By Dr. Mercola
The potato has had a long history. The Incan tribe from the highlands of Peru worshipped the potato and people from Ireland blamed the potato for the Great Famine when a blight destroyed potato crops across Europe.1 Today, the potato is the fourth largest food crop in the world.
The potato is a perennial plant that is high in starch and has more potassium than bananas.2 The vegetable is also source of vitamin C and B-6, and is sodium and fat free. However, while there are benefits to the vegetable, it is also high in carbohydrates; one medium potato contains 37 grams of carbohydrates. I recommend you limit your net carbohydrates (total carbs minus fiber) to between 50 and 80 grams per day, depending upon your metabolism.
This means a single potato can be 45 percent to 75 percent of your daily net carb amount. The consumption of fresh potatoes has declined in the past 50 years, dropping from 61 pounds per year per person in 1970 to 36 pounds per year per person in 2008.3 However, consumption of processed potatoes, such as french fries or potato chips, has increased over the same period.
Processed potatoes cooked at high heat contain byproducts that are known carcinogens and trans fats linked to a number of health conditions. Recent research has now found a potential link between fried potato consumption and increased risk of death.
The Lowly Potato
In 1536, the Spanish Conquistadors arrived in Peru and discovered potatoes. They brought them back to Europe, and before the end of the 16th century sailors were planting them along the northern coast of Spain.4 By 1589, they reached Ireland and over the next 40 years spread across the rest of Europe.
In the mid-1840s a blight on potatoes wiped out most of the crop in many countries across Europe, especially in Ireland where the potato had become a staple. Over the course of the blight, nearly 1 million people died from starvation or disease, and another 1 million people emigrated from Ireland to Canada and the U.S.5
Some believe Marie Antoinette, the last queen of France before the revolution, enjoyed the flower blossoms from the potato plant so much she put them in her hair and her husband, King Louis XVI, wore them in his buttonhole.6 Historians think this was an attempt to encourage farmers to plant more potatoes.
As Europe and North America adopted the potato, it initiated a template for an agriculture industrial complex, eventually leading to the use of intensive fertilizer and of arsenic as the first artificial pesticide to eradicate the Colorado potato beetle.7 Competition to manufacture potent arsenic blends opened the modern pesticide industry.
Fried Potatoes May Increase Your Risk of Death
McDonald's has sold millions more fries each year with the simple question, "Would you like fries with that?"8 Also known as an upsell, this simple technique has contributed to ever increasing waistlines for their customers. Now, researchers have found those who eat fried potatoes two or more times each week may double their risk of death from all causes.9
Eating potatoes that were not fried was not linked to an increase in mortality risk according to the researchers.10 The authors had been tracking nearly 4,400 people over eight years to study the effects of osteoarthritis when they decided to include an evaluation of the participants' intake of potatoes and the impact it had on their lives.
In analyzing the data from the study, the researchers found that people who ate fried potatoes had double the risk of death during the study. Fried potatoes included french fries, hash browns and potato chips. Any preparation of potatoes that required frying was included in the fried potato category in the study.
The data from the study was observational, which presents challenges to extrapolating the results. The gold standard for medical research is randomly controlled experimental studies. These are often costly, while observational studies can be completed more economically.11 However, observational studies may not enable researchers to accurately link cause and effect.
The study could correlate french fries with an increased risk of death, but the researchers could not assume that french fries caused the death. The researchers tried to control for variables, but as this was an observational study, other factors that may have been involved could have been missed.12
However, while this type of study precluded the ability to establish a link between an increased intake of french fries and death, performing a controlled study would be unethical as the researchers would have to ask participants to increase their consumption and then measure risk of death.
In 2014, Americans ate an average of 112 pounds of potatoes each year; 33 pounds were fresh potatoes and 78 pounds were processed.13 The potential danger of eating pounds of fried potatoes is generated by acrylamide, a chemical produced when the starchy potato is fried at high temperatures.
