Are Potatoes Healthy?

by brenda on February 17, 2012

{photo credit}

The potato leads all other vegetables in worldwide production. More potatoes are consumed in the United States than any other vegetable, around a third of a pound/150 gm per person per day. ~On Food and Cooking

But are they healthy?

This is a big question! I have read many different studies on the potato, and I want to share with all of you what I have learned.

First, the nutritional properties of a potato:

What Good is there in a Potato?

1 medium potato contains:

  • Protein (digestible) 2 g
  • Potassium 926 mg
  • Phosphorus, 121 mg
  • Magnesium, 48 mg
  • Calcium, 26 mg
  • Iron, 1.87 mg
  • Sodium, 17 mg
  • Zinc, .62 mg
  • Copper, .204 mg
  • Manganese, .379 mg
  • Selenium, .7 mcg
  • Vitamin C 16.6 mg
  • Niacin 2.439 mg
  • Vitamin B1 .111 mg
  • Vitamin B2, .083 mg
  • Pantothenic Acid .65 mg
  • Vitamin B6 .538
  • Folate 48 mcg
  • Vitamin A 17 IU
  • Vitamin K 3.5
  • Vitamin E .07
  • Yellow fleshed varieties have caroteniods (lutein, zeaxanthin)
  • Purple and blue ones have antioxidant anthocycanins
While this list is impressive, there are better sources of every one of these minerals and vitamins. Most pro-potato sites claim that potatoes are high in Vitamin C. Yet, when you look at most lists of “Vegetables that are high in Vitamin C, potatoes are not even mentioned. They are higher in Niacin than many, if not all other vegetables (though much lower in Niacin than grains, like buckwheat).

Is it true? Are Potatoes Poisonous?

“Among familiar foods, only the potato accumulates potentially troublesome alkaloid levels, which make greened potatoes and potato sprouts bitter and toxic. ~On Food and Cooking

Potatoes contain significant levels of the toxic glycoalkaloids solanine and chaconine. Most commercial varieties contain 2-15 mg of solanine and chaconine per 1/4 lb of potato. The solanine and chaconine sit below the skin’s surface on the tuber.

The potato belongs to a poisonous order–the Solancae. ~The Chemistry of Food and Nutrition

Potatoes that look green have been exposed to light and likely contains higher levels of solanine and chaconine. If you find a green potato, peel it deeply or throw it away. Green skin on a potato is a sign of abnormally high alkaloid levels. ~On Food and Cooking

Potatoes that contain high levels of solanine and chaconine will also be bitter, and may cause a burning sensation in the throat. Too high of levels can cause headaches, diarrhea, cramping, neurological problems, a coma and even death. Never eat strongly bitter potatoes.

There have been no reports of deaths from eating potatoes within the last 50 years. As long as you are not making potato leaf tea or eating green potatoes, you should be fine. A green potato contains more than 10 times the U.S. National Toxicology Program’s suggested daily limit  for consumption of glycoalkaloids. In other words, stay away from green potatoes.

How Digestible are Potatoes?

Well, that depends. Do not consume uncooked potatoes–our bodies were not designed to digest them and cannot process them.

In order to digest cooked potatoes, both the saliva and the gut need to have an adequate amount of the enzyme amylase. Medical science is baffled by study after study where people did not have this pancreatic enzyme at all–not that it was diminished, but that it was missing entirely. When these patients have been put on a monosacharide diet (like GAPS), their symptoms of diarrhea have ceased. In short, if you’ve got Gut Dysbiosis, stay away from potatoes.

Even if you do not think you’re lacking amylase, potatoes may not entirely digest in your gut. Potatoes contain Amylopectin B, which

Resists digestion to some degree. ~Wheat Belly

In fact, after a person eats a potato (anybody, even with adequate amylase levels), 3% of that potato’s starch sits in the gut, indigestible.

Resistant starch is starch that is indigestible to human digestive enzymes. When starchy foods like potato or taro or rice, are cooked, the starch is gelatinized to a form that is readily digested by human amylase; but if it is allowed to cool, some of this gelatinized starch re-forms into resistant starch. Gut bacteria prolifically convert resistant starch to butyrate. ~The Perfect Health Diet

This study compared the digestibility of carbohydrates in the intestines of a pig vs. the intestines of a man. The pig’s intestines contain a large population of bacteria that are capable of breaking down whatever starches are not digested by amylase. Humans do not have this kind of bacteria population in their gut. Instead, the starch from the potatoes sits in the gut and ferments.

