Page 113 - The Manga Guide to Biochemistry
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Vitamin D is also a type of steroid created from cholesterol. Since Vitamin D is pro-
duced when ultraviolet rays strike our skin, it’s very important for human beings
to be exposed to the sun.
Ultraviolet (UV) ray
Cholesterol 7-Dehydrocholesterol CH2
OH
HO Vitamin D3
In addition, cholesterol plays other very important roles, such as being a raw
material of bile acid,* which is required for digestion and the absorption of fat in the
small intestine.
Wow! Cholesterol has a ton of important jobs! I had no idea...
That’s right. When people who pay attention to their health (like your father) talk
about cholesterol, usually a negative image, like arteriosclerosis or obesity, comes to
mind, but cholesterol is actually an extremely important substance for our bodies.
Jeez, now I’m really confused. Why does such a vital substance make us think of
illness, unhealthiness, or being overweight?
Don’t worry, we’ll unravel that mystery soon enough...
* Bile acid is created in the liver, stored in the gallbladder, and secreted to the duodenum.
Biochemistry in Our Everyday Lives 99
