Five health benefits of vitamin D that might surprise you

While we all know that supplementing vitamin D in the winter can decrease your chances of catching a cold or flu, many of us may not realize that the first rays of spring sunshine should not come as a cue to put your vitamin D away with your winter jacket. Although more sunlight means we'll make more vitamin D, I still recommend taking at least 2,000 IU daily. And here’s why:

1. It improves muscle function If you have chronic pain you may want to reassess your vitamin D levels.

New research shows, for the first time, a link between vitamin D and muscle function -- including recovery from exercise and daily activities. It also explains why lower levels can lead to physical fatigue. Similar research done with adolescent girls found that vitamin D is positively related to muscle power, force, velocity and jump height.

And while you may not be too worried about your jump height, this research is relevant if you find it hard to even get to the gym -- let alone hit your personal bests while you're there.

2. It blunts your appetite Beyond the clear impact on our mood, gloomy pre-spring weather can indeed make us fat. We produce vitamin D when our skin is exposed to the ultraviolet B (UVB) rays in bright sunlight. Beyond the established immune-enhancing benefits, rising vitamin D levels are also known to activate the production of leptin, which helps us slim down by signalling our brain and our stomach.

A study from Aberdeen University found that adequate levels of sunlight can significantly reduce obesity. After monitoring more than 3,100 post-menopausal women living in northeast Scotland over a two-year period they discovered that women who had the highest BMI also had the lowest amounts of vitamin D in their blood.

3. It can protect lung function The sunshine vitamin will not only help you feel better, you'll breathe easier too. According to a new study from researchers in Boston, vitamin D deficiency is associated with worse lung function and more rapid decline in lung function over time in smokers. This research suggests vitamin D may protect against some of the effects of smoking on lung function. The number one protector? Not smoking!

4. It can help you shed your winter weight Vitamin D has been proven to lower insulin, improve serotonin levels, enhance the immune system, control appetite and even improve fat-loss efforts.

A study completed by a team at Massey University showed women who were given a daily dose of 4,000 IU of vitamin D3 showed improvements in their insulin resistance after six months of supplementation.

If that’s not enough, research from the University of Minnesota found that higher vitamin D levels in the body at the start of a low-calorie diet improved weight-loss success. Scientists determined that as vitamin D increased in the blood, subjects ended up losing almost a half-pound more on their calorie-restricted diet.

5. It can lower blood pressure A 2012 study, presented at the European Society of Hypertension meeting in London, shows that vitamin D supplementation can help lower blood pressure in patients with hypertension. Similarly, additional research found that vitamin D deficiency in premenopausal women may increase the risk of developing high blood pressure even 15 years later – certainly a great reason to your levels optimized today for healthy aging.

Bottom line: It’s not all made equal Despite all the health benefits, heading to the supplement store and picking out a vitamin D supplement blindly isn’t enough. You have to choose wisely.

New research funded by the Biotechnology and Biological Sciences Research Council (BBSRC) has shown that vitamin D3 supplements could provide more benefit than their close relative vitamin D2. The researchers analysed the results of 10 separate studies, involving more than 1,000 people, comparing the health benefits of vitamin D2 and D3, and found "a clear favouring" of vitamin D3 supplements in raising vitamin D serum levels in humans.

If you flip the label around, you can look for it to say D3 versus D2. If you prefer liquid, place the drops directly under your tongue for best absorption.

To find out more about how you can maximize your vitamin D levels visit the Vitamin D Council.

Natasha Turner, N.D. is a naturopathic doctor, Chatelaine magazine columnist, and author of the bestselling books The Hormone Diet and The Supercharged Hormone Diet. Her newest release, The Carb Sensitivity Program, is now available across Canada. She is also the founder of the Toronto-based Clear Medicine Wellness Boutique. For more wellness advice from Natasha Turner, click here.