Vitamin D is not truly a vitamin - our bodies can make it upon exposure to sunlight, and in it's active form, it is considered to be a hormone (specifically it has hormone-like effects on mineral absorption, bone mineralization and some secretions). Scientists are discovering that Vitamin D has more to it than just supporting bone and muscle health (it is extremely important in maintaining bone density). Everything from prevention and treatment of some cancers (has been found to have anti-tumor properties), Type 1 Diabetes, MS and cardiovascular disease and more. Vitamin D effects many body systems and functions - more than 30 different body tissues contain receptors for the active Vitamin D hormone, calcitriol. Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as an increased susceptibility to infection. Researchers are also finding that much higher levels of Vitamin D are required for optimal health than previously thought.
Studies show that the farther you live from the equator, the greater the risk they have of dying from breast, colon, ovarian, and prostate cancer. They are even showing that taking vitamin D supplements may cut the risk of pancreatic cancer nearly in half.
The classic deficiency disease of Vitamin D in children is rickets, characterized by stunted growth, delayed tooth development, weakness and irreversible bone deformities. If you think rickets is a thing of the past, children in the US are being treated for rickets due to Vitamin D deficiency. In adults, hypocalcemia (low levels of blood calcium), osteomalacia (reduction of the mineral content of the bone), and osteoporosis (reduction in total bone mass) are associated with Vitamin D deficiencies.
What can you do about it?
It is possible to make all the Vitamin D you need from the sun, depending on how close the equator you are, the season, and your skin colour. We do have the ability to store Vitamin D, and to a certain extent, we can get by with more sun in the summer and less in the winter. However, for us living above the 49thparallel (generally the Canada/USA border), adults can expect their serum levels to drop to the lower end of the normal range, or even below, during winter months. In Edmonton, “Vitamin D Winter” lasts from about October to March. Infants and children have limited Vitamin D reserves, so they need a supplement or fortified food source in regions farther from the equator.
Adult recommendations on getting enough Vitamin D from the sun include 10-15 minutes a day of mid-morning to late afternoon sun on as much exposed skin as possible including the face and hands (this is for light-skinned people). Darker-skinned people need thirty minutes to three hours daily, depending on skin colour! At the same time, we need to be aware of over exposure which can increase our risk of skin cancer. For us light-skinned folk, if you’re getting pink – it’s too long and time to get in the shade. Infants and children cannot depend on adequate skin exposure, especially during the winter months.
In Alberta, you'll be hard pressed to find any doctor that will order blood work to confirm your Vitamin D status - the official response is that they know everyone is deficient. Alberta Health recommends that everyone supplement.
Food generally is low in Vitamin D. The richest food sources are fish liver oils and fatty saltwater fish such as sea bass, halibut, tuna, cod and herring. Free range egg yolks are also a good source. Milk is also fortified with Vitamin D, however, I generally do not recommend any food item that needs to be fortified to make it “better”.
There are two forms of Vitamin D; D2 which is generally made from yeast, and then D3 which is made from the skins of sheep, cows and pigs as well as from sheep’s wool. Researchers have found that D2 is about 60 percent as effective as D3 in raising serum Vitamin D levels. Vegetarians should take this in to account and adjust their intakes accordingly. As with any supplements, you get what you pay for – so stick with high end practitioner grade brands such as Genestra, Prairie Naturals or SISU.
Health Canada has recommendations depending on your life stage, however most supplements come in 1000iu doses for adults. The Vitamin D council has their own recommendations, but either way – check with your doctor first before beginning any supplement program! I usually recommend a product that has D3as well as Vitamin K2– the K2 helps in the absorption and use of calcium and phosphorus – essentially over supplementation with D3alone can result in problems of excess calcium in the blood.
*Symptoms of too much vitamin D include nausea, loss of appetite, headache, diarrhea, fatigue and restlessness.
If you need help determining your optimal supplementation, for Vitamin D and more, make sure to check out my Custom Supplement Planning!