29 Questions
Which of the following statements about fat-soluble vitamins is true?
Fat-soluble vitamins require bile and dietary fat for absorption.
What is the role of vitamin D according to the text?
Vitamin D is important for bone health, normal functioning of the parathyroid gland, and regulation of the immune system.
What is the transportation method for fat-soluble vitamins after absorption?
Transported with fats through the lymphatic system in chylomicrons before entering the blood.
How are water-soluble vitamins eliminated from the body?
In urine
What increases the risk of toxicity with high intakes of fat-soluble vitamins?
The ability to be stored in body fat
What is the main function of vitamin E?
Antioxidant protection
Which statement is true about water-soluble vitamins?
They cannot be stored in body fat and are eliminated in urine.
What is the risk of deficiency with fat-soluble vitamins, as mentioned in the text?
Intakes can vary without a risk of deficiency as long as there are average intakes over time.
What is the role of vitamin K?
Blood clotting and bone health
Why are fat-soluble vitamins not easily excreted, as mentioned in the text?
Because they can be stored in body fat
What is the role of Vitamin C in bone health?
Assists in the formation of healthy collagen, essential for bone health
What happens when concentrations of solutes in the blood increase?
The brain releases antidiuretic hormone (ADH) to signal the kidneys to reabsorb water
What is the principal positively charged ion inside cells?
Potassium (K+)
What is the recommended intake for adults for drinking water?
2.7-3.7 L/day
What happens in water intoxication (overhydration)?
Too much water relative to the amount of sodium in the body results in a drop of sodium levels
What are the early symptoms of mild dehydration?
Headache, fatigue, loss of appetite, dry eyes and mouth, dark-colored urine
What is the role of antidiuretic hormone (ADH) in response to increased plasma osmolarity?
ADH release increases and water is reabsorbed
What happens when solute concentration is low?
ADH level decreases, and more water is excreted into the urine
What is the consequence of a deficiency of water in the body?
Reduces the blood volume, affecting the delivery of oxygen and nutrients to cells
Which vitamin is primarily responsible for regulating calcium levels in the blood?
Vitamin D
What is the primary function of Vitamin E?
Acting as an antioxidant
How is Vitamin D synthesized in the skin?
Ultraviolet light converts 7-dehydrocholesterol to vitamin D3
Which vitamin is easily lost through urination and requires frequent replenishment?
Vitamin C
What is the active form of Vitamin D that regulates calcium levels in the blood?
1,25-dihydroxy vitamin D
Which vitamin is found in cell membranes and can have its antioxidant function restored by Vitamin C?
Vitamin E
What is the main role of Vitamin C in the body?
Acting as an antioxidant
Which vitamin is needed for collagen crosslinking and antioxidant functions?
Vitamin C
How is Vitamin E transported to the liver?
By chylomicrons
What converts 7-dehydrocholesterol to vitamin D3 in the skin?
Ultraviolet light
Study Notes
Vitamin D and Vitamin E Functions and Deficiencies
- Vitamin D is consumed in foods, obtained from fortified foods, synthesized in the skin, and travels in the blood to the liver.
- Ultraviolet light converts 7-dehydrocholesterol to vitamin D3 in the skin.
- Enzymes in the liver and kidneys convert vitamin D to its active form, 1,25-dihydroxy vitamin D, which regulates calcium levels in the blood.
- Vitamin D maintains calcium and phosphorus levels for various bodily functions, including bone mineralization and hormone release.
- Vitamin D deficiency leads to inefficient calcium absorption and bone abnormalities.
- Vitamin E primarily functions as an antioxidant, with alpha-tocopherol being the only form utilized by humans.
- Vitamin E is transported to the liver by chylomicrons and is needed for neutralizing free radicals.
- Water-soluble vitamins B and C are easily lost through urination and require frequent replenishment.
- Vitamin C acts as an antioxidant, aids in collagen production, and is important for the immune system and iron absorption.
- Collagen crosslinking and antioxidant functions are dependent on the presence of vitamin C.
- Reactive oxygen molecules, generated from environmental sources and cellular respiration, can be neutralized by vitamin C.
- Vitamin E, being lipophilic, is found in cell membranes and its antioxidant function can be restored by vitamin C, which donates an electron back to it.
Test your knowledge of vitamin D and vitamin E functions and deficiencies with this quiz. Learn about their sources, conversion processes, roles in the body, and the impact of deficiencies.
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