As the glorious days of summer are now upon us, the concern for our children’s skin and exposure to the sun’s harmful rays is on everyone’s mind. But has sun protection gone too far? Can it actually be detrimental to our children’s health? There’s no doubt about the overwhelming evidence that over-exposure to UVA/UVB rays can lead to cancer, but covering up also deprives our bodies of the benefits of vitamin D.
New research shows the possibility that vitamin D may play a protective role in the prevention of cancer, and may even possibly improve chemotherapy survival. But do we really want to abandon the very sun protection that’s meant to prevent the more than one million new cases of skin cancer diagnosed each year for the benefits of this vitamin? Vitamin D is also a fat-soluble vitamin, and we all know its importance in building healthy bones. However, over the last 15 years, research has shown that it also acts as a hormone, regulating many different physiological processes such as calcium and phosphorus balance, immune function and insulin activity.
Let’s take a closer look at how the body obtains and uses this valuable vitamin. There are several forms of vitamin D: vitamin D2 (ergocalciferol), which is found in foods such as fish liver oils, eggs, oatmeal and alfalfa; vitamin D3 (cholecalciferol) which is made by our body when exposed to ultraviolet B (UVB) rays with a UV index greater than 3; and vitamin D5, a synthetic form. Of the three, D3 is considered the most natural and most active form of vitamin D; however, vitamin D does require conversion by the liver and kidneys before it becomes fully active. Approximately 75% of the body’s vitamin D supply is obtained through the skin from exposure to ultraviolet B rays from the sun. Thirty minutes of sun exposure in a bathing suit without sunscreen produces approximately 10,000 IU of vitamin D3. Interestingly, the body will self-regulate and only generate the Vitamin D it needs, so it is impossible to generate too much vitamin D from sunlight exposure. On the other hand, if you live north of the 30th parallel, which includes most of the United States, you can only get adequate vitamin D3 from sunlight for six months out of the year; from April through September.
Furthermore, cloudy and smoggy days reduce the necessary UV rays needed to form Vitamin D3 by 50%. Yet another consideration is the time of day you are exposed to the sun. UVB exposure is less during early morning and late afternoon, as the sun’s radiation must pass through more of the Earth's atmosphere at an angle that reduces its intensity. An interesting study conducted by Dr. Dianne Godar of the U.S. Food and Drug Administration (FDA) indicated that UVA light, not the UVB light that causes suntans and allows your body to produce vitamin D, may be responsible for the melanoma epidemic.
Dr. Mercola, an osteopathic physician and health activist who approaches medicine holistically, further emphasizes that UVA rays penetrate the skin more deeply than UVB rays and may be a much more important factor in photoaging, wrinkles and skin cancers. He further emphasizes that the optimal time to be in the sun for vitamin D production is as near to noon as possible; between 10 am and 2 pm. During this time, you need the shortest exposure time to produce vitamin D because UVB rays are at their most intense. Plus, when the sun goes down towards the horizon, the UVB is filtered out much more than the dangerous UVA. Lathering on the sunscreen, even weak ones (SPF 8), also blocks your body's ability to generate vitamin D by 95%. In fact, studies show that most children do not get enough vitamin D. In October 2008, the American Academy of Paediatrics (AAP) responded by doubling the amount of vitamin D it recommends for babies and children to 400 International Units (IU) per day. Without sufficient vitamin D, children can develop rickets, while a deficiency in adults can lead to osteomalacia. Deficiency can also be a contributing factor in osteoporosis, tetany and myopia as well as Seasonal Affective Disorder (SAD), caused by a melatonin imbalance initiated by lack of exposure to sunlight. So perhaps the sun’s rays aren’t always our enemy, after all. Perhaps there is a time and a place for sunscreen, too. However, deciding if and when to use sunscreen is a controversial topic, and the decision is a personal choice. But as a parent, I feel we should all be informed about the hazards and benefits of sunscreen use in order to make the best decision for our children’s health.
The skin is our largest organ and absorbs everything we put on it, including all the chemicals in the sunscreens we use. Many of the chemical ingredients commonly added to sunscreens are toxic and help create free radicals, especially oxybenzone. Health concerns include hormone disruption and cancer. Another ingredient, octinoxate, the most widely used sunscreen ingredient, due to its low potential to sensitize skin, had estrogenic effects in laboratory animals as well as disrupting the thyroid hormone and brain signalling. It has also been found to kill cells in mice, even at low doses, when exposed to sunlight. According to Mercola, these questionable ingredients should be avoided:
Fortunately, there are all-natural ways to protect yourself from sunburn that you can use as opposed to toxic commercial sunscreens. First, diet plays a key role. The cells in our bodies are built from the raw materials we eat. The more suitable our food choices are, the better cell structures we can build to help the body resist damage from the sun. A diet that contains essential fatty acids, as well as fresh raw vegetables full of phytonutrients that contain antioxidants, will help provide needed resistance to the sun’s damaging rays. Obviously covering up is key when outdoors for any extended period of time. However, if you do opt to wear sunscreen, it’s important to always read labels carefully as some sunscreens claim to be “natural”, but really aren’t.
