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Semester 2: Micronutrients
Fat soluble vitamins: Chemistry, functions, digestion, absorption, utilization, transport, deficiency, toxicity, interaction
Fat soluble vitamins
Chemistry
Fat soluble vitamins include vitamins A, D, E, and K. They are characterized by their solubility in fats and oils, allowing them to be stored in the liver and fatty tissues. These vitamins are organic compounds and play crucial roles in various bodily functions, including vision, bone health, and antioxidant protection.
Functions
- Vitamin A: Essential for vision, immune function, and skin health. - Vitamin D: Regulates calcium and phosphorus metabolism, promotes bone health. - Vitamin E: Acts as an antioxidant, protecting cell membranes from oxidative damage. - Vitamin K: Important for blood clotting and bone metabolism.
Digestion
Fat soluble vitamins are primarily absorbed in the small intestine along with dietary fats. Their absorption depends on the presence of bile salts, which emulsify fats and facilitate the uptake of these vitamins.
Absorption
In the intestines, fat soluble vitamins are incorporated into micelles and absorbed through the intestinal wall. The presence of dietary fat enhances their absorption, and they are transported as part of chylomicrons into the lymphatic system before entering the bloodstream.
Utilization
Once in the bloodstream, fat soluble vitamins are transported by carrier proteins to various tissues. They can be stored in the liver and adipose tissue, releasing them into circulation as needed for physiological functions.
Transport
Transport of fat soluble vitamins occurs via lipoproteins and specific binding proteins. For instance, vitamin A is transported by retinol-binding protein, while vitamin D is carried by vitamin D binding protein.
Deficiency
Deficiencies in fat soluble vitamins can lead to various health issues: - Vitamin A deficiency: Night blindness, immune dysfunction. - Vitamin D deficiency: Rickets in children, osteoporosis in adults. - Vitamin E deficiency: Neuromuscular problems. - Vitamin K deficiency: Increased bleeding risk.
Toxicity
Fat soluble vitamins can accumulate in the body, leading to toxicity if taken in excessive amounts. Symptoms include: - Vitamin A toxicity: Liver damage, headache, blurred vision. - Vitamin D toxicity: Hypercalcemia, kidney damage. - Vitamin E toxicity: Increased bleeding risk. - Vitamin K toxicity: Interference with anticoagulant medications.
Interaction
Fat soluble vitamins can interact with each other and other nutrients. For example, high doses of vitamin E can interfere with vitamin K activity, impacting blood clotting. Synergistic relationships also exist, such as between vitamins A and D in bone health.
Water soluble vitamins: Types, chemistry, functions, same aspects as fat soluble
Water soluble vitamins
Types of Water Soluble Vitamins
Water soluble vitamins include Vitamin B complex and Vitamin C. Vitamin B complex consists of several vitamins such as B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin). Vitamin C is also a part of this category.
Chemistry of Water Soluble Vitamins
Water soluble vitamins typically contain various functional groups and polar structures that allow them to dissolve in water. Most of these vitamins have complex carbon structures with nitrogen and sulfur in addition to hydroxyl and carboxyl groups, contributing to their reactivity and solubility.
Functions of Water Soluble Vitamins
These vitamins are vital for numerous physiological functions including energy metabolism, red blood cell production, immune function, and collagen synthesis. They are involved in enzymatic reactions, acting as coenzymes or precursors for vital biochemical processes.
Comparison with Fat Soluble Vitamins
Unlike fat soluble vitamins (A, D, E, K), which require dietary fats for absorption and can be stored in the body's fatty tissues, water soluble vitamins are absorbed directly into the bloodstream and excess amounts are excreted through urine. This necessitates the regular intake of water soluble vitamins through diet.
Sources of Water Soluble Vitamins
Water soluble vitamins are found in a variety of foods. Fruits, vegetables, whole grains, legumes, and lean meats are rich sources. For instance, citrus fruits provide Vitamin C, while various grains and meats provide B vitamins.
Macrominerals: Calcium, phosphorus, magnesium, sulfur, chlorine, sodium, potassium - distribution, digestion, utilization, deficiency, toxicity
Macrominerals: Calcium, Phosphorus, Magnesium, Sulfur, Chlorine, Sodium, Potassium
Calcium
Calcium is widely distributed in the body, primarily in bones and teeth. It represents about 1.5 to 2 percent of body weight.
Calcium is absorbed in the intestines via active transport and passive diffusion. The presence of vitamin D enhances absorption.
Used for bone formation, muscle contractions, blood clotting, and nerve transmission.
Symptoms include brittle bones, rickets in children, and osteoporosis in adults.
Excess calcium can lead to kidney stones, constipation, and impaired absorption of other minerals.
Phosphorus
Phosphorus is found in every cell of the body, with high concentrations in bones and teeth, composing about 85 percent of the body's phosphorus.
Phosphorus absorption occurs in the small intestine and is influenced by dietary factors.
Essential for bone health, energy metabolism, and the formation of DNA and RNA.
Can lead to bone pain, weakness, and disruptions in energy metabolism.
High levels can result in cardiovascular disease and may lead to renal damage.
Magnesium
Magnesium is predominantly found in bones, followed by muscles and soft tissues, constituting about 0.05 percent of body weight.
Absorbed mostly in the small intestine through active transport.
Involved in over 300 enzymatic reactions, muscle function, and nerve transmission.
May cause muscle cramps, anxiety, and cardiovascular disturbances.
Excessive magnesium can lead to diarrhea, lethargy, and cardiac arrest.
Sulfur
Sulfur is part of amino acids and forms various compounds in the body; it is found in skin, hair, and nails.
