Ever wonder why you feel more energetic during the summer than you do in the winter? This may be due to a lack of sunlight on dreary winter days. Your body uses sunlight to synthesize vitamin D which helps maintain bone health, regulate the immune system and influence mood.
What Are the Benefits of Vitamin D?
Vitamin D’s role in bone health is well-known. It regulates calcium and phosphorus absorption to build and maintain bone structure. A deficiency may lead to soft bones in children (rickets) and fragile, misshapen bones in adults (osteomalacia). Vitamin D’s role doesn’t stop here — it’s intricately involved in the immune, endocrine and cardiovascular systems. This is why a deficiency in vitamin D is linked to so many different maladies.
Vitamin D deficiency has been linked to depression and weight gain as well as more serious health problems including breast cancer, colon cancer, prostate cancer and heart disease. Studies show that people with higher levels of vitamin D have a lower risk of these diseases, although the studies don’t definitively prove that a lack of vitamin D causes them — or that vitamin D supplements lower the risk for developing these diseases.
How You Make Vitamin D from Sunlight
Your skin makes vitamin D during the sunny months. When 7-dehydrocholesterol, a cholesterol, comes into contact with ultraviolet B (UVB) rays on the skin it is converted into a precursor to vitamin D. The precursor is stored until your body needs to use that vitamin D to do its job. In the winter months, however, you can’t efficiently produce vitamin D, especially if you live above 37 degrees north (which, in the U.S., is anywhere north of Texas) or below 37 degrees south of the equator.
Getting Vitamin D Through Your Food
In addition to getting some sun exposure so that your body can make vitamin D, it’s also a good idea to get vitamin D in your diet. There aren’t too many foods that have the nutrient, but here are a few that are easy to add to your meals:
1. Mushrooms: These are the only vegan-friendly food source for vitamin D. Mushrooms make vitamin D from sunlight the same way our skin does. Wild mushrooms are your best bet because they have adequate exposure to sunlight. Commercially grown mushrooms may not get enough sunlight for vitamin D production unless they’re grown under UV lamps. Shiitake and button mushrooms both have vitamin D, although they contain significantly less than what you should be getting on a daily basis. For example, a serving of shiitake mushrooms has about one-thirteenth of your daily value.
2. Fatty Fish: Fatty fish like salmon (especially wild caught) and tuna are the best natural sources of vitamin D. A 3-ounce serving of Sockeye salmon has more than 100 percent of the daily value of vitamin D. Cod liver oil, sardines, mackerel and swordfish are also great sources (although swordfish is often contaminated with high levels of mercury, so eat it in moderation and avoid it altogether if you’re pregnant).
3. Egg yolk: Though they get a bad rap for cholesterol content, egg yolks aren’t all bad. In addition to being a great source of protein and vital amino acids, a single egg yolk has 10 percent of the daily value of vitamin D. So, instead of discarding all of the yolks when making your scramble, consider using one yolk (out of three or four eggs).
There are also several fortified sources of vitamin D. Milk products are often D fortified because vitamin D aids in calcium absorption. Many breakfast cereals are also fortified, so one way to get your daily dose is to have a bowl of cereal in the morning.