The treatment of diabetes before the era of insulin consisted of various dull and unpalatable diets. One of the diets was designed by the French physician, Bouchardat, who replaced the dangerous foods (starch and sugar) with other foods like protein and fat. His "animal food" diet consisted mainly of fatty meat, however, the French Doctor encouraged the patients to wash their "animal diet" down with red wine. Dr. Bouchardats book "De la diabète sucré" recommended 1-4 litres of Claret or Burgundy of proper maturity at least four years old per day. The ample supply of wine served its purpose as an important carbohydrate-free source of energy with the added bonus of making the meals tolerable for thousands of diabetic patients.

An ounce of prevention

Type 2 diabetes (non-insulin dependent diabetes) is a common condition affecting at least 3% of the middle aged and elderly population of the western world. Advancing age, obesity, upper body fat distribution, and a family history of diabetes are among the well established risk factors for this condition. Several large-scale epidemiological studies have suggested an inverse association between moderate alcohol consumption and risk for type 2 diabetes. Just about one drink per day almost halved the risk of type 2 diabetes among American nurses (1), middle aged British men (2), male health professionals (3), elderly East Boston residents (4), and US male physicians (5). Other studies have reported null (6-7) or even positive associations (8-9) between alcohol consumption and risk of type 2 diabetes. In these studies relatively small sample sizes, as well as the small number of cases and the differences in the measurements of alcohol consumption levels, may explain some of the results.

Alcohol may increase insulin sensitivity

Some studies have suggested that moderate consumption of alcohol may increase insulin sensitivity (9-11). In several cross-sectional analyses regular alcohol consumption has been associated with decreased insulin resistance (12-15). Early reports on the acute effects of alcohol on glucose metabolism indicated a decreased insulin sensitivity (16-17). These studies, however, were performed in a relatively small number of individuals with rather large amounts of alcohol administered intravenously over short time periods.

The insulin-resistance syndrome, a defect in the ability of the body tissues to respond adequately to insulin, also comprises hypertension, hyperuricaemia, high levels of plasminogen activator inhibitor I, low HDL-cholesterol levels, high triglycerides and dense LDL-cholesterol particles. Each of the components of the syndrome is considered a risk factor for atherosclerosis. Therapeutic options to improve insulin sensitivity are scarce and mostly limited to changes in life-style, such as weight loss, cessation of smoking, and increased physical activity. This list may now be extended with a moderate consumption of alcohol (18).

Alcohol and CHD in people with diabetes mellitus

Age-adjusted rates of coronary heart disease are substantially higher among diabetic men and women than among those without diabetes. In general populations epidemiological studies have consistently demonstrated an inverse association between moderate alcohol consumption and CHD incidence and mortality. The results of the Physicians Health Study suggest that light to moderate alcohol consumption is associated with similar risk reductions in CHD among diabetic and non-diabetic men (19). Furthermore, data from the Nurses Health Study showed that just about a drink per day halved the risk of CHD among nurses with type 2 diabetes compared with non-drinking diabetic nurses (20).

According to the Wisconsin Epidemiological Study of Diabetic Retinopathy (21) the lowered risk of CHD found with increasing alcohol intake appeared greater than those found in many general population studies (up to 80% lowered risk vs 20%-60%). One mechanism for the cardio-protection may be the reaction of acetaldehyde with protein-bound Amadori products. Amadori products typically arise from addition of sugars such as glucose to protein amino groups and they are the precursors of advanced glycation end products (AGE). AGEs accumulate over time on plasma lipoproteins and vascular wall components and play an important role in the development of diabetes and age-related cardiovascular disease. Ethanol is metabolized to acetaldehyde, that can react to a model Amadori product producing a chemically stabilized complex that cannot progress to AGE formation. In a model study diabetic rats fed an ethanol diet for 4 weeks showed a 52% decrease in haemoglobin-AGE products compared with diabetic controls (22).

Moderate alcohol consumption should not routinely be discouraged

"Although potential risks of alcohol consumption must be considered, these data suggest that moderate alcohol consumption is associated with reduced CHD risk in women with diabetes and should not be routinely discouraged", Caren G. Solomon et al concluded from the Nurses Health Study data (20). Several short-term studies confirm, that moderate consumption of wine with a meal has no adverse effect on the glycaemic control of diabetic patients (23-24). The participants in the Finnish study included 10 type 1 diabetic patients treated with insulin and 16 type 2 diabetic patients treated with diet alone or with diet and oral drugs (24). On the experimental day the patients were given 40 ml of Vodka as an aperitif, 400 ml of red wine with the meal, and 40 ml of cognac with coffee after the meal!

