Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
27 Oct

Potatoes: Part Deux

potatoes2Last week, I made the case that potatoes aren’t nearly as bad as some people make them out to be. They’re carby, sure, but lean, active people who can tolerate carbs are way better off eating potatoes than grains, and even for low-carbers, a potato makes for a good, gluten-free cheat meal. Their place in your diet depends on the metabolic context. In my so-called “final word,” I said there isn’t one, at least not ordained from above. You have to figure out for yourself whether or not they fit into your diet. You might even say you have to go with your gut on this one (in more ways than one, as you’ll see).

So: potatoes. Just what are we to make of them? They are lumpy, white things that appear mostly harmless. They are, some would say, non-toxic sources of essentially pure starch. But actually, there’s more to the potato than glucose. First, the standout numbers for a standard white potato, baked, just the flesh (skin removed), 200 grams worth (which is a decent sized Russet):

Carbs: 43 g
Fiber: 3 g
Protein: 4 g
Fat: 0.2 g
Vitamin C: 20 mg
Magnesium: 50 mg
Potassium: 782 mg
Copper: 0.43 mg

That’s actually pretty decent. It’s certainly more interesting than rice. It contains very little phytate, so the minerals will be plenty absorbable. The carbs are almost all starch, meaning they’re perfect for replenishing glycogen stores after a workout. It’s a solid tuber, and a better, more nutritious starch source than are grains.

I also promised to discuss the secondary concerns people have with potato consumption. More specifically, I’m going to get into the potentially toxic glycoalkaloid content, the intestinal permeability issue, and the anecdotal reports of joint pain and inflammation.

Potatoes, being the reproductive organs of potato plants, have “passive” defenses against predators. They are stem tubers. They can’t run or bare teeth, so they chill underground to stay safe and employ toxic chemical defenders. For a group of smart, tool-wielding apes like ourselves, that first line of defense is easy enough: dig ‘em up. The second is a bit more difficult to circumvent: the toxic glycoalkaloids are in the potato itself. If we plan on eating the potato, we plan on eating the glycoalkaloids, too.

The glycoalkaloids most prevalent in potatoes are alpha-solanine and alpha-chocanine, which the plants use to repel pests. Most of the glycoalkaloids are luckily concentrated in the skin of the potato, forcing less refined pests to eat through the toxic stuff to get to the good stuff. We have the luxury of employing peelers (pinky in the air, no doubt) to avoid most of the glycoalkaloids (which are not reduced through cooking; you have to physically remove them). This is probably why traditional potato-eating cultures peel the potatoes they eat, unless you count the urbanized Quechua migrant eating cheesy tater skins at the Chili’s in Lima. And, as commenter Anand points out in Don’s excellent post, our ancestors would have definitely removed the charred skins after roasting tubers directly in the hot coals. These days, the most common potatoes, like Russets, also tend to have the lowest amount of glycoalkaloids (see Stephan’s chart); this is no accident, instead being the product of generations of careful agricultural selection by farmers. Throughout history, then, humans have tended to avoid the bulk of potato glycoalkaloids, either unwittingly, by peeling potato skins, or by selecting the low-glycoalkaloid varieties that didn’t provoke stomachaches, digestive issues, or inflammation and sold well at the market.

But glycoalkaloids remain. Are they harmful? Certainly, but the devil lies in the details. High dose glycoalkaloids are clearly harmful, but most peeled normal potatoes do not contain high doses of glycoalkaloids (again, I refer to Stephan’s chart). Most studies showing harm used supra-physiological doses of pure glycoalkaloids; one of the only studies to show harm using physiological doses that you’d normally get from eating potatoes used intestinally permeable rats with a genetic proclivity toward inflammatory bowel disease. This is a useful study, though, because it tells us that potatoes might be a danger for humans with leaky guts or existing inflammatory bowel disease. I’m sure you know someone in that position. It may even be you, or a loved one. How common is leaky gut? It’s difficult to know for certain, but I think looking at how many people still eat wheat, grains, sugar, and vegetable oil as a significant portion of their diet can give us a pretty good idea.

