Health, nutrition and well-being

What is health? The World Health Organization (WHO) defines health as a state of complete physical, mental and social well-being, and not merely the absence of disease. A person may have no illness at all and still not be healthy if they are constantly stressed, lonely or exhausted. Health is also a fundamental human right, as the 1948 Universal Declaration of Human Rights recognises: everyone, whatever their age, gender, religion, caste, income or nationality, should have the chance to reach the best possible health.

Three dimensions of health:

• Social health: getting along with family, friends, neighbours and institutions such as school or the workplace; communicating well, adjusting and cooperating. Social support helps a person face stress, solve problems and recover from illness.
• Mental health: using one's abilities, handling normal stress, keeping good relationships and bouncing back after setbacks. It does not mean never feeling sad or worried; it means being able to cope, recover and carry on.
• Physical health: the body working properly: being fit, able to do daily activities without unusual tiredness, and able to resist disease.
• The three are interlinked. A long illness that keeps a student away from school can cause anxiety about falling behind, and then withdrawal from friends: physical, mental and social health all suffer together.

Health care is partly each person's responsibility and partly the community's and government's, because a healthy population is needed for social and economic development. Health care is of three types:

• Preventive: stopping disease before it happens: vaccination, safe water, sanitation, spraying to control mosquitoes before the rainy season.
• Promotive: improving and maintaining health: nutrition education, exercise, regular check-ups of eyes or blood pressure.
• Therapeutic (curative): treating illness after it occurs: medicines, surgery, rehabilitation.

It is given at three levels:

• Primary: the first point of contact with the health system, for common problems: a primary health centre, sub-centre or local clinic.
• Secondary: specialist care to which patients are referred, usually at district hospitals.
• Tertiary: highly specialised, intensive care at large hospitals and medical institutes.

Measuring health. Because health has many dimensions, no single figure describes a population's health. Health indicators include mortality (death rates), morbidity (how much illness occurs), disability (limits on normal activity), nutritional status, the availability of health services, and quality of life.

Nutrition and health are interlinked. Good nutrition builds and maintains the body, helps it resist infection and gives energy for work and study. Illness, in turn, often reduces appetite, increases nutrient needs and depletes the body's reserves. There are more than 50 nutrients: macronutrients (carbohydrate, protein, fat, fibre), needed in large amounts, and micronutrients (minerals such as iron, iodine and calcium, and vitamins), needed in small amounts. Needs vary with age, sex, body size, activity and health: an adolescent in a growth spurt needs more protein, calcium and iron.

Optimum nutrition helps a person keep a healthy weight and muscle, resist infection, cope with physical and mental stress, and improves productivity at work and learning at school. Well-nourished children concentrate and remember better.

WHO's four factors for nutritional well-being:

• Food and nutrient security: steady access, all year round, to enough nutritious food that is available, affordable and safe.
• Care for the vulnerable: special attention to infants, pregnant and nursing women, the sick and the elderly.
• Good health for all: preventive and curative health services, since infections drain nutrients.
• A safe environment: clean surroundings, safe drinking water, sanitation and control of pollution.