How Much Sun for Vitamin D?
During winter many of us don’t spend much time outside and when we do we are covered up. While, here in Queensland where I live, our winter is our dry season and we often have lovely sunny days and the angle of the sun still allows some vitamin D synthesis. Despite this, many people spend too much time indoors throughout the seasons, so it can hard for them to make adequate vitamin D.
Many patients that I test in the clinic come back deficient for vitamin D, even when they are apparently getting lots of sunshine. With vitamin D being a very important nutrient for a whole range of health issues, in particular a strong and healthy immune system, it is important that we get enough.
So what is the optimal level for Vitamin D?
There has been much debate about the optimal level for vitamin D. The standard ranges have not been changed for many years, despite evidence that humans living outdoors and exposed to plenty of sunshine would naturally have much higher levels than the standard 50nmol/L range quoted as normal.
The interesting thing about vitamin D is that the body will only make as much as it needs, and when exposed to more sun, it turns the UV sunlight preformed compounds into other molecules, including anti-cancer compounds! So we have a very cool inbuilt mechanism to naturally protect ourselves from UV damage and cancer.
It follows, that people who naturally get plenty of sun and opportunity to make vitamin D, are probably going to have the right amount of vitamin D for optimal health. The research also attests to this fact, showing that those getting lots of sun all tend to sit around 140-160nmol/L. I have found this in my clinic many times, the surfers and gardeners all tend to have great vitamin D levels!
New scientific consensus recommends an optimal range of vitamin D for general health is 100-150 nmol/L (40-60 ng/ml), based on overwhelming evidence about the association between vitamin D and many diseases. There is also evidence that levels above 150 nmol/L may provide additional benefit for prevention of breast and other cancers as well as treatment of diseases such as psoriasis, asthma and rheumatoid arthritis. Levels above 200nmol/L are probably excessive and normally only get that high through over-supplementing, not over-sun exposure.
Getting it the natural way – from the sun!
As we have seen, the best and most natural way to get vitamin D is by exposing your bare skin to sunlight (ultraviolet B rays). This can happen very quickly, particularly in the summer when the sun is directly overhead. The angle of the sun to your skin determines whether vitamin D can be made efficiently or not. This is why in winter, when the sun is lower and closer to the southern horizon, we find it harder to get enough UV rays.
You don’t need to tan or burn your skin to get vitamin D. You only need to expose your skin for around half the time it takes for your skin to turn pink and begin to burn. It is important to always avoid getting sunburnt as this is damaging and is linked to some skin cancers.
But just how much vitamin D is produced from sunlight and how long do you need in the sun to get your daily intake? Well this depends on the time of day, where you live in the world and the color of your skin. Also, remember that the more skin you expose the more vitamin D is produced.
Winter exposure must occur during midday hours to maximise the sun’s UV rays.
Darker skins and southern latitudes require increased time.
|
Skin Type |
Skin color | Skin characteristics |
| I | White; very fair; red or blond hair; blue eyes; freckles | Always burns, never tans |
| II | White; fair; red or blond hair; blue, hazel, or green eyes | Usually burns, tans with difficulty |
| III | Cream white; fair; with any eye or hair color; very common | Sometimes mild burn, gradually tans |
| IV | Brown; typical Mediterranean Caucasian skin | Rarely burns, tans with ease |
| V | Dark Brown; mid-eastern skin types | Very rarely burns, tans very easily |
| VI | Black | Never burns, tans very easily |
Winter Sun Exposure for Optimal Vitamin D in South East Queensland **
- Fair Skin – around 7 mins each day during midday
- Dark Skin – 30-60 minutes each day during midday
So remember to grab some extra sunshine and be sure to not wash the precious oils of your skin with body soaps
and washes and just wash the dirty bits. The oils in your skin which trap the UV rays and make vitamin D will be easily washed away with soap and water…along with over use of sunscreen, this is another reason why we have low vitamin D levels in this modern era of obsessive hygiene!
If you are unable to get enough sun due to your work or activities being based indoors, a supplement is normally required to maintain good vitamin D levels. I like to use the bioactive form, which is called calcifediol, which is the vitamin D compound that your liver makes from precursors formed from sun exposure. It is particularly good if you have genetic issues with conversion of vitamin D and can help get levels up quickly. Otherwise, if you grab a standard supplement (hydroxycalciferol) you will normally need at least 3000-5000iu per day to correct a deficiency.
Source: http://www.vitamindcouncil.org/
Information from “Vitamin D and Health in Adults in Australia and New Zealand: Position Statement 2012″
