Everything you need to know about Vitamin D

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The Sun and vitamin D
You may have heard about the importance of having good levels of Vitamin D, but you might be wondering why there is so much talk around this particular vitamin, especially in Paleo circles.

Vitamin D is not actually a vitamin. It’s a fat soluble hormone that the body is able to produce under the right conditions, and it can’t be obtained from eating, with the exception of naturally fatty cold water fish such as salmon and mackerel, and foods that are artificially fortified with it, like cereals and milk. The Paleo lifestyle does not include cultivated grains, and many frown on drinking milk for other reasons, so if you don’t like fish, what can you do?

Our bodies are designed to make Vitamin D through direct exposure to sunlight, specifically, ultraviolet radiation (UVB), but most people don’t spend enough time in the sun to get adequate amounts of this essential nutrient.

Why do we need it?

First, it’s important to understand that Vitamin D levels, like calcium levels, must be maintained in the blood serum. If homeostasis is not achieved, the body will draw it from the bones or elsewhere in the body. Vitamin D is responsible for or assists in a lot of different processes.

  • Bone health – In building bone, it helps absorb calcium
  • Blood calcium – It assists in releasing calcium and phosphate from bone when blood calcium is low
  • Inflammation – Works at the cellular level to activate receptors that signal inflammation reduction
  • Cell differentiation – In growth and development, it regulates the proliferation and specialization of cells
  • Cognition – Individuals with severely reduced Vitamin D levels are 60% more likely to experience cognitive decline
  • Immune system – It plays a role in antimicrobial response in part by disrupting bacterial cell membranes.
  • Autoimmune function – It inhibits B cell proliferation and differentiation, preventing antigens from maturing so tolerance to self is maintained
  • Breast cancer – More than 200 epidemiological studies link Vitamin D deficiency to breast cancer
  • Infection – It produces 200 anti-microbial peptides, including a naturally occurring broad spectrum antibiotic
  • Rickets – Vitamin D deficiency causes soft and irregular or distorted bone development in children
  • Gene activity – It regulates 3,000 of our 24,000 genes
  • Weight and appetite – At the primal level, high D levels indicate summer, a time of abundant food and building the body’s strength. We store less and sleep less but more efficiently. The low D level signals us to sleep more and store fat for spring
  • The colonic biome – Low D levels affect populations of bacteria in our intestines and affect the entire GI tract

Low levels of Vitamin D are associated with poor sleep, memory loss, depression, hypertension, stroke, heart disease, anemia, cancer, balance difficulties, pain, infertility, polycystic ovary syndrome, endometriosis, and a host of other ailments.

Figuring out what might affect your Vitamin D level isn’t that difficult. Here’s a look at some of the major factors:

  • Where you live. The closer you live to the Equator, the more UVB will reach the surface of the planet during winter, the most crucial time for not getting strong sunlight D. If you live in Canada, for example, you may make very little Vitamin D from November through February. People wear more clothing (long sleeves, coats, boots, gloves) covering most of their body and further preventing the sun from reaching their skin.
  • Season. Even if you live closer to the Equator, winter sun is much weaker than summer sun.
  • Air quality. This is something you may not have thought would be a factor, but particles in the air absorb UVB rays and scatter them. The lack of concentration of sunlight diminishes your skin’s ability to produce Vitamin D.
  • Ozone. There’s an upside to holes in the ozone caused by pollution. Ozone is the unstable toxic gas that’s formed from oxygen by electrical discharges. It absorbs UVB radiation causing atmospheric holes, thus allowing more sunlight to enter and reach the planet.
  • Sunscreen. Technically, sunscreen is designed to block UVB light and prevent sunburn. If you use enough of it, your body won’t be able to make Vitamin D.
  • Tanning beds. UVB rays can cause sunburn, but UVA rays give you a nice golden tan and this is why most tanning beds made today only contain UVA rays. You won’t get any Vitamin D here, and if you’re using them in lieu of getting real sunlight, you’re missing out altogether.
  • Skin color. We know that melanin is the substance that gives your hair, skin, and eyes their natural color (pigment). In a complicated process, Vitamin D works in the skin to block or compete for UVB in an attempt to protect the skin from burning, but at the same time, it blocks the substance that starts Vitamin D production. If your skin is naturally dark, you’ll need more sun exposure to generate the production of Vitamin D.

Vitamin D is also in direct competition for absorption with folate (Vitamin B9), another vital constituent of our health. Our skin gets darker in the presence of sunlight to reduce our absorption of Vitamin D and prevent folate deficiency.

  • Weight. Body fat soaks up Vitamin D, storing it for emergency use when intake is low or production is diminished. If you have very little body fat, you won’t be able to store much of it, but if you’re obese, other factors may prevent its release.
  • Age. Aging reduces the levels of the substance that allows UVB light to be made into Vitamin D. Older people are also less likely to spend hours lying in the sun or taking part in outdoor activities.
  • Gut health. The stomach, pancreas, liver, and small intestine all have an effect on how much is absorbed, so celiac disease, pancreatitis, Crohn’s, and cystic fibrosis can reduce absorption.
  • Liver health. Steps that are essential to D metabolism can’t occur if bile production is insufficient.

How much Vitamin D do we need?

The recommended daily intake of Vitamin D for people ages 13 to 50 is 200 IU (International Units) and 400 IU for older people. It has been demonstrated however that this recommendation is much lower than the actual appropriate intake.

The tolerable upper intake levels have been set at 2000 IU per day in Canada and the US, but evidence shows that doses up to 10,000 IU are perfectly healthy. Read this article for some facts about a study that debunks the current Vitamin D toxicity myth. On the bright side, when you get your Vitamin D directly from sunlight, there are mechanisms that protect you from getting too much.

If you decide to go with a supplement, you should be comfortable choosing one that contains from 2,000 IU to 5,000 IU. Someone living in a tropical area and who is exposed to sunlight all day long could get as much as 12,000 IU a day just from the sun.

Choose a Vitamin D3 supplement (the more bio-available form). Try to choose one that comes in a gel capsule since Vitamin D is a fat soluble Vitamin and the body needs fat to absorb it (yet another reason to get enough fat in your diet).

Note: The FDA has been caught in a difficult position because D has wrongly been labeled a vitamin instead of a hormone, and they generally don’t allow hormones to be put into our food. Because of this, the recommended levels remain fairly low.

Could you be at risk?

If you think you may have a Vitamin D deficiency, you can order a test from your doctor. You may be at higher risk if you:

  • Have been diagnosed with osteopenia or osteoporosis, or you have a family history of it
  • Are very thin or obese
  • Smoke
  • Are peri -or post- menopausal
  • Have had a hip, wrist, or spine fracture
  • Take bone thinning corticosteroids
  • Live above 40 degrees north latitude or don’t get much sunlight
  • Don’t eat fish, Vitamin D fortified foods, or Vitamin D supplements
  • Use sunscreen regularly

What you can do to get more Vitamin D

  • Have fun under the sun frequently. Our ancestors got their vitamin D for millions of years this way, but use some caution and wisdom. Getting 10 to 15 minutes of strong sunlight on your face, arms, back, or legs without sunscreen a few times a week is enough to generate your body’s vitamin D needs for a week. After that, use sunscreen, go under the shade or wear protective clothing to reduce the risk of skin cancer.
  • Eat fish. Regular portions of wild salmon or other fatty fish each week can provide significant amounts of Vitamin D.
  • Supplement. Consider taking a quality bioavailable Vitamin D3 supplement or fresh cod liver oil in liquid form.

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