The sunshine vitamin! This wonderful fat-soluble vitamin, often referred to as a steroid hormone, helps to strengthen bones, boost the immune system and maintain proper body weight. In this post, we will discuss how to get it, how much you need and what forms are best....but first, let's delve into the amazing things it does for our bodies!
Vitamin D is essential for our bodies to absorb and utilize calcium and phosphorus, two minerals needed for the maintenance and structure of healthy bones. We used to think straight calcium was the cat's meow when it came to preventing bone disease, but now we know that without Vitamin D along with the calcium, we can very easily end up with demineralized and weakened teeth and bones.
This is how the dance of Vitamin D and calcium works: the active form of vitamin D (calcitriol) increases calcium absorption in the intestines and decreases calcium excretion in the urine. It is like a gatekeeper that says, “absorb more and excrete less—we need it!” This ensures there is enough calcium for muscle contraction, maintenance of blood pressure, and bone health. When there is not enough Vitamin D in the body, calcium absorption decreases significantly. The bones may get robbed of calcium to provide the muscles and blood with the amount of calcium needed to function properly. This can result in osteoporosis or soft weak bones (osteomalacia).
According to the Vitamin D Council "Use of Vitamin D appears to be a better option for reducing dental caries than fluoridation of community water supplies, as there are many additional health benefits of Vitamin D and a number of adverse effects of water fluoridation such as fluorosis (mottling) of teeth and bones." [I]
Weston A. Price, author of Nutritional and Physical Degeneration, was a dentist who studied the diets and nutrition of various cultures. He found that primitive people who consumed raw milk and organ meats were some of the most attractive and healthy people in the world. They had beautiful straight teeth, well-formed bone structure, and excellent health. Raw milk, organ meats, and root vegetables consumed by these cultures are phenomenal sources of fat-soluble vitamins A, D, E, and K, which are all essential for strong bones and teeth. He also found that when a modern Western diet of flour, sugar, and modern processed vegetable fats was introduced to these cultures, health declined rapidly [III].
For those who are willing to consume foods rich in fat-soluble nutrients, their diets will support healthy teeth and bones, so that fluoridation and additional Vitamin D is not necessary. For those who have been diagnosed with Vitamin D deficiency, and who find that changing their diets to include the nutritious foods mentioned in this section is not an option, Vitamin D supplements do have their place and can serve these people well.
Vitamin D2 (Ergocalciferol) vs. D3 (Cholecalciferol)
There are two forms of Vitamin D, D2 and D3. Vitamin D2 is derived from fungal or plant sources by activating ergosterol with ultraviolet light. It is not naturally present in the human body or other vertebrates, and is therefore not well absorbed. Although doctors still prescribe supplemental Vitamin D2, Vitamin D3 is the preferred form recommended by the majority of experts. D3 is found in animal foods and is made in the skin when we are exposed to sunshine. Supplemental forms contain the same substance that is produced in our skin when we are exposed to sunlight. This is usually derived from either cod liver oil or lanolin.
Vitamin D and Sunlight
Since Vitamin D can only be found in a few foods such as liver and fatty fish (herring, mackerel, salmon, sardines and tuna), we must be sure to expose ourselves to enough sunlight. Vitamin D is produced by synthesizing cholesterol in the skin when exposed to sunshine. While it is easily obtained in warmer climates—latitudes nearest the equator, it is difficult to come by in places like Alaska where people live in low light for a long period of time during the year. In areas such as this, people must consume an abundance of fatty fish and liver to be sure to get this nutrient. Vitamin D supplementation may be necessary for these folks living in northern latitudes where sun exposure is limited.
