A Winter Essential: Vitamin D

Posted on by Paula Gallagher

Coats, mittens and hats are a must for cold winter months, but you may want to add another item to the list of winter must-haves – vitamin D. Vitamin D is also one of the most discussed vitamins relative to deficiency, especially when it comes to winter.

There are many claims made about vitamin D, so let’s step back and isolate what research supports. Vitamin D is a fat-soluble nutrient. The sun is the primary source of the nutrient, but it is also found in cod liver oil, swordfish, salmon, canned tuna, beef liver, egg yolks, sardines and fortified dairy products.

Let's look at our main source of vitamin D, the sun. When your skin is exposed to the UV rays of the sun, a specific type of cholesterol in your skin starts the process of making vitamin D. The newly converted vitamin D is stored in your fat cells and remains there until it is called into action. Vitamin D that is consumed as a supplement or through foods is absorbed through your small intestine and moves on to conversion. When vitamin D is called into action, the liver and the kidneys convert the D3 to the form your body uses.

So who may be at at risk of vitamin D deficiency?

  • Deficiencies are most often associated with a lack of direct UV sun. So if you live in northern climates or protect your skin with sunblock, you may be deficient.
  • Deficiencies are also common in people with intestinal disorders, which affects their absorption of fat-soluble vitamins such as vitamin D.
  • Infants that are breastfed may not be getting enough vitamin D, unless the mother has an adequate amount of vitamin D stored.
  • The more melanin you have, the more you are protected from the sun's UV rays, which may also result in vitamin D deficiency.
  • Older adults cannot synthesize vitamin D as efficiently, which may lead to a deficiency.

Vitamin D is also known to help grow and maintain your bones. It does so by helping the body absorb dietary calcium and phosphorus from your intestines. Subsequently, low levels of vitamin D can increase the risk of fractures and bone-related diseases such as osteoporosis. An unhealthy gut can also limit the absorption of vitamin D, ultimately affecting calcium absorption. Vitamin D became associated with reducing heart disease because blood calcium levels are critical for cardiac function. Your heart’s dependency on calcium levels is so essential, that it will steal calcium from the bones to maintain normal function. But your bones bear the brunt of the loss, and as calcium levels drop, bone density decreases, leading to bone-related injuries and diseases. Vitamin D has a vital role in regulating healthy cell growth and restricting the blood supply to tumors, which is why it is a highly regarded supplement for cancer prevention. This is especially true for prostate cancer, where there are a large number of vitamin D receptors. Vitamin D is also required to help your brain produce the neurotransmitter called serotonin. Serotonin is the happy hormone that creates a feeling of joy. A deficiency in vitamin D can produce the opposite effect and may lead to mild to moderate depression. Your body also requires vitamin D to help provide energy, which is why on those dark, dreary days, you may appear to be more tired. Vitamin D helps keep your immune system healthy and more resilient in fighting off infection and viruses.

Most people require supplements to get the vitamin D they need. New research is recommending 1,000 IU a day. Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) are the two types most often found in supplement form. Vitamin D2 is produced by yeast and fungal sources that are irradiated, whereas vitamin D3 is made from either sheep’s wool or fish oil. D3 is also the form of vitamin D that is produced by the body. D3 is more biologically active and is the preferred choice because your body naturally produces a specific enzyme in the liver that helps to metabolize vitamin D3. Pathway Vitamin D3 drops are a great option. The absorption and process of metabolizing vitamin D2 take longer and are not as efficient. If you are a vegan, vegetarian, or do not like the source materials, there are vegan options as well.

Photo from here, with thanks.