Get Up to 48% Off on Select Fermented Products Get Up to 48% Off on Select Fermented Products


Surprise! Vitamin D Can Help or Hinder Your Weight Management

Sun Exposure

Story at-a-glance -

  • A study of more than 4,600 women age 65 and older shows that having low vitamin D levels can contribute to mild weight gain. Women who had insufficient levels of vitamin D gained about two pounds more compared to those with adequate blood levels of vitamin D during the 4.5-year long study. Those with insufficient levels also weighed more at the outset of the study
  • More than half of obese adolescents seeking weight loss surgery are deficient in vitamin D, according to a recent study. Eight percent were found to have severe deficiencies, and teens with the highest BMIs were the most likely to be vitamin D deficient. Less than 20 percent had adequate vitamin D levels
  • Two newer vitamin D tests, designed to be faster and less expensive than previous tests, appear to be inaccurate more than 40 percent of the time, according to preliminary study findings. The Abbott Architect test produced results that were either 25% too high or too low, about 40% of the time. The Siemens Centaur2 test was either too high or too low in 48% of samples, compared to a previously established vitamin D testing method
  • An inexpensive and convenient way to get your vitamin D levels tested on a regular basis is to join the GrassrootsHealth D*Action Project, which provides accurate home-testing kits

By Dr. Mercola

Vitamin D, once thought to influence little more than bone diseases such as rickets and osteoporosis, is now recognized as a major player in overall human health. Most recently, new studies suggest that your vitamin D status can even help or hinder your weight management, which I'll review below.

It's a tragedy that dermatologists and sunscreen manufacturers have done such a thorough job of scaring people out of the sun. Their widely dispersed message to avoid the sun as much as possible, combined with an overall cultural trend of spending more time indoors during work and leisure time has greatly contributed to the widespread vitamin D deficiency seen today.

Vitamin D is actually not a vitamin at all but a potent neuroregulatory steroidal hormone, shown to influence about 10 percent of all the genes in your body. We now know this is one of the primary reasons it can impact such a wide variety of diseases, including:

Cancer Hypertension Heart disease
Autism Obesity Rheumatoid arthritis
Diabetes 1 and 2 Multiple Sclerosis Crohn's disease
Flu Colds Tuberculosis
Septicemia Aging Psoriasis
Eczema Insomnia Hearing lossex
Muscle pain Cavities Periodontal disease
Athletic performance Macular degeneration Myopia
Pre eclampsia Seizures Fertility
Asthma Cystic fibrosis Migraines
Depression Alzheimer's disease Schizophrenia

Vitamin D Deficiency Contributes to Weight Gain in Older Women

A new study of more than 4,600 women age 65 and older shows that having low vitamin D levels can contribute to mild weight gain.1 Previous research has already showed that obese individuals tend to have low vitamin D levels. Women who had insufficient levels of vitamin D gained about two pounds more compared to those with adequate blood levels of vitamin D during the 4.5-year long study. Those with insufficient levels also weighed more at the outset of the study.

According to

"The study can't say whether low vitamin D is causing the weight gain or just reflecting it. 'The study is the first step that we need to evaluate whether vitamin D might be contributing to weight gain,' [lead researcher Erin] LeBlanc says. But there are some theoretical ways that low vitamin D could contribute to weight gain, she says. Fat cells do have vitamin D receptors. 'Vitamin D could affect where fat cells shrink or get bigger.'"

Here, vitamin D levels above 30 nanograms per milliliter (ng/ml) were considered "sufficient." As I've previously reported, based on the latest vitamin D research this is still far below optimal, so it's difficult to say what the outcome might be if you were to actually optimize your levels by getting your blood level above 50 ng/ml. Still, despite this low "sufficient" level, 80 percent of the women in the study were found to have insufficient levels, meaning below 30 ng/ml. This gives you an idea of just how widespread this problem really is.

Vitamin D Deficiency Common among Adolescents Evaluated for Weight Loss Surgery

A second study found that more than half of obese adolescents seeking weight loss surgery are deficient in vitamin D. Eight percent were found to have severe deficiencies, and teens with the highest BMIs were the most likely to be vitamin D deficient. Less than 20 percent had adequate vitamin D levels. The research correlates with previous studies showing vitamin D deficiency in adults seeking bariatric surgery. (The results were presented at The Endocrine Society's 94th Annual Meeting in Houston on June 26.)

According to Science Daily:3

"'This is particularly important prior to bariatric surgery where weight loss and decreased calcium and vitamin D absorption in some procedures may place these patients at further risk,' said study lead author Marisa Censani, M.D., pediatric-endocrinology fellow at Columbia University Medical Center, in New York City.

...'These results support screening all morbidly obese adolescents for vitamin D deficiency, and treating those who are deficient, particularly prior to bariatric procedures that could place these patients at further risk,' Censani said."

