns Hopkins Medicine: "What is Resistant Starch?"
- American Journal of Plant Science: "The Effect of Potato Varieties and Processing Methods on Glycemic Response"
- Nutrients: "Starchy Carbohydrates in a Healthy Diet: The Role of the Humble Potato"
- Harvard T.H. Chan School of Public Health: "Lectins"
- The Journal of Immunology: "Plant Lectins Activate the NLRP3 Inflammasome to Promote Inflammatory Disorders"
- Mayo Clinic Connect: "Know Your Lectins"
- National Capital Poison Center: "Are Sprouted Potatoes Safe to Eat?"
- Bon Appetit: Potatoes