Tomorrow is June 20th – the summer solstice and longest day of the year!  The sun will reach it’s highest point in the Northern Hemisphere letting us experience its most direct rays and providing us with approximately 16 hours of daylight.  It is also the day we make the most vitamin D in the shortest period of time at our latitude provided we spend a bit of time outside.

Why is vitamin D so important to us?  Vitamin D is so critical to our survival we ensure our needs are met by manufacturing our own, but it can only be made in presence of sunlight.  Current research is just beginning to discover how essential vitamin D is to maintaining both physical and mental health.  Yup, sunshine really does make you happy!

Top 10 Vitamin D Facts

1. Vitamin D is produced by your skin in response to exposure to ultraviolet radiation from natural sunlight and is one of the most powerful healing chemicals in your body.
2. In order to produce vitamin D in the skin it must be free of sunscreen, sun blocks and clothing, all of which interfere with the process.  Even weak sunscreens (SPF 8) block your body’s ability to generate vitamin D by 95%. Sunscreen products can actually cause disease by creating a critical vitamin deficiency in the body.   Also, UV rays cannot penetrate glass. You don’t generate vitamin D when sitting in the sunshine if you are inside your car or at home.
3. The farther you live from the equator, the longer the exposure you need to the sun in order to generate vitamin D. Canada, the UK and most US states are far from the equator.  This means individuals living in these areas require more sunlight to manufacture adequate vitamin D.
4. Vitamin D regulates blood pressure, reduces stress and tension, relieves body aches and pains by reducing muscle spasms, reduces respiratory infections, helps in differentiation of the cells, aids in insulin secretion, helps fight depression, improves overall skin health by reducing wrinkles, makes skin soft, strong, and smooth, and improves cardiovascular strength by providing a protective lining for the blood vessels.
5. Sufficient levels of vitamin D are crucial for calcium absorption in your intestines. Without sufficient vitamin D, your body cannot absorb calcium, rendering calcium supplements useless.  It helps the intestine absorb nutrients, including calcium and phosphorus. This ensures strong bones and a strong immune system.  Vitamin D provides calcium balance in the body that prevents osteoporosis or arthritis.
6. The closer to the Earth’s poles you live, the more important it is to supplement with vitamin D during the winter months.  It is impossible for your body to manufacture adequate vitamin D with the sunlight available between the autumnal and vernal equinoxes.
7. People with dark skin pigmentation may need 20 to 30 times as much exposure to sunlight as fair- skinned people to generate the same amount of vitamin D. This is why prostate cancer is epidemic among black men—it is a simple but widespread sunlight deficiency.
8. It is nearly impossible to get adequate amounts of vitamin D from your diet. Sunlight exposure is the only reliable way to generate vitamin D in your own body.  A person would have to drink 10 tall glasses of vitamin D fortified milk each day just to get minimum levels of vitamin D into their diet.
9. Chronic vitamin D deficiency cannot be reversed overnight; it takes months of vitamin D supplementation and sunlight exposure to rebuild the body’s bones and nervous system.
10. It is impossible to generate too much vitamin D in your body from sunlight exposure: your body will self- regulate and only generate what it needs.

So, if we have the ability to make all we need, why are so many people vitamin D deficient?  We simply do not spend enough time outside.  This illustration shows the vitamin D levels of our ancestors and the responding change in vitamin D levels as our lifestyles have moved indoors.

Remember, our genes have not changed much since the earliest humans evolved and our modern needs closely match our ancestral capabilities.  We, as modern humans, do retain the ability to make nearly the same amount of vitamin D as our ancestral counterparts when our skin is exposed to UV stimulus.  But, as this graphic depicts, the amount of vitamin D we consider to be “normal’ is now far below the level we’ve evolved to have as our “normal”.

During the summer months when we have the greatest capacity to manufacture vitamin D, the sunscreen we use almost completely prevents this process by blocking the required UV stimulus.  During the winter months, when the sun’s rays are weakest, we’d have to stand outside all day naked to have a hope of manufacturing the vitamin D we require.  I don’t know about you but naked, winter, and outside are not things that go together!

What can we do to meet our needs all year round?   Between the autumnal equinox (autumn) and the vernal equinox (spring) try a Vitamin D3 supplement.  Vitamin D3 (cholecalciferol) is the form of vitamin D your body makes in your skin with a UV stimulus.  During the winter months the sun’s rays are simply not strong enough to provide the UV stimulus necessary to make vitamin D.  Supplementing with 1,000 – 5,000 IU of vitamin D3 will ensure your needs are met.  Remember vitamin D is a FAT SOLUABLE vitamin that REQUIRES DIETARY FAT to be absorbed and assimilated into your body!  From the vernal equinox (spring) to the autumnal equinox (autumn) spend 15 – 20 minutes outside without sunscreen between 10 am and 2 pm when the sun’s rays are the strongest.  The more skin you expose during this time, the more D you make.  On days you can not get outside, continue with your vitamin D3 supplement.

If you suspect that you might have a vitamin D deficiency speak with your doctor about getting a 25-hydroxy vitamin D test – also called the 25-OH vitamin D test or the Calcidiol 25-hydroxycholecalciferol test – as part of your routine blood work.  This test will accurately measure the level of active vitamin D circulating in your bloodstream and will help you assess your current vitamin D needs.

Related articles

• The Sun and You (nourishednutrition.com)