A tennis court in Georgia was an unlikely spot for a Dutchwoman and a German to meet. But sure enough, that's where Kristel de Groot and Michael Kuech first encountered each other, while students at Valdosta State University. The college tennis players soon became a couple.

Three and a half years later, at age 24, Kuech learned he had testicular cancer. As chemotherapy sapped his energy level day by day, de Groot struggled with seeing him suffer. That's when the health-food guru inside her sprang into action. With the help of her aunt, an orthomolecular nutritionist--one who specializes in dietary supplements--she dug into various bags of vitamin-rich "super grains" in her kitchen and began a strict smoothie cleanse for Kuech. And he actually started to feel better--more alert and energized, de Groot, now 28, says.

"The mixes helped him rebuild his immunity, energy levels, and overall health after finishing chemo," she says.

What was then just a slapdash regimen would, in 2015, transform into Your Super, a Venice, California-based direct-to-consumer superfoods supplement company that makes plant-based powders and delivers them to health-conscious eaters around the world. De Groot won't reveal revenue, but the company says it has sold more than 500,000 containers of the powders, which start at $29.90. It has also attracted $7.1 million in funding, from PowerPlant Ventures, a growth equity fund in Manhattan Beach, California, along with seed-stage funders Döhler Ventures and 500 Startups.

Each mix, which can be turned into a smoothie or sprinkled on top of meals, is tailored for a specific health benefit. There's the Super Green mix, which promises immunity building. Forever Beautiful aims to produce healthy skin, and the Skinny Protein mix is for those looking to gain some healthy weight.

Ingredients include now-ubiquitous health foods like matcha and chia seeds. Others are less familiar to Westerners. There's maca, an ancient Peruvian root; baobab, an African coconut-like fruit but with a dry interior; and moringa, a skinny-looking Indian plant. While these have been staples in their native lands for thousands of years, de Groot says, they've only recently been introduced to the American and European markets as nutrient-rich "superfoods."

According to Your Super and the many other companies peddling them, such superfoods boast health benefits, as they often contain vitamins and antioxidants. These can allegedly help prevent cancer and other chronic illnesses--though the Food and Drug Administration is explicit in resisting those claims. Even so, these products have been gaining in popularity in recent years. Global market research firm Mintel found that there was a 202 percent increase in the number of food and drink products launched in the superfood space between 2011 and 2015.

Superfoods are not just a fad, says Dan Gluck, managing partner at PowerPlant Ventures. PowerPlant led the latest Series A investment round in January, investing $5 million in tandem with German firm Döhler Ventures. He says consumers are increasingly willing to switch to healthier diets, and supplements are just one part of it. PowerPlant is generally interested in "plant-centric companies" that are taking animal protein and dairy out of the food system, which the venture firm believes is "broken, inefficient, and inhumane."

"We think we're just at the tip of the iceberg right now," says Gluck. "We're in the early innings of a major food revolution."

Of course, Your Super is just one of many supplements businesses attempting to cash in on the clean eating trend. There's Amazing Grass and Nested Naturals. There's also Amanda Chantal Bacon's Moon Juice, the Goop-endorsed purveyor of various supplemental powders, which counts Gwyneth Paltrow as an early acolyte.

Besides having to deal with stiff competition, any company in this space faces risks if economic shifts spark a downturn, as superfoods and their ilk will likely be the first to go. These nutrient-rich foods are considered "discretionary spending," says Gluck when asked about potential headwinds facing the company.

Jed Fahey put this risk another way: "Do we need them? Hell, no. Will they be good for us? Hell, yes." Fahey is a nutritional biochemist specializing in plant chemistry and an assistant professor at Johns Hopkins University.

But for people who need to customize their diet for health reasons, superfoods become much more important--as they were for Kuech during his recovery. "The subset of people who need to highly engineer their diets is probably well served by something like this," Fahey says. "It comes from a very holy and sacrosanct place."

De Groot says she and Kuech, who has now been cancer free for six years, still consume at least five servings daily of their own supplement mixes, in smoothies, oatmeal, and homemade snacks like hummus and popcorn.

"Nothing makes me more excited than sharing that healthy living is not that complicated," de Groot says. "Your Super is leading the movement by educating people how powerful superfoods can be."