Red wine: a daily glass for two years did not shrink artery plaque

The heart promise of red wine has had a randomized test, in adults with type 2 diabetes who did not previously drink. In the 2-year CASCADE trial, 174 of them drank 5.1 fl oz (150 ml) of red wine, white wine or water daily. Carotid plaque volume changed by -1.3 mm3 with red wine and -1.4 mm3 with water, with no difference between groups (p = 0.9). This was a test inside a trial, not a reason for people with diabetes who do not drink to start. In 54 people with type 2 diabetes, 5.1 fl oz (150 ml) of red wine at dinner for 6 months left average 24-hour blood pressure no different from mineral water. The idea that the polyphenols do the work was tested too. In 29 obese adults, 600 mg a day of red wine polyphenol extract for 8 weeks did not improve insulin sensitivity measured by clamp. In 18 male smokers, only dealcoholized red wine lowered a blood marker of lipid oxidation over 2 weeks, and ordinary red wine did not. The EU refused to authorize the claim that red wine polyphenols help vascular function, which means the evidence submitted was judged insufficient.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• UK composition data list red wine at 10.7 g alcohol and 76 calories per 3.5 oz (100 g), with 0.2 g sugars. — CoFID 2021 Wine, red (17-752) (n = 1 record) Evidence E source
  Per 100 g: alcohol 10.7 g, energy 76 calories, sugars 0.2 g, potassium 110 mg, iron 0.90 mg

What a real portion looks like

• US dietary survey data count a glass of red wine as 180 g, roughly 19 g of alcohol at UK composition values. — FNDDS Wine, red, food code 93401010 (fdc 2710688) (n = 1 record) Evidence E source
  1 glass = 180 g; 1 fl oz = 30 g; half bottle = 375 g

What your body absorbs

• In a crossover RCT in 12 men, quercetin from 25 fl oz (750 mL) of red wine reached lower plasma levels than the same 14-16 mg dose from fried onions. — 12 healthy men, 25 fl oz (750 mL) red wine vs 50 g fried onions vs 13 fl oz (375 mL) black tea, 4 days each (n = 12) Evidence B source
  Plasma quercetin after wine lower than after onions (P < 0.05), similar to tea
• In radioiron studies in 33 people, nonheme iron absorption was 2 to 3 times higher from white wine than from polyphenol-rich red wines, an effect the authors judged unlikely to affect iron balance. — 33 human subjects, extrinsically labeled test meals (n = 33) Evidence C source
  Nonheme iron absorption 2-3 fold higher with white vs red wine

What cooking and storage change

• In a crossover study in 10 volunteers, soaking turkey cutlets in red wine before heating fully prevented the post-meal rise in plasma MDA, versus a 75% reduction when wine was added after heating. — 10 healthy volunteers, 250 g turkey cutlets with 6.8 fl oz (200 ml) red wine (n = 10) Evidence B source
  Plasma MDA rise of 160 nM after plain meal; 75% lower when wine added after heating; completely prevented when soaked before heating

What it does to your health

• In the 2-year CASCADE RCT in 174 adults with type 2 diabetes, 150 ml/day of red wine did not change carotid plaque volume compared with water (-1.3 vs -1.4 mm3). — 174 previously abstaining adults with type 2 diabetes, 5.1 fl oz (150 ml) red wine, white wine or water daily for 2 years (n = 174) Evidence B source
  Carotid total plaque volume change: red wine -1.3 mm3, water -1.4 mm3, p = 0.9 between groups
• In a 6-month RCT in 54 adults with type 2 diabetes, 5.1 fl oz (150 ml) of red wine at dinner did not change average 24-hour blood pressure versus mineral water. — 54 abstainers with type 2 diabetes, 5.1 fl oz (150 ml) dry red wine or water at dinner, 6 months (n = 54) Evidence B source
  Mean 24-h BP no difference; transient night-time systolic drop -10.6 vs +2.3 mm Hg (P = 0.031)
• NIH ODS notes that even 8.1 fl oz (240 ml) of red wine a day for 2 weeks can lower serum folate in healthy men, though not below adequacy. — Healthy men; people with alcohol use disorder Evidence E source
  Serum folate significantly decreased, not below 3 ng/ml

Safety, limits and interactions

• In a crossover RCT in 12 men, a 8.5 fl oz (250 mL) glass of red wine raised cisapride exposure by a non-significant 15%, but one participant had a doubling, suggesting CYP3A4-related drug interactions in some people. — 12 healthy men, cisapride 10 mg with 8.5 fl oz (250 mL) red wine, grapefruit juice or water (n = 12) Evidence B source
  Cisapride AUC 115% with red wine (not significant) vs 151% with grapefruit juice; one subject doubled
• In a double-blind challenge study in 18 people with red wine-induced asthma, 9 had a significant drop in peak flow, and the worst reactions always followed high-sulfite wine. — 18 patients with history of red wine-induced asthma, up to 13 fl oz (385 ml) wine (n = 18) Evidence B source
  9 of 18 had peak flow fall >15%; most severe reaction always after high SO2 wine
• CDC states there is no known safe amount of alcohol in pregnancy, and red wine is no exception. — Pregnant women Evidence E source
  Guidance; no effect size
• Red wine is an alcoholic drink. CDC defines moderate drinking as two drinks or less in a day for men and one drink or less in a day for women, says people younger than 21 and people who are or might be pregnant should not drink at all, and states that even less than 1 drink per day can raise the risk of certain cancers. — adults of legal drinking age (21 or older), people younger than 21, pregnant people Evidence E source
  Moderate use: 2 drinks or less a day for men, 1 or less for women, under 1 drink a day can raise risk of certain cancers
• The US alcohol institute (NIAAA) says MAOI antidepressants such as tranylcypromine and phenelzine combined with alcohol may cause serious heart-related side effects, and that the risk of dangerously high blood pressure rises when MAOIs are mixed with tyramine, which it says is found in red wine and beer. — People who drink alcohol while taking common prescription or over-the-counter medicines (n = -) Evidence E source
  MAOIs + alcohol: serious heart-related side effects; MAOIs + tyramine (red wine, beer): dangerously high blood pressure