How Acrylamide Affects Your Health
Acrylamide, a byproduct of processing, is one of the most hazardous ingredients found in potato chips, hash browns and french fries. The browning process is what produces the chemical, so boiling and steaming doesn't create it. Beginning in 2013, the U.S. Food and Drug Administration (FDA) recommended Americans reduce the amount of browned and overcooked foods that may be high in acrylamide.14
The FDA continues to recommend people cut back on the amount of foods high in acrylamide, as the chemical has been shown to cause cancer in animals and may also be responsible for causing cancer in humans.15 Acrylamide is also found in coffee, cereals, crackers, breads and dried fruit, to name a few. In fact, it may be found in up to 40 percent of calories eaten each day.16
In a study evaluating the amount of acrylamide found in chips, researchers found levels over the upper limit set by the European Union (EU) in 16 of the 92 brands tested.17 Currently, the EU set the upper limit at 1,000 micrograms per kilogram (mcg/kg) for crisps and they are considering lowering that benchmark to 750 mcg/kg, as acrylamide has been demonstrated and identified by the World Health Organization as a cancer risk.18
Although scientists knew the chemical was present in plastics and water treatment facilities, it wasn't until 2002 that scientists discovered it was present in foods. While acrylamide is a known carcinogen, links have been found between acrylamide-hemoglobin levels and estrogen receptor positive breast cancer.19 Higher levels of dietary acrylamide have also been linked to an increased risk of postmenopausal endometrial and ovarian cancer.20
Storing starchy vegetables, such as potatoes, in the refrigerator increases the amount of acrylamide produced if you do cook them at high heat or brown them.21 The process of increasing the amount of sugar in the potato that then produces more acrylamide during cooking is called "cold sweetening." Instead, raw potatoes should be stored in a cool, dark place above 42 F (6 C).
Trans Fat Found in More Than Potatoes
Acrylamide exposure is not the only risk associated with fried potatoes. Trans fat products are often used to fry the potatoes and chips, adding another layer of risk. This short video shows you some of the foods where trans fat may hide. There are two types of trans fats; one is made by hydrogenating vegetable oil in a chemical process and the other is found in natural meat products and has no harmful effects on your health.
Processed trans fats have been linked to heart disease,22 insulin sensitivity23 with type 2 diabetes,24 inflammation,25 damage to the lining of your blood vessels26 and cancer.27 Aside from french fries and potato chips, harmful trans fats may also be found in:28,29,30
Cakes and cookies
Cream filled candy
Pancakes and waffles
Creamy frozen drinks
Asian crunchy noodles
Eating Potatoes Linked With Negative Health Conditions
Steaming or boiling potatoes may reduce your exposure to acrylamide and trans fat, but the potato itself may still increase your risk for other health conditions. They are high in carbohydrates, creating a blood glucose spike and resulting release of insulin. One cup of potatoes has a similar effect on your blood sugar as a can of Coke.31 This roller coaster effect of rising and crashing blood sugar often leaves you feeling hungry within hours, leading to overeating, weight gain and an increasing risk of type 2 diabetes.32
In 2010, more than 2 in 3 adults were considered either overweight or obese33 and in 2014, 9.3 percent of the population had been diagnosed with type 2 diabetes.34 These numbers are continuing to rise each year, and both of these conditions contribute to heart disease, stroke and a higher risk of death.
A recent study published in The BMJ found that those who ate four servings per week of baked, boiled or mashed potatoes had an 11 percent increased risk of high blood pressure.
Those who ate french fries or potato chips four times a week raised their risk by 17 percent.35 High blood pressure in turn increases your risk of cardiovascular disease and stroke and is linked to kidney disease and peripheral vascular disease. In other words, while potatoes carry some health benefits, they are best eaten baked or boiled in moderation.
Some French Fries Are Worse Than Others
Although all french fries are unhealthy, some are worse than others. In this short video, American journalist, author and activist Michael Pollan explains how "the desire for a certain kind of [french fry] leads to a certain kind of agriculture." McDonald's french fries are made with Russett Burbank potatoes, a particularly difficult potato to grow.