Sulfur is obtained from dietary proteins and is metabolized into sulfates in the liver.
Important for protein synthesis, antioxidant function, and detoxification processes.
Rare but may cause joint pain and inflammation.
High sulfur levels can result in gastrointestinal disturbances.
Chlorine
Chlorine is mainly found in extracellular fluid as chloride ions, contributing to fluid balance.
Absorbed in the intestines, primarily from dietary salt.
Crucial for maintaining osmotic pressure, fluid balance, and stomach acid production.
Can lead to disturbances in acid-base balance and dehydration.
High levels may cause high blood pressure and kidney problems.
Sodium
Sodium is predominantly found in extracellular fluid, essential for hydration and nerve function.
Readily absorbed in the intestines.
Vital for fluid balance, nerve transmission, and muscle contraction.
Can lead to hyponatremia, causing headaches, fatigue, and confusion.
Excess sodium intake is linked to hypertension and cardiovascular diseases.
Potassium
Potassium is primarily found inside cells, and it is vital for cellular function.
Absorbed in the intestine, with a significant intake from fruits and vegetables.
Key for maintaining fluid balance, muscle contractions, and heart function.
Can cause muscle weakness, cramps, and cardiovascular issues.
Elevated potassium levels can lead to cardiac arrhythmias and muscle paralysis.
Micro and trace elements: Iron, copper, iodine, fluoride, zinc, selenium, chromium, molybdenum, manganese, nickel, cadmium - physiological functions, deficiency, toxicity
Micronutrients
Iron
Essential for oxygen transport and storage, part of hemoglobin and myoglobin.
Can lead to anemia, fatigue, weakened immune function.
Excessive iron can cause organ damage and is toxic, leading to conditions like hemochromatosis.
Copper
Involved in iron metabolism, collagen synthesis, and neuropeptide production.
May result in anemia, bone abnormalities, and increased susceptibility to infections.
High levels can cause liver damage and neurological problems.
Iodine
Crucial for the production of thyroid hormones which regulate metabolism.
Can lead to goiter and developmental issues, particularly in pregnant women.
Excessive iodine can cause thyroid dysfunction, leading to hyperthyroidism.
Fluoride
Important for dental health and bone strength.
Can increase susceptibility to dental caries.
Excessive fluoride can lead to dental fluorosis and skeletal fluorosis.
Zinc
Vital for immune function, protein synthesis, wound healing, and DNA synthesis.
May cause growth retardation, hair loss, and increased risk of infection.
Can lead to nausea, vomiting, loss of appetite, and impaired immune function.
Selenium
Antioxidant properties and important for thyroid hormone metabolism.
Can cause Keshan disease and affect immune function.
Excess selenium can lead to selenosis, with symptoms like gastrointestinal issues and hair loss.
Chromium
Enhances insulin action and is important in carbohydrate, fat, and protein metabolism.
May result in impaired glucose tolerance, leading to diabetes.
Generally low risk, but excessive amounts can lead to respiratory issues.
Molybdenum
Involved in enzyme function and metabolism of sulfur-containing amino acids.
Rare, but may cause metabolic disturbances in severe cases.
Excessive molybdenum can lead to gout-like symptoms.
Manganese
Involved in bone formation, blood sugar regulation, and antioxidant function.
Can lead to impaired growth, skeletal abnormalities, and reproductive issues.
Excess can cause neurotoxicity and a Parkinson-like syndrome.
Nickel
Role in enzyme function, especially in the metabolism of certain hormones and lipids.
Not well-documented, but may affect certain enzyme activities.
High levels can cause allergic reactions and respiratory issues.
Cadmium
Not essential, but can affect certain biological processes at low levels.
Not applicable as it is not an essential nutrient.
Can lead to kidney damage, bone loss, and is classified as a human carcinogen.
Homeostasis maintenance: Electrolyte content, functions, sodium, potassium, chloride absorption and imbalance, hydrogen ion balance, water functions and balance
Homeostasis maintenance: Electrolyte content, functions, sodium, potassium, chloride absorption and imbalance, hydrogen ion balance, water functions and balance
Electrolyte Content
Electrolytes are minerals in the body that carry an electrical charge. Key electrolytes include sodium, potassium, and chloride. They are essential for various physiological functions, including nerve transmission, muscle contraction, hydration, and pH balance.
Functions of Electrolytes
Each electrolyte plays crucial roles: Sodium helps regulate fluid balance and blood pressure. Potassium is vital for proper muscle function and heart health. Chloride contributes to stomach acidity and maintaining osmotic pressure.
Sodium Absorption and Imbalance
Sodium is primarily absorbed in the small intestine and plays a significant role in maintaining fluid balance. An imbalance, either through excess intake or loss, can lead to hypernatremia or hyponatremia, affecting blood pressure and overall health.
Potassium Absorption and Imbalance
Potassium is absorbed via the intestinal tract and is important for nerve signal transmission and muscle contraction. Imbalances can result in hyperkalemia or hypokalemia, posing risks such as cardiac arrhythmia.
Chloride Absorption and Imbalance
Chloride absorption occurs mainly in the intestines along with sodium. It works closely with sodium to help maintain electrolyte balance. An imbalance can lead to conditions such as metabolic acidosis or alkalosis.
Hydrogen Ion Balance
Hydrogen ions play a crucial role in maintaining the body's pH balance. The body regulates hydrogen ion concentration through buffers, respiratory control, and renal function, ensuring that the internal environment remains stable.
Water Functions and Balance
Water is critical for life, functioning as a solvent, temperature regulator, and nutrient transporter. Homeostasis requires maintaining water balance, with inputs from ingestion and outputs through urine, sweat, and respiration.
