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1 Commonwealth of Australia Copyright Act 1968 Warning This material has been copied and communicated to you by or on behalf of under Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further copying or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice.

2 DTN2PNU Principles of Human Nutrition Lecture: Alcohol Lecture Prepared by: Dr Regina Belski & Associate Professor Catherine Itsiopoulos Department of Dietetics and Human Nutrition latrobe.edu.au CRICOS Provider 00115M

3 Structure of alcohol CH 3 CH 2 OH (ethanol) Methyl group H H Atwater Factor 1g = 29kj H C C OH Carboxyl group H H * Cannot be stored in body & Toxic See Chapter 7 pp Whitney and Rolfes Understanding Nutrition 29

4 Metabolism of alcohol Absorption Stomach 20% alcohol if absorbed but is proportional to the amount of food present Small intestine rapid absorption - jejunum Liver site of alcohol metabolism 3 Pathways of Alcohol metabolism in the liver: Pathway 1 Alcohol Dehydrogenase Pathway NAD Nicotinamide adenine dinucleotide (contains niacin) TPP (thiamin ) co factors in alcohol metabolism both B vitamins high turnover in the energy pathway Pathway 2 MEOS stands for microsomal enzyme oxidizing system recruited with chronic or acute excessive intake. Same pathway is recruited for drug, poisons metabolism. Alcohol is a poison. Activating this pathway effectively makes the liver more efficient at breaking down alcohol and enhances tolerance to alcohol. Therefore there can be problems giving anaesthetic and other drugs to alcoholics Pathway 3 Excretion of 5% alcohol via the lungs in the basis of the breathalyzer 30

5 Metabolic effects of alcohol Inhibition of glucose metabolism (hepatic gluconeogenesis) Competition for thiamin in the glucose pathway Increase in lactic acid Increase in lipid synthesis (fatty liver/ high triglycerides) Decrease in protein synthesis Increase in effect of drugs (slowed metabolism) Interference with vitamin D and B6 synthesis Diuretic effect Dehydration: the main cause of hangover + low blood glucose levels (hypoglycaemia) 32

6 Rate of metabolism of alcohol Fixed rate of alcohol metabolism Limited by the amount of the enzyme alcohol dehydrogenase present This enzyme is largely produced by gut bacteria which ferment undigested starches 5-8 g alcohol/h* (approx)= mg/kg/h average of 100mg/kg/h How long does it take a 65kg male to metabolise 3 standard drinks? 30 g = 4.6 hours How long does it take a 50kg female to metabolise 3 standard drinks? = 6 hours *NHMRC

7 Short-term effects of alcohol Alcohol is a depressant and a narcotic (anaesthetic) Interferes with REM sleep (deep sleep) Increase in blood flow to the skin rosy flush increase in blood pressure Increased risk of gouty arthritis High risk of injury and accidents 34

8 Alcohol doses and brain response (short-term effects) No. of drinks Blood alcohol (%) Short term effects Judgement impaired Control impaired Loss of muscle coordination Vision impairment Out of control Amnesia /death Adapted from: Whitney & Rolfes (2002, p. 235) 35

9 Long-term effects of alcohol Stomach alcohol increases acid secretion Pancreas pancreatic damage, secondary diabetes Liver direct toxin.cirrhosis (hardening of the liver) Small bowel change in morphology of cells - malabsorption iron overload Brain depressant.sleep disturbance acetaldehyde acts as a direct toxin B6 (pyridoxine) & B1 (thiamin) deficiency Wernicke s encephalopathy, Korsakoff s psychosis 36

10 Other complications Cancer of pancreas and liver Foetal alcohol syndrome Malnutrition Folic acid, B6 Obesity (beer gut) Increase in blood pressure and stroke Cardiovascular disease Diminished libido (lack of sex drive) 37

11 Beneficial effects of alcohol Moderate alcohol intakes reduction in blood clotting Low alcohol intakes anti-spasmodic effect upon blood vessels Increases High Density Lipoprotein (HDL) Moderate alcohol (glass red wine with meal) important Feature of Mediterranean Diet: 1-2 glasses/day Always with meals Don t get drunk 38

12 Reducing the risk of alcohol-related harm over a lifetime New Australian Guideline 1 No more than 2 standard drinks on any day No different between men and women Drink less frequently over a lifetime (weekly rather than daily) o Reduces risk to 1/100 o Harm proportional to age» Greatest yrs (50% prevalence) Source: NHMRC

13 Reducing the risk on a single drinking occasion New Australian Guideline 2 No more than 4 standard drinks on a single occasion No different between men and women Double relative risk (RR) of injury/harm at 4 drinks on a single occasion Risk increases exponentially with > 4 drinks on a single occasion Source: NHMRC

14 Guidelines for children and adolescents New Australian Guideline 3 Under 15 yrs greatest risk of harm yr the safest option is to delay the initiation of drinking for as long as possible Alcohol affects brain development and leads to alcohol related problems in later life Source: NHMRC

15 Standard alcoholic drinks? Beverage (% alcohol) Volume (ml) Alcohol content (g) Beer (4-5%) 2/3 can (250mL) Low alcohol beer (2-3%) Wine (8-14%) Fortified wine (18-20%) Spirits (40%) Coca Cola or any softdrink or fruit juice Bacardi and coke 1 small can (375 ml) Energy (kj) 100mL (sweet white) 60mL mL (1 nip) can (375mL) mL

16 Number of Australian standard drinks in common containers Volume No of standard drinks Medium Light beer (3.5%) 1 can 1 Regular beer (4.9%) 1 can 1.5 Wine (9.5-13%) 750 mlbottle ml Average restaurant serve of Wine 12% Alc./Vol ml Full strength beer 4.9% Alc./Vol ml Pre-mixed spirits 5% Alc./Vol Pre-mixed spirits (around 5%) 1 can 1.5 Spirits 1 nip (30 ml) 1 One drink isn't always one standard drink 43

17 Summary- Alcohol Absorbed across walls of stomach Metabolised using numerous pathways Main AD MEOS Lost through breath Alcohol content of standard drinks = 10g ethanol 1 glass of wine, or 1 can of full strength beer does not = 1 standard drink 44

18 References Whitney, E., Rolfes, SR, Crowe, T., Cameron-Smith, D. & Walsh, A. (2011). Understanding Nutrition: Australia and New Zealand Edition. South Melbourne, Australia: Cengage Learning Australia. (accessed 22/03/12) Images courtesy of Microsoft office Clip Art unless otherwise attributed AIHW 2008 the 2007 National Drug Strategy Household Survey, AIHW, Canberra. NHMRC Australian Alcohol Guidelines to reduce health risk from drinking alcohol. NHMRC 2009 See Deakin V. Alcohol: The legal drug in Sport. Sports Coach 1999; 22 (2): NHMRC Dietary guidelines for Australian adults. A guide to healthy eating. NHMRC 2003, p (under revision 2009) NHMRC Dietary Guidelines for Children and Adolescents in Australia. A guide to healthy eating. NHMRC 2003, p (under revision 2009) National Alcohol Strategy Towards safer drinking cultures, Australian Gov Policy F1C3/$File/nas pdf 45

19 Thank you latrobe.edu.au CRICOS Provider 00115M