The Paleo Diet newsletter on nightshades pointed out a couple studies showing increased inflammation markers upon potato feeding, but one altered multiple dietary factors simultaneously (not just potatoes) and the other used potato chips. Was it the rancid seed oil the chips were fried in, or the potatoes? Was it the wheat bread or the potatoes? These tell us very little about the effects of whole, untarnished potatoes on inflammation.

I can also see potato glycoalkaloids being problematic in the context of the inflammatory standard American diet (rich in gluten, omega 6, and sugar). This is similar to the persuasive argument that casein is only problematic once gluten has perforated the gut lining and allowed entry. Do potatoes pose an issue for people with intact guts? As it stands now, there is very little published evidence that potato gycoalkaloids cause problems in metabolically health individuals without compromised guts, but there are anecdotal accounts.

Like my own. I avoid grains, vegetable oils, and excessive sugar, and I’m pretty darn healthy, but I have found that eating potatoes on a regular basis, especially potatoes with the skin, seems to lead to joint pain in my feet and ankles (of all places). So I don’t eat them on a regular basis. This doesn’t happen when I eat other starchy foods, like yams or squash. Only with white potatoes. That said, I still eat the odd spud – though I prefer Yukon golds, red potatoes, fingerlings, or any of the strange farmers’ market varieties. I’ve heard from people who get crippling joint pain from a single potato meal, though, so I’m not sure what to say about potatoes for everyone.

If you feel up to it, head out to the store and try some potatoes. The basic Russets are good, but dozens of varieties exist. Grocery stores should carry Yukon golds, red potatoes, fingerlings, and maybe a couple boutique varieties, but the real interesting ones are found at farmers’ markets. At the local Santa Monica market, there’s a whole stand devoted to potatoes of all kinds. They’ve probably got a dozen varieties, and it’s always changing. Purple potatoes, half yellow/half purple potatoes called Laker potatoes (hey, it is LA), tiny little red ones the size of gumballs, multicolored gnarled ones that look like an old crone’s rheumatic claw – these guys are committed to their tuberous artistry. Even for someone who doesn’t eat a ton of potatoes (I, honestly, don’t train hard enough anymore to require a lot of glycogen repletion), I find myself generally picking a handful or two up when I’m there. I’m rarely disappointed.

Always store your potatoes in a cool, dark area. Avoid light exposure, which can turn them green and increase the glycoalkaloid density. Cut off any sprouts or stems; better yet, just toss ‘em altogether if they sprout. You don’t want to take the risk, and they’re cheap enough to sacrifice. For heavy lifters and highly active exercisers who want to incorporate potatoes, it makes sense to bake a bunch at once and store them in the fridge for easy post-workout consumption. They’ll stay good in the fridge for about a week and a half. For PBers interested in trying a carb refeed, potatoes are a great choice.

Other bloggers have put up some incredible series on potatoes. By and large, they agree that humans have a long and storied history with potatoes and other tubers, and I find it difficult to argue. Reading their thoughts has made me reevaluate my own views on potatoes. I highly suggest reading both series.

Don’s Primal Potatoes series, in which he makes a strong argument for the tuber’s prevalence in our ancestral diets (especially when game was lean), even making the case that tubers gave us an advantage in the hunt: Primal Potatoes

Stephan’s Potatoes and Human Health series, in which he goes into more detail on the glycoalkaloid concerns (short version: very little evidence that normal levels of potato glycoalkaloids poise a problem for healthy humans) and discusses several traditional cultures that fared well on high-potato diets: Parts 1, 2, 3.

A Few Additional Thoughts on Potatoes

It is impossible to argue with your own personal anecdotal evidence. Anecdotes won’t stand up to peer review, but I find it difficult (and unwise) to discount a barrage of them.

If you’re overweight, avoid potatoes for the carb count and because you’re probably still fairly inflamed, and potatoes might aggravate your condition.

If you’re sensitive to nightshades (tomatoes, peppers, eggplant are the common ones) and have experienced negative effects from consuming them in the past, be wary of potatoes. Potatoes are also nightshades.

If you have a known autoimmune disease, a leaky gut, or are especially sensitive to dairy, grains, eggs, or nuts, avoid potatoes until it clears up.

If you insist on “cheating” with wheat, avoid potatoes to minimize any collateral damage to your gut.

If you need an affordable source of whole food calories, consider potatoes.

