ACE Health Coach Certification Practice Test

Which micronutrient can be induced in the body through small amounts of sunlight exposure?

1. Iodine

2. Vitamin D

3. Phytochemical

4. Vitamin E

The correct answer is: Vitamin D

Vitamin D is unique among micronutrients because it can be synthesized by the body when the skin is exposed to ultraviolet B (UVB) rays from sunlight. This process begins when UVB rays convert a compound in the skin, 7-dehydrocholesterol, into pre-vitamin D3, which is subsequently transformed into active vitamin D (calcitriol) through further conversion in the liver and kidneys. This natural synthesis is a crucial mechanism for maintaining adequate levels of vitamin D, which is essential for bone health, immune function, and overall well-being. In contrast, iodine, phytochemical, and vitamin E do not have a similar synthesis pathway involving sunlight. Iodine must be obtained through diet, primarily from seafood, dairy products, and iodized salt. Phytochemicals are compounds produced by plants, and while beneficial, they are not synthesized by the body. Vitamin E is also acquired through dietary sources like nuts, seeds, and vegetable oils and does not involve any sun exposure for its synthesis. Thus, the ability to produce vitamin D via sunlight exposure sets it apart as the correct answer.