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  • Let's say you really need to find reliable information

  • about the best diet for high blood pressure,

  • or heart disease, or diabetes.

  • Where do you go?

  • Do you go to a website sponsored by Big Pharma

  • that wants to sell you pills to fix your problem?

  • Or, do you want to treat the cause?

  • Welcome to the Nutrition Facts Podcast

  • with the latest peer- reviewed research

  • on the best ways to eat healthy and live longer.

  • Today we take a close look at a multi-faceted

  • and often misunderstood root vegetable.

  • And we start with a little trick about lowering their glycemic impact.

  • If you systematically pull together all the best studies

  • on potato consumption and chronic disease risk,

  • an association is found for the risk

  • of type 2 diabetes and hypertension.

  • Yeah, but that was for French fries.

  • Consumption of boiled, baked, or mashed potatoes was not

  • associated with the risk of high blood pressure,

  • but there was still a pesky link with diabetes.

  • Overall, potato consumption is not related to the risk

  • for many chronic diseases, but boiled potatoes

  • could potentially pose a small increase in risk for diabetes.

  • That's one of the reasons some question whether they should

  • be counted as vegetables when you're trying to reach

  • your recommended daily servings of fruits and vegetables.

  • If you look at other whole plant foodsnuts, vegetables,

  • fruits, and legumes (which are beans, split peas,

  • chickpeas, and lentils)— they're associated with

  • living a longer life.

  • Significantly less risk of dying from cancer,

  • dying from cardiovascular diseases like heart attacks,

  • and 25 percent less chance of dying prematurely

  • from all causes put together.

  • But no such protection is gained from potatoes

  • for cancer, heart disease, or overall mortality.

  • So, the fact that potatoes don't seem to affect mortality

  • can be seen as a downside.

  • Now, it's not like meat, which may actually

  • actively shorten your life, but there may be

  • an opportunity cost to eating white potatoes,

  • since every bite of a potato is a lost opportunity

  • to put something even healthier in your mouth

  • something that may actively make you live longer.

  • So, potatoes are kind of a double-edge sword.

  • The reason that potato consumption may just have

  • a neutral impact on mortality risk is that

  • all the fiber, vitamin C, and potassium in white potatoes

  • might be counterbalanced by the detrimental effects

  • of their high glycemic index.

  • Not only are high glycemic impact diets robustly

  • associated with developing type 2 diabetes,

  • but current evidence suggests that

  • this relationship is cause-and-effect.

  • A front group for the potato industry called

  • the Alliance for Potato Research and Education

  • funded a study that found that intake of non-fried potato

  • does not affect blood sugar markers,

  • but that's compared with the likes of Wonder Bread;

  • so, that isn't really saying very much.

  • Foods with a glycemic index (GI) above 70

  • are classied as high-GI foods, high glycemic index foods,

  • and those lower than 55 are low-GI foods.

  • Pure sugar water, for example, is often standardized at 100.

  • White bread and white potatoes are way up there

  • as high glycemic index foods.

  • When you compare them to an intact grain, like barley groats

  • (also known as pot barley), a super-low GI food,

  • you can see how refined grains and potatoes are simply no match.

  • Is there any way we can have our potatoes and eat them too,

  • by somehow lowering their glycemic index?

  • Well, if you boil potatoes and then put them

  • in the fridge to cool, some of the starch crystallizes

  • into a form that can no longer be broken down

  • by the starch-munching enzymes in your gut.

  • However, the amounts of this so-called resistant starch

  • that are formed are relatively small, making it difcult

  • to recommend cold potatoes as the solution.

  • But when put to the test, you actually see a dramatic drop

  • in glycemic index in cold versus hot potatoes.

  • So, by consuming potatoes as potato salad, for instance,

  • you can get nearly a 40 percent lower glycemic impact.

  • The chilling effect might, therefore, also slow the rate

  • at which the starch is broken down and absorbed.

  • So, individuals wishing to minimize dietary glycemic index

  • may be advised to precook potatoes

  • and consume them cold or reheated.

  • The downside of eating potatoes cold is that they might not

  • be as satiating as eating hot potatoes.

