Booster Juice has the blues. A few of its products now bear the colour, one that’s rarely found in food (outside of blueberries), all part of a food trend that's fast gaining ground--and social-media posts.

Its new Blue Raspberry Smoothie, Blue Illusion Smoothie Bowl, and Blue Majik Chia Pudding get their hue not from an artificial colouring or dye but a natural substance that comes from certain tropical bodies of water.

Here’s how: Spirulina is a type of blue-green algae that, when properly harvested, contains essential amino acids, while also being a plant-based source of complete protein. It’s available in supplement, powder, and liquid form.

Spirulina has two pigments: the deep-green chlorophyll, which is present in most green vegetables; and phycocyanin, which is sometimes called “blue spirulina” because of its unique shade.

Becoming more common is the extraction of this blue substance. Phycocyanin can be purchased in powder form at some health-food stores (with Unicorn Superfoods and E3Live being among the producers), and a small amount lends the same blue hue to whatever food you add it to.

That rare colour makes it instantly Instagrammable. 

The nutritional value of phycocyanin, when used in isolation, hasn’t been well-researched. However, some evidence shows that the substance is high in B vitamins, appealing to vegetarians and vegans who aren’t getting those nutrients from animal products.

And while a teaspoon or two of powder isn’t going to give you all the protein you need on any given day (and while most dietitians would recommend getting nutrients from whole foods), you could add the stuff to your own home-made smoothies, smoothie bowls, or other dishes (with Greek yogurt or protein powder thrown in for a protein boost) for your own true-blue menu.

Booster Juice (various locations) is adding the natural blue algae to some of its core products, many of which are high in protein or other nutrients. Its blue foods are being served for a limited time and include the Blue Illusion Smoothie Bowl (with pineapple, bananas, coconut milk, vanilla frozen yogurt, and phycocyanin, topped with coconut, fresh blueberries, and granola); the Blue Raspberry Smoothie, made with pineapple, bananas, raspberries, fresh lime juice, and phycocyanin; and Blue Majik Chia Pudding (vanilla almond milk, coconut milk, honey, and phycocyanin, topped with fresh raspberries).