They must also be free of blemishes, so to eliminate the aphids that cause net necrosis in the potato, farmers will use an exceptionally toxic pesticide. It is so toxic they cannot venture into the fields for five days after spraying, and harvested potatoes have to off-gas in atmospheric-controlled sheds for six weeks before they're even safe to eat.
Your best potato choice are sweet potatoes. While they share the same name, they don't come from the same family of plants and have many more health benefits than the standard white potato you find in french fries, hash browns and mashed potatoes. Both white and sweet potatoes have the same number of grams of carbohydrates, but sweet potatoes have more than double the amount of fiber, thereby reducing the glycemic load on your body.
This fiber content may be referred to as digestive resistant fiber, an important prebiotic necessary for the nourishment of beneficial bacterial colonies in your gut. A large number of studies have linked an imbalanced gut microbiome with a number of diseases, including obesity, depression, anxiety and inflammatory diseases.36
Minimize Your Acrylamide and Trans Fat Exposure
Thus far, acrylamide has been found in foods heated to 250 F (120 C), which includes most processed foods. Basing your diet on whole foods, with a significant amount eaten raw, slightly cooked or steamed, is one of the best ways to avoid this cancer-causing byproduct. Raw foods are also recommended for general good health as it helps to optimize your nutrition.
For a step-by-step guide to making the transition to a healthier diet as simple as possible, see my optimized nutrition plan. For the times you would like to cook your food, keep the following tips in mind:
- Frying, baking and broiling appear to be the worst offenders, while boiling or steaming appear to be safer
- Longer cooking times increase acrylamide, so the shorter the duration of cooking, the better
- Soaking raw potatoes in water for 15 to 30 minutes prior to roasting may help reduce acrylamide formation during cooking. Chilling the potatoes after cooking (and other starch-rich foods such as rice and pasta) will make it healthier by turning much of that starch into digestive-resistant starch that helps optimize your gut health. Potato salad is perhaps one of the healthiest ways to eat your potatoes
- The darker brown or blackened the food, the more acrylamide it contains, so avoid overcooking your food
- Acrylamide is found primarily in plant-based carb-rich foods such as potatoes and grain products (not typically in meat, dairy or seafood)
Healthier Potato Recipes
Sweet potatoes are a deliciously sweet and satisfying potato option you may eat baked or in a tasty potato salad.
Sweet Potato Fries
- One sweet potato
- Sea salt, coarse
- Black pepper, ground
- Olive oil (coconut oil can serve as an even healthier option as it withstands heat better)
- Heat the oven to 450 F. You may or may not peel the potato. If you don't peel the potato, clean the skin.
- Cut the potato into large chunks about 1/2- to 3/4-inch thick.
- Place the sweet potato fries onto a baking sheet and sprinkle a pinch of sea salt and ground black pepper. Next, drizzle the fries with about 1/8 cup of oil. You may add more if you wish.
- Place in the oven for 15 minutes. Afterward, take them out and flip and return to oven for 10 minutes.
- May take 1 1/2 hours to make and can serve two to three people.
Sweet Potato Salad courtesy of BBC Good Food:37
- 2 1/2 pounds sweet potato, peeled and cut into chunks
- 1 tablespoon coconut oil
For the dressing
- 2 shallots (or half a small red onion), finely chopped
- 4 spring onions, finely sliced
- Small bunch chives, snipped into quarters or use mini ones
- 5 tablespoons sherry vinegar
- 2 tablespoons extra-virgin olive oil
- 2 tablespoons honey
- Heat oven to 350 F. Toss the sweet potato chunks with coconut oil and salt and pepper; spread on a baking parchment-lined baking sheet. Roast for 30 to 35 minutes until tender and golden. Cool at room temperature.
- When just about cool, whisk together the dressing ingredients and gently toss through the potato chunks — use your hands to avoid breaking the potatoes.