In a healthy gut, fermented potato starch turns into butyrate. There is much talk about whether this is good for us or not. Several studies show that high concentrations of butyrate in the gut can prevent colon cancer. Some cancers, like pancreatic cancer, seem to be fed by a production of butyrate (through autophagy) and some cancers are healed or prevented by it. People are talking about butyrate’s ability to help our body manage metabolic and physical stress. Side Note: This may be why some people believe that a Paleo-lifestyle can lead to adrenal fatigue (and I agree). The main sources of butyrate are  1. in Butter and 2. produced in the gut from dietary fiber like starches and grains. Paleo eaters, in general, are not eating butter (though Paleo is changing–maybe some do eat butter now?) or grains.

This study showed that potatoes that have been cooked and cooled (like for potato salad) are 12% indigestible (instead of 3%, from freshly cooked potatoes). And yet, Paul Jaminet says:

“Cold potatoes provide gut-healthy resistant starch.” ~The Perfect Health Diet

There are studies showing that people who have Chron’s Disease and Ulcerative Colitis are lacking butyrate. I find this SO fascinating, because I have also learned that most people with these severe digestive disorders *improve* from a diet like GAPS or SCD. Jordan Rubin is a prime example! I am wondering if the lack of butyrate in their intestines is due to the fact that their body does not have the enzymes necessary to convert grains and starches to butyrate? I have not been able to find the answer to this question.

At any rate, people with Gut Dysbiosis cannot break down the starch in potatoes–we know that much. It probably does not turn into the beneficial, cancer fighting butyrate. If you’re on GAPS, I suggest getting your butyrate from butter (which has much higher levels, anyways), heal your gut, and then think about adding in other butyrate-producing foods like potatoes!

How do Potatoes Impact our Blood Glucose Levels?

Potatoes provide 300 calories of glucose per pound and are 18% carbohydrate by weight.

“The foods that raise blood glucose levels the most are foods rich in glucose itself, including starchy foods as potatoes and rice that our enzymes digest into glucose.” ~On Food and Cooking

There was a study that proved a relationship between potato and french fry consumption and Type 2 Diabetes.

In The Perfect Health Diet, Paul Jaminet says,

“..it is possible to obtain a large share of calories from ‘safe starches’ such as taro, yams, sweet potatoes, and white rice without much risk of diabetes, obesity, or heart disease.”

He recommends potatoes as one of the “safe starches” in other parts of the book, as well.

Dr. Natasha recommends starting with “new potatoes,” which are tiny, young potatoes. There was a study that showed that the glycemic index of new potatoes was significantly lower than the GI of mature potatoes (which have a very high glycemic index). This means that mature potatoes will cause your blood sugar to spike–while young, new potatoes won’t have as much of an effect on your blood sugar.

Do Potatoes Cause Arthritis?

Potatoes are a nightshade vegetable.

The medical literature does not contain reports of nightshade poisoning, but anecdotally some people report sensitivity to these foods. A writer for the Weston A. Price Foundation suggests that nightshade toxins promote calcification of soft tissues and arthritic symptoms, and recommends that anyone with arthritis, sclerodoma, or muscle and bone pain test for nightshade sensitivity by removing nightshades from the diet entirely for six weeks, followed by a nightshade party day….If symptoms improve on the nightshade free diet and return with the party, this indicates nightshade sensitivity. ~The Perfect Health Diet

If you search the net, you will find anecdotal stories of people who say that avoiding nightshade vegetables cured their arthritis. Yet, if you search medical studies for this topic, there aren’t any. My gut feeling (ha, ha!) is that these people have Leaky Gut, and of course, their body is going to react negatively to particles of food that get into the blood stream. Maybe nightshade vegetables are more toxic than other foods when they are in the blood–so avoiding them may provide relief for these people, but not total healing. They need to heal & seal their gut with a diet like GAPS, and then nightshade vegetables will not create issues for them any longer!

Are French Fries OK?

If you’re wanting to eat any french fries besides homemade ones, don’t. In 1990 McDonalds switched from cooking french fries in beef tallow to cooking in vegetable oil. Most commercial establishments now fry their french fries in this rancid, soy-based oil. If you don’t think you’re eating much of the oil, think again.