It’s absolutely incredible how fast adequate levels of Vitamin D can be restored by sunlight. In fact, the human skin can produce approximately 10,000 IU of Vitamin D in response to 10-30 minutes of summer sun exposure. That’s over 16 times your daily requirement for Vitamin D! Even better, six days of light sunlight exposure, without sunscreen, can make up for 49 days of no sunlight exposure because the body can store Vitamin D in that useful little love handle around your middle. During periods of sunlight, Vitamin D is stored in fatty tissues and then released when sunlight is gone. Another great thing about getting your Vitamin D from the sun is that your body knows when enough is enough. That uncomfortable feeling you get when you are on the brink of a burn is your body’s way of telling you that you’ve had your fill—all you have to do is listen. As your skin gets darker, it produces less Vitamin D and you can stay out longer without burning. Sunning yourself for 10-30 minutes is generally recognized as a safe way to obtain more than adequate amounts of Vitamin D.
Am I Vitamin D deficient?
While 10-30 minutes of sunlight a day seems like a breeze, the reality is that the majority of us aren't getting it! Deficiency symptoms may include fatigue, depression, aching bones, or gut issues. The best way to check is to have your physician run a blood test.
Sunscreen a Cause of Cancer?
Sunscreen, as it turns out, may not be as beneficial as you previously thought. In fact, almost half of the 500 most popular sunscreen products may actually increase the speed at which malignant cells develop. More and more studies are being released that connect sunscreen to increased risk of skin cancer [II]. Until a solution to this potential problem is introduced, it seems the best solution is to wear long sleeve shirts, light weight pants, and hats to protect you from overexposure to sunlight if you know that you are going to outside for an extended period of time.
How Much is Enough?
Recommended Daily Allowance (RDA):
600 IU for ages 1 to 70
800 IU for those over age 70
Upper Level Intake (UL) is 4,000 IU/day for children 9 years and older, adults, and pregnant and breast-feeding teens and women.
Many practitioners feel these recommended amounts are too low and that we should receive more. Vitamin D toxicity from foods is very difficult, and some professionals recommend daily doses up to 5000 IU. It has been documented that doses this high can be very beneficial for the treatment of certain conditions. I agree with this approach when indicated for certain individuals.
The only danger in supplemental Vitamin D is that it ends up stored in fatty tissue when adequate levels are reached, thus increasing the risk of toxicity when taken at ultra-high doses. Incredibly high doses can cause the intestines to absorb too much calcium, causing high levels of calcium in the blood. This can lead to calcium deposits in soft tissues such as the heart and lungs. Confusion and disorientation, kidney stones or kidney damage, nausea, vomiting, constipation, poor appetite, and weakness can also be symptoms of too much Vitamin D, although rare.
Food Sources of Vitamin D
To give you an idea of how much Vitamin D can be found in foods, here is a list:
1 slice braised liver (31,714 IU)
1-tablespoon cod liver oil (13,600 IU)
3 oz smoked Chinook salmon (583 IU)
1 ½ fillet of sockeye salmon (815 IU)
3 oz rainbow trout (645 IU)
½ fillet Atlantic or Pacific halibut (367 IU)
1 hard-boiled egg (44 IU)
You will soon notice that liver, cod liver oil, salmon, and eggs are powerful sources of fat-soluble vitamins. Many people think of the liver as a storage place for toxins but I think of it as a storage tank for nutrients! Yes, the liver filters toxins, but what it filters, it excretes to eliminate from the body. Plus, eating properly prepared liver is not only incredibly nutritious, but also delicious! Have you ever tried it?
[I] Grant, William. "Ultraviolet-B and vitamin D reduce risk of dental caries." Vitamin D Council, 2011. Web. May 2016. <https://www.vitamindcouncil.org/blog/ultraviolet-b-and-vitamin-d-reduce-risk-of-dental-caries/>.
[II] Rosso S, Sera F, Segnan N, Zanetti R. "Sun exposure prior to diagnosis is associated with improved survival in melanoma patients: results from a long-term follow-up study of Italian patients." PubMed. European Journal of Cancer, 2008 Jun; 44(9):1275-81. Web. May. 2016. <http://www.ncbi.nlm.nih.gov/pubmed/18406602>.
"Vitamin D: Fact Sheet for Health Professionals". U.S. Department of Health and Human Services. National Institutes of Health, 2016. Web. May. 2016. <https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/>.
[III] Weston, Price A. Nutrition and Physical Degeneration. Price-Pottenger Nutrition Foundation, 8th Edition. 2009.