Fast Five Quiz: Common Nutritional Deficiencies

Romesh Khardori, MD, PhD

Disclosures

February 26, 2019

Vitamin D insufficiency is highest among people who are elderly, institutionalized, or hospitalized. In the United States, 60% of nursing home residents and 57% of hospitalized patients were found to be vitamin D-deficient. However, vitamin D insufficiency is not restricted to elderly and hospitalized persons; several studies have found a high prevalence of vitamin D deficiency among healthy, young adults. A study determined that nearly two thirds of healthy, young adults in Boston were vitamin D-insufficient at the end of winter.

Vitamin D deficiency is the most common cause of nutritional rickets. Rare genetic forms of rickets occur because of defects in vitamin D metabolism. Vitamin D-dependent rickets type I occurs because of a defect in renal 25-hydroxyvitamin D-1 alpha-hydroxylase that results in decreased 1,25(OH)2 D production. Vitamin D-dependent rickets type II occurs when a mutation exists in the VDR gene.

Although not always required for the diagnosis of vitamin D insufficiency, a serum PTH value may be used to help establish the diagnosis of vitamin D insufficiency. Often, patients with vitamin D insufficiency have a corresponding elevated PTH level, indicating secondary hyperparathyroidism. An inverse relationship exists between PTH and 25(OH)D levels. Usually, PTH levels decrease after the correction of vitamin D insufficiency.

Sensible sun exposure, especially between the hours of 10:00 AM and 3:00 PM, produces vitamin D in the skin that may last twice as long in the blood compared with ingested vitamin D. Individuals who do not have exposure to sunlight are at risk for vitamin D deficiency if they do not ingest adequate amounts of foods that contain vitamin D. However, most dietary sources of vitamin D do not contain sufficient amounts of the vitamin to satisfy daily requirements. Foods thought to contain high amounts of vitamin D3 are oily fish, such as salmon, mackerel, and bluefish, as well as fortified milk and other dairy products.

The following foods contain the indicated amounts of vitamin D, as reported by the US Department of Agriculture's Nutrient Data Laboratory:

  • Fortified milk (8 oz): 100 IU

  • Fortified orange juice (8 oz): 100 IU

  • Fortified cereal (1 serving): 40-80 IU

  • Pickled herring (100 g): 680 IU

  • Canned salmon with bones (100 g): 624 IU

  • Mackerel (100 g): 360 IU

  • Canned sardines (100 g): 272 IU

  • Codfish (100 g): 44 IU

  • Swiss cheese (100 g): 44 IU

  • Raw shiitake mushrooms (100 g): 76 IU

  • Most multivitamins (1 tab): 400 IU

Read more on vitamin D deficiency.

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