Vitamin D (also called “calciferol”) is a fat-soluble vitamin many people don’t get enough of. In fact, some studies have shown that more than 40% of Americans have a vitamin D deficiency. Known as the “sunshine vitamin” due to the skin’s ability to produce vitamin D when exposed to ultraviolet (UV) rays from sunlight, it has numerous health benefits for people of all ages.  

Why Is It Important? 

Vitamin D has numerous benefits. Studies have shown that it promotes calcium absorption in the gut and aids in maintaining adequate calcium and phosphate levels. This process is essential to preventing bone disorders such as rickets in children and osteomalacia and osteoporosis in adults. In addition, vitamin D has been shown to reduce inflammation, promote glucose metabolism, regulate the immune system, and improve mood. Research has also shown that it can potentially aid in preventing certain cancers, multiple sclerosis, and even cardiovascular disease, although studies are ongoing.  

How Do We Get Vitamin D?  

Vitamin D is naturally present in foods such as fish-liver oils, fatty fish (such as salmon), mushrooms, egg yolks, and liver. In some countries, such as the United States, vitamin D is often added to milk and other foods. It is also produced from cholesterol in your skin with adequate sun exposure. The amount of vitamin D a person’s skin makes when in the sun depends on many factors, including skin tone, geographic location, weather conditions, time of year, and time of day. 

How Much Is Enough?  

The skin can only produce a limited amount of vitamin D at one time. Once the body has reached this limit, spending more time in the sun will not continue to increase vitamin D levels. Some studies have indicated that 10-15 minutes of sun exposure three times per week is enough to maintain healthy levels among adults. However, this can vary based on skin color, location, etc. It’s important to remember that excess sun exposure can increase the risk of skin cancer and that there is currently no known level of sun exposure that increases vitamin D levels without increasing the risk of skin cancer.  

Current dietary guidelines recommend a total daily intake of 15 mcg (600 IU) for adults aged 19-50 and 20 mcg (800 IU) for adults > 70. Taking more than the recommended amount is not beneficial and can potentially be harmful. Because vitamin D increases calcium absorption in the gastrointestinal tract, too much vitamin D can lead to elevated calcium levels within the blood (hypercalcemia), which can produce symptoms such as nausea, vomiting, muscle weakness, pain, loss of appetite, dehydration, excessive urination, excessive thirst, and kidney stones. 

Final Verdict 

Regular sun exposure is the most natural way to get enough vitamin D. Studies show that 10-15 minutes daily, three times a week, is enough time to maintain recommended levels. However, if you’re planning to stay in the sun for an extended period of time, it’s best to apply sunscreen after 10–30 minutes of unprotected sun exposure to help prevent sunburn and skin cancer. Vitamin D can also be obtained from milk, other fortified foods, eggs, fish oil, and liver. If taking a supplement, make sure not to take more than the recommended daily amount to avoid toxicity.  

As always, speak with your healthcare provider before starting new supplements or activities to determine the right option for you.