TV’s Dr. Oz calls kale a “nutritional superstar” rich in vitamins K, A and C as well as manganese and fiber.

On the website, Kathleen Zelman labels kale “the queen of greens” and says it’s recognized for its “exceptional nutrient richness, health benefits and delicious flavor.”

And The World’s Healthiest Foods website — — calls kale “one of the healthiest vegetables around,” and says it can lower cholesterol and the risk of at least five kinds of cancer.

It’s reviews like those that may have sparked a 136% increase in kale foodservice sales over the past year for San Miguel Produce, Oxnard, Calif., said vice president Jan Berk.

But kale’s popularity explosion didn’t happen overnight.

“For us, it’s been a growing category for four to five years,” Berk said.

The company offers three kinds of kale — green, red and Tuscan — and several varieties, including chopped, blends and salads.

For years, kale was something chefs put on a plate as a garnish, said Brent Scattini, vice president of sales for Gold Coast Packing Inc., Santa Maria, Calif.

“Now people are eating it, and we don’t seem to be able to get enough of it,” he said.

Kale has become a health craze, he added.

“People are using it for juicing, and you’re seeing multitudes of different kale salads in the marketplace,” Scattini said.

“Our kale numbers continue to grow,” said Ernst Van Eeghen, director of marketing and product development for Church Brothers LLC, Salinas, Calif. “It’s a nutritional powerhouse.”

Van Eeghen isn’t surprised that the category has been expanding.

“I am surprised with the pace,” he said.

The company has increased its kale acreage in response to sales that have more than tripled in the past three years, he said.

The popularity of kale at various eating spots makes total sense, said Hudson Riehle, senior vice president of research for the National Restaurant Association, Washington, D.C.

“Just as the consumer’s palate has become much more sophisticated over the years, it’s entirely logical that relatively new produce introductions to them through the restaurant venue become more mainstream,” he said.

“If you look at mentions of kale on restaurant menus, it’s becoming more popular, and therefore more consumers are becoming exposed to it in the restaurant venue,” he said.

Riehle said it’s likely that kale will continue to become more popular on restaurant menus.

Walter P. Rawl & Sons Inc., Pelion, S.C., has been growing kale for more than 25 years for foodservice, said Ashley Rawl, director of sales, marketing and product development.

Most recently, it has found favor with consumers in supermarkets and shoppers have “gained an understanding of how tasteful and nutritious it is.”

Kale has transitioned from being a garnish to starring in soups, pastas and juices, he said.

While kale sales have increased in the foodservice category, the sales boost has not been as great as it has been at retail, he said.

Prices are higher than they were a year ago, he said, “but not tremendously.”

While kale has become a hot commodity in both foodservice and retail outlets, most suppliers believe that while it will remain popular, that popularity will reach a peak and then sales gradually will start to taper off.

Berk said she sees sales of other greens picking up.

“People are looking for flavor profiles,” she said, and all the greens are in the nutrient-dense category.

Scattini said he’s heard speculation from the culinary world that “kale’s already passé and it’s on its way down, but I can’t say that what’s happening in the marketplace reflects that,” he said.

One thing the industry has learned, he said, is that consumers are interested in “superfood-type items.”

“As an industry, we’re going to need to be prepared to understand what is going to be the next superfood, and what is going to be the format that we’re going to have to take it to market in,” he said.