Sunscreen and Vitamin D: What You Need to Know

Judy Gerstel | June 14th, 2017

Worried that your sunscreen may be blocking your intake of Vitamin D?

It’s definitely the season to slather on the anti-sun stuff.

And take note: clouds are not sunscreens.

But studies show that, even when we use sunscreen, we’re not terribly efficient about it.

And that’s why we still get some of the Vitamin D from the sun in summer, even if we’re heavily into the Coppertone.

Here’s why:

* Sunscreen, by definition, screens out most of the sun’s harmful ultraviolet rays – but not all.  It’s not “sunblock.”

* If you use a product with an SPF 30, for example, one-thirtieth or 3.3 per cent of the radiation, the majority of which is UVB, is transmitted.

* Sunscreens are almost never applied in a concentration that provides the level of protection tested and advertised on the bottle or tube.

* The tested level that determines the SPF is 2 mg. per centimeter squared. Studies have found that most people use only about 0.5 mg.

* That means a sunscreen supposedly providing SPF 16 protection is actually providing only SPF2 when the typical 0.5 mg is applied.


* Also, coverage is not even because the lotions and potions accumulate in the furrows of the skin, leaving the ridges less protected.

* Sweating, coming into contact with sand, swimming or engaging in vigorous activity can remove most of the sunscreen and people aren’t all that careful about replacing it in a timely fashion.

* Rarely are all exposed body parts covered with sunscreen. One study, for example, found that adults using sunscreen on their children in summer often missed the ears, neck, feet and legs.


* Even if you are getting some “D” from the sun, however, it may not be enough, especially because aging skin is less able to process the previtamin D3 (which the body turns into Vitamin D).

* Researchers compared the amount of previtamin D3 produced in skin from 8- and 18-year-old subjects with the amount produced in skin from 77- and 82-year-old subjects. They found that aging can decrease by greater than twofold the capacity of the skin to produce previtamin D3.

* The best way to top up your intake of “D”: eat fatty fish like salmon, tuna, mackerel (and fish oil); beef liver; cheese, egg yolks and and “D” fortified foods, including some dairy products, orange juice, soy milk, and cereals.

* It’s also a good idea to ask your doctor to check your “D” levels as part of annual physical blood tests.