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Vitamin B12
Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Vitamin B12 in Present Knowledge in Nutrition. In homeotherms on a balanced test ration the niacin requirement is generally estimated to be about ten times that of the thiamine requirement. It is essential for cardiovascular function, and development and function of skeletal muscle , the retina , and the central nervous system. Together, the "Big Six" are the elemental macronutrients for all organisms. Ascorbic acid is involved in the formation of chondroitin sulphate and intercellular ground substance. Neurological changes, such as numbness and tingling in the hands and feet, can also occur [ 5 , 31 ].

What is a Nutrient?

Plant Parts and Their Functions

Of the six essential nutrients you just read about, 3 of them are called Macronutrients, while the other 2 are Micronutrients. Macronutrients include carbohydrates , fats , and proteins. They are called macronutrients as they are required in large amounts to fuel the body. Energy is measured in calories and they are essential for the body to grow, repair and develop new tissues, conduct nerve impulses and regulate life process.

You probably wonder if water should be included in this category. Water might not always be considered a macronutrient, but it sure is an essetial nutrient needed for all body functions in large amounts. Water regulates the body temperature by our sweat. Remember that water contains no calories. These nutrients include minerals and vitamins. Unlike macronutrients, these are required in very minute amounts. Together, they are extremely important for the normal functioning of the body.

Their main function is to enable the many chemical reactions to occur in the body. Nevertheless micronutrients do not function for the provision of energy. These nutrients are necessary for the body to function properly. The six essential nutrients include carbohydrates, protein, fat, vitamins, minerals and water. Carbohydrates are the main energy source for the brain. Without carbohydrates, the body could not function properly.

Sources include fruits, breads and grains, starchy vegetables and sugars. Make at least half of the grains you consume whole grains. Whole grains and fruit are full of fiber, which reduces the risk of coronary heart disease and helps maintain normal blood glucose levels.

Protein is the major structural component of cells and is responsible for the building and repair of body tissues. Protein is broken down into amino acids, which are building blocks of protein. Nine of the 20 amino acids, known as essential amino acids, must be provided in the diet as they cannot be synthesized in the body. Ten to 35 percent of your daily calories should come from lean protein sources such as low-fat meat, dairy, beans or eggs.

Fat is an energy source that when consumed, increases the absorption of fat-soluble vitamins including vitamins A, D, E and K. Twenty to 35 percent of your daily intake should come from fat. Choose healthy options such as omegarich foods like fish, walnuts and vegetable-based oils. Omega-3s help with development and growth. Limit intake of saturated fats such as high-fat meats and full-fat dairy.

The principal biological functions of calcium may be summarised as follows;. Calcium is essential for the normal clotting of blood, by stimulating the release of thromboplastin from the blood platelets. Calcium is an activator for several key enzymes, including pancreatic lipase, acid phosphatase, cholinesterase, ATPases, and succinic dehydrogenase.

Through its role in enzyme activation, calcium stimulates muscle contraction ie. Calcium, in conjunction with phospholipids, plays a key role in the regulation of the permeability of cell membranes and consequently over the uptake of nutrients by the cell. Calcium is believed to be essential for the absorption of vitamin B12 from the gastro-intestinal tract.

Dietary sources and absorption: Calcium is readily absorbed through the gastro-intestinal tract through vitamin D 3 action , gills, skin and fins of fish and crustacea. In general, dietary calcium absorption is facilitated by dietary lactose by forming a soluble sugar-calcium complex and by high gastric acidities by aiding solubilization of the calcium salt.

The principal biological functions of phosphorus may be summarized as follows;. Phosphorus is an essential component of phospholipids, nucleic acids, phosphoproteins casein , high energy phosphate esters ATP , hexose phosphates, creatine phosphate, and several key enzymes.

As a component of these important biological substances, phosphorus plays a central role in energy and cell metabolism. Inorganic phosphates serve as important buffers to regulate the normal acidbase balance ie. Although soluble phosphorus salts can be absorbed through the skin, fins and gills of fish and shrimp, the concentration of phosphorus in fresh and sea water is low, and consequently body phosphorus requirements are usually met from dietary sources.

This organic form of phosphorus must first be hydrolyzed within the gastro-intestinal tract by the enzyme phytase to inositol and phosphoric acid before it can be utilized and absorbed by the animal. As with calcium, the absorption of inorganic phosphorus salts is facilitated by high gastric acidity; the more soluble the salt the higher the availability and absorption of phosphorus.

The principal biological functions of magnesium may be summarised as follows;. Magnesium is an activator of several key enzyme systems, including kinases, ie. Through its role in enzyme activation, magnesium like calcium stimulates muscle and nerve irritability contraction , is involved in the regulation of intracellular acid-base balance, and plays an important role in carbohydrate, protein and lipid metabolism.

Rich dietary sources of magnesium include; meat and bone meal, rice bran, kelp meal, sunflower seed meal 1. Magnesium is readily absorbed through the gastro-intestinal tract, gills, skin and fins of fish and crustacea.

As with calcium and phosphorus, a proportion of the magnesium contained in plant foodstuffs may be present in the form of phytin Ca or Mg salt of phytic acid. Sodium, potassium, and chlorine occur almost entirely in the fluids and soft tissues of the body, sodium and chlorine being found mainly in the body fluids, and potassium occuring mainly in the cells.

They serve a vital function in controlling osmotic pressures and acid-base equilibrium. They also play important roles in water metabolism. Although the principal role of sodium in the animal is connected with the regulation of osmotic pressure and the maintenance of acid-base balance, sodium also has an effect on muscle irritability, and plays a specific role in the absorption of carbohydrate.

Potassium is the major cation of intracellular fluid, and regulates intracellular osmotic pressue and acid-base balance. Like sodium, potassium has a stimulating effect on muscle irritability.

Potassium is also required for glycogen and protein sysnthesis, and the metabolic breakdown of glucose. Chlorine is therefore essential for the regulation of osmotic pressue and acid-base balance. Chlorine also plays a specific role in the transport of oxygen and carbon dioxide in the blood, and the maintenance of digestive juice pH. Rich dietary sources of sodium, potassium and chlorine include: Potassium, sodium and chloride are readily absorbed from the gastrointestinal tract, skin, fins and gills of fish and crustacea.

The principal biological functions of sulphur may be summarised as follows;. Sulphur is an essential component of several key amino acids methionine and cystine , vitamins thiamine and biotin , the hormone insulin, and the crustacean exoskeleton.

As the sulphate, sulphur is an essential component of heparin, chondroitin, fibrinogen and taurine. Several key enzyme systems such as coenzyme A and glutathione depend for their activity on free sulphydryl SH groups. Sulphur is believed to be involved in the detoxification of aromatic compounds within the animal body. Rich dietary sources of the sulphur containing amino acids include fish meal, chicken eggs, and hydrolysed feather meal the latter containing primarily cystine, Table 5.

Sulphur containing amino acids and to a lesser extent inorganic sulphates are readily absorbed from the gastrointestinal tract of fish and shrimp. The principal biological functions of iron may be summarised as follows;. Iron is an essential component of various enzyme systems including the cytochromes, catalases, peroxidases, and the enzymes xanthine and aldehyde oxidase, and succinic dehydrogenase.

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