Guidelines Dietary - Eat For Health

3.4.3 How limiting intake of alcohol may improve health outcomesAlcohol begins to affect the brain within 5 minutes of consumption, with blood alcohol concentration peaking after30–45 minutes. It takes approximately 1 hour for the liver to clear the alcohol from one standard drink from thebody, although this time varies depending upon liver size, lean body mass, individual alcohol tolerance and genescontrolling the expression of alcohol-metabolising enzymes in the liver. 844-846 Because the rate of metabolism isfixed, rapid consumption of multiple drinks results in a higher blood alcohol concentration. 794Young adults who drink heavily tend to have smaller prefrontal cortices and white matter, structural abnormalitiesof white matter and reduced hippocampal volumes. 847,848 These structural changes lead to a diminished ability toretrieve verbal and non-verbal material and poorer performance in attention-based tests. 836The loss of brain tissue that occurs in people with chronic alcoholism seems to occur independently of Wernicke’sencephalopathy and may be related to ethanol toxicity and poor nutrition.• Cardiovascular effects: The effect of alcohol on the cardiovascular system is complex. Alcohol can raise bloodpressure and increase the risk of arrhythmias, shortness of breath, some types of cardiac failure, haemorrhagicstroke and other circulatory problems. However, low levels of alcohol raise HDL cholesterol and reduceaccumulation of plaque in arteries. 810,849 Alcohol can also have a mild anticoagulant effect.• Diabetes: Alcohol affects the management of type 1 and type 2 diabetes through its effects on diet andcontrol of blood glucose levels. Alcohol interferes with the action of insulin, insulin secretagogues andglucagon, thereby increasing the risk of hypoglycaemia in people with type I or 2 diabetes who take thesemedications. 850,851• Dementia: The suggested protective relationship between alcohol and dementia may relate to the effect ofalcohol on blood lipids as one of the causal factors of dementia is microvascular changes within the brain. 852,8533.4.4 Practical considerations: limit intake of alcoholOf Australians aged over 14 years, 83% reported having consumed alcohol at least once in the 12 monthspreceding the 2007 National Drug Strategy Household Survey, with 8% drinking alcohol on a daily basis andabout 47% consuming alcohol at least weekly. 854 The majority of Australians who reported consuming alcoholalso reported moderating their intake, primarily to reduce the risk to their health. Methods included countingand limiting the number of drinks, eating food while consuming alcohol, alternating between alcoholic andnon-alcoholic drinks and drinking low-alcohol drinks. 854Guideline 3Nearly all alcohol is consumed as drinks, principally beers, wines, spirits and ciders. Alcoholic drinks contain fewother nutrients except for the bioactive flavonoids found in wine (mainly red wine). Alcoholic drinks are usuallyconsumed with foods, either as part of a meal or accompanied by snack foods, increasing the associated energyintake. Some alcoholic drinks are mixed with additives including stimulants, sugars and other flavours.The apparent average consumption of alcohol is estimated at 10.08 L per person over 15 years old per year, 855and declines with age. 856 Consumption is 45% higher in the Northern Territory than in the rest of Australia.The average consumption equates to an additional 650 kJ/day for every person over 15 years of age from alcohol.Alcoholic drinks that contain added sugar have even more energy. If alcohol is consumed in addition to the normaldiet, leading to excess energy intake compared to requirements, weight will increase.A full stomach reduces the rate of absorption of alcohol into the bloodstream. Drinking alcohol in combinationwith eating therefore reduces the rate at which blood alcohol content increases. Drinking coffee, having a coldshower, vomiting or exercising do not reduce blood alcohol content. 794Pregnant and breastfeeding womenAlcohol consumption by pregnant women may harm the unborn baby. Heavy daily drinking or heavy episodes ofdrinking have the most risk, and the risk from low-level drinking (one or two drinks per week) is likely to be small.However there is no lower limit that can be guaranteed to be completely safe, so avoiding alcohol while pregnantis the safest option. 794There is limited evidence from human research on the effects of maternal alcohol consumption during lactationand infant development. In Australia, it is suggested that mothers who do consume alcohol are more likely tostop breastfeeding before six months compared to mothers who do not drink. 857,858 Animal and observationalLimit intake of foods containing saturated fat, added salt, added sugars and alcoholNational Health and Medical Research Council83