Date of Award

5-2003

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Susan Sullivan

Second Committee Member

Adrienne A. White

Third Committee Member

Phillip Pratt

Abstract

Vitamin D plays an important role in bone development during adolescence and a deficiency during this time may have detrimental effects on bone development later in life. With the inability to synthesize vitamin D during the winter months in Maine, this age group may be at higher risk for vitamin D insufficiency. The purpose of this study was to assess the vitamin D status of adolescent girls in Maine throughout the year to determine the extent of seasonal fluctuations in serum twenty-five hydroxyvitamin D (25(OH)D) levels. Another aspect of this study was to examine dietary intake of vitamin D during the winter months and determine if dietary intake of vitamin D in the subjects was adequate to maintain normal serum 25(OH)D levels. The final objective was to verify the reliability of the vitamin D fortification process in the three milk processing facilities in Maine, as milk is one of the few foods fortified with vitamin D.

Twenty-four adolescent girls between the ages of 10.4 and 13.1 years had serum 25(OH)D levels measured in September 2001 and again in March 2002. During January 2002 and February 2002, the twenty-four subjects kept food records for four, nonconsecutive days, and the subjects reported their food records during telephone interviews the next day. Reported intake was then entered into Nutritionist Pro (First Data Bank, 2001) and analyzed for average dietary intake of vitamin D from milk and other dietary sources. At the same time the food records were kept, milk samples from the three milk processors in Maine were purchased at local stores and analyzed for actual vitamin D content. This information was used to determine the accuracy of vitamin fortification of milk processed in Maine.

Although the mean dietary intake of vitamin D was just above the Adequate Intake (AI) of 5 pg, with 83% of dietary vitamin D intake coming from fluid milk, less than half of the subjects met the AI for vitamin D. Additionally, milk from one of the three processors in Maine averaged 80% of the fortification goal of 400 IU of vitamin D per quart of milk. There was a significant decrease in serum levels of 25(OH)D from September to March in the subjects with almost half of the subjects having serum 25(OH)D levels below the normal range to maintain health. With significant decreases in serum 25(OH)D levels from summer to winter in adolescent girls in Maine, the fortification of milk with vitamin D needs to be monitored to assure a consistent supply of vitamin D to the public. Further studies need to examine the extent of vitamin D insufficiency in adolescent girls in Maine. Also, an increased intake of dietary vitamin D should be encouraged to decrease the incidence of vitamin D insufficiency during adolescence.

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