If you’re having trouble recovering from workouts on a very low-carb diet, try adding some post workout potatoes for the glycogen. Your muscles, having been drained of glycogen, will be insulin sensitive and most of your dietary glucose will go to good use.

If you’re stalling on weight loss as you near your goal, try carb refeeds with potatoes to restore leptin and jumpstart the leaning out process.

If potatoes give you fits, don’t eat them. You’re not missing much beyond a cheap source of calories that converts to glucose almost instantly. If lots of people you trust on other matters are reporting problems with potatoes, be mindful, be wary, and always pay close attention to how they affect you.

Thanks for reading and let me know what you think in the comment board. Grok on!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Well this is exciting, I always felt SO guilty when I would find myself eating the odd baked potato… now that I know it’s not SO bad, I’ll consider it part of my carb refeed strategy!

    Tara wrote on October 28th, 2010
  2. But, better yet by far, eat sweet potatoes!!!!

    Betterways wrote on October 28th, 2010
    • Why are they better? Aren’t they more sugary? Or is it just their name that plays a trick on me :-)

      Patriq wrote on October 28th, 2010
  3. This is really interesting……ive only been ‘primal’ for about 10 months now and i stumbled upon this way of life because i suddenly found myself having very severe reactions following the eating of potato’s and was intrigued to educate myself in matters of a healthier diet.
    I havent looked back!!! I feel great, have heaps of energy, my skins improved and ive lost nearly a stone. With reference to pains in ankles/feet, i always had problems with swelling in my lower limbs and now its gone….coincidence???……

    kelly wrote on October 28th, 2010
    • this is incredle. This sounds exactly like my story. I have only been Primal for 3 weeks though.

      Elizabeth wrote on February 22nd, 2011
  4. What a great site. And great to find real science in witty and plain English. This is the kind of exchange that feeds my mind as potatoes are sustaining my body.
    Chris Voigt, the 20 Potatoes a Day guy

    Chris Voigt wrote on October 28th, 2010
    • What I’d like to see from your experiment is before and after numbers for these measures of health:

      CRP
      homocysteine
      full VAP cholesterol panel

      Don Wiss wrote on October 28th, 2010
  5. i just love potato dishes. may it be just a simple mashed potato. im not afraid of the carb it would bring because i read from one article that potatoes has lower carbs. it’s a matter of moderating what we eat. we can’t fully blame it on the potato.

    pinky black wrote on October 29th, 2010
  6. I’ve found the key is to have organic potatoes every now an then like twice a week in small portions.

    Oliver wrote on November 1st, 2010
  7. Good post Mark, You look at it from more sites. But why take the risk? We know that sweet potatoes and yams do not cause problems. The percentage of people with a leaky gut and suffering from autoimmune diseases (http://bit.ly/a9Gvjk) is much higher than is often thought. Perhaps it even affects us all. Why are people still trying to prove that unhealthy neolithic foods are (when prepared in a special energy spoiling manner) edible for men?

    Hans wrote on November 5th, 2010
  8. Has the question on eating the skin of sweet potatoes been answered yet? Good? bad?

    Tommy wrote on November 8th, 2010
  9. I remember reading somewhere (I think Wikipedia, but there may still be wisdom in it) that in Medieval Europe before potatoes were brought over from the New World, parsnips were used in places that potatoes later came to dominate.
    With that in mind, what are the thoughts on parsnips round here? Personally, I love them.

    Kieran wrote on April 15th, 2011
  10. I prefer potatoes to grains. I don’t see the harm in the occasional potato but I prefer them with fat – such as chips done in dripping or roasted in goose fat. On their own I find them a bit stodgy but with fat they don’t have that effect. I get bloating from a jacket potato without fat but not from chips or roasties. Does the fat make them go down better? I don’t know. I see them as not something I would cook (as well as the carbs they are time consuming to prepare)but if my friend (who makes a mean roast and uses goose or duck fat)invites me over to share it I am no way gonna turn that down

    Polecatz wrote on April 29th, 2011
  11. Side-note: I wonder if the glycoalkaloids are high in the actual green part of the potato plants too. I just remember always hearing that you should not but the potato leaves in your compost bin… maybe this is why?

