Immunization

While immunity is being acquired a person develops symptoms of the disease. But some infections can be prevented by allowing the body to acquire active immunity artificially. This is achieved by the introduction into the body of a vaccine made from dead or weakened microorganisms that are no longer capable of causing the disease itself. When injected into the skin or bloodstream (or as in the case of polio vaccine, swallowed) they stimulate B lymphocytes to produce antibodies but no significant disease symptoms. And if, or when, the body encounters the real disease causing microorganisms, it is already protected against infection because the memory cells immediately produce antibodies.

Booster shots may be needed at later dates to ensure that active immunity is still effective. Vaccines are available against many formerly dangerous diseases including polio, measles an d diphtheria. Immunization programmes for children have virtually eliminated most common childhood diseases, and confer immunity into adult life. But vaccination is advisable for travelers to countries where they may contract potentially fatal diseases not previously encountered. Sometimes antibodies themselves from external sources are injected into the body to provide protection without stimulating the immune system. This is called artificial passive immunity and is useful in providing instant protection where a disease might kill the person before their active immune system has time to come into operation. Examples include gamma globulin, given against hepatitis A infection; anti toxin to treat tetanus; and anti rabies injections.

Diets and Dieting!

The word diet is commonly used these days to describe an eating regime followed by someone in order for him or her to lose weight, even though in its correct usage the word simply describes what we eat each day. A diet designed for weight loss is better described as a slimming diet, and there are many of these to choose from. As the percentage over weight and obese children and adults in the western world steadily increases as a result of increased in activity and increased consumption of junk food – so new slimming diets, and books on slimming, become available in order to commercially exploit fatness. However, most of these diets are not effective because they fail to promote long term weight loss and in fact may well cause the slimmer to end up fatter and heavier than when they started the diet. Being overweight will of course affect an individual’s health and reducing body weight will help to reduce those health risks. But to be healthy, a diet designed to reduce body weight needs to be in tune with the body’s physiology.

 An effective diet should promote the loss of fatty or adipose tissue from the body so that its overall fat content is reduced. To do this successfully, the dieter should eat a well balanced high carbohydrate, high fiber low fat diet with energy content of between 1200 and 1500 calories per day, combining this with regular exercise. This should cause a weight loss of 0.45 to 0.95 KG per week, that weight loss being mainly in the form of fat. At the same time, exercise will build up muscle tissue which pound for pound consumes far more energy than fat does as well as increasing metabolic rate, the rate at which the body burns carbohydrates and fat to release energy. Once the desired weight has been reached – and the body fat content has been reduced to within safe limits- then the dieter can gradually increase his or her calorie consumption while maintain the same balance of foods in order to keep at the weight for life.

Other sliming diets put the body in a defensive stance. Because its calorie intake has been severely reduced the body reduces its metabolic rate to conserve its fat energy reserves and actually burns lean muscle tissues in order to provide energy. When the diet stops the body diverts as much spare food energy as possible to build up its fat reserves in case another calorie famine happens and in consequence the diet regains lost weight and ends with more fat than before

Bulimia nervosa and Food Poisoning

Bulimia nervosa

 Like anorexia, bulimia is an eating disorder found most commonly among younger women, often those who have had anorexia. Bulimics crave food but fear becoming fat. They indulge in binge eating by consuming vast amounts of food and then induce vomiting and use laxatives. This constant bingeing and vomiting can cause severe medical problems. Sufferers from bulimia require the same medical care as anorexics.

 Food poisoning

This refers to illnesses caused by eating food contaminated by certain micro organisms or the toxins, they produce. Worldwide, the incidence of food poisoning is on the increase. This is probably due to the growing use of convenience foods, such as cook chill meals, and the consumption of fast foods, which are easily subject to contamination by the people who make and serve them. Spores in raw rice, chicken beef, water or milk contaminated faeces are caused by Bacillus cerus and Campylobacter fetus. Botulism and Clostridium Perfinges are through food contaminated with bacterial toxin. Meat or vegetables contaminated by faeces. Amoebic dysentery can caused by food or water contaminated by faeces. Norwalk virus can infect through contaminated shell fishes and the rotavirus can introduced to our system by contaminated water or food. Undercooked poultry or egg can cause Salmonella. Food that contaminated by contact with wounds are the reason for the Staphylococcus.

Obesity and Anorexia Nervosa

Obesity:

 The condition in which the body has so much fat is called obesity. Someone is considered to be obese if their weight is 20 percent over their ideal maximum or if their BMI is greater than 30. Around 30 percent of people in western countries are overweight and around five percent of them are obese. Long term obesity is a serious threat to health. It increases significantly the chances of developing high blood pressure, coronary artery disease, stroke, adult onset diabetes mellitus, certain cancers, osteoarthritis, back pain and varicose veins. Obese patients are advised under medical supervision, to lose weight using a calorie reduced diets and increased aerobic exercise.