  • But you may get the best of both worlds by cooling them

  • then reheating them, which is exactly what was done

  • in that famous study I profiled in my book How Not to Diet.

  • The single most satiating food out of the dozens tested

  • was boiled then cooled then reheated potatoes.

  • There's actually an appetite- suppressing protein in potatoes

  • called potato protease inhibitor II,

  • but the way you prepare your potatoes makes a difference.

  • Both boiled and mashed potatoes are significantly

  • more satiating than French fries.

  • That was for fried French fries, though.

  • What about baked French fries?

  • Folks had a big drop in appetite after eating

  • boiled mashed potatoes, compared to white rice or white pasta,

  • which is right where fried French fries were stuck,

  • as well as baked French fries.

  • So, though they may be your BFF, they're not very satiating.

  • In our next story, broccoli, vinegar, and lemon juice

  • are put to the test to blunt the glycemic index of white potatoes.

  • White potatoes have a high glycemic index, and consumption

  • of high glycemic impact foods may increase the risk of diabetes.

  • Normally after a meal, we'd like our blood sugars

  • to just gently, naturally rise and fall.

  • But with high glycemic foods like potatoes, you get an

  • exaggerated blood sugar spike which leads your body

  • to over-compensate with insulin forcing your blood sugars

  • lower than when you started, which results in negative metabolic

  • consequences such as a rise in triglyceride fats in the blood.

  • However, potatoes are a good source of potassium, vitamin C,

  • and polyphenols, which may counterbalance the glycemic impact.

  • This may explain why potatoes appear to have a neutral effect

  • when it comes to lifespan, unlike other whole plant foods,

  • that have been associated with actively living longer.

  • In my last video, I detailed my nip-and-nuke method,

  • where the act of chilling potatoes can dramatically lower their

  • glycemic index, even if you then reheat them in a microwave.

  • How else might we reduce the glycemic impact of white potatoes?

  • The answer is the same way you make anything better

  • in your nutritional lifeadd broccoli.

  • The co-consumption of two servings of cooked broccoli

  • with your mashed potatoes would certainly do it,

  • immediately cutting the insulin demand by nearly 40 percent.

  • In contrast, adding chicken breast makes things worse

  • and adding tuna fish makes things even worse still,

  • nearly doubling the amount of insulin your body has to pump out.

  • Why does plant protein make things better,

  • but animal protein make things worse?

  • Because decreased consumption of branched-chain amino acids

  • improves metabolic health. I cover this in my book

  • How Not to Diet as well as my video on the topic.

  • Speaking of How Not to Diet, remember the section on vinegar?

  • Here are the blood sugar and insulin spikes someone with

  • prediabetes can get from eating a bagel.

  • Eat that same bagel with a tablespoon or so

  • of apple cider vinegar diluted in about a quarter cup of water,

  • though, the impact is significantly less.

  • Does it work for potatoes too?

  • Simply chilling potatoes may cut down on the blood sugar

  • and insulin spikes, but to get significant drops in both,

  • you just have to add about a tablespoon of vinegar

  • to drop levels by 30 to 40 percent.

  • And that was just plain white distilled vinegar.

  • Is it the vinegar itself, or would any acidy condiment do?

  • In a test tube, lemon juice appeared to have a remarkable

  • starch-blocking effect, but you can't know if it works

  • in people, until you... put it to the test.

  • And indeed, lemon juice reduces the glycemic responses to bread.

  • And not just by a little, but by like 30 percent.

  • Now, the subjects were drinking a half cup of lemon juice,

  • but that makes it even more remarkable that it helped because

  • that added an extra half teaspoon of sugar,

  • and yet they still had a better blood sugar response.

  • Vinegar is more potent, though.

  • Just one to two tablespoons a day of vinegar diluted in water

  • can significantly improve both short- and long-term

  • blood sugar control in diabetics, which is why clinicians

  • may want to incorporate vinegar consumption as part

  • of their dietary advice for patients with diabetes.

  • Finally today, are yellow- fleshed potatoes

  • healthier than white? Let's find out.

  • The high glycemic impact of potatoes may increase the risk

  • of type 2 diabetes, perhaps by chronically overstimulating

  • the insulin-producing cells in the pancreas.