Diabetes and wine

Good news for drinkers! More evidence that alcohol (and especially wine) could prevent diabetes

wine glass with red wine

A new study has shown that drinking moderately three or four times a week may protect people against diabetes.

In this Danish study, the association between alcohol drinking patterns and diabetes risk in men and women from the general ]population were examined (based on data from the Danish Health Examination Survey 2007–2008). The Danish scientists, led by Professor Janne Tolstrup from the University of Southern Denmark, publishing their findings in the journal Diabetologia.

76,484 survey participants (28,704 men and 41,847 women) were followed for a median of 4.9 years. Self-reported questionnaires were used to obtain information on alcohol drinking patterns, i.e. frequency of alcohol drinking, frequency of binge drinking, and consumption of wine, beer and spirits, from which drink-specific and overall average weekly alcohol intake was calculated. Information on incident cases of diabetes was obtained from the Danish National Diabetes Register. The investigation did not distinguish between the two forms of diabetes, Type 1 (where insulin needs to be injected daily) and the much more common but less serious Type 2.

During follow-up, 859 men and 887 women developed diabetes. Compared to teetotallers, men who drink three to four days a week are 27 per cent less likely to develop the condition, and women 32 per cent less likely.

The lowest risk of diabetes was observed at 14 drinks/week in men (HR 0.57 [95% CI 0.47, 0.70]) and at 9 drinks/week in women (HR 0.42 [95% CI 0.35, 0.51]), relative to no alcohol intake. Compared with current alcohol consumers consuming <1 day/week, consumption of alcohol on 3–4 days weekly was associated with significantly lower risk for diabetes in men (HR 0.73 [95% CI 0.59, 0.94]) and women (HR 0.68 [95% CI 0.53, 0.88]) after adjusting for confounders and average weekly alcohol amount.

The study researchers concluded that "Our findings suggest that alcohol drinking frequency is associated with risk of diabetes and that consumption of alcohol over 3–4 days per week is associated with the lowest risk of diabetes, even after taking average weekly alcohol consumption into account."


They also found that wine had the most substantial effect, probably because it contains chemical compounds that improve blood sugar balance. For both men and women, seven or more glasses of wine per week lowered the risk of diabetes by 25 per cent to 30 per cent compared with having less than one drink of wine.

But gin and some other spirits had a negative effect on women, with just one drink a day increasing the risk of diabetes by 83 per cent. One to six beers per week reduced diabetes risk by 21 per cent in men but had no effect on women.

Janne Tolstrup, of the University of Southern Denmark, said that she conducted the research because of previous studies showing an apparent connection between drinking and diabetes. She said she wanted to see if the pattern of drinking as well as the absolute quantities played a role. “I’ve done a lot of research into the association between alcohol drinking patterns and the risk of coronary heart disease,” "It is very evident that if you compare two men drinking the same amount, the risk depends on how they spread it out.” She wanted to see if the same applied to diabetes.

The cause of the positive effect of alcohol and particularly wine is not clear, although some studies have suggested a link between alcohol and the length of time insulin remains in the blood when it is released by the pancreas in response to glucose/sugar.  Insulin is used to regulate blood sugar levels and those deficient in it need to inject it and monitor their glucose levels.

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Of course the normal disappointing response to the results to avoid jeopardising future funding from the health authorities and sponsors. Professor Tolstrup said “I’ve been asked whether I would recommend drink. Of course not,” she said. “Alcohol is related to more than 50 diseases and conditions. We know among women for instance that the risk of breast cancer increases linearly with drinking. If you want to make any recommendations, you should look at everything.”

When he says “I’ve been asked whether I would recommend drink. Of course not,” but why not. The evidence is strong for a positive effect on health, particularly with wine. Don't be a slave to conventional prohibitioniest thinking!

Some public health bodies including Public Health England’s have an official alcohol guidance which states that there is “no safe level” of drinking. However this new evidence gives further complelling evidence that as well as protecting people from heart diease and stroke, it can help prevent diabetes. Therefore most epidemiologists argue that there appears to be an overall health benefit from a small amount of drinking, even if some government bodies tend to reject this view. 

Given the French Paradox, where moderate drinking in the French has helped to overcome bad habit like excessive cholesterol consumption and smoking and this new study, it appears the naysayers are getting it wrong. Some cancers like breast cancer risk is elevated at a relative level, but overall moderate alcohol, with exercise and good food, plus avoiding smoking seems like the ticket to a long and happy life! Abstaining from alcohol is just no fun at all!

