The diet is important from just before the cradle to just before the grave. Nutrients, in sufficient quantities to provide a balanced diet, are important before and during pregnancy, during the baby’s growth and from child to elderly. During pregnancy the mother must increase energy intake. During lactation, energy intake is also increased. A steady balanced diet is essential, in the right quantities, throughout life, to maintain healthy growth and development. The first part of this two part article looks at the background to nutrition and the digestive process. Part two will conclude with the role of diet from pre-conception to old age.
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 acid, 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.
