Updated: May 19
Vitamin D is a fat-soluble vitamin that has been in and out of the press throughout this pandemic because it is required to regulate our immune function. There are two main forms, known as vitamin D2 and D3.
D3 or cholecalciferol is formed in the skin when cholesterol is exposed to sunlight and by consuming animal-sourced foods. This is the reason Vitamin D is often called the sunshine vitamin. A mere 20 minutes of direct sunlight on bare skin can produce 10,000 International Units (IU) of vitamin D. Limiting factors such as your location, season, skin pigmentation, sunscreen, age, absorption ability and level of air pollution means there is no one size fits all prescription for intake. The National Cancer Institute has reported an increase in melanoma year over year, although the reason(s) remain unclear. Hedge by considering natural, chemical free sunscreen brands, avoiding oxybenzone and retinyl palmitate. Remember to check your skin and be mindful of any moles that are growing, sore/tender, have irregular color or border. Reach out to your dermatologist to investigate if you have concerns.
Vitamin D2 is obtained mainly through plant sources and fortified foods. An interesting fact about vitamin D is that in its active form it is closer to a hormone, like cortisol. This means it has a deeper function than a vitamin compound. In addition to supporting the immune system Vitamin D is necessary for promoting calcium absorption in the intestine, maintaining calcium and phosphate levels in the blood, cell growth, and neuromuscular function.
The ideal way to obtain vitamin D is through plenty of sunlight combined with nutrient dense whole foods. This isn’t easy for people who live at latitudes above thirty-seven degrees south of the equator who can not get enough UVB energy from the sun to make the vitamin D they need between November and February each year. These individuals may want to consider supplements with their primary physician. The further away from the equator you live, the less vitamin D producing UVB light reaches the earth’s surface in your area during the winter months. Although there are several reasons, we require D there is not a large selection of food sources for us to absorb it through.
If you are looking to increase your vitamin D levels through natural foods, consider wild-caught salmon as one of the best food source of vitamin D. A single serving contains more than the generally suggested Daily Value (DV). The highest food source is cod liver oil with one tablespoon providing up to 1360 IU. Sardines contain over 40% of the DV, and tuna contains just under 25%. Pasture-raised eggs are a good source of dietary vitamin D, with about 10% of the DV per egg. The vitamin D is concentrated in the yolk, so you will need to eat the whole egg to get it. Some mushroom species, including shiitakes, contain as much as 5% of the DV. You can see from the above list how easy it is to become deficient when relying on diet alone, especially for picky eaters.
If you have noticed the addition of vitamin D on milk and orange juice labels be aware that there are some drawbacks when relying on fortified sources alone. Individual nutrients added to processed foods are not absorbed as efficiently compared to nutrients naturally occurring in whole foods. This is because whole foods contain synergistic nutrients that work together to enhance the bioavailability and utilization of each other in our bodies. For example, milk that has been processed to remove the fat loses the fat-soluble vitamins A, D, and K. Although vitamins A and D are added back, our bodies cannot absorb them without a fat vehicle, nor can they function optimally without the assistance of vitamin K. Health care practitioners often refer to A, D and K as the winter triad for this reason.
In addition to decreased risk of flu, Vitamin D has been linked to improved cognition/moods, reduced inflammatory response, decreased risk of cardiovascular disease/osteoporosis and diabetes. If you are curious to know your own level of Vitamin D explore testing with your primary physician, Homeopath or Naturopathic Doctor. To set expectations,be aware that correcting a deficiency can take up to a year or more under medical supervision.
Fare thee well, @Kasyholisticgirl
Blog note: Target/optimal DV information is not listed in the article because supplementation/absorption is individual and should be done through blood testing as part of an individualized medical treatment plan. For additional context supplement 2,000-4,000 IU for maintenance. 5,000-10,000 IU under doctor supervision for deficiencies.