In the US, bariatric weight-loss surgery, such as gastric bypass surgery, is becoming increasingly common among all age groups, including children. Gastric-bypass surgery involves surgically removing a section of your stomach, which limits the amount of food it can hold. However, this procedure is fraught with risks, and maintaining proper nutrition post-surgery is a common challenge that can result in malabsorption syndromes. It's important to remember that vitamin D, as well as vitamin A, E, and K are fat-soluble, and need a certain amount of healthy fat to be absorbed properly.

What is the OPTIMAL Level of Vitamin D?

The ideal way to optimize your vitamin D levels is through adequate, safe sun exposure or using a safe tanning bed. However, whether you're tanning or using a vitamin D supplement, it's important to get your vitamin D levels tested to ensure you're within the optimal range of 50-70 ng/ml. For more information about proper sun exposure and how to determine whether you can actually get enough vitamin D from the sun at your location during different times of year, please see this previous article. As mentioned earlier, the "normal" 25-hydroxyvitamin D lab values are typically between 20-56 ng/ml. "Sufficient" levels are often considered to be around 30 ng/ml, as in the studies above.

However, this range is too broad to be ideal, and too low to support optimal health.

Beware that any level below 20 ng/ml is considered a serious deficiency state, increasing your risk of as many as 16 different cancers and autoimmune diseases like multiple sclerosis and rheumatoid arthritis. The OPTIMAL value that you're looking for is 50-70 ng/ml. Keeping your level in this range, and even erring toward the higher numbers in this range, is going to give you the most protective benefit.

But how do you get within that range?

While vitamin D experts typically recommend 35 IU's of vitamin D per pound of body weight, it's important to understand that there's no one dosage recommendation that will be applicable for everyone. The only way to determine how much vitamin D you really need is to get your levels tested at regular intervals to make sure you're staying within the optimal range of 50-70 ng/ml, and adjust your dosage accordingly. If you're supplementing, you may find that you don't need to supplement during the summer, if you're getting sufficient amounts of sun exposure, for example. But you won't know if you don't get your levels tested.

What is the OPTIMAL Way to Obtain Vitamin D?

There is simply no question in my mind that you were designed to receive your vitamin D from ultraviolet B exposure on your exposed skin and ideally this should come from the sun. For virtually the entire history of the human race this is how vitamin D was obtained. Although vitamin D is in some animal foods it is in relatively low quantities and to my knowledge there are no known ancestral populations that thrived on oral vitamin D sources. Although we can absorb vitamin D orally because it is a fat soluble vitamin, there is strong emerging research that suggests this lacks many of the benefits of vitamin D.

The majority of the research documenting the benefits of optimized vitamin D levels was done with those that had not taken oral vitamin D but had increased their levels naturally through exposure to the sun. I personally have not taken any oral vitamin D for over two years and have been able to consistently keep my levels over 60 ng/ml. This is partly related to the fact that I work in a sub-tropical environment in the winter.

If I could not do that there is no question that I would still not use oral vitamin D but would use a high quality safe tanning bed that used electronic ballasts that did not emit any dangerous EMF.

How to Know if You're Getting Vitamin D from Your Sun Exposure

The caveat here is that not all sun exposure will allow for vitamin D production. The key point to understand is that sunlight is composed of about 1500 wavelengths, but the only wavelength that makes your body produce vitamin D are UVB-rays, when they hit exposed skin. The UVB-rays from the sun must pass through the atmosphere and reach where you are on the earth in order for this to take place. This obviously does not occur in the winter for most of us, but the sun's rays are also impeded during a fair amount of the year for people living in temperate climates.

So how do you know if you have entered into the summer season and into the time of year, for your location, where enough UVB is actually able to penetrate the atmosphere to allow for vitamin D production in your skin?

Due to the physics and wavelength of UVB rays, they will only penetrate the atmosphere when the sun is above an angle of about 50° from the horizon. When the sun is lower than 50°, the ozone layer reflects the UVB-rays but let through the longer UVA-rays.

So the first step is to determine the latitude and longitude of your location. You can easily do this on Google Earth, or if you are in the U.S. you can use the TravelMath Latitude Longitude Calculator to find your latitude and longitude. Once you have obtained that you can go to the U.S. Navy site to calculate a table to determine the times and days of the year that the sun is above 50 degrees from the horizon.

Translated to the date and time of some places on the globe, it means for example: In my hometown of Chicago, the UVB rays are not potentially present until March 25, and by September 16th it is not possible to produce any vitamin D from the sun in Chicago. Please understand it is only theoretically possible to get UVB rays during those times. If it happens to be cloudy or raining, the clouds will also block the UVB rays. For a more detailed understanding of this, please view the following video, and/or read through the corresponding article.

