Balancing UV Protection & Vitamin D Supplementation! What Is This Innovative Sunscreen Born in the UV Haven of Australia?

Since contributing to the maintenance of immune function, vitamin D has gained attention in the wake of the COVID-19 pandemic.

The sunscreen that focuses on this vitamin D, coming from UV-rich Australia, is "solarD."

What kind of nutrient is vitamin D? How is SolarD different from regular sunscreens? We talked with Keiko Shiga from Ambrosia K.K.

Various Actions of Vitamin D, Including Bone & Immune Function

Vitamin D, which is a type of fat-soluble vitamin, is also surprisingly known to be a type of hormone.

"Hormones are substances produced in the body that act on organs through the bloodstream. Vitamin D can be supplemented through food and supplements, but it can also be produced in the body by sunlight, acting on organs as well."

The appropriate range of vitamin D levels varies somewhat by testing institutions, but a typical blood concentration is considered to be 30–75ng/mL.

So, what kind of actions does vitamin D have?

"The main actions include the formation of bones and teeth, muscle contraction, nerve transmission, and regulation of immune function. In recent years, there has been a lot of research on vitamin D globally, and various papers have been published.

"For instance, there are reports that supplementing vitamin D can safely reduce the worsening of asthma, and that a higher blood concentration of vitamin D lowers the risk of cancer, along with therapeutic effects on patients with depression."

Reasons to Recommend Generating Vitamin D through Sunbathing

Methods to obtain vitamin D include mainly diet, supplements, and sunbathing.

"Salmon, sardines, and mushrooms are high in vitamin D. While supplementation may be necessary for those severely deficient in vitamin D, sunbathing to generate vitamin D in the body is recommended.

"The reasons are simple: it costs nothing, once enough vitamin D is secured, the body automatically stops production, and the vitamin D produced by sunlight remains in the blood longer than through other methods.

"Moreover, experts suggest that it is desirable to obtain half of the daily required amount of vitamin D from sunlight."

So, how much sunlight is needed?

"The time required to generate vitamin D depends on the time of day, season, latitude, and skin type such as Caucasian, Black, or Asian.

"For example, research teams from the National Institute for Environmental Studies and Tokyo Kasei University calculated the sunlight exposure time needed for adults to generate 220 IU of vitamin D—considered the amount needed per day. They found that during clear weather in December, 8 minutes of sunbathing with hands and face in Naha was sufficient while in Tsukuba, it took 22 minutes, and in the higher latitude of Sapporo, it required 76 minutes."

However, with changes in clear or cloudy weather, summer or winter, and the degree of skin exposure, the required time cannot be said clearly.

There are several points to effectively generate vitamin D.

"First, sunbathe between around 10 AM and 3 PM. Generation of vitamin D significantly decreases in the early morning or near evening. Additionally, vitamin D cannot be made through glass, so it's essential to go outdoors.

"According to the National Institute for Environmental Studies, it's understood that some vitamin D can still be generated even in the shade. The area of skin exposed to sunlight also affects the amount produced, so if you want to obtain the required amount in a shorter time, increasing skin exposure is also a trick."

Many people may want to avoid sunburn even for health reasons. However, staying indoors to avoid outdoors and taking protective measures like sunscreen or UV-cut clothing can actually be significant causes of vitamin D deficiency.

This brings us to the creation of the sunscreen "solarD."

Sunburn Prevention as a Major Cause of Vitamin D Deficiency

SolarD was born in Australia, a country rich in ultraviolet rays.

"In Australia, it's said that ultraviolet ray levels are 5 to 7 times higher than in Japan. This means it is theoretically an environment conducive to generating vitamin D.

"However, after enjoying outdoor sports for many years, SolarD founder Matthew Collett was diagnosed with a deficiency after undergoing a vitamin D test."

In Australia, known as a country with high ultraviolet (UV) radiation, the slogan "Slip, Slop, Slap" has long encouraged sun protection measures such as wearing long sleeves, applying sunscreen, and wearing hats.

However, due to the use of sunscreen, the production of vitamin D has been hindered, resulting in 40% of the population being vitamin D deficient. In January 2023, the Australian government recognized the crucial importance of vitamin D for health and has softened these guidelines.

The UVB Filtering Technology that Doesn't Inhibit Vitamin D Production

However, as the term photoaging suggests, UV rays are a significant enemy for the skin. Therefore, Matthew contemplated whether it was possible to generate vitamin D while using sunscreen and developed the "UVB Filtering Technology."

"UV rays have various wavelengths, but only a part of the UVB rays can produce vitamin D.

"Sunscreens are usually formulated to block all UV wavelengths, but SolarD is designed to allow only the wavelengths necessary for vitamin D production to pass through. This design is called UVB Filtering Technology.

"At the same time, it achieves a high level of sunscreen effectiveness with SPF50+ and PA++++."

In an experiment conducted by SolarD using samples of SPF15, SPF30, and SPF50, it was found that as the SPF value increases, the amount of wavelengths necessary for vitamin D to penetrate decreases, but even with SPF50, a sufficient amount of vitamin D can be produced.

Finally, I was also informed about how to self-check for vitamin D levels.

It is suggested that those who meet three or more criteria may likely be vitamin D deficient and should consciously aim to increase their levels.

As the UV radiation increases in the upcoming season, why not incorporate sun protection measures that also consider health?