Sources of vitamin D
There are 5 significant groups of vitamin D, with the primary sources covering D2 and D3. Ergosterol and ergocalciferol, also known as vitamin D2, are found in plants. The body develops cholecalciferol, or vitamin D3, from exposure to sunlight. This vitamin is stored in body fat and released when needed. All forms of vitamin D are absorbed in the small intestine and metabolized by the liver and kidneys. Vitamin D2 can be tolerated in larger amounts, but D3 is considered more potent and longer-lasting. Supplements come in both D2 and D3, which plays a part in the debate on sun exposure versus supplementation.
Sunlight and vitamin D
Sunlight exposure is one of the best natural sources of vitamin D, specifically vitamin D3. The UVB rays help synthesize the cholesterol in skin cells, initiating vitamin D production. Daily sunlight exposure can provide enough vitamin D3 for optimal health. However, several factors affect overall efficacy. The time of day, location, and body parts exposed to the sun play significant roles in vitamin D3 absorption. Skin color is another factor. People with lighter skin need less than 20 minutes per day. Darker skin complexions need more than 1 hour. Some studies show that sunlight can create 1000IU in just 15 minutes. In some cases, the body can produce more than 10,000IU in 1 hour.
Supplements and vitamin D
Vitamin supplements are a synthetic form of Vitamin D. D2 is created by irradiating yeast, fungus, and plant matter. On the other hand, D3 supplements come from animal sources. The biggest advantage of supplements is the ability to control the dosage. Some supplements come from as low as 400IU to as high as 10,000IU. As a result, doctors often prescribe vitamin D supplements to help treat deficiencies and related conditions. These deficiencies include poor calcium absorption, osteoporosis, hypothyroidism and immune deficiencies.
Can sunlight compare?
Being in the sun provides the most natural form of vitamin D. As naturally wonderful as sunlight is, in many ways, taking a supplement is the best bet. There are too many external factors that affect sun exposure. Insufficient sun exposure, weather, and current lifestyle cannot guarantee consistent daily sunlight. While helpful against overexposure, sunscreen may also limit the necessary UVB exposure for vitamin D. Consistent supplementation and consuming vitamin D-rich foods can make up for these deficiencies.
The best of both worlds
Sunlight and supplements can work together to ensure that you are getting the best of both forms of this essential vitamin. Physical factors like age, health and estimated sunlight exposure help determine appropriate dosages. If vitamin D deficiency is a concern, start with a simple blood test to check vitamin D levels. From there, speak with a doctor for the best supplement to improve health while limiting overdosing.