Why step out of the dark

Tuesday, September 9, 2008

Catch Some Healthy Rays
By Jon Herring

Have you ever noticed how you feel happier when you have a chance to sit or walk in the warm sun? Doesn't just going outside on a sunny day calm your nerves and lift your spirits?

By contrast, consider what happens and how you feel during the cold and dreary winter months. Many of us experience darker moods. We are more likely to become sick with colds and flu. We often gain weight and crave carbohydrates.

Then, come spring and summer, these symptoms magically disappear without treatment. Well, there is a reason for this.

Your body needs sunlight just like it needs nutrients. In many ways, your physiology is as closely linked to the sun as that of plants. Plants use sunlight to photosynthesize chlorophyll. By a comparable process your body uses sunlight to photosynthesize vitamin D -- a molecule that is vitally essential to almost every aspect of your biochemistry and physiology.

Decades of scientific research prove the importance of vitamin D. In addition to the noticeable lift it gives your mood, it also helps lower blood pressure, cholesterol and blood sugar; improves your immunity; regulates your weight; increases muscle strength; normalizes sleep cycles; and boosts brain function.

It has also been shown to prevent many chronic diseases, including the three biggest killers of our generation -- heart disease, cancer, and diabetes.

On the other side of the coin, a deficiency of vitamin D is clearly associated with increased risk of a long list of health conditions, including everything from Alzheimer's, Parkinson's and autism, to bone and muscle pain, behavior disorders, depression, gluten intolerance, arthritis, multiple sclerosis, infertility and tooth decay... just to name a few.

And here's why this should matter to you:

It is estimated that more than 90% of the population is deficient in this vital nutrient (technically, it is a hormone), at least part of the year. That means there is a good chance that YOU are deficient, putting your health at risk, including potentially doubling your risk of cancer. With fall and winter weather coming soon, this is something you should address right away.

There are several risk factors for vitamin D deficiency. The most obvious is your lifestyle and the amount of sunlight you are exposed to. If you work indoors, spend most of your time indoors, and get very little sunlight on your skin, you are almost certainly deficient.

Three to five days per week, you should aim for at least 15 to 20 minutes in the sunlight (with as much of your skin exposed as possible).

Where you live is also a factor. In the mid to higher latitudes, UV-B radiation is extremely limited during the fall, winter and spring. In his book, The UV Advantage, Dr. Michael Holick shows that any area north of 35° latitude (or south of the corresponding latitude in the southern hemisphere) will not receive enough UV radiation to trigger adequate vitamin D production for approximately six months out of the year. In the US, this is anywhere above Atlanta, Georgia.

That means even if you spend a significant amount of time outside, about half the year the sun is too low in the sky for your body to produce vitamin D. Likewise, if you usually wear sunscreen when you are exposed to the sun, you are likely to be deficient. A sunscreen with an SPF of 8 reduces vitamin D production by 95%!

Other risk factors for vitamin D deficiency include your age (as you age, you need more sun to produce vitamin D), your skin type (darker skin types need more sun to produce vitamin D), and even your weight (vitamin D becomes trapped in body fat and cannot exert its effects).

In any case, the only way to really know if you are deficient is to have your blood tested for levels of 25-hydroxyvitamin D, also called 25(OH)D. It's best to measure twice a year -- once at the end of winter when your levels are lowest, and once at the end of summer when your levels are highest. At the very least, you should get an annual measurement. The gold standard vitamin D test is from the company DiaSorin.

To get an idea of what "normal" is, let's look at populations living near the equator where we all evolved from. At or near the equator, the average person has vitamin D levels around 50 ng/mL. This is considered optimal.

