L9 Fat-Soluble Vitamins Quiz

Basics of Human Nutrition

• This is a course titled NUTR 202, part of the Department of Clinical Nutrition.
• The course covers fundamental aspects of human nutrition, particularly fat-soluble vitamins.

Fat-Soluble Vitamins

• Learning objectives include identifying vitamin types, functions, sources, and requirements.
• Students will also learn about symptoms and diseases associated with deficiencies of discussed vitamins.

Learning Objectives

• Students should be able to identify the types and functions of different vitamins.
• Students should know at least two sources of each vitamin.
• Understand the symptoms or diseases from vitamin deficiencies.

Introduction

• Fat-soluble vitamins differ from water-soluble vitamins.
• They require bile for digestion/absorption.
• They travel through the lymphatic system.
• Excesses are stored in adipose tissues.
• They are not readily excreted, increasing the risk of toxicity.
• The answer to the question about fat-soluble vitamins is given in the form of bullet points.

Antioxidants

• Antioxidants protect cells from free radicals.
• Free radicals have an unpaired number of electrons.
• These radicals form when oxygen interacts with molecules.
• These form reactive molecules which can damage cells like DNA and membranes.
• Antioxidants safely interact with free radicals, preventing cell damage.

Vitamin A

• Vitamin A consists of retinoids.
• Retinoids include retinol, retinal, retinoic acid and retinyl esters.
• Functions include critical roles in vision, bone growth, reproduction, cell division, regulation of the immune system, and antioxidant activity.
• A vitamin A precursor is Beta-carotene.
• Animal forms of vitamin A are more effective than plant forms.
• Vitamin A's role in vision involves light converting to electrical impulses.
• The retina cells contain rhodopsin (a protein+retinal).
• Light changes cis-retinal to trans-retinal which sends electrical signals to the brain.
• Vitamin A's role in maintaining mucous membrane integrity is critical for healthy cells.
• Reproduction and growth are also important functions of vitamin A.
• It is important for sperm development, normal fetal development and growth.
• Crucial for bone remodeling, too.
• Vitamin A deficiency is prevalent in developing countries.
• Deficiency can lead to increased risk of infectious diseases, causing night blindness/blindness (xerophthalmia).
• Keratinization is a characteristic symptom when vitamin A is deficient.
• This can block hair follicles causing white lumps or hyperkeratosis.
• Vitamin A toxicity is possible with concentrated amounts from supplements.
• It can damage cells, especially with high intakes.
• Children are most vulnerable to this.
• Vitamin A toxicity can lead to bone and birth defects.

Vitamin D

• Vitamin D exists in two forms: cholecalciferol (animal) and ergocalciferol (plant).
• Both forms need activation before functioning fully.
• The active form of vitamin D is 1,25-dihydroxycholecalciferol.
• Vitamin D is stable and not easily oxidized.
• It's not affected by storage, or processing of food.
• Vitamin D is a hormone essential to making/maintaining bones.
• It aids in the absorption of calcium and phosphorus.
• Protects against cognitive decline in brain and nerve cells.
• Vitamin D deficiency can be from dark skin, lack of breastfeeding, lack of sunlight exposure, or low consumption of fortified milk.
• The likely deficiency associated with lack of Vitamin D is Calcium.
• Rickets is a symptom of vitamin D deficiency.
• This may cause bowed legs and beaded ribs.
• Vitamin D toxicity is rare.
• Excess amounts via supplements are dangerous.
• Excess can raise blood calcium levels and form stones in soft tissues.
• Excess vitamin D can harden vessels and lead to death.
• The best sources of vitamin D are sunlight exposure, animal products (fatty fish and beef liver), and small amounts in dairy products.

Vitamin E

• Vitamin E has two subgroups: tocopherols and tocotrienols.
• Only alpha-tocopherol remains in the body.
• Its main function is an antioxidant.
• It is aided by vitamin C and selenium.
• Transported in blood by lipoproteins.
• It prevents hemolytic anemia in premature infants.
• Its antioxidant properties are used commercially to prevent food spoilage.
• Primary deficiency is rare. Secondary may be from fat malabsorption (like cystic fibrosis).
• Deficiency can lead to splitting of red blood cells due to oxidized PUFAs—leading to anemia, neuromuscular dysfunction.
• Muscle coordination, reflex effects, vision can be impaired.
• Vitamin E Toxicity is rare. But high doses can interfere with vitamin K blood-clotting activity
• Liver regulates Vitamin E levels.
• The most significant sources are vegetable oils, seeds and nuts.

Vitamin K

• Vitamin K consists of several compounds crucial for blood clotting.
• It is destroyed by light and alkalis.
• Absorbed from the small and slightly larger intestine—needs bile from the liver and fats in the diet.
• Newborns are given a dose by intramuscular injection.
• The blood-clotting process depends on several factors that use vitamin K.
• Primary vitamin K deficiency is rare. Secondary can be from antibiotic use or bile production issues in the liver, sterilizing the gut
• Insufficient dietary intake, or antibiotic use can lead to a deficiency.
• Babies have sterile guts, so vitamin K is often given at birth due to this.
• Vitamin K toxicity is not common and generally doesn't have adverse effects with high intakes, there is no UL.
• High doses potentially reduce the effectiveness of blood thinners.
• Good sources of vitamin K are green vegetables (collards, spinach, cabbage).
• There is also vitamin K in vegetable oils like soybean and canola oils.

Test your knowledge on fat-soluble vitamins in the NUTR 202 course. This quiz covers types, functions, sources, and deficiency symptoms of these essential nutrients. Perfect for students wanting to reinforce their understanding of human nutrition.