Alcohol is a popular beverage consumed in large quantities all over the world for centuries. A large variety of alcoholic beverages are manufactured from a number of vegetable sources. Malted barley and other cereals are used in the manufacture of beer while grapes are used commonly for wine. Though there are many alcohols, the alcohol that is consumed as a beverage is a chemical compound with two carbon atoms, known as ethanol.
Alcohol as a source of energy!
Ethanol provides energy and produces 29.3 kJ/g (8 kcal/g), but many alcoholic drinks also contain sugar, which increases their calorific value. For example, one pint of beer provides 1045 kJ (250 kcal), making a heavy drinker gain weight if he or she continues to drink.
How is alcohol metabolised in the body?
Ethanol is absorbed along the whole length of the digestive tract, rapidly from the stomach and most rapidly from the small intestine. The rate of absorption is influenced by the volume ingested, the nature of the alcoholic drink, the concentration of ethanol in that and the presence of food in the stomach. In the body ethanol (ethyl alcohol) is oxidized, to acetaldehyde. Acetaldehyde is then converted to acetate, 90% in the liver mitochondria. Acetate is released into the blood and oxidized by peripheral tissues to carbon dioxide and water.
What is a “Standard Drink”?
Unit of alcohol is defined as a measure of ‘safe level’ of alcohol that can be consumed with minimal health problems associated with alcohol consumption. Ironically the safe level does not rule out adverse medical, psychological or social consequences as the effects vary depending on the individual.
Measures of 1 unit of alcohol (8 g) =
1/2 pint of beer
1 single measure (25 ml) of spirit like whiskey, gin, vodka
1 small glass of wine or small glass of sherry
So………think before you drink!
· Daily maximum alcohol consumption should be 3 units for men and 2 units for women to achieve this use a standard measure
· Those who take more than daily maximum levels should cut down the alcohol intake
· One drink free day per week is recommended
· It is best not to drink when driving or operating machinery; when taking certain medication or if there is certain medical conditions; if pregnant or breast feeding.
· Do not drink during the daytime
But all those who drink ought to remember that health can be damaged even without being ‘drunk’ and regular heavy intake is more harmful than occasional binge drinking. Here, all the long-term effects of excess alcohol consumption are due to excess ethanol, irrespective of the type of alcoholic beverage; i.e. beer and spirits are no different in their long-term effects.
Imact of Alcohol on Health!
In many countries, alcohol consumption is becoming a major problem. Excess consumption of alcohol leads to following major problems, which can be present in the same patient:
· Physical damage to various tissues
· Psychological problems causing alcohol dependence syndrome
· Social problems
The amount of alcohol that produces damage varies and not everyone who drinks heavily will suffer physical damage. For example, only 20% of people who drink heavily develop cirrhosis of the liver. The effects of alcohol on different organs of the body is not the same; in some patients the liver is affected, in others the brain or muscle. The differences may be genetically determined.
Liver…….the commonest target!
Alcoholic liver disease is the most common physical damage caused by alcohol. In general the effects of a given intake of alcohol seem to be worse in women. The following figures which carry risk of developing liver damage are for men and should be reduced by 50% for women:
· 160 g ethanol per day (20 single drinks) carries a high risk
· 80 g ethanol per day (10 single drinks) carries a medium risk
· 40 g ethanol per day (five single drinks) carries little risk
Since the main site of oxidation of alcohol is liver, the deleterious effects are mostly seen in the liver. The structure of the liver cell is affected with constant use of alcohol and the initial change is fatty liver which can lead to fibrosis later.
Effects of Alcohol on Metabolism
The oxidation of a large quantity of alcohol affects the metabolism of other compounds. There is interference with carbohydrate metabolism, with inhibition of glycolysis (formation of glucose from glycogen which is a storage compound) and gluconeogenesis (formation of glucose from other substances other than glycogen like fatty acids, amino acids), resulting lowering of blood sugar level.
It inhibits the synthesis of certain specific proteins such as serum albumin, transferrin and complement thus contributing to increased susceptibility for infections. There is decreased oxidation of fatty acids and an accumulation of triacylglycerols in the liver. Alcohol increases plasma lipoproteins, cholesterol and triacylglycerols. There is interference of uric acid excretion leading to hyperuricaemia which cause tender swollen joints commonly in the big toe, which is known as gout.
Alcohol and Nutrition
Chronic alcoholism causes several nutritional deficiencies. There may be impaired gastric secretion and loss of appetite. Malabsorption syndromes may also be caused secondary to disorders of small intestine, pancreas and liver, resulting in deficiencies of amino acids, calcium, folic acid and vitamin B12.
Regular intake of alcohol results in decreased utilization of some nutrients. It inhibits the conversion of thiamin (a B vitamin compound – B1) to thiamin pyrophosphate in the liver. Thiamin deficiency contributes to both neurological (confusion, Wernicke–Korsakoff syndrome) and some of the non-neurological manifestations (cardiomyopathy).
Over Consumption…….Alcohol Intoxication!
If a person takes a very high amount of alcohol acutely they get which exceeds the individual’s tolerance for alcohol and it produces behavioral or physical abnormalities. Here after a brief period of excitation generalized nervous system depression occurs. The changes occur with rising alcohol levels are given below;
20–99: impaired coordination, euphoria
100–199: ataxia, poor judgment, labile mood
200–299: marked ataxia and slurred speech; poor judgment, labile mood, nausea and vomiting
300–399: Stage 1 anesthesia, memory lapse, labile mood
400: Respiratory failure, coma, death
Alcohol can hit almost all the organ systems!
Central nervous system – Fits, Alcohol hallucinations, Wernicke–Korsakoff syndrome, Polyneuropathy, Peripheral neuropathy, Cerebellar degeneration, Dementia
Gastrointestinal system – Acute gastritis and peptic ulcers, Oesophageal varices, Carcinoma of the oesophagus or large bowel, Acute or chronic pancreatitis, Liver disease
Muscles – Acute or chronic myopathy
Cardiovascular system – Cardiomyopathy, Beriberi heart disease, Cardiac arrhythmias, Hypertension (high blood pressure)
Metabolism – Hyperuricaemia (gout), Hyperlipidaemia (high lipid levels in blood), Hypoglycaemia (low blood sugar), Obesity
Endocrine system – Pseudo-Cushing’s syndrome
Respiratory system – Chest infections
Haematological system – Macrocytosis (large red cells due to direct toxic effect on bone marrow or folate deficiency) causing megaloblastic anemia, Thrombocytopenia (low platelet counts), Leucopenia (low white cell counts)
Bone – Osteoporosis, Osteomalacia
Effects on fetus – Facial abnormalities, Low weight, Low intelligence, Over-activity (All these effects are collectively called fetal alcohol syndrome)
Therefore, though alcohol is a beverage that is thought to bring pleasure, on excessive consumption, it can cause harm to almost all the organ systems in the body. So, it is always safe to know the limits and consume. In fact, it is proven that consumption of alcohol, strictly within the safe limits combined with regular exercise can reduce the risk of heart disease.