Solar D, a sunscreen that for the first time enables the body to produce vitamin D with no loss of sun protection factor, will be on sale in the US from this summer. A study published in PLOS ONE describes the findings.
While vitamin D is available in a few foods, including fish-liver oils, fatty fish, mushrooms, egg yolks and liver, very little is taken in by diet, and the main source for people around the world is the sun.
In total, 80% of human vitamin D intake is synthesized in the skin as a result of solar or artificial ultraviolet-B (UV-B) radiation.
However, vitamin D deficiency and insufficiency constitute a major health problem worldwide. Vitamin D deficiency affects around 40% of children and 60% of adults globally, particularly in the US, Canada, Europe, Asia, India, South America and Australia.
Low vitamin D levels tend to be prevalent in people who live in northern latitudes, those who cover up for fear of tanning or for medical or religious reasons, and people who work indoors.
Why do we need vitamin D?
Researchers have also linked it to some cancers, autoimmune diseases such as type 1 diabetes, multiple sclerosis and rheumatoid arthritis, infectious diseases, type 2 diabetes, cardiovascular problems and neurocognitive disorders, including Alzheimer's disease.
- In 2001-2006, 67% of the US population had appropriate levels of vitamin D
- 24% were at risk of having inadequate levels and 8% were at risk of deficiency
- 1% had excessive, potentially harmful levels of vitamin D
The National Osteoporosis Foundation recommend that people should have 400-800 IU of vitamin D a day and that those over 50 years old need 800-1,000 IU, but individuals will differ. Pregnant women and people with obesity, for example, will need more.
How much vitamin D the body can get from sun exposure depends on several factors.
When and where a person exposes their skin to the sun affects how much vitamin D the body will produce. Catching the rays in the middle of the day, generally from 11 am-3 pm, will boost vitamin D levels, as will living near the equator.
In the summer, at noon, someone with a fair complexion that tans gradually would need 6 minutes of sun exposure to achieve 1,000 IU of vitamin D in Miami; in Boston, the same person would need 1 hour.
Pale skin makes vitamin D more quickly than darker skin, and if a larger area of skin is exposed, more vitamin D will be produced.
Air pollution, altitude, cloud and being behind glass all reduce the amount of vitamin D that the body can produce.
Can you have too much vitamin D?
It is also possible to have too much vitamin D, but this would not normally result from diet or sun exposure. According to the Vitamin D Council, toxicity can occur after taking 40,000 IU per day for 2 months or more, or as a result of a very large one-time dose.
Excess vitamin D can cause the liver to produce too much of a chemical called 25(OH)D. This can lead to high levels of calcium in the blood, or hypercalcemia.
Symptoms include nausea or vomiting, feeling thirsty or needing to urinate more often, muscle weakness or pain, bone pain, tiredness and confusion. However, both hypercalcemia and these symptoms can result from other conditions.
However, a lack of vitamin D is more likely, and this has been fueled by fears of developing skin cancer, resulting in people either avoiding the sun or covering up with sunscreen.
Applying sunscreen with a sun protection factor (SPF) of 30 protects against melanoma, but it also reduces the skin's capacity to produce vitamin D by almost 98%.
Protection from the sun and the need for vitamin D
As well as the threat of non-melanoma skin cancer, ultraviolet (UV) radiation from the sun is known to cause erythema, which is a skin disorder resulting from hypersensitivity. Protection from the harmful rays is sought in sunscreens.
The European Commission (EC) state that a sunscreen with an SPF of 6 offers "low protection," an SPF of 15 provides "medium protection" and an SPF of 30 gives "high protection."
Researchers at Boston University in Massachusetts designed four tests to measure the levels of protection and vitamin D optimization for sunscreens containing different combinations of compounds that are known to absorb UV radiation.
They found that one product, Solar D, offered the same protection as other SPF 30 sunscreens, while allowing for up to 50% more production of vitamin D in-vitro.
The researchers told Medical News Today that the effects have not yet been tested on humans.
Dr. Michael F. Holick, PhD, professor of medicine, physiology and biophysics at Boston University School of Medicine and an endocrinologist at Boston Medical Center, explains that Solar D was "designed with compounds with differing filter compositions to maximize vitamin D production while maintaining its sun protection for reducing erythema or burning of the skin."
Dr. Holick told MNT:
"The ingredients in the sunscreen are essentially identical to most of the major brands, with the minor adjustment of the formulation to enhance the transmission of ultraviolet light that specifically make vitamin D3 in the skin."
When we asked whether the sunscreen would offer the same protection against melanoma, Dr. Holick told us, "There is no reason why it should not be as effective as other sunscreens."
Solar D is already on sale in Australia. Dr. Holick informed us that the sunscreen will be available in different SPF levels, and the lower the SPF, the more vitamin D will be produced.
The Solar D research was funded by Exposure Scientific, LLC/Nexidus, Ltd, Pty.
MNT reported last year on the development of sunscreens in which the amount of toxins which pass into the bloodstream is limited by using bioadhesive nanoparticles (BNPs).