Sunday, November 3rd marks the end of daylight savings in America and the beginning of longer, darker days. While this may prove glorious for bats and other furry creatures of the night, fewer hours of sunlight can lead to serious health consequences for humans including those that stem from vitamin D deficiency.
According to the American Journal of Clinical Nutrition, vitamin D deficiency is now recognized as a pandemic; its primary cause â€“ lack of exposure to sunlight.1 Itâ€™s true; most vertebrates rely on exposure to sunlight for their bodies to produce sufficient amounts of vitamin D. Itâ€™s also true that during winter, there is a higher prevalence of vitamin D deficiency across North America.1
The Health Role of Vitamin D
The primary function of vitamin D is to help our bodies maintain normal blood levels of calcium and phosphorus. By aiding in the absorption of calcium, vitamin D helps our bodies form and maintain strong, healthy bones.2 Vitamin D also plays an important role in heart, lung, brain and muscle function.1
The Health Consequences of Vitamin D Deficiency
To date, there are a number of health conditions that are linked to vitamin D deficiency, including osteopenia, osteoporosis, rickets in children and fractures in adults. Low levels of vitamin D are also associated with common cancers, autoimmune diseases, hypertension, and infectious diseases.1 Researchers are beginning to discover that, because vitamin D deficiency may also increase the severity of some diseases, vitamin D supplementation is an important part of disease management.3
Groups at Risk for Vitamin D Deficiency
For many people, eating foods naturally rich in, and fortified with, vitamin D and being exposed to a moderate amount of sunlight is enough to maintain adequate vitamin D levels.4 Some groups of people however, are at higher risk of vitamin D deficiency than others. Talk to your healthcare provider about getting a blood test to check your vitamin D levels if you identify with any of the following:4
How Much Sunlight Do You Need?
First weâ€™re told to stay out of the sun because too much of it causes skin cancer. Now weâ€™re told that too little sun can cause vitamin D deficiency that can lead to serious health conditions. Indeed, there is a Catch 22 when it comes to sun exposure and our health. So, what level of sun exposure is considered safe?
The American Journal of Clinical Nutrition reports that people can generally obtain ample vitamin D levels from a combination of diet, supplements, and incidental protected sun exposure.5 This type of sun exposure can be obtained on a daily basis by simply walking around the block or mowing the lawn while wearing sunscreen with an SPF of at least 15 to thirty.
Dietary Sources of Vitamin D
Unfortunately, unless itâ€™s been added, there are few food sources that are rich in vitamin D. Thankfully, your body generally produces enough vitamin D from exposure to sunlight. During winter, or any time of year when sunlight exposure is limited however, consider eating a variety of foods that are naturally packed with vitamin D. These include:6
Supplementing Your Diet with Vitamin D
Since 2000, there has been a lot of controversy over the benefits of vitamin D supplementation and how much is sufficient. The current, recommended daily allowance (RDA) for vitamin D is based on age and is as follows:4
Higher doses of vitamin D, as recommended by your doctor, may be necessary to correct deficiencies (especially in winter) and for post-menopausal women.
Please note: Â As a supplement, taking too much vitamin D can lead to serious health consequences. Before purchasing a vitamin D supplement, talk to your healthcare provider about which dose of vitamin D is right for your specific health condition.
Author: Deborah Leader RN, BSN, PHN