Dr. Mercola: Can Potatoes Be Considered Healthy?

• Potatoes, which are rich in fiber, vitamins B and C and minerals like potassium, are the world’s third largest crop, taking their place behind rice and wheat
• The majority of potatoes are served in the form of french fries and potato chips, exposing you to acrylamide — a potentially neurotoxic chemical that results when potatoes are heated to very high temperatures to produce a browned or charred surface
• The health benefits of potatoes vary widely depending on how they are prepared, the portion size and frequency of consumption
• A Consumer Reports’ analysis of 50 baby food products indicates even organic brands of sweet potatoes are vulnerable to heavy metal toxicity due to the fact soil conditions vary widely around the globe

By Dr. Mercola

According to the U.S. Department of Agriculture (USDA),¹ potatoes hold the top spot for highest daily per capita consumption of vegetables in the American diet, edging out tomatoes. This means the average person consumes 48 pounds of potatoes annually, of which about 40 percent are frozen.

While commonly known as a vegetable, due to their nutritional composition, potatoes are better classified as a starch. On the positive side, potatoes are rich sources of fiber, vitamins B and C and minerals like iron and potassium. When cooked then chilled, regular potatoes become a resistant starch, making them easier to digest.

Sadly, the majority of potatoes sold and consumed in the U.S. and elsewhere are in the form of french fries and potato chips. You should avoid these potato types due to the lack of nutrition they provide and also as a way to reduce your exposure to a neurotoxic chemical called acrylamide, which is found in browned or charred foods.

Also, because potatoes are grown in soil, and soil conditions vary widely around the globe, you may be increasing your exposure to toxic pesticides and heavy metals every time you eat a tuber. For that reason, it’s best to purchase organic potatoes and moderate your intake, keeping in mind that even organic brands can be tainted with heavy metals.

The Origin of Potatoes

As a member of the Solanaceae or nightshade family, regular potatoes are related to eggplants, peppers and tomatoes. As such, they are a potentially inflammatory food. Potatoes originated in South America, specifically in the Andes Mountains region, and 4,000 edible varieties are said to exist worldwide.²

In the 16th century, Spanish explorers introduced potatoes to Europe. Due to their vitamin C content, potatoes were used during sea voyages to help combat scurvy. In the 18th century, Irish immigrants brought the potato to the U.S.

Today, potatoes are cultivated worldwide, taking their place behind rice and wheat as the world’s third largest crop in terms of human consumption.³ Notably, due to their moderate-to-cool climates, the states of Idaho and Washington produce about half the potatoes consumed in the U.S.⁴

Each type of regular potato, as well as sweet potato, varies in shape, size, color, flavor and nutritional content.

What Makes Potatoes Healthy?

As mentioned in the featured video, a medium plain baked potato eaten with its fiber-rich skin contains just 160 calories per serving. It also contains about 4 grams of fiber and 4 grams of protein. In terms of nutritional benefits, potatoes are:

• Rich in vitamin C
• An abundant source of B vitamins, including vitamin B6 (pyridoxine), folate, niacin, pantothenic acid and thiamin
• Full of minerals such as copper, iron, magnesium, manganese, phosphorus and potassium
• A source of phytonutrients, which have antioxidant effects, such as caffeic acid, carotenoids and flavonoids
• A good supply of soluble and insoluble fiber, which may help prevent constipation and optimize your LDL cholesterol

About the potassium level in potatoes, Victoria Jarzabkowski, a registered dietitian nutritionist on the President's Council on Fitness, Sports & Nutrition, said, “All potatoes are potassium-rich. They have even more potassium than a banana, and a lot of it is found in the skin.”⁵

In terms of the impact of potatoes on blood pressure, CNN noted, “Potatoes … offer vitamin B6, vitamin C and iron, and are an excellent source of potassium. A medium potato provides about 20 percent of the recommended daily value for potassium, an important mineral that may help blunt sodium's effects on blood pressure.”⁶

According to the USDA National Nutrient Database, a 100-gram potato with its skin on also contains significant portions of calcium, niacin, phosphorous and folate.⁷

A very small 2013 study⁸ published in the Annals of Nutrition and Metabolism suggested potatoes exert a greater influence on your satiety — in terms of their ability to reduce your appetite after being consumed — than other carbohydrate side dishes such as pasta.

Cautions About Potatoes: Watch Out for Heavy Metals

Despite their many beneficial properties, potatoes are best consumed in moderation due to their high starch content. Another reason to eat potatoes only occasionally has to do with the soil in which they are grown.

Given the amount of pesticides and heavy metals in ground soil worldwide, unless you grow your own, you cannot be certain of the toxin load you may be ingesting with your favorite tuber. To reduce as much toxicity as you can, it’s vital you choose organic potatoes to avoid the many chemicals routinely sprayed on conventional tubers.

