By Joanna Loveys BNatMed HbT MNZAMH
Without sunlight, plants wouldn’t thrive and grow and neither would we! Sunlight is our greatest source of “The Sunshine Vitamin” - Vitamin D - which is critical for good health and vitality. One of the great things about vitamin D is that our bodies are capable of producing it. Even just 10 minutes sun exposure can give you a boost. Vitamin D absorption starts when those UVB rays from the sun hit our skin.
What is it?
Vitamin D is actually a fat soluble steroid that helps the body absorb other nutrients. Synthesised from sunlight, and not solely from our diet, the natural version is called cholecalciferol – the synthetic version (ergocalciferol) is produced by exposing plants to UVB rays and we find this listed on food labels or in supplements. There are actually 5 different types of vitamin D!
The problem is that most of us are not getting enough of it. You might say, well, I eat a healthy balanced diet, I take a multivitamin every day, I drink vitamin D fortified milk and I spend a lot of time outdoors so my vitamin D levels are fine – and you could well be right, but if you are feeling fatigued, have general joint and muscle cramps, aches and pains, chronic pain, poor concentration, weight gain, high blood pressure, poor sleep, bladder problems, headaches, constipation or diarrhoea then you may have a vitamin D Deficiency.
Why do we need it?
- A vital nutrient for our bones, works with calcium through body processes to maintain healthy bone structure.
- The immune system needs Vitamin D to help prevent and treat disorders such as asthma, rheumatoid arthritis, diabetes, Hashimoto's Thyroiditis, Graves’ disease, Crohns disease and MS. Boosting the immune system also helps you fight back when colds and flu’s strike.
- The growth of normal cells.
- The production of insulin in the pancreas - it may help to reduce the insulin resistance of type 2 diabetes.
- Involved in blood pressure regulation.
- Coronary heart disease = helps to regulate the hormone system that regulates blood pressure and water (fluid) balance, reduces insulin resistance and blood vessel wall inflammation.
- Normal skin function
- Dental health
- Mood – can play an important role in the treatment of depression
- Normal brain development
- Support in chronic and acute disease states
How does it work?
When you get a dose of sunshine, your body’s internal processes step in and a naturally occurring cholesterol absorbs the UVB rays and gets converted into cholecalciferol (the previtamin form of vitamin D) which travels through the bloodstream to the liver, then the kidneys, to be converted to a form of vitamin D that your body can use. Once the Vitamin D is in its correct form it works closely with calcium. Now, the body stores vitamin D from its summer sun exposure but by the time winter comes you may already be deficient.
Why are we deficient in Vitamin D?
There can be multiple reasons we get deficient in vitamin D but not getting enough sun is the main one. Other reasons are:
Skin pigmentation: the darker the skin colour the more difficult for the skin to produce vitamin D, people with darker skin may need more sun exposure because the darker skin pigment acts a bit like a sunscreen.
Sunscreen: blocks UVB rays from the sun, although sunscreen is necessary to protect from skin cancer and aging, it makes it harder to get all the vitamin D we need. Now I am NOT for a minute saying don’t use sunscreen! – Some tips to get enough vitamin D follow!
Body Fat and Obesity: Many studies have shown a strong connection between obesity and low vitamin D levels = people who struggle with fat absorption will almost certainly struggle with Vitamin D deficiency. The more overweight you are the less vitamin D you will have. Vitamin D is a fat-soluble vitamin so it gets stored in your fat. This isn’t so great because we need the vitamin D circulating in your bloodstream. Maintaining a healthy weight helps ith vitamin D levels.
Illness: including people with pancreatic enzyme problems, cystic fibrosis, coeliac disease, cancer, chrohns disease and kidney disease or those who have had bariatric surgery.
Where you live/seasons: It’s much easier to get your quota of sunshine in the summer, but during autumn and winter the sun is at a lower angle and those who live in the northern hemisphere are particularly at risk because some parts of the NH don’t get a whole lot of vitamin D for 8 months of each year. Lucky for us we are in the Southern Hemisphere!
Aging: as we age our ability to produce vitamin d reduces drastically because the kidneys are less able to make the conversion. Studies have shown that a 70 year old make 4 times less vitamin D than a 20 year old. Gardening, sitting outdoors, outdoor leisure activities help to build up vitamin D in the elderly.
Air pollution: This is a biggy! Big urban areas with smog and pollution make it difficult for the UVB rays to get through and down to us
Where do we find it?
Basically we get Vitamin D through sunlight, supplements and food sources.
Sunlight – 10 minutes a day exposure is all you need! We can’t make vitamin D when it is filtered through glass either as this filters out most of the UVB rays which stimulate vitamin D production.
Food Sources: Fatty fish such as salmon, tuna, and mackerel are very good sources of vitamin D as are egg yolks, raw milk, mushrooms and cod liver oil. Fortified foods including margarine, some yoghurts and breakfast cereals.
RDA – How much should I have per day?
19-30 5mcg per day
31-50 5mcg per day
51-70 10 mcg per day
>70 15mcg per day
(Source: Australia and New Zealand Nutrient Reference Values)
Osiecki, H. (2012). The Nutrient Bible (8th ed.). Queensland: Bio-Concepts Publishing.
Pauling, L. (2014, December 04). Linus Pauling Institute - macronutrient center. Retrieved December 04, 2014, from Linus Pauling Institute - Oregon State University: http://lpi.oregonstate.edu/infocenter/vitamins.html
The Natural Standard Database. (2014, December 04). Retrieved December 04, 2014, from The Natural Standard Database: https://naturalmedicines.therapeuticresearch.com/
Zealand, N. R.-A. (2014, December 29). Nutrient Reference Values - Australia and New Zealand. Retrieved December 29, 2014, from Nutrient Reference Values: http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n35.pdf