Even Easier if You Have Apple System

Alternatively, if you have an iPhone or iPad you can download a free app called D Minder, which will make all the calculations for you. It was made by an Apple developer who was motivated to simplify the process after he watched the video above.

From a health perspective, it doesn't make much sense to expose your skin to the sun when it is lower than 50 degrees above the horizon because you will not receive any valuable UVB rays, but you will expose yourself to the more dangerous and potentially deadly UVA rays. UVA's have a longer wavelength than UVB and can more easily penetrate the ozone layer and other obstacles (like clouds and pollution) on their way from the sun to the earth. UVA is what radically increases your risk of skin cancer and photoaging of your skin. So while it will give you a tan, unless the companion UVB rays are available you're likely doing more harm than good and should probably stay out of the sun to protect your skin.

During the times of the year when UVB rays are not present where you live you essentially have two options: You can use a safe tanning bed or you can swallow oral vitamin D3.

Alternative to the Sun – A Safe Tanning Bed

During the summer months, you can generally get enough vitamin D from just spending some time outside every day. Under optimal environmental exposures your body can produce about 20,000 IU of vitamin D per day with full body exposure, about 5,000 IU with 50 percent of your body exposed, and as much as 1,000 IU with just 10 percent of your body exposed.

In the winter months however, and/or times of the year when insufficient amounts of UVB rays reach your location, you will most likely not get enough vitamin D. In that case, I recommend using a safe tanning bed, which is still better than oral vitamin D.

One of the caveats here is to make sure you're not being exposed to harmful EMF exposure. Most tanning equipment, and nearly all of the early beds from which these studies were conducted, use magnetic ballasts to generate light. These magnetic ballasts are well known sources of EMF fields that can contribute to cancer. If you hear a loud buzzing noise while in a tanning bed, it has a magnetic ballast system. I strongly recommend you avoid these types of beds and restrict your use of tanning beds to those that use electronic ballasts.

Warning: Newer Vitamin D Tests Often Inaccurate, Study Finds

Doctors are becoming increasingly aware of the importance of vitamin D. According to Medscape, vitamin D testing has increased six- to 10-fold over the last decade, and has become one of the most frequently ordered lab tests. However, it's important to know that there can be significant differences between available vitamin D tests, and according to a recent study, two newer tests appear to be inaccurate more than 40 percent of the time.

The findings are still preliminary and have not yet been peer-reviewed. The study was presented at the annual meeting of The Endocrine Society in Houston on June 23-26.4 According to

"Researchers say newer tests tend to overestimate the number of people who are deficient in vitamin D... The new tests, made by Abbott and Siemens, were approved by the FDA last fall. They're part of a wave of faster, less expensive tests designed to help laboratories keep up with a boom in demand for vitamin D testing... Holmes and his team wanted to see how well the new tests performed compared to an older, more expensive, and more time-consuming reference method... They ran blood samples from 163 patients on all three tests.

The Abbott Architect test was outside an acceptable margin of error – meaning that the results were either 25% too high or too low, about 40% of the time.

The Siemens Centaur2 test was either too high or too low in 48% of samples.

...The new tests use blood proteins called antibodies that bind to vitamin D. They're faster because they look for vitamin D in samples of whole blood. In the older, reference method, vitamin D is separated from the blood and measured. The older test can also measure two different forms of vitamin D: Vitamin D2... found in fortified foods and... high-potency supplements that doctors prescribe... and Vitamin D3, the form of the vitamin that the body makes naturally after skin is exposed to sunlight.

The newer test can't distinguish between the two different types of D.

Holmes says vitamin D2 seems to confuse the tests. He says the tests' inability to accurately measure that form of the vitamin means that doctors can't tell if their patients are getting any benefit from it or if they're taking their supplements as directed.

...In absolute numbers, the reference test showed 33 patients out of 163 were deficient in vitamin D, while the Abbott test showed 45 people were vitamin D deficient, and the Siemens test pointed to deficiency in 71 patients." [Emphasis mine]

Your Best Bet for Regular Testing: Sign Up with the D*Action Project

To avoid such testing problems and help you get on an inexpensive, regular testing schedule, I highly recommend joining the GrassrootsHealth D*Action Project6; a worldwide public health campaign aiming to solve the vitamin D deficiency epidemic through focus on testing, education, and grassroots word of mouth. When you join D*action, you agree to test your vitamin D levels twice a year during a 5-year program, and to share your health status to demonstrate the public health impact of this nutrient.

There is a $60 fee each 6 months for your sponsorship of the project, which includes a complete new test kit to be used at home (except in the state of New York), and electronic reports on your ongoing progress. When you finish the questionnaire, you can choose your subscription option. You will get a follow up email every 6 months reminding you "it's time for your next test and health survey."

This is probably one of the least expensive and most convenient ways to take control of your health. To join now, please follow this link to the D*Action sign-up.