Vitamin D: Are We Getting Enough?


Vitamin D is an essential nutrient that has gained a significant amount of attention as of late. According to recent research, studies suggest that this vitamin may go beyond bone health and extend into other critical functions such as cognitive and immune health, as well as reducing the risk of certain diseases such as cancer, heart disease, stroke, and diabetes.

In regards to vitamin D's food sources, unless you enjoy a diet including fatty fish (salmon, tuna, swordfish, sardines) or cod liver oil, it can be hard to get enough vitamin D naturally without eating additional fortified foods or supplements. Fortified dairy and/or plant milk products, cereals and orange juice are often excellent sources of vitamin D. Mushrooms (great source for vegans/vegetarians), eggs, cheese, and beef liver contain small amounts of vitamin D.

While diet is a reliable source to obtain vitamin D, there is also another route. Vitamin D is unique from other nutrients as it acts as a hormone that the body can synthesize from the sun, also referred to as cholecalciferol (D3). Although there are two major ways of attaining vitamin D (food intake and sun exposure), there is still an estimated 40-75% of people worldwide that are deficient in vitamin D levels. Researchers have concurred the combination of sparse vitamin D food sources, as well as limited sun exposure due to potential geographical and cultural barriers are to blame for this apparent vitamin D deficiency.

Although the sun is an excellent source of vitamin D, the high risks of extended sun exposure must be kept in mind. There are many factors that can affect the skin’s ability to produce vitamin D, including season, time of day, latitude, air pollution, cloud coverage, sunscreen, body exposure, skin color, and age. While physicians may push for a greater vitamin D intake, it is important to consider the detrimental health risks, such as skin cancer. This is why it is not only crucial to apply sunscreen, but also consult with your doctor whether or not taking supplements is a good idea. Since it is difficult to determine exactly how much vitamin D you obtain from time in the sun, it is important to weigh the risks of skin cancer with potential vitamin D health benefits.

ARE WE GETTING ENOUGH?

The majority of people on a global scale are not obtaining enough vitamin D, as most are not consuming and/or spending enough time in the sun to obtain the proper levels. The Recommended Daily Allowance (RDA) for vitamin D for adults 19 years and older is approximately 600 IU (15 mcg) daily for men and women, and for adults >70 years it is approximately 800 IU (20 mcg) daily. Older adults need more vitamin D because throughout aging, the skin is less efficient in producing vitamin D, as well as less sun exposure due to less time spent outside.

Recent research suggests that going over the recommended vitamin D intake levels can present a multitude of potential health benefits. These benefits are no longer limited to bone health, as evidence has quickly revealed its role in overall health and longevity. Some of these health benefits include muscle strength, heart disease prevention, cancer prevention, increased immune function, and reducing the risk of premature death to name a few.

However, there is such a thing as too much vitamin D. This is why it is appropriate to stay within the established Tolerable Upper Limit (TUL) of 4,000 IU. This number meets the needs of most healthy people, and gives physicians the confidence to recommend supplementation, and allow research at higher vitamin D levels. There is a potential to obtain too much vitamin D in supplemental form, but not from sun exposure due to the skin’s regulatory role, only producing what is needed.

SPECIAL NOTE FOR OUR RUNNERS AND OUTDOOR ENTHUSIASTS:

The great thing about spending a sufficient amount of time outdoors is that vitamin D levels are met with ease. Whether you are training for a marathon, swimming laps in an outdoor pool, or taking a long walk on a trail, regular sun exposure is the most efficient and natural way to receive enough vitamin D. With just 10-30 minutes of midday sunlight, several times per week, healthy blood levels of vitamin D can be maintained. If you find yourself spending more time outdoors than this, and at peak hours of sunshine, it is crucial to remember to apply (and re-apply) sunscreen. If you have darker skin you may need to spend a tad bit more time outside in order to gain enough vitamin D, as exposure time depends on your skin’s sensitivity to the sunlight.

Overall, let’s make sure we are getting adequate amounts of vitamin D in order to best benefit our health long-term. Eat a variety of foods in your diet, and spend at least 10-30 minutes in the sunshine several times per week. Through our diet and lifestyle, we can maintain proper vitamin D levels to keep our bones, brain, heart, and immune system at their very best!

By: Erika Richter, Intern