Carbohydrate source of energy

In an energy-sufficient diet, carbohydrate can replace fat as a source of energy. In some populations, fat intakes are very low and body weight and health are maintained by high intakes of carbohydrate.

Beyond its continuing maintenance needs for energy, the body periodically needs relatively larger amounts of energy to do work or to engage in other vigorous physical activities.

Carbohydrates are the preferred energy source for athletes as they are the most efficient in producing the necessary fuel for energy requirements.

Human derive their energy mainly from carbohydrate (55 – 65%), although they can also utilize fats and proteins for this purpose.

Two main macronutrients provide energy for replenishing adenosine triphosphate (ATP) during exercise:
*Muscle and liver glycogen
*Triglycerides within adipose tissue and exercise muscle

During prolonged exercise, carbohydrates such as muscle glycogen and blood glucose derived for liver glycogenolysis are the primary energy substrate. One gram of carbohydrate supplies 4 kcal of energy.

The carbohydrates that are important in nutrition include the sugars, the starches, the dextrin, and glycogen. Cellulose, pectin, and other carbohydrate are not important nutritionally.

In adults, it is important that the amount of energy ingested be matched to the amount of energy expended. Maintenance of energy balance is important in order to avoid obesity and its associated co-morbidities such as diabetes and cardiovascular disease.

Carbohydrates constitute the main source of energy supplied by foods and may account for up to 100% of the total dietary caloric intake. In an average Westerns diet carbohydrates contribute around 50% of the ingested calories.
Carbohydrate source of energy 

Food sources of magnesium

Magnesium is require by seven key enzymes for glycolysis pathway. Magnesium also participates in muscle contraction and blood clotting.

Magnesium supports the heart, increases brainpower, causes strong peristalsis, and also help build storing bones.

Magnesium is available in many foods. However, most people in the United States probably do not get as much magnesium as they should from their diet.

Magnesium is ubiquitous in foods. This mineral enters human diet mostly from plants. Whole grains, many vegetables, legumes, tofu, and some seafood are good sources, and chocolate contains modest amounts.

Foods with highest magnesium content include milk and other dairy products, meats, seafood, and blackstrap molasses.

Beverages rich in magnesium are coffee, tea and cocoa. Cocoa seems to be the number one source of magnesium.

Magnesium also can be found in whole unprocessed foods in the diet. However, different methods for calculating amounts of magnesium in foods have often lead to conflicting results.

Food sources of magnesium

Sources of Vitamin D

Diet is not a major source of vitamin D. Perfectly reasonably and well balanced diet may not supply the amount required to prevent deficiency.

Some food items that naturally contain small amounts of vitamin D include oil fish such as salmon, mackerel and blue fish. Cod liver oil is the best source of vitamin D.

The two basic substances with vitamin D activity D2 and D3, occur only in yeast and fish liver oils.

Vitamin D is also present in small quantities in vegetables, meat and egg yolk.

The main food source are those to which crystalline vitamin D has been added. Milk, because it is commonly used, has prove to be the most practical carrier.

The most efficient source of the vitamin is not a food at all, but exposure to sunlight, which transforms a related pro-vitamin substance in the skin into a substance which the kidney can change into active vitamin D.

Sunlight, in the form of ultraviolet-B radiation, providing 90-100% of the requirement for most people who are exposed to adequate sunlight.

Like other fat soluble vitamins, the sunlight activated pro-vitamin D can be stored away in the liver.

Vitamin D can also be obtained from nutritional supplements, For example, multivitamin supplements typically contain 400 IU vitamin D and pharmaceutical preparations can contain as much as 50,000 IU vitamin D per capsule/tablet.
Sources of Vitamin D

Mineral of Calcium in Human Body

Calcium is the most abundant divalent cation of the body, representing about 1.5% to 2 % of total body weight.

Calcium in the body roses from an average of 24 grams at birth to about 1300 grams at maturity.

Over 99% of the total calcium of the body located in the bones, where it accounts for 39% of the total body bone mineral content and in the teeth, mostly as hydroxyapatite.

Physical Function
Structural component of bones and teeth; role in intracellular and hormonal secretion regulation, muscle contraction, blood clotting, and activation of some enzyme systems.

The calcium in bones serves as a reservoir for calcium that is needed throughout the body.

Calcium also is the key factor in normal transmission of nerve impulses. The movement of calcium into nerve cells triggers the release of neurotransmitter at the junction between nerves.

Deficiency symptoms
The symptoms of calcium deficiency includes rickets, osteomalacia, osteoporosis, scurvy, tetany, parathyroid hyperplasia, stunted growth, laryngospasm.