Patients with well controlled non-insulin-dependent diabetes mellitus could consume moderate amounts of sweet wine and sherry without detriment to their glycaemic control (25). They were given a standard meal with 50 ml sherry and 250 ml wine on each of two evenings. On one occasion they received dry drinks, and on the other, sweet drinks. A Danish experiment evaluating the effects of 300 ml dry and 300 ml sweet white wine in 12 type 2 diabetic patients found no impact on the glycaemic control whether the wine was dry or sweet (26). An investigation of seven British beer drinkers with type 1 diabetes demonstrated an increase in blood glucose concentration proportional to the carbohydrate content of the beer (27). Based on the results of their study Henderson et al suggest that diabetic patients should be advised to choose beers with a carbohydrate content of at least 3 grams and not more then 7 grams per half-pint.

You should always have your drink with food

Many studies have shown that alcohol causes a prominent reduction of the gluconeogenetic pathway in the liver; i.e. alcohol inhibits the formation of new glucose (blood sugar) from amino acids and other precursors. For this reason, when alcohol is given to fasting (glycogen-deficient) subjects, it leads to serious hypoglycaemia (28). Within a period of three years, five diabetics who manifested severe hypoglycaemia after the ingestion of alcohol have been seen on the wards of the Boston City Hospital. In each of these patients, alcohol appeared to augment the hypoglycaemic effect of insulin and induce irreversible neurologic changes. The combination of fasting + insulin +alcohol in a diabetic patient may result in dangerously low blood sugar levels, however, the comatose person with an odour of alcohol on his breath run the obvious risk of being mistaken for an ordinary drunk. If brought to the police station instead of the hospital the unfortunate hypoglycaemic drunk diabetic may well die.

Normally the risk of hypoglycaemia is low among otherwise healthy elderly fasted patients with type 2 diabetes taking oral sulfonylurea medications. A study from the University of New Mexico Clinical Research Center has demonstrated that low doses of alcohol may predispose elderly type 2 diabetic patients to sulfonyl urea-induced low blood sugar during a short-term (24 h) fast (29). Drinking moderate amounts of beer or wine with your meal makes sensible drinking especially for diabetic patients in treatment with either insulin or oral antidiabetic medications.

For all people, including diabetic patients, the consumption of food is accompanied by a significant decrease of antioxidant defences due to the generation of oxidative stress. Red wine ingestion has been demonstrated to be accompanied by a significant increase of plasma antioxidant power. To explore the possibility that red wine consumption may reduce oxidative stress produced in diabetic patients during meals Ceriello et al from Udine General Hospital gave 10 male type 2 diabetic patients a standard meal plus 300 ml Italian Merlot (30). The red wine had a much higher antioxidant TRAP activity (6.1 mmol/l) than an Italian white wine (1.2 mmol/l). In a report from Bordeaux, French scientists demonstrate that drinking 200 ml red wine with a meal does not increase blood glucose in type 2 diabetics and red wine may even lead to a slight decrease mediated by the non-alcoholic compounds in wine (31).

Should patients with diabetes drink to their health?

This question is asked by M.Criqui and B.Golomb in an editorial of JAMA, July 21, 1999 (32)The US epidemiologists actually expect a greater absolute benefit in reduction in risk for CHD in older patients with diabetes compared with unselected populations, because they are at higher baseline risk of coronary heart disease. "However, in patients with diabetes, alcohol may both induce and mask potentially severe hypoglycaemia by exaggerating hypoglycaemic effects caused by other factors (eg, exercise or insulin, sulfonylureas, betablockers, or other drugs). But what is true for most patients with diabetes is true for other patients at high risk for CHD light to moderate alcohol consumption likely provides benefit, but is contraindicated in anyone who, for whatever reason, cannot restrict his or her drinking to light to moderate levels. For some patients, 1 drink is plenty, 2 is too many, and, unfortunately, 3 is not half enough."

Dr.Erik Skovenborg is a founder member of the Scandanavian Medical Alcohol Board, a specialist on alcohol and health and a member of the AIM Editorial Board

