Vitamin D is an essential fat soluble hormone obtained uniquely from the sun and from our diet. Considering Australians have plenty of opportunities to see the sun in comparison to other populations in the Northern and Southern Hemisphere, it is a crazy statistic that about four million Australians have a vitamin D deficiency and approximately 40% of the population in the US. One would easily guess that the reasons revolve around ‘more screen time’, the ‘slip slop slap’ campaign working a little too well and our dietary intake lacking in those foods high in Vitamin D.
The Role of Vitamin D
Vitamin D is best known for its role in bone health where it promotes the absorption of calcium from the intestines and ensures adequate mineralisation of bone needed for bone growth and bone remodelling. We know low calcium stores leads to higher risk of osteoporosis and bone fractures. There is evidence to suggest that Vitamin D does much more than this. There are Vitamin D receptors in many other parts of the body. These receptors are involved in immune function, cell growth and regulation and the reduction of inflammation. Vitamin D deficiencies or sub-optimal levels of Vitamin D have been associated with depression and mood disorders as well as neuromuscular disorders such as Multiple Sclerosis. Vitamin D may also play a role in the prevention of certain cancers.
From the sun to the body
Very simply put, our skin contains a substance called ‘7-dehydrocholesterol’, which is the precursor to Vitamin D3. The ultraviolet energy from the sun converts the precursor to the active form Vitamin D3.(1) This conversion happens in the liver and the kidneys.(2)
Risk factors for deficiency
The number one risk factor for Vitamin D deficiency is limited exposure to the sun. Other reasons include:
- Those who spend much time indoors such as shift workers and aged care residents.
- More time spent on computers and less time outdoors.
- The overuse of sunscreens and covering up in the sun for the prevention of skin cancer.
- Less sun exposure in winter months.
- People with naturally dark skin, which has a natural sun protection factor of up to 15.
- People who cover themselves for religious or cultural reasons.
- Populations of people who live in cooler clients with less sunlight exposure. For instance living in southern parts of Australia, there is a higher risk of deficiency than those in the north regions.
- People with gut inflammatory conditions such as Crohn’s Disease, celiac disease, inflammatory bowel disease, liver and kidney disease.(3)
- People with intestinal disorders that limit absorption of fat and those with kidney or liver diseases that reduce the conversion of vitamin D to its active form
- Certain medications such as antibiotics and anticonvulsants.
Sources of vitamin D
We gain a little of our Vitamin D from our foods. Sources highest in Vitamin D include:
- Dairy products — such as cheese, butter and fortified milk
- Fatty fish eg salmon, sardines, tuna
- Oysters , prawns
- Cod Liver Oil
- Egg yolks
- Beef liver
If you think you are at risk of deficiency of Vitamin D deficiency then a blood test to ascertain your levels is a good place to start. Lifestyle, exposure to the sun and dietary intake are all factors to consider when considering supplementation. Many multivitamins have a small dose of Vitamin D however a Vitamin D3 supplement might necessary depending on your lifestyle and health status.
How much sun exposure
Sensible, regular sun exposure will ensure adequate Vitamin D levels. The time of exposure will change depending on your location and the season. You may find sun exposure in the summer months a lot easier than the winter. In Australia, 6-10 minutes of regular sun on your arms and legs outside the hours of 10 am and 2 pm is preferable to prevent burning. In the winter, longer periods of up to 40 minutes may be needed in the middle of the day to gain the same amount of UVB exposure.
The reality is, our lives are filled with an abundance of desk time, screen time, sunscreens and protective clothing so please consider this all-important vitamin. The right amount of ‘D’ is an essential ingredient for good health.
All of our posts reflect our philosophy at A Healthy View www.ahealthyview.com, a whole real food perspective on food and life. Extremes do not work, but clean, whole, tasty and easy food choices can create a lifetime of good habits that lead to a lean, happy, and healthy person. Contact us on our website for our next Low Sugar Lifestyle program or a nutritional consult.
Article by Sara Millikin
- Harvard Health Publications. Harvard Medical School; June 2009. Available from: http://www.health.harvard.edu/mens-health/vitamin-d-and-your-health
- Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Ross AC, Taylor CL, Yaktine AL, et al., editors. Dietary Reference Intakes for Calcium and Vitamin D. Washington (DC): National Academies Press (US); 2011. Available from: http://www.ncbi.nlm.nih.gov/books/NBK56061/
- Boston University. Available from http://www.bu.edu/news/2011/01/18/busm-researchers-find-vit-d-absorption-diminished-in-crohn%E2%80%99s-disease-patients/