I wrote about the nutritional power of purple produce back in 2009 for the Chicago Tribune The Color Purple: Disease Fighter.
Purple is not simply a popular trend in fashion. This color of royalty, dubbed the “new black” by fashionistas, is also the new black in food. In produce aisles, at farmers markets and on restaurant menus, you can now find a growing array of heirloom and specialty vegetables with a distinctive purple hue — purple potatoes, tomatoes, carrots, beans, corn, asparagus, peppers, baby artichokes and cauliflower. Beyond the pleasing appearance on the plate, the purple color is a cue for nutritional power.
Here’s just a snapshot of some of the research:
- A USDA-funded study found that a couple of servings of purple potatoes a day helped lower blood pressure as much as oatmeal. Joe Vinson, a professor of chemistry at the University of Scranton in Pennsylvania, analyzed 18 patients who ate six to eight small purple potatoes (about the size of a golf ball) twice daily for a month and found their blood pressure dropped by 3.5 and 4.3 percent without gaining weight. Most of the study participants were either overweight or obese, and many were already taking medications for high blood pressure during the study.
- Researchers in Great Britain used genes from snapdragons to generate higher production of anthocyanins in tomatoes, which resulted in intensely purple tomatoes with anthocyanins levels comparable to blackberries and blueberries. The life span of cancer-susceptible mice was significantly extended when the diet included the purple tomatoes compared with the normal red tomatoes.
- Anthocyanins from purple corn were the most potent in inhibiting the growth of colon cancer cells compared to the other vegetables and fruits evaluated by Ohio State University researchers.
- Rats who ate black raspberries — which are particularly rich in anthocyanins — were 50 percent less prone to developing cancerous tumors in the esophagus. The study, also conducted at Ohio State University, found that the berries helped fight cancer by reducing inflammation, suppressing growth of cancer cells and triggering cancer cell death.
purple cauliflower courtesy of gorgeoux on flickr
Sue Perry, wrote in the Feb/March issue of ShopSmart, a publication from Consumer Reports:
“If purple cauliflower, Brussels sprouts and wax beans haven’t hit your supermarket, they will — and you should buy them…The explosion of these veggies is expected to be so big that 2013 has been dubbed the Year of Purple Produce by Frieda’s.”
Despite the hot trend and health-promoting potential of the color purple, an analysis by the Produce for Better Health Foundation found that only 3 percent of the fruits and vegetables consumed in the U.S. are from the purple or blue category. I’m hoping that will change if more supermarkets start featuring purple produce. (Freida’s is encouraging supermarkets to create a purple section in the produce aisle and is providing merchandising materials for retailers to help showcase “the power of purple.”)
Part of the problem appears to be the perceived bitterness of these deeply-hued vegetables. Unfortunately, our modern-day produce has purposely been bred to enhance palatability and get rid of the purple, asserts Jo Robinson, author of Eating on the Wild Side: The Missing Link to Optimum Health, in a fascinating New York Times article: Breeding the Nutrition Out of Our Food. An accompanying chart, Nutritional Weaklings in the Supermarket, compares anthocyanin levels in purple potatoes, carrots and other heirloom vegetables or wild species compared to their cultivated cousins.
Throughout the ages, our farming ancestors have chosen the least bitter plants to grow in their gardens. It is now known that many of the most beneficial phytonutrients have a bitter, sour or astringent taste. Second, early farmers favored plants that were relatively low in fiber and high in sugar, starch and oil. These energy-dense plants were pleasurable to eat and provided the calories needed to fuel a strenuous lifestyle. The more palatable our fruits and vegetables became, however, the less advantageous they were for our health.
So purple tones were once deemed as undesirable. Now we know they’re a cue for nutritional prowess. I remember when I was working on the Chicago Tribune article a few years back that the late James Joseph, a neuroscientist at the USDA Human Nutrition Research Center on Aging at Tufts University and co-author of The Color Code: A Revolutionary Eating Plan for Optimum Health, told me:
“If I could only eat one color per day, it would be purple. There is more data on purple than any other color right now.”
I’ve been a fan of purple vegetables for a long time. That’s why when the folks at Frieda’s asked if they could send me some of their purple vegetables I enthusiastically said yes! I don’t frequently accept products from companies to review, but this time I agreed. I was eager to try some of the newer items, such as purple sweet potatoes, purple artichokes, and purple kohlrabi.
One of my favorites was the Stokes Purple Sweet Potato, which is an intensely deep purple potato that was discovered by a grower in Stokes County, North Carolina (see this article LATimes that looks at the mysterious history of this tuber). Actually, these sweet potatoes were amazing. I’ve eaten purple potatoes before (which originate from Peru), but this was the first time I’ve had purple sweet potatoes. The photo below shows a raw potato sliced open, so you can see how the color intensifies after cooking. Frieda’s recommends wrapping in foil and baking at 350 degrees for 1.5 to 2 hours, which is exactly what I did. The flesh of the potato is denser than other sweet potatoes so it takes longer to bake.
I also sliced one of the largest of the purple sweet potatoes Hasselback-style and drizzled with olive oil before baking.
You can find more recipes at Frieda’s, including Stokes Purple Sweet Potato Salad with Chipotle Vinaigrette and Sweet Potato Muffins. Here’s a video they put together to give you more serving ideas (and you can see how striking the purple color truly is).
I also loved the purple artichokes, which I steamed and served with a Sriracha dipping sauce.
My shipment also included some purple baby artichokes (Fiore Viola) that I steamed first, then cut in half and roasted with olive oil, kosher salt and freshly ground pepper.
Frieda’s is selling a wide variety of purple vegetables and fruits: Stokes Purple Sweet Potatoes, Sangria Artichokes. Fiesole Baby Artichokes, Fiore Viola Artichokes, Purple Cauliflower, Baby Purple Cauliflower, Purple Kohlrabi, Graffiti Eggplant, Radicchio, Kale Sprouts, Purple Asparagus, Red Onions, Purple Potatoes, Passion Fruit, Purple Wax Beans, Baby Purple Brussels Sprouts, Champagne Grapes and Concord Grapes. Look for them in your local supermarket or specialty store. Expect to see anthocyanins gain even greater attention. Just don’t be tempted to buy these phytonutrients in pill or capsule form. You’re better off with the whole fruit or vegetable.
Disclosure: I received free products from Frieda’s Specialty Produce. I was not compensated for writing this post.