Luckily, there are plant sources of D3 out there. The ideal option, according to Ferira, is algae. "Organic algal-sourced vitamin D3 is the cream of the crop for vitamin D," says Ferira.
Though harder to find, algal-sourced vitamin D3 can make for a supplement that's both sourced from plants and more sustainable.
VegD3®, for example, is a non-GMO, USDA organic, plant-origin, environmentally sustainable algal vitamin D3 option that's chemically identical to the D3 you'd get from the usual animal-based lanolin. The process of creating this algae-based vitamin D3 is also free of pesticides (something that can't always be guaranteed for sheep-based options), according to the brand.
Since plant-based supplemental sources of vitamin D have traditionally offered vitamin D2, VegD3® offers a unique source that's both sustainable and the form of D the body prefers and needs daily (aka, this is an essential-fat-soluble micronutrient you must consume because your body can't synthesize it).
In fact, VegD3® is a premium algal D3 ingredient that is produced "at a U.K.-based research center using advanced technology that has zero negative impact on the local environment," Ferira says.
This is a big deal considering that the other plant-derived option for vitamin D3 comes from lichen, which takes many years (to decades) to grow and then has to be removed from its natural ecosystem for the vitamin D to be extracted, adds Ferira. "Plus there are animals that were relying on this lichen for their nourishment. It's now gone," Ferira says.
Not to mention, the lichen that D is pulled from may be contaminated—and the concentration of D3 you can ultimately end up with can vary significantly based on the type of lichen harvested and the season it's harvested in, she says.
All of these factors make it a far less ideal plant source of vitamin D3 for supplements than a high-quality algae—particularly VegD3®, which is produced without contamination concerns or taking a toll on the environment.