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Chester County Press

Oakshire Naturals turning mushrooms into Vitamin D2 gold

09/01/2023 03:23PM ● By Richard Gaw

The story of how Oakshire Naturals became the world’s leading provider of Vitamin D2 mushroom powder is one told through lab experimentation, layers of approval and eventual worldwide distribution, but the proper and chronological tracking of the product known as EARTHLIGHT® began when curiosity and destiny collided when founder and CEO Gary Schroeder was a master’s student at Penn State in the late 1970s.

“My master’s research at Penn State was around the factors that affected the sizing of mushrooms,” Schroeder said from the company’s office in Avondale. “Why do some mushrooms grow small, some medium and some large, and how do we help to control that? There had been some work done in that area, but there were more open questions than answered questions.

“We learned a lot, and I was told 25 years later that my research was highly cited by others because we learned that the nature of what we do is foundational.”

It was then, between 1978 and 1980, when Schroeder – with degrees in plant science and plant pathology -- realized that he couldn’t just be a mushroom farmer; that within the confines of his chosen professional path, the mushroom growing industry held secrets and solutions that he felt destined to find. 

“As an undergraduate, the entrepreneurial bug began to bite me, and a lot of that came from my experience in leadership training I learned from the Boy Scouts,” Schroeder said. “I thought, ‘I can become an entrepreneur,’ but the question became, ‘Where and what?’ What I was learning back then about the mushroom industry that significant technology was just starting to come out that would eventually change the entire character of growing mushrooms.”

A national discussion
After spending the next four years getting his start in the industry, Schroeder began Oakshire Mushrooms in 1985 on a 24-acre property near Kennett Square, and quickly became a pioneer in the growing and marketing of specialty mushrooms, and was the first in the U.S. to grow and market commercial-scale Portobello and Shiitake mushrooms.

The volume of Oakshire’s sales skyrocketed when it signed a brand licensing fee with Dole that permitted Oakshire to place the Dole logo on its products.  

In 2008, Schroeder became part of a national discussion of industry leaders charged with the task of determining future marketing strategies for the mushroom by identifying – and then selling – its nutritional identity.  

“If we are asked to identify the nutritional value of bananas, most of would know the answer: potassium,” Schroeder said. “Even though Portobello mushrooms contain more potassium than bananas, the industry wasn’t telling that story. As it had been known, exposing mushrooms to sunlight creates Vitamin D.

“So we thought, ‘How do we leverage this together, because with a powerful national brand (Dole) and some marketing muscle, I thought we could roll something out that would be very significant.”

In that same year, research and development let Oakshire to become the first company in the U.S. to create and patent a commercial light treatment process for mushrooms. The result was both innovative and groundbreaking: Oakshire was now growing – and marketing -- 100 percent DV Vitamin D mushrooms, an achievement that earned the company recognition for innovation in manufacturing.

“I found myself attending a lot of awards ceremonies, but after we rolled out the new product, the consumers just yawned,” Schroeder said. “Maybe the industry wanted to make the vitamin content of mushrooms our new identity, but we were hearing from consumers that they were buying fresh mushrooms because they liked the taste and texture.”

 Filling the gap
According to the U.S. Food & Drug Administration (FDA), a three-ounce serving of mushroom provides 400 international units (IUs) of Vitamin D2, but to Schroeder, it wasn’t enough.

“I drew an equation on a marker board and showed it to a lab technician, and at first he didn’t get it, but eventually he did,” Schroeder said. “Through all of these iterations and experimentations, we began to see that with a single gram, we could get between 40,000 and 50,000 international units of Vitamin D2.”

While the marketing of the nutritional value of mushrooms continued to motor quietly along, another innovation was being introduced to the industry: providing Vitamin D2 dried mushroom powder in capsule form, as a nutritional supplement. By 2012, the concept first entered the marketplace. Oakshire Naturals, the natural products division of Oakshire, was founded in the same year.

“Within three weeks, the FDA called us and said, ‘Stop. We don’t know what you’re doing,’” Schroeder said. “They told us that from a regulatory standpoint, there was a large void in supplying this product to the public, but the FDA kept telling us, ‘We think this product is safe, but someone has to pay for the data and put all of this together.

“Oakshire said to the FDA that we were willing to pay for the research because we thought we had a product that was worthy of that investment. 

“The FDA viewed us as a solution to the problem of how to fill this gap. They were very helpful, and each one of those regulators gave us guidance on how to navigate so many aspects of the project.”

Over the next several years, Schroeder and his colleagues met with FDA representatives in Washington, D.C. They spent endless hours in laboratories perfecting their product. They learned about the relegated world of dietary supplements. They wrote and rewrote formulas and examined possibilities. A number of their patents were awarded by U.S., Canada and Europe for the process.

After nearly one dozen years of exhaustive research and meetings, Oakshire Natural’s Vitamin D2 Mushroom Powder received approval of its Food Additive Petition from the FDA in 2019. 

“On the day it was approved, I asked the FDA what the next steps were, and the lead scientist told me, ‘We’re done. The science is fine, and we’re just waiting on the legal team to sign off,’” Schroeder said. “I was stunned, absolutely stunned.”

Creating larger possibilities
After additional regulations were passed, the product was published in the U.S. Federal Register in July 2020. Today, EARTHLIGHT® is the premier source for sustainable, plant-based, whole-food Vitamin D2. It is found in well over 200 supplement products in several countries around the world, and is also included in food items such as breakfast cereals, grain products and pastas, milk and dairy products, soups and broths and yeast-leavened bread and pastries. 

All of the mushrooms produced for EARTHLIGHT® are grown on organic mushroom farms in Avondale.

“If you were to speak to me when I was in college and tell me that by 2020, I would be producing a mushroom product that was distributed around the world, my reaction would have been, ‘Of course,’” Schroeder said. “Even back then, I was always thinking in terms of making a global and sustainable impact.

“It takes hundreds of gallons of water to make a single pound of almonds. Conversely, it takes the mushroom industry only 1.8 gallons of water to make a pound of mushrooms. We’re very efficient, and we’re using straw and leftover by-products, so the source for fresh mushrooms is ideal, and all we’re doing is introducing it to light.

“Ten years ago, there was no market for what we are now doing, but now that we are here, it creates larger possibilities.”

To learn more about Oakshire Naturals, visit