Juvenile onset of Type II Diabetes and the demonization of the potato

I came across a study from 2008 that has found that many children categorized as obese are getting too few calories and too little of four different micronutrients. This article at VitalChild has a good summary:

Researchers have long blamed childhood obesity and diabetes, especially in poor neighborhoods, on too much food and too little exercise.

But new findings from a San Antonio study point to another explanation: children living in poverty are obese in part because they don’t eat enough to meet the daily nutritional requirements needed for cell function and metabolism.

A 9-year-old should consume 1,400 to 2,200 calories daily to sustain their growth, said Dr. Roberto Trevino, director of the Social and Health Research Center, a nonprofit organization. But in the study of 1,400 inner-city children, 44 percent were consuming less than 1,400 calories, and 33 percent were obese.

“They were not overeating,” Trevino said. “This study shows these kids were not eating enough, and when they did eat it was all the wrong things.”

Missing from the children’s diets were four key nutrients: calcium, magnesium, potassium and phosphorus. All play important roles, but magnesium is involved in more than 300 enzymatic reactions in the body that help to spur metabolism and cell function.

When magnesium–found in cooked spinach, black beans, bran cereal and other foods–is missing from the diet, it can predispose an individual to diabetes, Trevino said.

I wonder how much of the recent uptick in Type 2 diabetes in children is caused by a lack of magnesium? Something to add to the “correlation does not equal causation” files: here we have an example of a third factor (lack of magnesium) contributing to both diabetes and high BMI.

At the bottom of the article, they list examples of foods high in each of the four micronutrients that the children in the study were lacking. The foods chosen for potassium were interesting:

• Potassium: Sweet potato, tuna, bananas, spinach, peaches

One food that is known for being high in potassium is conspicuously absent from this list: potatoes. I did a quick search for “potassium potatoes”, and the first page of this slideshow says, “The big surprise is that bananas don’t even make the top 10 list of superfoods with the most potassium!” But bananas made the VitalChild list even though they’re lower in potassium than potatoes. I’m assuming that this is because potatoes have been linked to obesity and the “obesity epidemic”–Walter Willett and the Harvard School of Public Health are big promoters of this idea.

The slideshow features potatoes at slide #5.

Potatoes: It’s America’s favorite vegetable, and one potato has 610 mg of potassium and 145 calories – if you eat the skin.

(Based on this data, a potato with skin removed has 73% of the potassium of a potato with the skin left on.)

Even per calorie rather than per weight/volume (and remember, the kids in this study weren’t getting enough calories*), the potatoes (with skin on) have more potassium than tuna, bananas, or peaches.

(Sweet potatoes do have a lot of potassium, though. From the slideshow: Sweet potatoes: This root vegetable is the top source of potassium – one potato has 694 mg of potassium – about 15% of the daily recommended amount – and just 131 calories.)

The paleo fad hasn’t helped the potato’s reputation. The paleo people seem to be pushing the “carbs=bad” line hard, but we did eat root vegetables in the hunter-gatherer days; they were mostly gathered by older women.

From Sarah Hrdy’s Mothers and Others (because you know I can’t resist an opportunity to quote Sarah Hrdy):

“[Anthropologists] O’Connell and colleagues propose that long-term trends toward a cooler, drier climate at the end of the Pliocene pressured the precursors of Homo erectus to seek new ways to supplement their primary diet of fruit. By around two million years ago, game was increasingly important, but its availability was unpredictable. A division of labor between men who hunted and women who gathered also became more critical. O’Connell and others suggest that when neither meat nor more nutritious plant foods like nuts were available, our ancestors fell back on large underground tubers that plants in dry areas use to stockpile carbohydrates.

“These storage organs occur throughout the savanna but are protected by a deep layer of sun-baked earth and are hard to extract. Savanna-dwelling baboons access shallower rhizomes and corms, and chimpanzees in the only population ever to be studied in a savanna habitat use pieces of wood to dig out shallower tubers, suggesting that australopithecines may have done so as well. But it takes special equipment to dig out larger, deeply buried tubers. This is why, except for a few burrowing mammals like mole rats equipped with shovel-shaped incisors, humans are the only primates who exploit this widely available but difficult-to-access food source.

“Even before cooking, the addition of tubers to the other plant foods gathered by women would have provided new incentives for food sharing between hunters and gatherers, as well as new opportunities for postreproductive women willing to enhance the survival of kin. For women who knew where to look and who were willing to walk long distances, dig into hard earth, and carry their bounty back to camp, tubers provided a widely available if not particularly palatable source of calories when other foods were in short supply.”

Of course, tubers gathered by old ladies just aren’t as exciting as prestige-earning big game. So maybe this is just another example of the promoters of the paleo diet being evolutionarily correct. Admittedly, wild tubers are not the same nutritionally as potatoes. But the idea that carbs or starchy vegetables are unnatural in the human diet is false. The demonization of the potato has gotten out of control.

*The amount of calories required by an individual is very specific to that individual, but I don’t think the reason that a large number of impoverished kids were getting less than recommended was that they group just happened to have lower calorie requirements.