Ideally, a sunscreen with titanium dioxide and zinc oxide are ideal choices, as well as coconut oil, vitamin E (Tocopheryl acetate, a preservative) and natural oils and shea butter (safe as thickeners and natural emulsifiers). Whether you choose to use sunscreen or not, always do your homework before you make a decision. If you do opt to use sunscreen, you should consider choosing a natural sunscreen with safe, non-toxic ingredients such as titanium dioxide and zinc oxide. Supplementation should also be considered when using sunscreen to ensure that the Dietary Reference Intakes (DRI) for Vitamin D set by the by government health bodies in the U.S. are met. Remember that choosing the right Vitamin D – cholecalciferol (the active form, D3) – is essential to keeping your children healthy.
How much Vitamin D do we need? According to the Institute of Medicine, Food and Nutrition Board (FNB). Dietary Reference Intakes (DRI): Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, DC: National Academy Press, 1997, adequate Intakes of vitamin D are as follows:
|Birth to 13 years||200 IU|
|14-18 years||200 IU||200 IU||200 IU||200 IU|
|19-50 years||200 IU||200 IU||200 IU||200 IU|
|51-70 years||400 IU||400 IU|
|71+ years||600 IU||600 IU|
However, many experts agree that the current recommendations for vitamin D are inadequate, and in October 2008, the American Academy of Paediatrics (AAP) responded by doubling the amount of vitamin D it recommends for babies and children to 400 International Units (IU) per day. Furthermore, increasing vitamin D to 1,000 UI per day, especially during the winter months and at higher latitudes, would likely improve the overall health of the U.S. population. Vitamin D tolerable upper intake levels according to the Institute of Medicine, Food and Nutrition Board (FNB) are as follows:
|Birth to 12 months||1,000 IU|
|1-13 years||2,000 IU|
|14+ years||2,000 IU||2,000 IU||2,000 IU||2,000 IU|
Even these upper limits are currently being challenged. Newer clinical trials conducted in healthy adults concluded that the data support upper limits as high as 10,000 IU per day. However, evidence is not sufficient to determine the potential risks of excess vitamin D in infants, children, and women of reproductive age. The FNB is currently reviewing data to determine whether updates to the DRI for vitamin D are necessary. How do you know if you’re deficient in Vitamin D? The only sure way to determine if you have a normal vitamin D level is to get your blood levels tested via a 25-hydroxy vitamin D or vitamin D 25 hydroxy test. The table below list the current guidelines for Vitamin D blood levels in nanograms per millilitre.
|Current guidelines for Vitamin D blood levels|
|Deficient||lower than 50 ng/ml|
|Optimal||between 50-65 ng/ml|
|Excess||greater than 100 ng/ml|
Foods that contain Vitamin D
|Food||IUs per serving*|
|Cod liver oil, 1 tablespoon||1,360|
|Salmon (sockeye), cooked, 3 ounces||794|
|Mushrooms that have been exposed to ultraviolet light to increase vitamin D, 3 ounces (not yet commonly available)||400|
|Mackerel, cooked, 3 ounces||388|
|Tuna fish, canned in water, drained, 3 ounces||154|
|Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup||115-124|
|Orange juice fortified with vitamin D, 1 cup (check product labels, as amount of added vitamin D varies)||100|
|Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces (more heavily fortified yogurts provide more of the DV)||80|
|Sardines, canned in oil, drained, 2 sardines||46|
|Liver, beef, cooked, 3.5 ounces||46|
|Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV)||40|
|Egg, 1 whole (vitamin D is found in yolk)||25|
|Cheese, Swiss, 1 ounce||6|
|* IU = International Units|
Dietary supplements Vitamin D supplementation can be found in two forms, D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D2 is manufactured by the UV irradiation of ergosterol in yeast, and vitamin D3 is manufactured by the irradiation of 7-dehydrocholesterol from lanolin and the chemical conversion of cholesterol. The two forms have been regarded as equivalent, but evidence suggests that they are metabolized differently. Vitamin D3 may be more than three times as effective as vitamin D2, so when choosing a Vitamin D supplement, it’s probably best to choose Vitamin D3. Please remember that Vitamin D should always be taken with calcium to avoid toxicity.