Here are the generally accepted graduated levels of vitamin D deficiency:

Extreme deficiency: 20 ng/mL (high risk of various conditions)
Clinically deficient: below 32 ng/mL (increased risk of various conditions)
Borderline deficient: below 35 ng/mL
Acceptable: 35-45 ng/mL
Healthy: 45-55 ng/mL, or
Optimal: 55 ng/mL
Excess: greater than 100 ng/mL
Intoxication: greater than 150 ng/mL
Ideally, you want to maintain a healthy year-round level around 50 ng/mL. The question now is, how much vitamin D do you need... and how can you get optimal levels when the sun is low in the sky?

The government says if you are a male or female between 1 and 50 years of age, you need only 200 IU of vitamin D per day. But according to current research, the government is dead wrong on this point. The recommended daily allowance will only serve to prevent the most serious deficiency.

In one study performed at Creighton University in Omaha, researchers found that adults will use 3,000 to 5,000 units of vitamin D per day, if it is available to the body.1 In other words, the amount your body actually uses on a daily basis is 20 times more than the government says you need!

Also consider how much vitamin D your body makes when exposed to sunlight. During the summer months, if you expose most of your body to direct sunlight until your skin turns very slightly pink, your body will produce approximately 20,000 IU of vitamin D. This is 100 times greater than the recommended daily allowance (RDA).

After a review of numerous studies, it appears that 4,000 IU of vitamin D per day, from all sources, is about optimal. If you get some (but not a lot) of sun exposure, then you probably only need to consume about 2,000 IU per day from food and supplements.

Finally, let's address how to get enough vitamin D when you cannot get it from sunlight.

It is important to recognize that very few foods naturally contain vitamin D. Those that do, provide only a small amount. For example, a 3.5 ounce portion of salmon (one of the richest food sources) contains just 360 IU. The same amount of sardines contains 270 IU. One egg delivers just 25 IU. You should definitely be consuming these foods, but don't expect them to affect your vitamin D status very much.

Cod liver oil is the most concentrated natural food source of vitamin D. But cod liver oil also contains a significant amount of vitamin A. And too much vitamin A can be harmful. To get the vitamin D you need from cod liver oil, could mean that you are consuming too much vitamin A. That's why I strongly suggest taking fish oil for the omega-3s (fish oil has no vitamin D), and getting your vitamin D from sunlight and dedicated supplements.

Most people should supplement with vitamin D in the late fall, winter, and early spring. You should also consider supplementing year round if you have darkly pigmented skin, are over 65, if you're overweight, or if you just can't bring yourself to go into the sun without sunscreen.

You can start by adding a good quality multivitamin to your daily routine. But most multivitamins are only a start. The average multi contains 400 IU of vitamin D -- only about 10 to 20% of what you need.

There are two companies that make dedicated vitamin D supplements I would recommend -- Carlson's and Bio-Tech Pharmacal. Carlson's brand is carried in many health food stores and they have products that contain 2,000 or 4,000 IU in small, easy to take gel caps.

For larger amounts, consider Bio-Tech Pharmacal, a federally licensed, FDA approved manufacturer that produces pharmacological doses of vitamin D in 1,000, 5,000, and 5,0000 IU strengths.

However, please note: you should never take more than 5000 IU of vitamin D on a regular basis without consulting a physician and having your blood levels tested. You want to measure your vitamin D levels periodically to make sure that you bring your levels into a healthy range, without overdoing it.

Don't wait. Arrange today, to have your vitamin D levels checked. If they're low, it's easy to fix. By taking these steps in the wintertime, you can boost your vitamin D to a healthy level year-round and dramatically reduce your risks of many chronic diseases.

Reference

Heany RP, et al. Am J Clin Nutr 2003; 77(1): 204-10.
[Ed. Note: Dramatically reduce your risk of heart disease, cancer and diabetes... by spending just a few minutes each day in the sun? Yes you can! Achieving optimal vitamin D levels is one of the most important (not to mention one of the cheapest and easiest) ways to ensure great health. And Jon Herring and Dr. Al Sears tell you everything you need to know in their groundbreaking new book, Your Best Health Under the Sun.]