Anorexia Nervosa:

 Popularly, but incorrectly, known as the “slimmers’ disease”, anorexia nervosa is an eating disorder found mainly among teenage girls and young women, and only rarely increases. In fact, one in hundred of the women suffer from the condition and increasing to one in twenty in those categories of women, such as dancers actors especially concerned with their bodies. Anorexia may be a phobia about being fat or a symptom of mental illness. Whatever its cause, however anorexia is a serious illness in which the individual starves herself and may die. She not only loses her appetite but, more seriously, fails to have a normal perception of the size and shape of her body- she thinks she is fat even when she is way below her normal weight. The main features of anorexia are as follows; excessive weight loss, over activity, secretive and defensive behavior, being choosy about food, obsessive exercising, tiredness always feeling cold , induced vomiting, use of laxatives, thinning of hair on heat, appearance of Languo (Baby hair) on the body, dry skin and cessation of periods (amenorrhea). Anorexics require medical treatment and counseling.

Diet and Diseases

Fats in foods are divided into saturated fats found mainly in meat and dairy products and unsaturated fats- found in fish and vegetable oils. Research has established a link between the high level of consumption of saturated fats in northern Europe and USA and the incidence of coronary heart disease, leading to death from heart attacks. Coronary artery disease is caused by the buildup of obstructions called atheromas that contain cholesterol.

Studies have indicated a strong link between diet and the chances of developing certain cancers. Cancers of the colon, rectum and stomach may be up to 90 percent diet dependent and diet may be responsible for up to 35 percent of cancers in western countries. For example, there appears to be a close correlation between levels of fat consumption and incidence of breast cancer. In Japan fat provides 22 percent of energy requirements in the diet and the death rate from breast cancer is four per 100,000 people, in USA, fat provides 40 percent of energy requirements and the death rate is 24 per 100,000. Dietary components linked to cancers include:

Excessive alcohol- cancers of the bowel, liver, mouth, oesophagus, stomach and throat, especially in smokers;

 Fatty and low fiber foods – breast and bowel cancers;

 Pickled foods- stomach cancer;

Salt- cured meat and fish, nitrate- cured meat- throat and stomach cancers.

 Dietary recommendations to reduce cancer risk:

 Eat foods rich in fiber daily.

 Eat fresh vegetables only.

 Eat less fat.

 Consume alcohol in moderation.

 Eat fewer smoked and salted foods.

 Keep weight at recommended level.

A Healthy Diet

The food that we eat provides us with the energy to power all our body activities, the materials for the growth and repair of body tissues, and the vital chemicals essential for the metabolic reactions that take place in all cells. To be healthy, a diet should:

Consist of a wide variety of natural foods that provide a balance of carbohydrates, fats,, proteins, vitamins, minerals and fibre.

 Supply the body with sufficient energy to meets its needs;

Include only low levels of foods, such as those containing saturated fats, that increase the risk of developing diet related diseases, for instance coronary artery disease.

 Each person has a certain requirement for energy, depending on their age and the amount of activity (or other forms of energy consumption, such as breastfeeding) involved in their daily life. Energy is derived from energy rich foods such as carbohydrates and, to lesser extent, fat. A diet that results in taking in more energy than the body requires in those conditions leads to obesity, while insufficient energy intakes leads to weight loss.

Vitamins and Minerals

     Vitamins and minerals are substances required in small amounts, that essential for the normal, healthy functioning of the body normal growth and development, energy productions, body maintenance, and general well being and vitality.

       Vitamins are a diverse group of organic substances that cannot be manufactured by the body – except for the vitamin D (which is produced in the skin when it is exposed to sunlight) and niacin (made in the body from the amino acid tryptophan) – and must, therefore, be obtained from food. Absence of one or more vitamins from the diet will, in time, lead to well defined deficiency diseases such as scurvy, beriberi or ostemalacia. The 13 major vitamins, each of which is found in many different foods, are divided into two groups. Fat soluble vitamins- A,D,E, and K – are found in fat or oil containing foods, and are stored in the liver, so that daily intake of these vitamins is not really essential. In fact, excessive consumption of fat soluble vitamins, usually by taking too many vitamins tablets, can be harmful. Deficiency of fat soluble vitamins is usually caused by disorders that stop the intestine absorbing fat efficiently. Water soluble vitamins- the B complex vitamins and vitamin C are not stored in the body (apart from vitamin B 12). To avoid deficiency, therefore, food containing water soluble vitamins should be eaten each day to keep supplies “topped up”. Because water soluble vitamins are destroyed by prolonged cooking, processing and storage, fresh or lightly cooked foods make the best sources.

     Minerals are simple chemical elements that cannot be made by the body but must be present in the diet o maintain good health. There are 20 minerals known to be essential in small amounts, in addition to carbon, oxygen, hydrogen and nitrogen, which are needed in large amounts to construct the body’s framework. Some, including calcium phosphorous, potassium, sulfur, sodium magnesium and chlorine and some traces of minerals such as iron cobalt copper zinc molybdenum iodine and selenium are also important for mammals.