Have you had your dose of D today? Vitamin D, that is. This essential vitamin helps to build healthy bones, boosts your immune system and plays an important role in preventing certain cancers and type-2 diabetes. It’s also been linked with weight loss. However, even in sunny countries growing numbers of people are low in vitamin D from lack of sun exposure. Too much sun increases the risk of skin cancer as we all know, but too little can damage our health as well. The challenge: getting the right balance.
How the body makes vitamin D
Vitamin D is actually a hormone and not a proper vitamin per se. That means it is a compound made in one part of the body that causes another part to respond. We make vitamin D by first making a precursor in the skin from cholesterol. Ultraviolet rays from the sun hit the precursor and convert it to a pre-vitamin D. The liver and the kidneys do the rest to produce the active form of the vitamin.
Sunlight is the most effective way of manufacturing vitamin D, but we can also obtain limited amounts from some foods.
Vitamin D’s role in the body
Vitamin D is a member of the intricate bone-making team composed of several other vitamins and minerals. Its main job is to maintain blood concentrations of calcium and phosphorus so they are absorbed into your bones to make them dense and strong. If levels are low, calcium is leached from your bones, eventually making them more brittle and vulnerable to breaks.
Vitamin D also targets cells in the brain and nervous system, immune system, pancreas, skin and muscles. Because it has numerous functions in the body it may be valuable in treating several disorders.
Vitamin D deficiency
Vitamin D deficiency creates a calcium deficiency and this increases the risk of several diseases, especially osteoporosis and rickets. It is also implicated in certain cancers, chronic fatigue syndrome and cardiovascular disease.
A recent study conducted by pathologists at Monash University in Melbourne found people with higher levels of vitamin D in their blood were less likely to develop type-2 diabetes. In another study, women halved their risk of breast cancer by ensuring optimal vitamin D levels. Another found a 43% reduction in the risk of pancreatic cancer from taking vitamin D supplements.
If, like many people, you’re watching your weight, you may be interested to hear about a recent study which reported that overweight women who increased their low levels of vitamin D before starting a diet were more successful at losing weight. So, if you’ve got a weight loss goal, it may pay to check your levels.
Daily intakes of vitamin D
The symptoms of vitamin D deficiency can take years to develop and many people only discover there’s a problem when a bone breaks or they feel erratic muscle pain. The easiest way to determine vitamin D levels is with a blood test. The optimal level is 125 nanomoles per litre (nmol/L).
The Australian Ministry of Health recommends:
- 19-50 years – 5 µg a day
- 51-70 years – 10 µg a day
Who is at risk of vitamin D deficiency?
People most at risk are office workers who, even if sun comes through the window, don’t receive the benefits because glass blocks important UV-B rays. The elderly and housebound often don’t obtain enough UV, as are city-dwellers subject to dense air pollution. People who cover-up with clothing and those with dark pigmentation also need more UV exposure to produce adequate levels. Diligent SPF 30+ sunscreen users can also find themselves in the danger zone by blocking UV rays from penetrating the skin.
Body weight affects vitamin D levels with a body mass index of 30 and above implicated in lowered levels. People with digestive or mal-absorption disorders are also at risk.
Getting enough D in your day
The easiest way to prevent vitamin D deficiency is through mild sun exposure, healthy eating and, in some cases, supplements.
For most people, exposing the hands, arms and face on a sunny day before or after the peak UV period on most days of the week is sufficient to maintain vitamin D nutrition. A brisk walk in the morning is the perfect way to get some vitamin D and some exercise in a combined package.
Another way to source the sunshine vitamin is through food. Significant sources include cod liver oil, mushrooms, oily fish such as salmon, veal, liver, beef and vitamin D fortified bread, butter, margarine and milk. It’s difficult to obtain all your requirements from food but our delicious scrambled eggs with smoked salmon for breakfast is a good start to the day. For lunch try our ocean trout panzanella salad. For dinner, feast on our beef rendang tok.
You can also increase vitamin D levels with supplements. This is particularly helpful for people who can’t get into the sun. Choose supplements that provide vitamin D3 (cholecalciferol) rather than vitamin D2 (ergocalciferol). Consult your medical practitioner for the best dosage for you.