Vitamin D deficiency is pandemic, spanning many continents and including all ages, genders and racial/ethnic groups. Currently, world-wide attention is focused on the importance of vitamin D in optimizing health and preventing disease. This focus is largely the result of the scientific discovery that vitamin D receptors are present in nearly every tissue and cell in the body and that adequate vitamin D status is essential for optimal functioning of these tissues and cells. An impressive body of research has accumulated over the past two decades providing new information about the role of vitamin D in prevention of a broad range of diseases.
What is Vitamin D?
Contrary to what the name might represent, Vitamin D is actually a Hormone, rather than a Vitamin. It is a precursor to a steroid hormone. Vitamin D’s major biologic function in humans is to maintain serum calcium and phosphorus concentrations within the normal range by enhancing the efficiency of the small intestine to absorb these minerals from the diet
There are two forms of vitamin D: vitamin D2 and vitamin D3. Both offer benefits, but one is more readily absorbed and utilised by the human body. Vitamin D2 is produced by some plant life in response to UV radiation. Mushrooms are an example, and some fortified foods will contain Vitamin D2 as an inexpensive way to boost nutrient quantity.
Vitamin D3 is the most biologically active form of Vitamin D found in humans and animals. The way our bodies make Vitamin D3 is by converting sunshine into chemicals that are used by the body. The cholesterol in our skin converts “pre-Vitamin D” and makes it into usable Vitamin D3. Pre-Vitamin D first travels through the kidneys and liver in the blood stream, and then is converted into a biologically active and usable substance called calcitriol.
Benefits of optimal Vitamin D levels
Calcium and phosphorus are essential for developing the structure and strength of your bones, and you need Vitamin D to absorb these minerals. Even if you eat foods that contain a lot of calcium and phosphorus, without enough Vitamin D, you can’t absorb them into your body. Other benefits include:
- Supports a healthy immune system
- Helps to balance mood
- Maintains proper brain function
- May reduce the risk of Type 1 and 2 diabetes
- Reduces the risk of developing rheumatoid arthritis
- Reduces risk of cancer
- May reduce hypertension
Best source of Vitamin D
Sunlight is the best and most natural way to get Vitamin D. Ultraviolet rays convert Vitamin D into the form that our bodies use, and unlike food and supplement sources, it is very difficult to get too much Vitamin D this way. In fact, Vitamin D produced in the skin may last at least twice as long in the blood compared with ingested Vitamin D.
How much sun do you need? Variables such as where you live, time of day, season, latitude, clothing, sunscreen use, skin pigmentation, and age affect the amount of Vitamin D converted in the skin. In countries like the UK and India, exposing your skin to the sun at midday has been shown to be most effective for producing optimal levels of Vitamin D. In Australia where the UV rays are very strong, it is recommended to go in the sun between the hours of 8am-10am and 3pm-5pm for 15-20 minutes per day. Expose as much as your skin as possible. Don’t use sunscreen as that inhibits the absorption of Vitamin D from the sun. If you’re going to be in the sun for a long period of time though, I’d suggest using a protective natural sunscreen like this one. Do some research about your particular location to find out when the safest sun exposure is.
The Vitamin D Society explains:
“Sun exposure is the main source of vitamin D, but excessive sun exposure is the main cause of skin cancer, including melanoma, the fastest rising type of cancer in the UK. Enjoying the sun safely, while taking care not to burn, can help to provide the benefits of vitamin D without unduly raising the risk of skin cancer.”
Other sources of Vitamin D
Portobello mushrooms Mushrooms are the only plant sources of Vitamin D. They can provide as much Vitamin D as a supplement. Portobello, maitake, morel, button and shiitake mushrooms are all high in Vitamin D. Here’s a tip: you can put the gills sun side up to boost their Vitamin D content. I would recommend a minimum of 6 hours.
Supplements If you’re not getting any proper daily sun exposure, then I believe supplementing is important. Here is the supplement I recommend. The current recommendations by the Vitamin D Council are healthy children under the age of one year should take 1,000 IU per day; over the age of one, 1,000 IU for every 25 pounds of body weight per day; healthy adults and adolescents should take at least 5,000 IU per day. Two months later, have a blood test to ensure you are in the healthy range.
Effects of low Vitamin D levels
- Reduced bone health and muscle function
- Muscle and joint aches
- Inability to concentrate
- Immune system decline
- Mood disorders and depression
- Bladder issues
- Weight gain
- May contribute to cardiovascular disease
- Can contribute to autoimmune diseases
Sunscreen and Vitamin D absorption
The Journal of Evidence-Based Complementary & Alternative Medicine states that the increased use of sunscreen is one of the risk factors for Vitamin D deficiency. Why is this? Wearing sunscreen with a sun protection factor of 30 reduces Vitamin D synthesis in the skin by more than 95%. If you’re in the sun for longer than 15-30 minutes I’d suggest using a protective natural sunscreen like this one.
How to check Vitamin D levels
Since 25(OH)D is the most plentiful and stable metabolite of Vitamin D in the human bloodstream, it is the best indicator of Vitamin D status. Talk to your doctor about having a blood test to measure 25-hydroxy-vitamin D levels. Be certain they do not order a test for 1,25-dihydroxy-Vitamin D, as this is a common error.
Ideal Vitamin D level
There is a lack of agreement when it comes to optimal Vitamin D levels. Author and Investigative Journalist Phillip Day makes the following statements in his book “Essential Guide to Vitamin D”:
The latest research recommends the following interpretations:
< 20 nmol/L – seriously deficient – immediate action required
40 nmol/L – very deficient
40 – 100 nmol/L – deficient
130 – 150 nmol/L – normal
170 – 200 nmol/L – therapeutic
>230 nmol/L – toxic threshold
This study suggests the most optimal serum levels for 25(OH)D appeared to be at least 75 nmol/l (30 ng/ml) and for cancer prevention, desirable 25(OH)D levels are between 90-120 nmol/l (36-48 ng/ml). Personally, I’ve come to the conclusion for optimal health you want your levels to be between 125 and 200 nmol/l. Definitely do your own research though and come to a conclusion that feels right for you.
Can you get too much Vitamin D?
Hypervitaminosis D is a state of Vitamin D toxicity. It’s not possible to experience Vitamin D toxicity from the sun alone. Excessive exposure to sunlight causes a photodegradation of previtamin D3 and Vitamin D3 to ensure that Vitamin D3 intoxication cannot occur. But what about toxicity in relation to oral supplementation?
The Journal of Evidence-Based Complementary & Alternative Medicine states that “no cases of Vitamin D toxicity have been reported in Vitamin D supplementation doses less than 10 000 IU/d.” In another recent study, Vitamin D supplementation of 1600 IU/d or 50 000 IU monthly was not associated with any signs of toxicity. This clinical trial evidence shows that a prolonged intake of 250 mug (10,000 IU)/d of Vitamin D3 is likely to pose no risk of adverse effects in almost all individuals in the general population.
A study suggests for most people, Vitamin D intake from food and supplements is unlikely to exceed the UL. However, they say for people who are at the upper end of the ranges for both sources of intake, particularly those who use many supplements and have a high intake of fish or fortified milk, may be at risk for Vitamin D toxicity.
This evidence suggests that Vitamin D is much more than a nutrient needed for bone health; it is an essential hormone required for regulation of a large number of physiologic functions. It is clear that sufficient levels of serum 25(OH)D are essential for optimizing human health.