The Pesticide Action Network North America’s “What’s on my Food?” website suggests 35 chemicals were found on potatoes by the USDA’s pesticide data program. Among the 35 chemicals noted are carcinogens and neurotoxins, as well as bee, hormone and reproductive disruptors.⁹

Even when you choose organic brands, keep in mind they likely contain heavy metals mainly because potatoes are grown in soil, which can be contaminated with metals such as arsenic, cadmium and lead.

Researchers behind a 2018 Consumer Reports’ analysis of 50 nationally distributed packaged baby food products for heavy metal toxicity, including several organic brands of sweet potatoes, stated:¹⁰

“Although foods certified as organic by the USDA do have benefits — including lower pesticide levels and less impact on the environment — avoiding heavy metals isn’t one of them. Twenty of the products in our test were labeled organic, and, as a whole, they were just as likely to contain heavy metals as the conventional ones.”

“Arsenic and lead, which have been used in the past as pesticides, are prohibited under organic regulations,” says Consumer Reports’ food labeling expert Charlotte Vallaeys. “Because these heavy metals are contaminants in the soil, there's no reason why organic baby foods would contain lesser amounts.”¹¹

Clearly, if organic sweet potatoes sold in small amounts as baby food have ignited health concerns about heavy metals, you can imagine eating a whole sweet potato also carries some risks.

Choosing reputable sources and eating potatoes in moderation are key to leveraging the nutritional benefits of tubers while minimizing the health risks. Also, as mentioned in the video above, rotating potatoes and other foods known to absorb heavy metals (such as rice) in and out of your diet can also help lower your exposure.

Regular Potatoes Versus Sweet Potatoes: Which Is Better?

While there are a few similarities, regular potatoes are decidedly different from sweet potatoes. As mentioned, potatoes (Solanum tuberosum) are part of the Solanaceae family, a plant group that produces a poisonous compound called solanine. For this reason, never eat the leaves or stems of nightshade plants.

Sweet potatoes (Ipomoea batatas) take their place in the Convolvulaceae family, along with morning glory vines. Unlike regular potato plants, which are highly toxic, the leaves of sweet potato plants can be eaten safely and are quite nutritious.

Potatoes have white or pale-yellow flesh with brown, red or yellow skins. They are either smooth or rough. On the other hand, sweet potatoes can appear in various colors, including cream, pink, purple, orange and yellow.

Some consider sweet potatoes to be a healthier choice than regular potatoes due to their higher levels of nutrients like vitamins beta carotene and C. Sweet potatoes are also an excellent source of beta-carotene, an antioxidant that gets converted to vitamin A in your body and is important for healthy eyes and skin.

As the name suggests, sweet potatoes are indeed sweeter: They contain about seven times the sugar content of regular potatoes. Because of the carbohydrates they contain, both potatoes and sweet potatoes will fill you up, give you energy and leave you satiated for a long time.

The choice of regular or sweet potato is a matter of personal preference and totally up to you. My only recommendation is to moderate your consumption of tubers, regardless of the type you choose. I also advise you eat regular potatoes only after cooking and chilling them to boost your body’s ability to digest them.

The Benefits of Resistant Starch

Most potatoes contain digestive-resistant starch, which consists of complex starch molecules that resist digestion in your small intestine. These starches slowly ferment in your large intestine, where they act as prebiotics, feeding your healthy gut bacteria.¹²

Because they are not digestible, resistant starches do not cause spikes in your blood sugar. In fact, research suggests resistant starches help improve insulin regulation, reducing your risk of insulin resistance.¹³

Surprisingly, many leftovers contain resistant starch. After being cooked and cooled in the refrigerator, starchy foods like pasta, potatoes and white rice develop resistant starches. About resistant starches, Paul Arciero, professor of health and human physiological sciences at New York’s Skidmore College, says:¹⁴

“Cooking the carbohydrate starch alters the chemical bonds in the food. The ensuing structure of those bonds during the cooling process is what makes them resistant to then being digested in the small intestine.”

The resistant starch remains in the food even after reheating. While potatoes have more resistant starch than sweet potatoes, the total amount of resistant starch in any food depends on the amount of resistant starch found in its raw form, as well as the manner in which the food is prepared.

Learn more about resistant starch and how it helps your body by watching the video above, which was produced by the Australian Commonwealth Scientific and Industrial Research Organization.

Health Effects of Potatoes: Diabetes and Blood Pressure

A study published in The American Journal of Clinical Nutrition¹⁵ observed an association between the consumption of potatoes and french fries and an increased risk of Type 2 diabetes. The research followed a large cohort of nearly 85,000 women over a 20-year period.