A summary of the effect of alcohol and wine on diabetes

There is good clinical data to suggest that moderate consumption of wine can reduce the risk of diabetes. Animal studies are suggestive that the polyphenol in wine, resveratrol, may be helpful in preventing and treating some metabolic diseases, including diabetes.

Salas-Salvadó J review  in 2011 "The role of diet in the prevention of type 2 diabetes" stated that "The conclusion is that there is no universal dietary strategy to prevent diabetes or delay its onset. Together with the maintenance of ideal body weight, the promotion of the so-called prudent diet (characterized by a higher intake of food groups that are generally recommended for health promotion, particularly plant-based foods, and a lower intake of red meat, meat products, sweets, high-fat dairy and refined grains) or a Mediterranean dietary pattern rich in olive oil, fruits and vegetables, including whole grains, pulses and nuts, low-fat dairy, and moderate alcohol consumption (mainly red wine) appears as the best strategy to decrease diabetes risk, especially if dietary recommendations take into account individual preferences, thus enabling long-time adherence."

In the 2011 review by Tomasz Szkudelski and Katarzyna Szkudelska "Anti-diabetic effects of resveratrol" (*Note that resveratrol is present in wine) they stated that "In the last few years, rodent studies and experiments in vitro provided evidence that resveratrol (3,5,4′-trihydroxystilbene)—a naturally occurring phytoalexin present in numerous plant species—exerts beneficial effects in the organism and may be helpful in preventing and treating some metabolic diseases, including diabetes. In general, the management of diabetes involves three main aspects: reduction of blood glucose, preservation of β cells, and, in the case of type 2 diabetes, improvement in insulin action. Data from the literature indicate that the beneficial effects of resveratrol in relation to diabetes comprise all these aspects". 

In a 2014 review by Khemayanto H "Role of Mediterranean diet in prevention and management of type 2 diabetes" where the authors identified 451 articles with the key words: “Mediterranean diet” and “diabetes” up to 14 April 2014 the authors summarised:

"Daily moderate intake of alcohol (usually after a meal) in the form of red wine is one of the characteristic of Mediterranean diet. Moderate alcohol drinking is associated with 30% reduction of the risk of type 2 diabetes in both genders. The strongest inverse association was observed at 22–25 g/day. However, heavy consumption in both men and women (above 50 g/day for women and 60 g/day for men) were no longer provided protective effect but actually increased the risk for diabetes. Moderate alcohol consumption (40 g/day) for 17 days enhanced insulin sensitivity and plasma adiponectin levels, without any changes in the plasma tumor necrosis factor α (TNFα). Adiponectin stimulated glucose utilization and fatty acid oxidation. Adherence to the Mediterranean diet was associated with higher levels of adiponectin because of moderate consumption of red wine, which is inversely related to diabetes."

"Numerous studies on diabetic rats revealed the anti-hyperglycemic action of resveratrol. Among different beneficial effects of resveratrol found in diabetes, the ability of this compound to reduce hyperglycemia seems to be the best documented. The anti-hyperglycemic action of resveratrol was demonstrated in obese rodents and in two animal models of diabetes: in rats with streptozotocin- induced diabetes or with streptozotocin- nicotinamide-induced diabetes. Some studies also revealed that administration of resveratrol to diabetic rats resulted in diminished levels of glycosylated hemoglobin (HbA1C), which reflects the prolonged reduction of glycemia."

"The anti-hyperglycemic effect of resveratrol observed in diabetic animals is thought to result from its stimulatory action on intracellular glucose transport. Increased glucose uptake by different cells isolated from diabetic rats was found in the presence of resveratrol. Interestingly, in experiments on isolated cells, resveratrol was able to stimulate glucose uptake in the absence of insulin. The stimulation of glucose uptake induced by resveratrol seems to be due to increased action of glucose transporter in the plasma membrane. Studies on rats with experimentally induced diabetes demonstrated increased expression of the insulin-dependent glucose transporter, GLUT4, as a result of resveratrol ingestion, compared with diabetic animals not given resveratrol. It should be mentioned, however, that in some experiments on rats with streptozotocin-induced diabetes, resveratrol appeared to be ineffective and failed to decrease blood glucose."

Clinical study in type 2 diabetics shows that moderate red wine intake modestly decreases cardiometabolic risk

A new clinical study published this month in the Annals of Internal Medicine which assessed the impact of randomly assigning alcohol abstaining patients with type 2 diabetes mellitus 150 mL of mineral water, white wine, or red wine with dinner for 2 years. 224 individuals started the study and 87% completed the 2 year review.

