ISSA Nutritionist Practice Exam

Which nutrient do many Americans regularly lack in their diets?

1. Vitamin A

2. Calcium

3. Vitamin D

4. Iron

The correct answer is: Vitamin D

Many Americans commonly lack vitamin D in their diets, primarily due to insufficient sunlight exposure and dietary intake. Vitamin D plays a crucial role in various bodily functions, including calcium absorption, maintaining bone health, and supporting the immune system. The body can produce vitamin D when the skin is exposed to sunlight, which is a primary source for many individuals. However, factors such as geographic location, lifestyle, skin tone, and the use of sunscreen can limit sunlight exposure, consequently reducing vitamin D synthesis. Additionally, while some foods are fortified with vitamin D (like dairy and cereals), many diets do not contain adequate levels of this nutrient, leading to deficiencies. In contrast, while some populations may be at risk for deficiencies in calcium, iron, or vitamin A, vitamin D deficiency is particularly widespread and often underdiagnosed. Thus, focusing on increasing vitamin D intake through diet or supplementation is important for addressing this common deficiency in the American population.