Diet in Nutrition, Health and Fitness P1

Even before pregnancy, diet plays an essential role in preparing the female body for a normal and healthy birth. Vitamin D deficiency could cause pelvic deformation, where normal delivery of child would be difficult. Vitamin B12 deficiency could cause infertility and a history of dieting would deplete any nutrient reserves in the body, giving rise to infertility and reduction of nutrients for the foetus.A diet consists of nutrients. Nutrients are classed as macro, required in large quantities and micro, required in small quantities. Macro nutrients include carbohydrates, proteins and lipids (fats). Micro nutrients include vitamins and minerals. Another product essential for a diet is water. Water is required in large quantities to aid metabolism, which occurs in an aqueous environment.Bread, cereals and potatoes contain carbohydrates, non-starch polysaccharides (nsp), water, vitamins and minerals.It is important to have an appropriate amount in the diet for the following reasons:Carbohydrates provide energy, which is essential for all metabolic processes within the body, including mechanical movement, respiration, growth, repair, cell metabolism, DNA replication, vision, transport within the body and maintaining homeostasis (constant internal body equilibrium such as constant blood pressure, body temperature, breathing rate, pulse rate).Glucose (broken down from carbohydrates) is also required for brain cells and the central nervous system.NSP’s (fibre) are particularly important in a diet because they act as roughage or bulk. The nsp’s are not digestible and therefore pass straight through the digestive system. However, because of the increase in the bulk of food, it passes through the system more quickly than if nsp’s were not digested. NSP’s ensure food is not left in contact with the gut lining for prolonged periods of time, which could have serious health effects, including cancer.Meat, fish, pulses contain protein, water, minerals and vitamins, nsp’s (in pulses) and lipids.Proteins exist in two states, fibrous and globular.Fibrous proteins have a structural role, eg tendons, ligaments, hair, growth and structure. Globular proteins function as enzymes which allows cell metabolism to occur, help in our immune system by producing antibodies to fight diseases and aid transport, both intra and extra cellular. They also work as hormones, and for growth and repair of body tissues and in blood clotting. Too much protein in our diet is removed as waste material; too little protein in our diet could result in muscle wasting and such diseases as marasmus and kwashiorkor.Protein constitutes 12-18% of the body’s mass.Milk and dairy products contain protein, lipids, water, vitamins and minerals.Fat and sugar contain carbohydrates, water, lipids, minerals and vitamins.Lipids are broken down into glycerol (a further source of glucose) and fatty acids, including essential fatty acids.The essential fatty acids are components of the body’s cells, especially in the formation of cell membranes. Lack of fatty acids can affect blood pressure, blood clotting and homeostasis. Excess fat, however, can be stored in the body in adipose tissues and possibly result in obesity and related health problems. Although, much obesity is the result of certain gene deficiency, which will be discussed in more detail in a further article.Lipids provide concentrated energy and can be stored for future use. Fat can store and transport fat-soluble vitamins, A, D, E, K. Lipids are the building blocks for cells and signalling molecules. The myelin sheath surrounding neurons is composed of lipid. Ingestion of lipids also reduces hunger pangs over a long period.Fruit and vegetables contain carbohydrates, nsp’s, vitamins and minerals. They are a very important source of nsp’s, especially when the skins of the vegetables or fruits are eaten. NSP’s are crucial in a diet for the reasons mentioned under bread, cereals and potatoes.Vitamins are organic compounds which occur as fat soluble and water soluble. They are important for signalling, such as gene coding and as antioxidants, which mop up free radicals (random free electrons) thus preventing many diseases such as cancer. The free radicals can enter the diet by ingestion with food or from environmental pollutants.Minerals are a group of inorganic chemical elements which are components of cells and tissue, used in homeostasis, communication between cells and are part of important molecules, including some hormones.Water is required for all metabolic processes, which occur in an aqueous environment. Processing of the food starts in the mouth, with teeth used for cutting, tearing, chewing and grinding the material into smaller particles in readiness for digestion.However, the process of digestion begins long before food enters the mouth. The anticipation, smell and look of food causes the brain to initiate the release of hormones, causing hunger pangs and the release of saliva to start the digestive process.Food is processed by Ingestion, Digestion, Absorption and Elimination.The alimentary canal is one long tube from mouth to anus.Our food is processed into smaller pieces by the teeth and mixed with saliva from the salivary glands, which moisten the food for easier transport and contains enzymes which start to break down carbohydrates. The food (bolus) is transported down the oesophagus by peristalsis (a rhythmic, muscular motion).The bolus enters the stomach and mixes with further enzymes, from the stomach, pancreas and liver, which break down carbohydrates further to smaller sugar molecules; proteins are broken down into smaller peptide chains. Hydrochloric acid is produced by the stomach to breakdown proteins and kills any undesirable micro-organisms.This mixture (chyme) enters the small intestine, where lipids are broken down into fatty acids and glycerol, proteins are broken down into amino acids; disaccharides are broken down into glucose. Absorption generally occurs in the small intestine. The glucose and amino acids are transported through the villi and micro-villi of the small intestine’s epithelium into blood capillaries. Fatty acids and glycerol are transported through the villi and micro-villi to the lacteals, which transport them, via the lymph system, to the blood vessels.The digested material enters the colon. The material is quite fluid and water is absorbed through the epithelial wall of the colon. Symbiotic, microbial activity takes place anaerobically in the colon. The bacteria complete the digestion of any salvageable material. Some bacteria synthesise vitamins which, with any existing minerals, are absorbed by the colon into the blood system. Gas (hydrogen, carbon dioxide and methane) are produced by the bacteria, which is emitted as wind. The waste is eliminated as faeces, which is composed of fibre, dead and alive bacteria, epithelial cells from the gastrointestinal tract, fatty acids and mucus from the colon lining.Ahh! The smell of food, the look and finally the taste. We start to feel hungry, saliva builds up in the mouth in readiness for the first part of the digestive process – ingestion. And so begins food’s journey from mouth to anus; the breakdown and assimilation of nutrients for health and fitness. As William Shakespeare penned in Macbeth “Now good digestion wait on appetite. And health on both!”

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