Summer means different things to each of us—longer, sunnier and warmer days, more outdoor activities, mosquitos and flies, BBQs and salads and swimming at the beach, pool or river. Summer from a health perspective also means more vitamin D.

Why do we need vitamin D?

Vitamin D plays an important role in having strong bones and healthy muscles. It helps to regulate the amount of calcium and phosphate we have in the body, by altering how much of these nutrients we absorb from digested food. Vitamin D also has a role in supporting our immune system and maintaining healthy skin.

Older people who have below the recommended levels of vitamin D are at higher risk of falls, muscle weakness and impaired balance. It increases their chance of fractures and developing osteoporosis.

Low levels of vitamin D have also been associated with a range of different diseases:

• Autoimmune diseases
• Heart disease and other metabolic diseases such as type 2 diabetes
• Some cancers
• Some neurological and mental health conditions.

Further research is underway concerning the role of vitamin D in health and the prevention of disease. The above listed observations for low vitamin D levels, are associated with these conditions and diseases. The type of research that has been conducted, so far, does not prove that the low vitamin D level caused the condition or disease.

What is the best source of vitamin D?

Sunlight is the best source of vitamin D. So vitamin D is different to other nutrients, as it is mainly produced by the skin and not sourced from food. The action of sunlight on our skin produces vitamin D3 (cholecalciferol), where as food provides vitamin D2 (ergocalciferol). Both types of vitamin D are converted to calcitriol (25 OHD), which is the active form of vitamin D.

How much sun do you need?

The Australian Cancer Council provides advice on safe sun exposure. The amount of sun we need on our skin e.g. face, arms and hands, varies on the time of year and where we live, as well as the darkness of our skin. People with fair skin need less time in the sun than people with darker skin.

The vitamin D produced by our skin can be stored up to 6 months. Therefore it is important to enjoy safe sun exposure during spring, summer and autumn, so we can lessen the risk of becoming deficient during winter—when there is less sun and we are less likely to stay outdoors, uncovered, due to cold weather conditions.

People who spend most of their time indoors or covered with clothing for work or religious reasons, are at higher risk of developing vitamin D deficiency.

You can link through to the Cancer Council’s brochure on ‘How much sun is enough?’

Food sources of vitamin D

• Fatty fish e.g. salmon, herring and mackerel
• Liver
• Eggs
• Fortified foods such as milk, yoghurt and cheese

The current nutrient reference value for vitamin D provides an estimate based on having access to minimal sunlight. However, food sources alone will not provide enough vitamin D.

Vitamin D supplementation

We all respond to supplementation of vitamin D differently. The level and frequency of dosage is best discussed with and monitored, through appropriate blood testing, by your healthcare practitioner.

Take every opportunity to enjoy small bursts of sunlight throughout the year. In summer it is easier to spend time outdoors, with our arms or legs uncovered, but long periods of sun baking are neither required nor recommended. Incidental activities are the best way to top up your vitamin D.