References:1.Stampfer MJ et al A prospective study of moderate alcohol drinking and risk of diabetes in women. Am J Epidemiol 1988;128:549-58. 2.Perry IJ et al' Prospective study of risk factors for development of non-insulin dependent diabetes in middle aged British men.' BMJ 1995;310:560-64. 3. Rimm EB et al' Prospective study of cigarette smoking, alcohol use, and the risk of diabetes in men.' BMJ 1995;310:555-59. 4.Gurwitz JH et al 'Risk factors for Non-Insulin-Dependent Diabetes Mellitus requiring treatment in the elderly.' J Am Geriatr Soc 1994;42:1235-40. 5.Ajani UA et al' Alcohol consumption and risk of type 2 diabetes mellitus among US male physicians.' Arch Intern Med 2000;160:1025-30. 6.Ohlsen LO et al. 'Risk factors for type 2 diabetes mellitus: thirteen and one half years of follow-up of the participants in a study of Swedish men born in 1913.' Diabetologia 1988;31:798-805. 7. Hodge AM et al ' Abnormal glucose tolerance and alcohol consumption in three populations at high risk of non-insulin-dependent diabetes mellitus.' Am J Epidemiol 1990;132:902-09. 8.Holbrook TL et al 'A prospective study of alcohol use and non-insulin dependent diabetes mellitus.' Am J Epidemiol 1990;132:902-09. 9. Facchini F et al 'Light-to-moderate alcohol intake is associated with enhanced insulin sensitivity'. Diabetes Care 1994;17:115-19. 10.Kiechl S et al. Insulin sensitivity and regular alcohol consumption: large, prospective, cross sectional population study (Bruneck study). BMJ 1996;313:1040-44. 11.Mayer-Davis EJ et al 'Moderate alcohol consumption in relation to higher insulin sensitivity:IRAS. Diabetes 1998;47:A409.12.Razay G et al Alcohol consumption and its relation to cardiovascular risk factors in British women. BMJ 1992;304:80-83. 13.Lazarus R et al Alcohol intake and insulin levels. Am J Epidemiol 1997;145:909-16.14.Mooy JM et al Determinants of specific serum insulin concentrations in a general Caucasian population aged 50 to 74 years (the Hoorn Stusy). Diabetes Med 1998;15:45-52. 15. Flanagan DEH et al Alcohol consumption and insulin resistance in young adults. Eur J Clin Invest 2000;30:297-301.16.Yki-järvinen H, et al Ethanol decreases glucose utilization in healthy men. J Clin Endocrinol Metab 1985;61:941-45.17.Shelmet JJ et al Ethanol causes acute inhibition of carbohydrate, fat, and protein oxidation and insulin resistance. J Clin Invest 1988;81:1137-45.18. Van de Wiel A. Hypothesis: Alcohol and insulin sensitivity. Netherlands Journal of Medicine 1998;52:91-94. 19.Ajani UAet al. Alcohol consumption and risk of coronary heart disease by diabetes status. Circulation 2000;102:500-5.20.Solomon CG et al. Moderate alcohol consumption and risk of coronary heart disease among women with type 2 diabetes mellitus. Circulation 2000;102:494-99.21.Valmadrid CT et alAlcohol intake and the risk of coronary heart disease mortality in persons with older-onset diabetes mellitus. JAMA 1999;282:239-46.22.Al-Abed Y et al. Inhibition of advanced glycation endproduct formation by acetaldehyde: Role in the cardioprotective effect of ethanol. Proc Natl Acad Sci USA 1999;96:2385-90. 23.Gin H et alShort-term effect of red wine (consumed during meals) on insulin requirement and glucose tolerance in diabetic patients. Diabetes Care 1992;15:546-48.24.Koivisto VA et alAlcohol with a meal has no adverse effects on postprandial glucose homeostasis in diabetic patients. Diabetes Care 1993;16:1612-14.25.Chellingsworth MC et al The effect of sweet wine and sherry as opposed to dry wine and sherry on acute glycaemic control in non-insulin-dependent diabetes. Practical Diabetes 1990;7:70-71. 26. Christiansen C et al Wine for type 2 diabetic patients? Diabetic Medicine 1993;10:958-61.27.Henderson B et al The effect of different beers on blood glucose concentrations in insulin-dependent diabetes. Practical Diabetes 1987;4:283-85. 28.Arky RA et al Irreversible hypoglycemia. JAMA 1968;206:575-78. 29.Burge MR, Zeise TM, Sobhy TA, Rassam AG, Schade DS. Low-dose ethanol predisposes elderly fasted patients with type 2 diabetes to sulfonylurea-induced low blood glucose. Diabetes Care 1999;22:2037-43.30.Ceriello A et al. Meal-generated oxidative stress in diabetes. The protective effect of red wine. Diabetes Care 1999;22:2084-85.31.Gin H et al Effects of red wine, tannic acid, or ethanol on glucose tolerance in Non-Insulin Dependent Diabetic patients on starch digestibility in vitro. Metabolism 1999;48:1179-83.32.Criqui MH et al Should patients with diabetes drink to their health? JAMA 1999;282:279-80.