Human Photosynthesis: How Longer Days Help Replenish Your Vitamin D
Unlike most vitamins, our bodies naturally generate vitamin D. When our skin is exposed to the sun—specifically ultraviolet UVB rays—a photochemical reaction (not unlike photosynthesis) occurs in our bodies, resulting in the creation of vitamin D.
But don’t use that as an excuse to stay out in the sun longer. UVB rays are the same ones that cause sunburn and can potentially lead to skin cancer if you’re overexposed.
Vitamin D and calcium are like Batman and Robin when it comes to bone health. Studies have shown that taking vitamin D and calcium supplements together help make your bones stronger than taking calcium supplements alone. This is because without vitamin D, your body doesn’t make enough of the hormone calcitriol, which aids in calcium absorption.
It turns out you aren’t imagining it: Seasonal Affective Disorder is real, and some scientists believe a lack of vitamin D is to blame. The further you live from the equator, the less sunlight you get in winter. If you live in the northern United States, you’re most likely not getting enough sunlight in the winter to accumulate your recommended daily amount of vitamin D.
Instances of vitamin D deficiency can lead to even worse afflictions than Seasonal Affective Disorder. In extreme cases, vitamin D deficiency can result in rickets, a softening of the bones that often leads to fractures and deformity.
Most people think of vitamin C when trying to fight off illness, but studies have also linked vitamin D deficiencies with an increased of risk of viral infections such as the flu and—historically—tuberculosis.
After noticing that people living closer to the equator had lower instances of certain cancers, scientists began to hypothesize that vitamin D may help prevent said cancers. Opinions differ wildly on this one (the National Cancer Institute has a good breakdown on the current state of the conflicting studies), but some research has suggested that vitamin D may help prevent colorectal, breast, cervical, and prostate cancers.
Now that you’ve seen some of the things vitamin D can do for your body, how can you make sure you get enough, especially if you find yourself spending winter in an overcast northern state? Well, vitamin D doesn’t naturally occur in many foods—but fortunately the foods it can be found in are often healthy and delicious.
Fatty fishes like salmon, tuna, and mackerel are great natural sources of vitamin D. And many dairy products, like cheese or yogurt, come fortified with the nutrient.
For many people—living close to or far away from the equator—supplements are a simple the way to ingest the necessary amounts of vitamin D.
If you are going to take supplements, be sure to stick to the recommended daily intake levels on the bottle. Vitamin D overdoses are extremely rare, but excessive intake has been linked with nausea, weakness, frequent urination, kidney problems, and excessive blood calcium levels. So stick to the recommended daily dose on the back of the bottle, and you should be fine.
If the new season has put a spring in your step, it might be because longer days naturally replenish your vitamin D. Your body needs this fat-soluble vitamin to function properly, as it affects many areas of your body, including your bones, brain, immune system, and muscles. But unlike many other vitamins, it’s easier to get your daily dose from an afternoon stroll than the foods you eat. Click through the slideshow to learn more about how vitamin D is one of the most important and fascinating nutrients you consume—and make!—on a daily basis.
The GOOD Wellness Project is an eight-month collaboration with Walgreens and Vitamin Angels, in support of the #100MillionReasons initiative to bring vital micronutrients to 100 million malnourished children across the globe by 2017. In order to gain clarity and raise awareness about health and well-being, we are diving into vitamins, alternative medicine, the effects of the environment on our body systems, and more, to provide a deeper understanding of what it looks like to live a healthy, well-balanced life.