nutri sci - 2

What are vitamins?

Organic compounds (C, H, N, O, S, P) found in small quantities in the diet, essential for basic functions.

What are the fat-soluble vitamins?

A, D, E, and K.

How are fat-soluble vitamins absorbed and transported?

Similar to that of fat.

Where can fat-soluble vitamins be stored?

Mainly in the liver and adipose tissue.

What is the risk of high doses of fat-soluble vitamins?

They can be toxic.

What is vitamin E known for?

It is an antioxidant.

What is the most relevant form of vitamin E?

Alpha-tocopherol.

How is vitamin E absorbed?

Absorbed with fats, incorporated into chylomicrons for circulation.

Where is vitamin E processed?

In the liver.

How is vitamin E excreted?

Via bile, feces, and urine after being processed in the liver.

What is the recommended dietary allowance (RDA) for vitamin E?

15 mg/day.

What is the upper limit for vitamin E intake?

Around 1000 mg/day.

What are the symptoms of vitamin E deficiency?

Retinopathy, peripheral neuropathy, ataxia, and lower immune function.

Which foods are high in vitamin E?

Especially vegetable oils.

What can destroy vitamin E?

Heat and oxidation.

What is vitamin A classified as?

A family of compounds known as retinoids.

What are the functions of vitamin A?

Light absorbing pigment in the eye and regulation of gene expression.

What is the active form of vitamin A?

Retinoic acid.

In what food sources is pre-formed vitamin A found?

Animal products, liver, dairy products, eggs, fish, and fortified foods.

What are carotenoids?

Plant pigments found in many fruits and vegetables that can be converted into Vitamin A.

What is beta-carotene?

A source of provitamin A that requires the enzyme BCO1 for conversion into Vitamin A.

What is the absorption efficiency of retinol and beta-carotene in the small intestine?

70-90% for retinol and lower for carotenoids.

What factors enhance the absorption of carotenoids?

Processing, such as cooking, can increase absorption.

What is the RDA for vitamin A for men and women?

900 µg RAE for men, 700 µg RAE for women.

What is the upper limit for vitamin A intake?

3000 µg.

What is a common deficiency symptom of vitamin A?

Night blindness and xerophthalmia.

What is the main function of vitamin K?

Primarily blood clotting.

How does vitamin K participate in bone health?

It is essential for the activation of proteins that participate in bone calcification.

What impact does warfarin have on vitamin K?

It interferes with the recycling of Vitamin K.

How is vitamin K absorbed?

In the small intestine, requiring fat/bile acids.

What is the RDA for vitamin K in men and women?

120 µg for men, 90 µg for women.

What food sources are high in vitamin K?

Green leafy vegetables.

What is the definition of vitamin D?

A fat-soluble vitamin important for maintaining calcium and phosphorus levels in the body.

What are the main food sources of vitamin D?

Liver, beef, veal, eggs, and fortified foods.

How is vitamin D absorbed?

About 50% efficiently in the distal ileum of the small intestine.

What role does sunlight play in vitamin D?

It synthesizes the majority of vitamin D from sun exposure.

What is the active form of vitamin D?

1,25-(OH)2D3 (calcitriol).

What regulates vitamin D metabolism?

Negative feedback on its own breakdown.

What deficiency disease is associated with vitamin D?

Osteomalacia in adults and rickets in children.

What is the upper limit of vitamin D intake?

4000 IU.

What is the principle of extracellular fluid (ECF)?

ECF accounts for ⅓ of body water.

What role does sodium play in fluid balance?

It's critically important for regulating body water and electrolyte balance.

What is the major ECF cation?

Sodium (Na+).

What are the two types of water loss in the body?

Insensible and sensible water loss.

How much water intake is recommended per kcal expended?

About 1 mL of water per kcal expended.

What hormone regulates water reabsorption?

Antidiuretic hormone (ADH).

What triggers the release of renin?

Decreased blood pressure.

What is the consequence of sodium deficiency?

Symptoms include muscle cramps, mental apathy, and loss of appetite.

What can acute sodium toxicity lead to?

Edema and hypertension.

What role does potassium play in the body?

It is a principal cation inside cells, critical for fluid balance, nerve, and muscle function.

What are the dietary requirements for potassium?

Minimum 2000 mg/day.

What is hypokalemia?

Low blood potassium levels.

What can cause hyperkalemia?

Overuse of potassium supplements.

What is the structure of the nephron?

The functional unit of the kidney.

What is the main function of the glomerulus?

Site of plasma filtration into the renal tubules.

What is the role of hormonal control in kidney function?

Regulates water and electrolyte balance.

What does the term 'excretion' refer to in kidney function?

Removal of final urine to the bladder.

What triggers the thirst sensation?

Excessive loss of body water leading to increased ECF osmolarity.

What can result from water intoxication?

Swelling of brain cells causing nausea, headache, and possibly coma.

What is the typical response to increased ECF osmolarity?

Strong desire to drink water.

What does ACE inhibitors do?

They lower blood pressure by inhibiting conversion of angiotensin 1 to angiotensin 2.