FAT-SOLUBLE VITAMINS

Chapter Introduction

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Soak Up the Sun? AN AILING GORILLA INSPIRES A LIFELONG INTEREST IN VITAMINS.

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LEARNING OBJECTIVES

Identify the fat-soluble vitamins and their primary functions (Infographic 10.1)
Describe the properties of the fat-soluble vitamins (Infographic 10.2)
Describe the role of vitamin D in blood calcium regulation (Infographic 10.3)
Identify excellent dietary sources of the fat-soluble vitamins (Infographics 10.4, 10.5, 10.9, and 10.11)
Describe the role of vitamin A in healthy vision (Infographic 10.6)
List sources of free radicals and describe how antioxidants can block oxidative damage (Infographics 10.7 and 10.8)
Explain how vitamin E works as an antioxidant in the cell membrane (Infographic 10.10)

In 2005, Michael Holick, PhD, MD, received a desperate call. Kimani, a young lowland gorilla—the first to be born at a local zoo—was dying. Could he help?

RICKETS a condition caused by vitamin D deficiency, characterized by “bowed” legs due to impaired bone mineralization, softening of bones, skeletal malformations, and muscular weakness

When Holick, an endocrinologist at Boston University, arrived at Franklin Park Zoo, his heart broke. The seven-month-old gorilla was so weak she could hardly nurse from her mother and her parents were exhibiting obvious signs of stress. After examining her, Holick could see immediately that Kimani had many signs of a disease called rickets, in which inadequate intake, or improper absorption or utilization of a few minerals leads to bone malformations and muscle weakness.

In humans, rickets affects bone development in children usually because of an extreme vitamin D and calcium deficiency. Although it is a relatively rare condition among humans in the United States, here it was in a young gorilla in captivity.

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Kimani the lowland gorilla suffered from the deficiency disease rickets, but her condition improved when given supplementary vitamin D.

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Kimani’s doctors had tried giving her a vitamin D supplement, but it hadn’t made much of a difference. Holick im-mediately told them to increase the dosage more than tenfold; this was no time to be conservative. Fortunately, Kimani responded to the treatment and her symptoms significantly improved. Although she will likely never be as tall as other gorillas her age, she eventually recovered from her bout with rickets. At her first birthday party, Holick was the guest of honor. The experience fascinated Holick and launched a lifelong interest in the functions of vitamins.

Vitamins are abundant in whole foods such as fruits and vegetables.

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