Vitamin D3 (also known as cholecalciferol) is a fat-soluble vitamin that is naturally synthesized by the body when the skin is exposed to sunlight. It was first described in 1936 and is on the World Health Organization’s list of essential medicines. You can look at the name cholecalciferol and see that it has something to do with calcium. It’s called fat-soluble because it will disperse throughout the body and store in your fat cells. Normally, your body does not produce vitamins. Vitamin D is the only one you can make naturally in your own body. Your body needs this nutrient for building and maintaining strong, healthy bones. Without vitamin D3, you may develop soft, thin, brittle bones that can lead to fractures. Most people know that you need calcium for strong bones, but did you know that you can’t absorb calcium unless vitamin D3 is there, too? That’s why you need sunlight. It’s the sunlight that stimulates your cells to start producing vitamin D3. More specifically, your body needs those UVB rays. However, there are a few factors that can affect how well your body can accept UVB, absorb it, and have it work like it should in your body such as:
- The strength of the sun which depends on:
- The time of day (obviously it should be during the day, preferably when the sun is shining the strongest)
- Season (is it a full sun summer day or a dark, dreary day in the winter)
- Altitude (how close to the sun you are based on sea level)
- Latitude (how close do you live to the equator)
- Cloud cover
- Your age
- Your skin tone (pigmentation)
- How much skin you have exposed, and
- How much sunscreen you put on and how well it blocks UVB rays (SPF)
Everyone needs vitamin D3 and we can all make it naturally in our bodies by getting enough exposure to the sun’s UVB rays. The amount of time you need to sit outside in the sunshine depends on the factors listed above but around 5-30 minutes 2x/week should recharge your D3 battery. To make it easy to remember, go out every SUNday for some fresh air and sunshine and every Wednesday (hump/slump day) to recharge. It’s interesting to note that many people who suffer from depression also have a Vitamin D3 deficiency. Although you do need to be cautious when sunbathing, don’t worry about overdosing on UVB. Your skin will naturally reach an equilibrium and eventually start degrading the excess as fast as it is created but you can overexpose your skin. We’ve all had those sunburns and none of us want skin cancer so if you haven’t been out in the sun for a while, you may need to get used to it slowly, starting with just 5 minutes at a time and working your way up over a week or two. However, not everyone can go out and get some sun. You also can get UVB from tanning beds and light bulbs. There are many people that fail to get enough UVB light who fit into this category such as:
- The frail
- The elderly
- The morbidly obese
- Anyone who is housebound
- Those who live in the Northern latitudes
- Those who work long hours indoors and
- Those who work night shift and sleep during the day
So how do you know if your vitamin D3 levels are good or if you have a deficiency? A simple blood test can give you and your doctor the answer. Most labs have similar but slightly different paraments but most often a level of 20 nanograms/milliliter to 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency. Vitamin D deficiencies are found in people with rickets, familial hypophosphatemia, hypoparathyroidism, and Fanconi syndrome. If you find out that you have a vitamin D deficiency, your doctor may advise you to take a vitamin D supplement and come back for a follow-up to keep an eye on your D3 levels. If it is warranted, a very large “loading” dose also may be given.
The Recommended Dietary Allowance (RDA) for vitamin D is:
- 400 IU* for infants up to 1 year
- 600 IU for adults up to age 70
- 800 IU for adults 70+
This varies by country and makes sense because those who live nearer to the equator have greater access to full sunlight for longer periods of time. *IU = International Units
There also are some drug interactions that you may need to talk to your doctor about before taking a vitamin D3 supplement. These include medicines that are listed as anticonvulsant, cholesterol lowering, weight loss, heart/blood pressure, steroid, stimulant laxative, and psoriasis medications.
If you are a vegan or vegetarian, be aware that industrial production of vitamin D3 is made by extracting lanolin from sheep’s wool. After cleaning, the cholesterol and waxes are extracted from the wool grease and undergoes a 4-step process to make vitamin D3 the same way your skin makes it. It is irradiated with UVB light, unwanted compounds are removed, and a resin is left behind. For vegans, there are plant-based sources of vitamin D3 supplements.
There are a few foods that contain vitamin D3 such as fish, beef liver, eggs, and cheese. It also can be found in fortified foods such as milk and yogurt. Vegans and vegetarians beware, it is primarily an animal by-product. Check the labels for vitamin D3 and/or cholecalciferol. Most people will choose to take a supplement and many of the over-the-counter (OTC) vitamin D3 supplements will be in the range of 1,000 IU to 10,000 IU. Let your doctor recommend your dose. Excessive doses can cause vomiting, constipation, weakness, and confusion and supplementation may not be effective in people with severe kidney disease.
Vitamin D3 is essential for strong healthy bones but it also may play a vital role as an anti-inflammatory, antioxidant, a neuroprotectant that supports your immune system, muscle function and brain cell activity. Studies are showing it to be a very beneficial vitamin for the human body, possibly even decreasing some types of cancer. However, much more research is needed in these areas. Be sure to go out and get some fresh air and sunshine, recharge your vitamin D3 stores and have a great day!
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