According to CNN,¹⁶ the positive association between potato consumption and the risk of Type 2 diabetes in the study was noted primarily in obese and sedentary women, “who are more likely to have underlying insulin resistance, which may intensify the adverse metabolic effects of higher-glycemic carbohydrates.”

A logical conclusion to draw from this research would be the need for moderation when it comes to potato consumption, especially fried potatoes. In general, it’s simply not wise to eat large amounts of potatoes unless you have the metabolic flexibility to burn fat as your primary fuel, get plenty of exercise and avoid long periods of sitting.

In terms of blood pressure effects, one group of scientists found eating six to eight small antioxidant-rich purple potatoes twice a day can have a positive effect on your cardiovascular system. The study authors said, “[P]urple potatoes are an effective hypotensive agent, and lower the risk of heart disease and stroke in hypertensive subjects, without weight gain.”¹⁷

In contrast, research completed in 2016, involving data extracted from three large cohort studies, associated the consumption of potatoes — most especially french fries — with an increased risk of high blood pressure.

The study authors asserted, “Replacing one serving a day of boiled, baked or mashed potatoes with one serving of a nonstarchy vegetable was associated with a lower risk of developing hypertension.”¹⁸

As you can see, the research results correlating potato consumption and blood pressure are mixed. So, much of how potatoes affect your health is going to depend on the types of potatoes you eat, how you prepare them and how often you eat them.

For certain, if you consume potatoes on a daily basis, I agree with the advice to replace one serving a day with a nonstarchy vegetable. Later in this article, I share recipes that use cauliflower and zucchini as substitutes for potatoes in two popular dishes.

Potatoes You Should Definitely Avoid

While plain baked potatoes can be good for you, potatoes that are fried in oil, such as french fries, hash browns and potato chips, are not healthy. As you may imagine, the process of frying potatoes significantly drives up their health-damaging potential.

One major reason to avoid fried potatoes is due to the unhealthy omega-6 vegetable oils involved in preparing them. Some of these oils, like canola and soybean oil, not only may be hydrogenated, but also genetically engineered.

Processed potato products may also contain trans fat and very often chemical additives and other processed ingredients known to contribute to chronic health conditions like cancer, heart disease and obesity.

Some suggest roasting potato wedges tossed in olive oil and rosemary is a healthier alternative to fried potatoes. While that may sound tasty, remember olive oil does not tolerate high heat and can easily be damaged at high oven temperatures.

If you insist on roasting or frying potatoes, try using coconut oil because it is stable enough to resist heat-induced damage. Or, better yet, check out my healthy tips on How to Bake Potatoes.

Why Fried Potatoes Are Particularly Bad for Your Health

While not immediately life-threatening, consuming fried potatoes also exposes you to a cancer-causing and potentially neurotoxic chemical called acrylamide. Acrylamide is the byproduct of a chemical reaction between sugars and the amino acid asparagine at temperatures above 250 degrees F (120 degrees C).

Carbohydrate-rich foods such as french fries and potato chips, which are heated to very high temperatures to produce a browned or charred surface, are likely to contain high amounts of acrylamide. Potato chips are, by far, the worst.

According to an analysis performed by the California-based Environmental Law Foundation, all potato chips tested exceeded the legal limit of acrylamide by a minimum of 39 times, and some by as much as 910 times!¹⁹

Data from the U.S. Food and Drug Administration (FDA) reveals that baked chips, which have been touted as healthier, may contain more than three times the level of acrylamide as regular chips.²⁰

Use Zucchini and Cauliflower to Make Healthy Potato Alternatives

An easy way to reduce your starch intake from regular potatoes is to substitute cauliflower and zucchini in dishes that used to be reserved exclusively for potatoes. With respect to zucchini, you may want to try my Scrumptious Baked Zucchini Tots recipe.

Steamed and mashed cauliflower, also known as “caulitators,” has a consistency similar to mashed potatoes and is a healthier alternative to regular mashed potatoes. Below is a simple recipe that feeds eight and can be prepared in about 20 minutes. For the best results, be sure to use organic, grass fed dairy products.

Should You Eat Potatoes?

Like most foods, potatoes can be either healthy or unhealthy depending on how you prepare them, as well as how much and how often you consume them. Eating an organic baked potato on occasion, as part of a balanced meal, can be healthy. On the other hand, consuming french fries and potato chips on a daily basis would not be a healthy choice.

Occasional consumption of sweet potatoes also can be beneficial because they contain just enough sweet to help curb your cravings for other sugary foods. Eating a sweet potato for dinner once in a while is far better than consuming a sugary dessert after the meal.

If you love potatoes, my advice is to take care how you prepare them, how you portion them and how often you add them to your plate. And, to avoid the concerns about potatoes and heavy metals, you might consider growing potatoes in your garden where you can ensure healthy soil.