“And the French fries? you would think those are mostly potatoes. Yet since half of the 540 calories in a large order of fries come from the oil they’re fried in, the ultimate source of these calories is not a potato farm but a field of corn or soybeans.” ~The Omnivore’s Dilemma: A Natural History of Four Meals

Typical thin French Fries contain about 35% oil. Steak cut fries contain 10-15% oil. If you don’t think that soy oil is bad for you, read my post: Why I am Anti Soy.

BEWARE of Genetically Modified Potatoes

In the 1990′s, they started adding the “gene for a lectin from the snowdrop plant” to potatoes. By itself, snowdrop lectin is perfectly safe for mammals but toxic to insects.

“Arpad Pusztai, a leading expert on plant lectins, tested the new genetically modified potatoes. Rats fed ordinary potatoes mixed with snowdrop lectin remained healthy, but rats fed the genetically modified potatoes developed damage to their intestines and immune systems. The damage was not due to snowdrop lectin, but derangement of potato biology from alterations to gene expression. The modification had triggered much higher expression of native potato toxins.” ~The Perfect Health Diet

Also, there was a study that showed that genetically modified potatoes caused proliferation of the gastric mucosa.

Only Buy Organic Potatoes!

It is particularly important to buy organic potatoes and onions. Regular commercial potatoes and onions have been treated with sprout inhibitors that cause cellular changes in test animals. ~Nourishing Traditions

The pesticides that are used on potatoes end up in the flesh of the potato. You cannot scrub these toxins away or peel them off. Some of the pesticides that are used on potatoes are known carcinogens, cause neurological problems, and cause hormone problems.

What is the Best Way to Store, Cook and Serve a Potato?

Potatoes contain glucose and fructose. Long term storage at room temperature reduces the glucose and fructose levels, which makes for crispier french fries and chips (cold storage maintains the levels). However, storage in light increases the glycoakaloids (toxins), and dark, cold storage reduces them.

Leftover potatoes or potatoes that are left warm for a few hours lack vitamin C. (So eat them right away?)

Baked potatoes lose more vitamin C than boiled potatoes. Yet;

Potatoes are rich in important potash salts; by boiling a large quantity is lost, by steaming less and by baking in the skins, scarcely any. ~The Chemistry of Food and Nutrition

So do we bake them or boil them?

The usual addition of common salt (sodium-chloride) to boiled potatoes is no proper substitute for the loss of their natural saline constituents. ~The Chemistry of Food and Nutrition

I guess if we bake them, they lack Vitamin C. But if we boil, them, they lack their natural salt. Take your pick? Eat some of each?

And finally, do not eat fruit with potatoes. The acid in the fruit may prevent your saliva from digesting the starch. I cannot think of a fruit and potato dish that anyone typically enjoys–maybe a strawberry milkshake and french fries? (If there are any actual strawberries in the strawberry milkshake!).

What are your thoughts? Do you eat potatoes? Are you going to start eating them now?

 

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  • Paula

    I discovered that any issues I had with potatoes vanished, when I began supplementing magnesium. The same was true with bananas.

  • Cory

    Oh, but I love my my mashed potatoes and gravy!

  • http://www.paleovillage.com/2011/04/20/what-are-thelectins/ What are the Lectins? – Paleo Village | Paleo Village

    [...] There’s A Link!Is Sugar Toxic? What to Do to Stop Eating So Much and Control Leptin ResistanceAre Potatoes Healthy? // 0) { //0==expires on browser close var cdate = new Date(); [...]

  • Rachel

    I’ve heard to only eat organic potatoes, so I try to do that. We did GAPS for a while and then potatoes didn’t seems to settle well with any of us, but now after a year off GAPS we seem to do fine. And now, being pregnant, (8 weeks) I don’t feel sick if I eat potatoes, so I’ve been having some every day.

  • Jacquie

    I love potatoes! I don’t think I could give them up very easily :)

  • http://www.wellfedhomestead.com/coming-off-of-the-gaps-diet Coming off of the GAPS Diet | The Well Fed Homestead

    [...] It was nothing like the arthritis I faced before GAPS, but it was still concerning to me. Remember the study about cooked, chilled potatoes? I actually think that potatoes that are cooked and then chilled are the hardest for our bodies to [...]

  • Kelly

    Question: If solanine is found in and just below the skin, are heavily peeled potatoes or potato starch (as found in many gluten free bread mixes) free of solanine?

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