In addition to the changes in the water group (Mediterranean diet only), red wine significantly increased good cholesterol (HDL high-density lipoprotein cholesterol) and decreased the total cholesterol ratio. Only slow ethanol metabolisers significantly benefited from the effect of both wines on blood glucose control. Across the 3 groups, no material differences were identified in blood pressure, adiposity, liver function, drug therapy, symptoms, or quality of life, except that sleep quality improved in both wine groups compared with the water group. Overall, compared with the changes in the water group, red wine further reduced the number of components of the metabolic syndrome.

So those using wine appeared not to have any negative effects and there were clear metabolic benefits. 

The details of the paper are included below:

Published online 13 October 2015

Two-Year Moderate Alcohol Intervention in Adults With Type 2 Diabetes
Yftach Gepner, MPH; Rachel Golan, RD, PhD; Ilana Harman-Boehm, MD; Yaakov Henkin, MD; Dan Schwarzfuchs, MD; Ilan Shelef, MD; Ronen Durst, MD; Julia Kovsan, MSc; Arkady Bolotin, PhD; Eran Leitersdorf, MD; Shoshana Shpitzen, MA; Shai Balag, MD; Elad Shemesh, MD; Shula Witkow, RD, MPH; Osnat Tangi-Rosental, BA; Yoash Chassidim, PhD; Idit F. Liberty, MD; Benjamin Sarusi, MSc; Sivan Ben-Avraham, RD, MPH; Anders Helander, PhD; Uta Ceglarek, PhD; Michael Stumvoll, MD; Matthias Blüher, MD; Joachim Thiery, MD; Assaf Rudich, MD, PhD; Meir J. Stampfer, MD, DrPH; Iris Shai, RD, PhD

Ann Intern Med. 13 October 2015,():  doi:10.7326/M14-1650

Background: Recommendations for moderate alcohol consumption remain controversial, particularly in type 2 diabetes mellitus (T2DM). Long-term randomized, controlled trials (RCTs) are lacking.

Objective: To assess cardiometabolic effects of initiating moderate alcohol intake in persons with T2DM and whether the type of wine matters.

Design: 2-year RCT (CASCADE [CArdiovaSCulAr Diabetes & Ethanol] trial). 

Setting: Ben-Gurion University of the Negev–Soroka Medical Center and Nuclear Research Center Negev, Israel.

Patients: Alcohol-abstaining adults with well-controlled T2DM.

Intervention: Patients were randomly assigned to 150 mL of mineral water, white wine, or red wine with dinner for 2 years. Wines and mineral water were provided. All groups followed a Mediterranean diet without caloric restriction.

Measurements: Primary outcomes were lipid and glycemic control profiles. Genetic measurements were done, and patients were followed for blood pressure, liver biomarkers, medication use, symptoms, and quality of life.

Results: Of the 224 patients who were randomly assigned, 94% had follow-up data at 1 year and 87% at 2 years. In addition to the changes in the water group (Mediterranean diet only), red wine significantly increased high-density lipoprotein cholesterol (HDL-C) level by 0.05 mmol/L (2.0 mg/dL) (95% CI, 0.04 to 0.06 mmol/L [1.6 to 2.2 mg/dL]; P < 0.001) and apolipoprotein(a)1 level by 0.03 g/L (CI, 0.01 to 0.06 g/L; P = 0.05) and decreased the total cholesterol–HDL-C ratio by 0.27 (CI, −0.52 to −0.01; P = 0.039). Only slow ethanol metabolizers (alcohol dehydrogenase alleles [ADH1B*1] carriers) significantly benefited from the effect of both wines on glycemic control (fasting plasma glucose, homeostatic model assessment of insulin resistance, and hemoglobin A1c) compared with fast ethanol metabolizers (persons homozygous for ADH1B*2). Across the 3 groups, no material differences were identified in blood pressure, adiposity, liver function, drug therapy, symptoms, or quality of life, except that sleep quality improved in both wine groups compared with the water group (P = 0.040). Overall, compared with the changes in the water group, red wine further reduced the number of components of the metabolic syndrome by 0.34 (CI, −0.68 to −0.001; P = 0.049).

Limitation: Participants were not blinded to treatment allocation.

Conclusion: This long-term RCT suggests that initiating moderate wine intake, especially red wine, among well-controlled diabetics as part of a healthy diet is apparently safe and modestly decreases cardiometabolic risk. The genetic interactions suggest that ethanol plays an important role in glucose metabolism, and red wine's effects also involve nonalcoholic constituents.