    Ines wrote on October 30th, 2011
  12. Its such as you learn my mind! You seem to grasp a lot about this, like you wrote the e-book in it or something. I believe that you simply could do with a few percent to pressure the message house a bit, however instead of that, that is wonderful blog. An excellent read. I will definitely be back.

    how to trade, how to trading wrote on December 9th, 2011
  13. Thank you for this post! I have just started the pb diet for the last few weeks and hubbie and I are about to start the 21 day challenge. I was wondering about potatoes as we have two teenagers (one whom is celiac ) and being able to keep potatoes in the diet in moderation will make a big difference for them and our budget. I find that we will usually peel them, put some olive oil and fresh garlic and grill them and they are very tasty without anything added. I will likely elminate mine, but it will make the transition for hubby easier ( on me as well )

    renee wrote on January 7th, 2012
  14. I didn’t read the full article but it’s saying that potatoes are OK to eat as long as you peel them right?

    But then I was wondering, most of the nutrients of the potato are in the skin right?

    William wrote on March 7th, 2012
  15. Are you eating organic potatoes? That might make a difference in how you feel also….

    Kathleen wrote on March 9th, 2012
  16. The Dutch eat massive amounts of potatoes (peeled and boiled). I taught English to a man who represents the EU potato farmers in Brussels and I asked him “why don’t people in Europe eat sweet potatoes? They are far more nutrient dense.” He had heard about them but never tried one! In northern Europe you can find sweet potatoes and yams in the Asian market shops, not the regular food stores. I have bought a few at the organic farmer’s market but they COST. A. FORTUNE. I paid 7 euros ($10) for two potatoes. It’s insane. We don’t have Whole Foods here (just in London) and I pay top euro for organic.. I miss America.

    jen wrote on June 23rd, 2012
  17. Ok, how can a potato be bad for you, I mean they are from the earth and people should consume foods grown from earth. Same with grains, it is grown from earth naturally like potatoes and now it is unhealthy for people, whaaat?

    Gabrielle wrote on June 26th, 2012
  18. Hi Mark,

    The part that does it for me is; “If you need an affordable source of whole food calories, consider potatoes.”

    I cut out potatoes years ago before I’d ever heard of Primal just because I knew I ate too many. My family always had, because we were broke.

    Now, I find myself broke again, by choice, because my partner and I are living lean after immigrating to a new country. I’m a large man and I eat A LOT. I feel plenty healthy and I’m losing weight, but I’m driving up our food bill to a level we can’t afford. Good greens and meat, I can eat them until the fridge is bare. I love it. But add even one small potato to my meal and it cuts what I need by a 3rd, which is a whole meal for my partner.

    Ideally, I’d eat all the greens and meats I want. But on a budget a single potato goes a long way.

    CB wrote on November 21st, 2012
  19. I’ve been fermenting white potatoes with recycled sour kraut brine. Can’t do much other that mash em, cause they fall apart in cooking. Love the built in sour cream flavor (with metric fckton of butter, of course).

    Can’t find quality research on the physiological effects on glycoalkaloids and such, but I assume it helps. Best that I could find was an article stating that this method is not used due to limitations on a commercial scale. Thanks capitalism, you never fail to disappoint me.

    Samtop wrote on January 14th, 2013
  20. Potatoes(cooked/baked) make my willy limp, whether eaten with butter, sour cream, or plain…
    Though I’ve had mashed potatoes with meat gravy and meat (moderate fattyness, butter in the mashed potatoes) and that didn’t cause any problem of the sort.

    Scott wrote on November 14th, 2013
  21. Hi,
    I left a post on one of your other articles about potatoes/sweet potatoes.

    After reading this article and how inflammation shows up eating potatoes, I think I have my answer.

    Around the same time I incorporated potatoes/sweet potatoes/rice and bananas into my diet, two separate areas of inflammation showed up – my right knee and right shoulder, both old injuries.

    Also, I don’t eat grains but since adding these food sources, my gut has had me passing gas, rumbling and also I put on 3.5kg in about 3 weeks!

    Do you agree that the new additions could be the source?

    Roz wrote on December 14th, 2013
  22. What about the distinction between modern hybridized potatoes and ‘heirloom’ or ancestral varieties? I’ve heard that there is more starch, and different starch, in commercial varieties.

    Keith Barrett wrote on April 21st, 2014

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