Red, Yellow or Purple Potato...which is better

I’ve been noticing these 1 lb pound bags of little potatoes at the grocery store lately and being a lover of potatoes I tend to choose them knowing that the varying colors are serving a greater purpose in my body more than a pound of red potatoes alone…. So why not tackle the science to back it up!

Potatoes Are Carbohydrates & Starches

At the basic building blocks, these little nuggets of goodness are a blend of carbohydrates and starches. Technically called tubers they are a blend of water and 25% dry matter (starch, sugars, nitrogen compounds, lipids, organic acids, phenolic compounds, mineral substances and non-starch polysaccharides [s]). The main determinant of color being the quantity of polyphenols.

If a potato is 100g, 80g is water, 18g carbohydrate and 2g protein. The protein is called Patatin, sometimes called tuberin, which is a glycoprotein that contains approximately 366 amino acids!). The 18g carbs are broken in non-starch polysaccharides (aka complex carbohydrates), micronutrients Vitamins C, B1, B2, B6, PP and K, minerals copper, iron and potassium. In fact, potatoes have more potassium than bananas!

Each Potato has its own properties:

Russet Potatoes - Russets are large potatoes with rough brown skin and pale flesh.
Yellow Potatoes - Yellow potatoes have thin gold skin and yellow flesh.
White Potatoes - White potatoes have thin beige or tan skin with pale flesh.
Red Potatoes - Red potatoes have thin red skin and pale flesh.
Purple (or Blue) Potatoes - Blue potatoes have dark purple or blue skin with matching purple flesh.
Fingerling Potatoes - Fingerling potatoes have a small, tubular shape and have a variety of skin and flesh characteristics.
New Potatoes - New potatoes are young potatoes that have been harvested early. They have thin, delicate skin and creamy flesh. Also called baby potatoes, they come in a variety of colors, usually red, yellow and purple).

Different Colors indicate different components

The main difference in potatoes come from their varying levels of health-promoting micronutrient levels aka its polyphenol content, aka their flavonoids content, aka their antioxidant content. And to a lesser degree, their Phenolic compounds content (which are groups of molecules that contain at least one phenol element). The major phenolic acids in potatoes are found in the skin [s].

The main difference in color (pigmention) varieties is due to the presence of additional specific phenolic molecules, called anthocyanins.

The concentration of flavonoid is two times higher in red and purple-fleshed potato. Flavonols are flavonoids with a ketone group and the building blocks of proanthocyanins. Flavonols are predominantly found in white and yellow-fleshed potatoes compared to red and purple-fleshed potatoes [s]. Colored potatoes have a higher total phenolic content (TPC) than yellow- and white-flesh potatoes, which resulted in higher antioxidant capacity than yellow and white potatoes[s].

Fun Fact: Flavonoids have anti-oxidative (coupling out free-radicals & toxins), anti-inflammatory, anti-mutagenic and anti-carcinogenic properties, plus they modulate key cellular enzyme function. There are reports of how consuming them has a decreased risk for Alzheimer’s Disease. The most studied flavonols are kaempferol, quercetin, myricetin and fisetin.

Red Potatoes - High in antioxidant, Vitamin C. The skin holds most of the potatoes fiber, and as compared to russet potatoes, red potatoes are lower in carbohydrates and calories, and higher in vitamin K and niacin.

Yellow - yellow are an excellent source of energy-boosting carbohydrates, vitamin C, and potassium, but are also a good source of vitamin B6, thiamin, and dietary fiber.

Purple - Contain the same nutrients as other (such as fiber, potassium, and B vitamins), but what sets them apart is their antioxidant content, anthocyanin.

Note: Preparation methods greatly impact anthocyanin contents with frying results in 40–60% loss in red potato cultivars, and 50–80% loss in purple potato [s,s]. Blanching and soaking result in the leaching of anthocyanin in the water because anthocyanin is highly soluble in water [s]. Studies have showed various cooking methods such as frying, baking, boiling, microwaving, and steaming reduced the level of anthocyanin in different potato cultivars by 83.15%, 25.67%, 14.66%, 14.01%, and 7.45%, respectively [s]. >> The takeaway - steaming is best to hold in the nutrients!

What else that is hugely correlated to health is that the darker color the potato, the lower the glycemic index.

For reference, the glycemic index of food is the measure of the foods effect on blood sugar and how quickly or slowly the food will affects blood sugar (glucose) levels after consumption. It's a scale of zero to 100, A high GI value (70–100) will cause a fast spike, medium value (50–69) will have a reasonable reaction rate, and a low GI value (20-49) will raise blood glucose slowly (which is what we want). For example, Quick Oats has a GI of 79 ± 3 while apples have a GI of 28. [s]

For potato’s the glycemic index of potatoes varies:

High GI (70 or higher) Russet, Red Skin, Gold, Yukon, Purple

Medium GI (56-69) - White with skin on

Low G1 (55) - boiled Sweet Potatoes

There is a direct correlation between potato polyphenol content and glycemic index (GI). I study was done comparing the color of potatoes to the GI load… researches found “a significant inverse correlation between polyphenol content and GI of the potatoes (r = -0.825; p < 0.05; n = 4). In vitro, polyphenol extracts of red and purple potatoes inhibited α-glucosidase by 37.4 ± 2.2% and 28.7 ± 3.2%, respectively [s]. They believe the pathway is through an inhibitory effect of anthocyanins on intestinal α-glucosidase which makes sense but I believe there is a fiber content component as well since varying colors also contain varying starch compositions.

The #takeaway:: Purple potatoes are better for your body because they 1. contain more polyphenols and 2. do not cause a significant glycemic spike.

Now, what is the best way to consume these nuggets of goodness.

Well, to maximize on their offerings of resistant starch (to feed the good bugs in your digestive system - for more info check out my Microbiome Post here) you’ll want to eat these purple potatoes cold. So steam them to lock-in all the anthocyanin antioxidant, let them cool completely then eat them. Maybe make a nice potato salad (using a oil/mayo that void of nasty PUFA’s). That is the top tier best way. There are lots more, you could roast them and let them cool and eat them with breakfast, that is what I have been doing more recently. Best thing is just to eat them! Experiment and see what fits best into your lifestyle and preferences.

I’ll add recipes as I find them Or share some that you have tried in the comments. Life is a #teameffort. We can’t do it alone.