 The high glycemic impact of potatoes may increase the risk of type 2 diabetes, perhaps by chronically over-stimulating the insulin-producing cells in the pancreas. In my last two videos, I explained that you can decrease the glycemic impact of white potatoes by eating them cold or chilling than reheating them, or adding broccoli, lemon juice, or vinegar. What else can we do? Well, if you remember, I had a video a few years back that showed how the pigments in brightly colored berries can act as starch blockers. So if you're going to eat a high glycemic food, you may be able to moderate its impact by spreading raspberries on your toast, for example, or adding strawberries to your cornflakes or sprinkling blueberries in your pancakes. No, I'm not saying you have to put blackberries in your baked potato, but given that the natural color compounds in fruits can slow down starch digestion, what about pigmented potatoes? Even just yellow potatoes like Yukon Gold may be preferable to white, but the best may be purple potatoes, not just purple skin potatoes, but purple fleshed potatoes. If you've never seen purple potatoes, they are remarkable. They have almost a neon blue glow, and not only do they look cool, but purple potatoes cause less of an insulin and blood sugar spike compared to even the yellow fleshed potatoes, suggesting that switching from yellow or white to purple could have a large potential public health benefit. How do we know it's the pigments themselves that are responsible, rather than other differences between the different potato varieties? Researchers tried adding a control comprised of berries and a potato starch jelly, but that would seem to add even more variables. In a test tube, extracts of purple and red fleshed potatoes can actually starch blockers. So hey, if you can extract and purify out the purple potato pigments, say that five times fast, you could remove any other effects of the different potato varieties by adding the purple pigments to yellow potatoes. And lo and behold, compared to just plain yellow potatoes, you can get a suppression of the blood sugar and insulin spikes. This way, you don't get that overshoot reaction, where your blood sugars can actually drop below fasting, like you might get otherwise. Instead, you get the gentler up and down in blood sugars you'd expect from a lower glycemic food. The authors suggest purple potato extracts could be produced and made into supplements or fancy functional foods, but these health-promoting compounds may be more cost-effectively received from consuming purple potatoes themselves. If you were paying attention, you might have caught in the tidal as it flashed by that the purple potato pigments may also affect inflammation. The Potato Association of America likes to paint potatoes as an anti-inflammatory food, but what they don't tell you is that this benefit may be limited to pigmented potatoes. If you randomize, people eat a small white potato every day for six weeks versus a yellow or purple flesh potato, the purple potato group achieves significantly lower levels of inflammation compared to the white potato group, measuring both C-reactive protein and interleukin-6. Pigmented potato consumption also alters oxidative stress. Oh, within hours of eating a large purple potato, you get a nice 60% bump in the antioxidant power of your bloodstream, and this translates into less free radical DNA damage. If you compare the antioxidant activity of white potatoes, yellow potatoes, and purple potatoes, Yukon Gold has about twice the antioxidant power of white, but purple has 20 times the antioxidant, which is comparable to what you might see in berries. Half a purple potato has about the same polyphenol antioxidant complement as half a cup of blueberries. Purple potatoes can increase the antioxidant capacity of our bloodstream, whereas straight white potato starch can act as a pro-oxidant and decrease it. Eat a purple potato and over the next eight hours, the antioxidant capacity of your bloodstream goes up. In contrast, if you eat white potato starch, devoid of any pigment, you can end up worse off than where you started. Okay, but does this translate into different physiological effects? Yes, indeed. Half people eat either purple potatoes or white potatoes for two weeks, and the purple potatoes improve the measure of arterial stiffness, whereas the white potato did not, and this translates into a drop in blood pressure, even in those already taking high blood pressure drugs, suggesting purple potatoes are an effective blood pressure-lowering agent. But what about the toxic glycoalkaloid compounds in potatoes? The toxic human dose starts around 2 to 5 milligrams per kilogram of body weight, and the lethal dose is not too far behind. The average amount of total glycoalkaloids in most potatoes, however, is less than 100 milligrams per kilogram. So, at the average American weight of 180 pounds, a toxic dose is like 4 to 9 pounds of potatoes. What happens when you're post that? Possible nausea, vomiting, and diarrhea that could easily be confused with something like gastroenteritis or food poisoning. Some people can start to get sick at just 1.25 milligrams per kilogram of body weight, or even 1 milligram per kilogram. That would only be about 2 pounds of potatoes at the average American weight. It's also possible they could start accumulating if you ate them day in and day out. But what about those people who go on a fad potato diet and eat meows 3 or 4 pounds a day? They can do that without risking getting sick only if they peel their potatoes, which removes nearly all the glycoalkaloids.