Deficiency of calcium lowers the body resistance and for the children become as easy prey to respiratory and intestinal infections.

Poor calcium intake affects mostly bone and muscle. Rickets occurs in children when the amount of calcium accretion per unit of bone matrix is deficient.

Hypocalcemia may result in tetany, a condition characterized by intermittent muscle contractions that fail to relax, especially in muscles of the arms and legs.

Food sources
Calcium is present in foods and dietary supplements as relatively insoluble salts.

Food sources of calcium include milk, milk products, sardines, clams, oysters, turnip greens, broccoli, legumes and dried fruits.

Majority of dietary calcium in industrialized countries comes from milk products.

When substantial amounts of grains are consumed, for like breads or as maize, these can be important sources, although the calcium in cereals rends to be less bioavailable than that in dairy products.
Mineral of Calcium in Human Body

Food sources of oils and fats

Food sources of oils and fats
Vegetable oils contain linolenic and other poly-unsaturated fatty acids. Although some of these can be synthesized in he body, linolenic acid which is required for growth and maintenance of normal skin, cannot be synthesized in the body.

Therefore, it has to be supplied in the diet and is termed essential fatty acid.

Therefore, it is necessary to include sufficient vegetable oils in the diet to meet body’s need of essential fatty acid.

Oils and fats are obtained from plants and animal source.

Vegetable oils include those extracted from groundnut sesame or gingelly, mustard, safflower, cotton seed, coconut and palm.

Butter and ghee are animal fats, extract from milk. These food source contribute visible fat in our dietary.

Foods which contain large amount of fat are the sources of hidden fat in the dietary.

These include nuts and oil seeds and animal foods such as milk eggs, fish and meat.
Food sources of oils and fats

Food Sources of Protein and its Deficiency

Food Sources of Protein and its Deficiency
Plants are the primary source of proteins, as they synthesize protein by combining nitrogen and water from soil with carbohydrate from the air. All animals and fish depend on the plants to provide them proteins.

Pulses, nuts, oilseeds, milk and milk products, eggs, poultry and meat are the good sources of protein in the diet.

Functions of protein
The principles functions of protein in the body are as follows:

• Building new tissues in growth stage of life, from conception up to adulthood, and after injury.
  
• Maintenance of tissues already built and replacement of regular losses
  
• As regulatory substance for internal water and acid base balance
  
• Formation of enzymes, antibodies, some hormones and one of the B-vitamins
  
• Formation of milk
  
• Energy supplies. Each gram of protein supplies four calories to the body

Deficiency of proteins
The deficiency of proteins and energy to a a varying extent is one of the most common nutritional deficiencies in some countries.

Children tend to have retardation of growth and adolescent have thin and lanky bodies, pregnant women gain insufficient weight an have babies who are low in weight at birth, who may be at risk.

Severe deficiency of proteins in early stage may result in development of kwashiorkor in small children. If severe protein deficiency is accompanied by lack of dietary energy, nutritional marasmus occurs.
Food Sources of Protein and its Deficiency

Food sources of protein

During digestion, large molecules of proteins are broken down into simpler units called amino acids.

Amino acids are necessary for the synthesis of complete body proteins and many others tissue constituent.

Proteins are described as essential and nonessential proteins or amino acids. The human body requires approximately 22 amino acids in specific patterns for the synthesis of its proteins.

All the essential amino acids must be present simultaneously in the diet in order for the other amino acids to be utilized – otherwise, the body remains in negative nitrogen balance.

A lack of vital proteins in the body can cause problems ranging from indigestion to depression to stunted growth.

The body can make only 13 of the amino acids -- these are known as the nonessential amino acids.

They are called non-essential because the body can make them and does not need to get them from the diet.

The nine of these amino acids can be produced are called essential amino acids, and they must be supplied in the diet.

They are methionine, threonine, tryptophan, leucine, isoleucine, lysine, valine, phenylalanine and histidine.

If the protein in a food supplies enough of the essential amino acids, it is called a complete protein.

If the protein of a food does not supply all the essential amino acids, it is called an incomplete protein.

All meat and other animal products are sources of complete proteins. Spirulina contains all the essential amino acids. Soy comes close to being a complete plant protein.

These include beef, lamb, pork, poultry, fish, shellfish, eggs, milk, and milk products.

Protein in foods (such as grains, fruits, and vegetables) are either low, incomplete protein or lack one of the essential amino acids. These food sources are considered incomplete proteins.

To obtain a complete protein form incomplete protein foods, one must combine them carefully so that those foods that are low or missing an essential amino acid will be balanced by another food that supplies that amino acid.
Food sources of protein