September Blog – Vitamin D
The only proven benefit of vitamin D is its role in helping calcium build strong bones. But that’s far from the whole story. Vitamin D helps regulate the immune system and the neuromuscular system. Vitamin D also plays major roles in the life cycle of human cells.
Vitamin D is so important that your body makes it by itself, but only after skins exposure to sufficient sunlight.
Dark skin absorbs less sunlight, so people with dark skin do not get as much vitamin D from sun exposure as do light-skinned people.
Your body must have Vitamin D to absorb calcium and promote bone growth. Too little vitamin D results in soft bones in children and fragile, misshapen bones in adults (osteomalacia). You also need vitamin D for other important body functions. Vitamin D deficiency has now been linked to breast cancer, colon cancer, prostate cancer, heart disease, depression, weight gain, and other maladies. These studies show that people with higher levels of vitamin D have a lower risk of disease, although they do not definitively prove that lack of vitamin D causes disease, or that vitamin D supplements would lower risk.
The Vitamin D Council, a scientist-led group promoting vitamin D deficiency awareness, suggests vitamin D treatment might be found helpful in treating or preventing autism, autoimmune disease, cancer, chronic pain, depression, diabetes, heart disease, high blood pressure, flu, neuromuscular diseases, and osteoporosis. However, there have been no definitive clinical trials.
That’s why the Institute of Medicine expert committee’s November 2010 review found no conclusive evidence that vitamin D, by itself, offers wide-ranging health benefits.
How can I get enough vitamin D?
Thirty minutes of sun exposure to the face, legs, or back without sunscreen at least twice a week should give you plenty of vitamin D.
But this much direct sun exposure might also expose you to potentially dangerous levels of cancer-causing UV radiation. Dermatology recommends against getting vitamin D from unprotected exposure to sunlight.
Unlike any other nutrient, most vitamin D is formed as a result of sunlight exposure on our skin. The most recent national surveys showed about one in three New Zealand children had too little vitamin D in their blood; nearer a half of adults.
During summer, being outdoors before 11am and after 4pm should allow enough sunlight to be absorbed to meet your vitamin D needs. We still need to practice good sun protection during the summer months. In winter, longer periods are required, around 30 minutes per day, with those people living in the south island of New Zealand needing more exposure because of the lower UV levels.
Talk to your doctor if you are concerned about your vitamin D levels or if you have limited exposure to the sun.
Which foods contain vitamin D?
Surprisingly few foods contain vitamin D, unless it’s added to the food. That’s because your body is built to get vitamin D through your skin rather than through your mouth. But once your body has enough, it doesn’t matter whether you got it through your skin or through your stomach.
There are three vitamin D super foods:
Salmon (especially wild-caught)
Mushrooms exposed to ultraviolet light to increase vitamin D
Other food sources of vitamin D include:
Cod liver oil (warning: cod liver oil is rich in vitamin A)
Tuna canned in water
Sardines canned in oil
Milk or yoghurt regardless of whether it’s whole, non fat, or reduced fat, fortified with vitamin D
Beef or calf liver
If you have any concerns about your personal Vitamin levels, a quick discussion with your doctor could help put your mind at ease.