Can you meet your vitamin D requirements just by eating mushrooms?

 

View this post on Instagram

 

A post shared by LYNDI COHEN // Nutritionist (@nude_nutritionist) 

While mushrooms commonly found in Indian dishes are nutritionally dense, can they truly fulfill all our vitamin D requirements through a simple sunbathing session as suggested by Cohen? 

Factors influencing the synthesis of vitamin D in mushrooms

Shubha Ramesh L, chief dietician and nutritionist at DHEE Hospitals says that vitamin D synthesis occurs when ergosterol, a compound present in mushrooms, is converted to vitamin D2 upon exposure to UV light from the sun. “This process is somewhat similar to how human skin synthesises vitamin D3 when exposed to sunlight.”

“While human skin primarily synthesises vitamin D3, mushrooms produce vitamin D2. The efficiency and type of vitamin D synthesised differ, with D3 generally being more effective in raising and maintaining vitamin D levels in human blood compared to D2,” Shubha asserts. 

Can leaving mushrooms out in the sun ensure consistent and reliable levels of vitamin D synthesis?

The efficiency of vitamin D synthesis in mushrooms can vary based on several factors including the type of mushroom, the duration and intensity of sun exposure, geographic location, and the specific time of year. For example, Shubha says that UVB radiation levels, which are crucial for vitamin D synthesis, are lower during winter months and in regions farther from the equator.

“Certain types of mushrooms, like maitake and portobello, are better at synthesising vitamin D due to higher initial concentrations of ergosterol.”

Depending solely on sun-exposed mushrooms for vitamin D might not be adequate for everyone (Source: Freepik)

Optimal duration for sun exposure to maximise vitamin D synthesis

Shubha explains, “The amount of vitamin D in mushrooms significantly increases with sun exposure. Research suggests that exposing mushrooms to midday sun for about 1-2 hours can substantially boost their vitamin D content.”

To maximise vitamin D synthesis without compromising the quality and safety of the mushrooms, she recommends that a balance needs to be maintained as overexposure can lead to drying and degradation of nutrients.

How does the vitamin D content of sun-exposed mushrooms compare to other dietary sources of vitamin D

Sun-exposed mushrooms can provide a significant amount of vitamin D2, according to Shubha, but the bioavailability and effectiveness of vitamin D2 are generally considered to be less than that of vitamin D3 found in animal products and supplements.

“Depending solely on sun-exposed mushrooms for vitamin D might not be adequate for everyone, especially those with higher vitamin D needs or those with limited access to consistent, effective sun exposure. Comparatively, fortified foods and supplements provide a more controlled and reliable dose of vitamin D3,” she stresses.

The variability in the vitamin D content of sun-exposed mushrooms due to environmental factors and the lesser efficacy of vitamin D2 might limit their effectiveness as the sole source for meeting daily vitamin D requirements.