diet and disease

The diet and disease - A variety of diseases are linked with diet. Diseases due to a deficiency of nutrients are a major problem in poor countries. In children, starvation or malnutrition may result in marasmus or kwashiorkor, while vitamin deficiencies may cause rickets or keratomalacia (a condition that causes blindness). Vitamin deficiencies may lead to beriberi, pellagra, or scurvy. In affluent countries, diseases due to deficiency are rare, occurring only in certain groups of people (such as alcoholics).

Instead, many disorders are due at least partly to overconsumption of food. Overeating causes weight gain and, in severe cases, obesity. The latter condition places a person at increased risk of disorders such as diabetes mellitus, stroke, coronary artery disease, and osteoarthritis. Diets causing weight gain tend to be high in fats and sugar, but may be low in valuable components such as fibre and vitamins.

GOOD DIETARY HABITS
• Eat fresh rather than preserved, packaged, or convenience foods.
• Eat plenty of vegetables and at least five portions of fruit every day. When raw or lightly cooked, they retain a higher nutritional value.
• Eat whole-grain products, including wholemeal bread.
• Cut down consumption of red meat; instead, eat fish, poultry, and pulses.
• Keep the fat content of your diet low and use polyunsaturated fats and vegetable oils rather than saturated fats.
• Cut down on sugar and salt in all foods.
• When choosing filling foods, eat potatoes in their skins, pasta, or rice.



FATS
A diet that is high in fats, particularly saturated fats (see fats and oils), may contribute to atherosclerosis (narrowing of the arteries due to accumulation of fatty deposits on the arterial walls); this, in turn, may lead to cardiovascular diseases such as coronary artery disease, stroke, and peripheral vascular disease. A high-fat diet has also been linked with cancer of the bowel (see colon, cancer of) and breast cancer.

ALCOHOL
Overconsumption of alcohol can lead to alcohol-related disorders. In the digestive system, it may cause cirrhosis of the liver, pancreatitis, and oesophageal cancer
(see oesophagus, cancer of); in addition, people who are dependent on alcohol often become malnourished. Drinking too much alcohol may cause cardiovascular problems such as hypertension (high blood pressure) and heart failure; neurological disorders such as Wernicke– Korsakoff syndrome; and mental or behavioural problems such as depression or violence.

SALT
A high salt intake may predispose a person to hypertension.

FIBRE
Fibre, found in fruit, vegetables, and grains, provides bulk, which helps the passage of food through the intestine and also aids the absorption of nutrients (see fibre, dietary). A lack of fibre is thought to be a contributory factor in digestive disorders such as diverticular disease (a condition in which abnormal pouches form in the colon), chronic constipation, and haemorrhoids.

VITAMINS
Many people’s diets contain too few natural vitamins; to remedy this problem, it is better to eat vitamin-rich foods than to take vitamin supplements. Women who are planning a pregnancy need to increase their intake of folic acid in order to reduce the risk of neural tube defects in the baby.

FOOD ALLERGIES
Many illnesses are commonly ascribed to food allergy, but it is only rarely that a definite link is proved. Nut allergies, which may cause the life-threatening reaction anaphylaxis, and coeliac disease (a reaction to the protein gluten, which is found in wheat and other cereals) are examples of genuine food allergies. (See also nutritional disorders.)