How Purple Foods Benefit Diabetes

For years, we’ve been told to eat the rainbow. After all, the brilliant variety of colors that distinguish fruits and vegetables offer profound health benefits by ensuring we get plenty of vitamins and other nutrients.

Who would have guessed that in the context of diabetes there might be a first among equals? That would be the color purple. 

We’ll get into the science of it below, but basically, researchers are finding that purple produce has intrinsic properties that they believe positively impact blood glucose and help reduce the underlying issues that cause disease progression.

Of course, to benefit from purple produce, you’ll want to incorporate it into your diet. Fortunately, these fruits and vegetables are just as delicious as their non-purple counterparts, but to give you further encouragement to enjoy them we’ve included some preparation ideas and recipe links.

Purple and Acylated Anthocyanins

For years, scientists have been enthusiastic about anthocyanins. They’re a class of flavonoids responsible for the orange, red, blue, and purple pigments in plants. There are some 8,000 different flavonoids, and they are ubiquitous in many edible plants.  

The list of anthocyanins’ potential health benefits is long and impressive. They are antioxidant, anti-inflammatory, anti-allergic, and anti-cancer. They improve gut health and metabolism, reduce the risk of heart disease, lower blood pressure, and protect brain function.

But more recent research seems to indicate that anthocyanins get a boost that produces beneficial impacts on type 2 diabetes if they are what is called “acylated.” This means that when an acyl group—a group of atoms—is joined to the anthocyanin molecule it changes the anthocyanin’s chemical properties and makes it more stable. 

The reported result is that these acylated anthocyanins now not only have probiotic properties, but they also have some increased impacts on diabetes. According to the researchers, they help regulate energy, metabolism, inflammation, and gut microbiota in type 2 diabetes. Yes, non-acylated anthocyanins from plants also do this, but the researchers believe that acylated anthocyanins have what they describe as a greater inhibitory effect on the two key enzymes that are responsible for how dietary carbohydrates turn into glucose through digestion, and consequently are more impactful.

The Power of Purple

How does purple produce fit in here? It appears that the greatest sources of acylated anthocyanin foods are purple produce, although there also are outliers—blood oranges, passion fruit, broccoli sprouts, red cabbage, red lettuce, red curly kale, red radish, and red onion. 

Purple produce includes berries, fruits, vegetables, and tubers, many of which are very familiar, such as blackberries, blueberries, concord grapes, black plums, and eggplant. Others you may only come across in a farmers market — pigmented potatoes, purple carrots, purple cauliflower, purple corn, purple peppers, purple sweet potatoes, and purple tomatoes. 

Six Purple Foods and How to Enjoy Them

Maybe you’re already regularly eating carrots, sweet potatoes, cauliflower, cabbage, and eggplant you likely have recipes and long-standing favorite ways of preparing them. Try adding that punch of purple, and you now have the potential to make visually powerful dishes that could even help you better control your diabetes. We’re hoping these examples will excite your interest.

Purple Carrots: Some varieties of purple carrots are tinted on their exterior and still orange inside. If you have these, grate them into a simple colorful salad. This recipe complements their deep flavor with lavender and thyme. If you have carrots that are purple all the way through, turn them into a purple carrot hummus. Love roasted carrots? Top with some Egyptian flavors, like dukkah. Unite purple carrots with apples for a naturally sweet, creamy soup. 
Purple Potatoes: Like other potatoes, you can boil or roast them, add them to soups and stews, or turn them into a salad. An easy way to get a tender interior with a crispy skin is to quarter them, spray with olive oil, toss with your favorite spices, and then roast them in an air fryer. A beautiful side dish is to bake them with herbs, spices, and balsamic vinegar. Or combine multiple anthocyanin foods in a soup of purple potatoes, purple or red cabbage, and red onion — along with black quinoa. 
Purple Sweet Potatoes: Like regular sweet potatoes, you can roast purple sweet potatoes, but they’re denser and may need more cooking time. Turn them into “fries” coated in an herb paste. Make healthy mashed potatoes with oat milk. And who wouldn’t love a purple sweet potato stuffed with crispy Tandori Masala seasoned chickpeas and a tahini dressing? Or try this Spiced Sweet Potato Casserole.
Purple Cauliflower: An easy and delightful way to cook cauliflower is to divide it into florets, then toss with garbanzo beans, lots of minced garlic and herbs, some grated parmesan cheese, and olive oil, then roast at 375 degrees for about an hour. Or how about a purple cauliflower sauté with garlic and saffron served over quinoa? Make riced purple cauliflower as the foundation of a low-carb bowl topped with other vegetables, roasted chicken or shrimp, and a vinaigrette.  
Purple Cabbage: Slice a head of purple cabbage into “steaks” that you can steam, sauté, or roast, topped with some olive oil and herbs and spices — or some umami-packed chili crunch. Give it a braise in apple cider vinegar. There are tons of ways to turn shredded purple cabbage into a colorful salad. Try combining it with grated (purple?) carrots, sunflower seeds, and cucumbers. Make a healthy slaw to add to your favorite tacos. 
Eggplant: Here’s what you need to remember if you’re eating eggplant for the acylated anthocyanin benefit: keep that purple skin on it. A simple way to prepare it is to find a smaller, thinner eggplant, remove the end, and slice in half lengthwise. Poke some holes in the flesh and spray with a neutral oil that will penetrate into the eggplant. Spread with minced garlic and ginger, a dash of sesame oil, and toasted sesame seeds. Roast at 375 degrees for about 30 minutes or until the eggplant is soft. Another approach is to slice eggplant into steaks and grill, topping with tomato sauce. Slice thin, grill, and roll up with marinara, reduced-fat mozzarella, and toasted pine nuts. Place in a casserole dish, spray with olive oil and a dash of whole wheat bread crumbs mixed with grated Parmesan, then run it under the broiler until browned. Serve as appetizers. Want an eggplant dip? Make baba ganoush, a Middle Eastern dip that features roasted tahini, cumin, garlic, lemon juice, and cayenne pepper. Or how about Hasselback Eggplant Parmesan? (Just go easy on the cheese and focus on the marinara.)

To be sure, purple foods aren’t the “cure.” But they’re a very beneficial component of a healthy, varied diet for people with type 2 diabetes. And it’s cool to know that you can add an extra healthy push by adding purple to your diet.