Alcohol is an interesting dietary component to discuss in detail. This simple molecule can be used as a model to underline the different modalities of nutrition, manufacturing, social, genetic predisposition and gender differences in metabolism, nutritional value and the consequences of excess. The popularity of alcohol results from its effects on mood and an induced sense of well-being. The ingestion of alcohol is a social activity; a meeting, occasion or function is better enjoyed by many in the relaxing ambience coincidental with the consumption of alcohol.
Ethanol provides 7 calories per gram. The full extent of how much energy is provided with an alcoholic drink varies with the beverage from the sugars accompanying beer, to the pure alcohol of vodka.
The use of yeast to ferment carbohydrates from fruit, grain, vegetables and other food sources for the production of alcohol is an age old custom. Great skill is employed in developing different forms of alcoholic drinks, wines, fortified wines, beers and spirits. Some carbohydrate sources, as in the starches in cereal grains, require preparation ( malting ) before fermentation, to convert the starch in maltoses. A by product is carbon dioxide which produces the “head” on beer and the bubbles in champagne. The limiting factor in alcohol production is the amount of sugar available to the fermentation process and the final alcohol content is of the order of 5% in beers and 11% in wines. To achieve the greater alcohol concentration in spirits the solution is distilled to 40% as in whisky, gin and brandy. Because toxic substances eg methanol also concentrate in such drinks the spirits are left in casks for prolonged periods of time to allow the noxious chemicals to filter out through the wood of the cask.
Beer 50 g/litre
Wine 110 g/litre
An old, crude measure of measuring the alcohol content of spirits. After soaking the gun powder in the alcoholic drink , if the gunpowder would still explode on being fired, then the spirit was more than half alcohol. In the Britain, Canada and Australia proof is 57% alcohol, in USA proof is double the alcohol content ie 40 % brandy is 80% proof )
In assessing alcohol intake an empirical unit has been defined equivalent to 8–10 g of ethanol. A unit is found in: one single measure of spirits, one glass of wine, a measure of fortified wine, ½ pint of beer or lager, or one small glass of sherry.
1. Ethanol is a nutrient whose principal popularity depends upon its effects on mood and an induced sense of well-being. Alcohol drinking is, in general, a social activity.
2. Alcoholic drinks are produced in many different forms. It is the constituents other than alcohol that give the beverage its particular taste.
3. Alcohol intake is measured by the unit; 1 unit is equal to 8–10 g of ethanol.
4. The existence of a U- or J-shaped relationship between alcohol intake and morbidity is discussed.
5. Alcoholism occurs more frequently in certain families. Cultural and genetic factors have been implicated.
6. Ethanol is metabolized initially by alcohol dehydrogenase to acetaldehyde, which is converted to acetate by the enzyme aldehyde dehydrogenase. The type , amount and distribution of isoenzymes of these enzymes affect the susceptibility to alcohol of women and some Mongol races.
7. Ethanol has destructive effects on all organs when drunk in excess, with consequences which affect the individual’s health.
Further ReadingFeyer A-M ( 2001) Fatigue : time to recognise and deal with an old problem. British Medical Journal. 322, 810-1
Fielding BA, Reid G, Grady M, Humphreys SM, Evans K and Frayn KN ( 2000) ethanol with a mixed meal increases postprandial triacylglycerol but decreases postprandial non-esterified fatty acid concentrations. British Journal of Nutrition 83, 597-604.
Goodwin, D.W (1985) Alcoholism and genetics — the sins of the fathers. Archives of General Psychiatry, 28–1, 238–43.
Helmutt K, Seitz MD and Oneta CM ( 1998) Gastrointestinal alcohol dehydrogenase. Nutrition Reviews 56, 52-60.
Kroke A, Klipstein-Grobusch K, Hoffman K, Terbeck I, Boeing H, Helander A ( 2001) Comparison of self reported alcohol intake with the urinary excretion of 5-hydroxytryptophol:5-hydroxyindole-3-acetic acid, a biomarker of recent alcohol intake. British Journal of Nutrition 85, 621-627
Lieber CS ( 2000) Alcohol : its metabolism and interaction with nutrients. Annual Review of Nutrition 20, 395-430.
Lucas, E.G. (1987) Alcohol in industry. British Medical Journal, 294, 460–1.
McCarver DG, Thomasson HR, Martier SS, Sokol RJ, Li T-K ( 1997) Alcohol dehydrogenase-2*3 allele protects against alcohol related birth defects among African Americans. Journal of Pharmacology and Experimental Therapeutics. 283, 1095-1101.
Murray, R.M., Clifford, C.A., Gurling, H.M.D., Topham, A., Clow, A. and Bernadt, M. (1983) Current genetic and biological approaches to alcoholism. Psychiatric Developments, 2, 171–92.
Nicolas JM, Fernadez-Sola J, Rober J, Antunez E, Cofan M, Cardenal C, Sacanella E, Estruch R, Urbano-Marquez A ( 2000) High ethanol intake and malnutrition in alcoholic cerebellar shrinkage. Quarterly Journal of medicine 93, 449-456.
Palmer, TN. (1991) The Molecular Pathology of Alcoholism, Oxford University Press, Oxford.
Philip P, Vervialle F, Le Breton P, Taillard J, Horne JA ( 2001 ) Fatigue, alcohol and serious road crashes in France: factorial study of national data. British Medical Journal 322, 829.
Pokorny, A.D., Miller, B.A. and Kaplan, H.B. (1972) The brief MAST: a shortened version of the Michigan alcoholism screening test. American Journal of Psychiatry, 129, 342–8.
Shaper, A.G., Wannamethee, G. and Walker, M. (1988) Alcohol and mortality in British men: explaining the U-shaped curve. Lancet, 2, 1267–72.