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8 Responses to Juvenile onset of Type II Diabetes and the demonization of the potato

  1. A Elizabeth says:

    Cycles of undereating followed by overeating, which happens with both food insecurity and yo-yo dieting, can result in insulin resistance, which in turn can cause PCOS or Type II diabetes. Oh, and guess what, insulin resistance can also lead to weight gain (unless it is REALLY severe, and then it may lead to muscle wasting). So we have, for poor (food-insecure) children, the following statement:

    food insecurity =>calorie fluctuations => insulin resistance => Type II Diabetes, weight gain

    And for body-insecure yo-yo dieters:

    Body shame => calorie fluctuations => insulin resistance => PCOS, diabetes, weight gain

    Children in poverty are sick because of food insecurity, not just because they’re eating processed food, which is what everyone in America seems to assume. And many adults who restrict food on purpose to lose weight suffer similarly to those who suffer from food-insecurity, yo-yo dieting themselves into insulin resistance..

    • Andy Jo says:

      This is very interesting. I do have one comment on it, however.
      As a person who has PCOS, I just want to say that it has a very strong ethnic and genetic component. The root cause is likely something other than insulin resistance, and/or they have a common cause. The PCOS likely magnifies the insulin resistance/diabetes causal chain.

      The focus on insulin resistance is quite recent. I was diagnosed in 1983, and back then all anyone was worried about was PCOS’ effect on fertility, and on its symptom of hirsutism. I’m not I don’t think doctors know as much about it as they say they do. I look forward to more serious scholarship if it ever gets funded. That is… if they ever quit hating on those of us fatties who have PCOS and get around to studying the interplay of complex genetic, endocrinological, environmental, and alimentary issues that result in the symptoms of PCOS and Type II diabetes.

      • A Elizabeth says:

        I was diagnosed in 2005 as a teen, and my endocrinologist said that in the vast majority of cases, insulin resistance is the root cause of PCOS. Insulin resistance increases the body’s requirement for insulin, resulting in hyperinsulinemia (high circulating insulin). The high insulin levels over-stimulate the ovaries, causing them to produce lots of androgen. Normally, the ovaries convert androgen to estrogen. If androgen production is really high, the ovaries can’t keep up and the excess androgen spills over into the bloodstream, then binds to androgen receptors all over the body, including in the skin, which can cause acne, unwanted hair, etc..

        I’m sure his version is much simpler than the reality. He did say that the pituitary gland can cause PCOS, but it isn’t as common.

        Insulin resistance has a huge genetic component, so that could be where the heritability of PCOS comes from. Also, all of the competent specialists recognize that women of all sizes can get insulin resistance and PCOS. 🙂

  2. Andy Jo says:

    I love this post! Thank you for it.

  3. JenC says:

    I wish the schools that have just cut the calorie content [and the protein content] of school lunches would read this post. It’s sad that all of the ‘expert efforts’ to reduce obesity by feeding children less will only make the ‘problem’ worse.

  4. julie says:

    I don’t understand the anti-potato sentiment. Even stranger, sweet potatoes are great healthy food, plain potatoes are devil incarnate? I like potatoes, though every time I bring them to work as part of lunch, the Irish guy in my group asks me if I’m on a diet. He eats them every day, because that’s how he grew up, but isn’t used to Americans eating them.

    • A Elizabeth says:

      The anti-potato sentiment comes from the fact that potatos are high on the glycemic index. What that means is that the carbs in the potato are very rapidly digested, which causes a blood glucose and insulin spike. Blood glucose and insulin spikes can lead to reduced insulin sensitivity, and eventually (in some people, if beta cell failure occurs) Type II diabetes. Sweet potatoes, in contrast, are low on the glycemic index, because they contain less starch, more fiber,and more sugar. This might seem counterintuitive, but starch is high on the glycemic index because it is simply a chain of glucose monomers. The enzyme amylase, which is present in both pancreatic juices and saliva, breaks the bonds between the monomers. On the other hand, sucrose (table sugar) is made up of one glucose molecule and one fructose molecule. In order for sucrose to be digested, first the bond between the glucose and fructose must be broken (this occurs in the small intestine). The glucose can then be absorbed and used for energy. However, the fructose has to be converted to glucose by the liver. Thus, fructose is low on the glycemic index, and sugary foods that have a higher ratio of fructose to glucose are lower on the glycemic index than sugary foods that have a lower ratio.glucose. For example, agave nectar is lower-glycemic that high fructose corn syrup. which in turn is lower glycemic than plain cornsyrup. High fructose corn syrup has approximately the same glycemic index as table sugar because the ratio of fructose:glucose is the same.

      Finally, I must note that the glycemic index of a meal can be low even if it contains a high-glycemic food such as a potato. This is because if protein, fat, or fiber are included in the meal, gastric emptying is delayed, and absorption in the small intestine happens more gradually. Also, glycemic load (which combines the glycemic index with the grams of carbs) is more useful for treating diabetes or PCOS than the glycemic index. For example, watermelon is high-glycemic, but since one slice doesn’t contain very many carbohydrates, the glycemic load of one slice of watermelon is low.

  5. emi11n says:

    Interesting post! I would point out that paleoists are not all against the potato, here is a post that actually supports us being designed to eat tubers: http://donmatesz.blogspot.com/2009/08/primal-potatoes-part-1.html. And here’s another: http://paleodietlifestyle.com/eat-your-starches-why-safe-starches-are-healthy/. And one more:http://paleodietlifestyle.com/fatty-meat-potatoes-dairy-and-paleo-2-0/

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