What people believe that the data does not support

• In an 8-week RCT in 29 obese adults, 600 mg/day of red wine polyphenols did not improve insulin sensitivity measured by clamp. — 29 obese volunteers (BMI >30), 600 mg/day red wine polyphenols or placebo for 8 weeks (n = 29) Evidence B source
  No significant change in clamp M-value (P = .65) or Matsuda index (P = .88)
• In a crossover RCT in 18 male smokers, only dealcoholized red wine lowered plasma F2-isoprostanes over 2 weeks, while regular red wine did not reduce lipid peroxidation. — 18 male smokers, red wine, white wine or dealcoholized red wine for 2 weeks each (n = 18) Evidence B source
  Plasma F2-isoprostanes decreased with dealcoholized red wine (p < .05), not with alcoholic wines
• A network meta-analysis of 7 clinical studies found that drinking red wine, coffee or tea did not reduce the effectiveness of dental bleaching compared with a white diet. — 7 clinical studies (4 RCTs, 3 non-randomized) of dental bleaching (n = 7 studies) Evidence C source
  Similar color change with pigment intake vs white diet (p>0.05); GRADE moderate
• The EU refused to authorize the claim that red wine polyphenols help vascular function and a healthy heart. — EU Register on nutrition and health claims Evidence E source
  Non-authorized

What is still unknown

• In UK Biobank data on 502,490 adults followed about 12 years, observational analysis linked red wine to a U-shaped curve for all-cause mortality and chronic kidney disease. — 502,490 UK Biobank participants, median follow-up about 12 years (n = 502490) Evidence C source
  U-shaped association in observational data; not a safe amount

The bottom line

A glass in US survey data is 180 g. UK data put red wine at 10.7 g alcohol and 76 calories per 3.5 oz (100 g), so a glass holds about 19 g of alcohol, more than the 14 g US standard drink, and the real figure depends on the wine. The observational picture is looser. In UK Biobank, 502,490 adults followed for about 12 years, red wine showed a U-shaped association with death from any cause and with chronic kidney disease. That is an association in people who chose how much to drink. The authors proposed weekly limits from that curve, but an association cannot show a safe amount, and genetic studies of the Mendelian randomization type have not confirmed a protective effect of moderate drinking. In a crossover trial in 12 men, 25 fl oz (750 mL) of red wine a day, a large dose of alcohol, gave lower plasma quercetin than fried onions. In radioiron studies from 1995 in 33 people, nonheme iron absorption was 2 to 3 times higher with white wine than with polyphenol-rich red wine, and the authors judged the effect unlikely to change iron balance. In 10 volunteers, soaking turkey cutlets in red wine before cooking fully prevented the post-meal rise in plasma MDA, against a 75% reduction when the wine was added after heating. That was one meal and a surrogate marker. The NIH Office of Dietary Supplements notes that 8.1 fl oz (240 ml) a day for 2 weeks lowered serum folate in healthy men, though not below the adequacy cutoff of 3 ng/ml. In a network meta-analysis of 7 studies of mixed design, drinking red wine did not reduce the effect of tooth bleaching compared with a white diet. The CDC states there is no known safe amount of alcohol in pregnancy and names red wine among the drinks that can harm. In a double-blind challenge study from 1986 in 18 people with a history of red wine asthma, 9 had a significant fall in peak flow, and the worst reaction always followed the wine high in sulfur dioxide. This page does not cover how alcohol interacts with medicines: we have no card on alcohol with glucose-lowering drugs or other regular medicines, so anyone taking one, including for diabetes, should ask a doctor or pharmacist before drinking. The one drug study we hold is small. In a crossover trial in 12 healthy men, a 8.5 fl oz (250 mL) glass raised exposure to the drug cisapride by 15%, which was not significant. The authors warn that people with high intestinal CYP3A4 could still see an interaction as marked as with grapefruit juice. We have no card on alcohol and cancer or on an upper limit for drinking, so this page cannot name a safe amount.

Compared with other foods

Sources

1. rwine-daily-r2-15 · food composition dataset
   Wine, red (CoFID 17-752): alcohol 10.7 g, energy 76 kcal, carbohydrate 0.2 g, total sugars 0.2 g, water 88.4 g, potassium 110 mg, iron 0.90 mg per 100 g
   CoFID 2021 (Public Health England, OGL v3.0), code 17-752 Wine, red · checked 2026-09-29
2. rwine-daily-r2-16 · food portion dataset
   Wine, red (FNDDS 93401010, fdc 2710688, WWEIA Wine): 1 fl oz = 30 g, 1 glass = 180 g, 1/2 bottle = 375 g, quantity not specified = 180 g
   USDA FNDDS, food code 93401010 Wine, red (FDC 2710688) · checked 2026-09-29
3. rwine-daily-r2-03 · RCT
   The plasma quercetin concentration after the consumption of wine was lower than that after onions (P: < 0.05) and not different from that after tea.
   J Nutr, 2001 · checked 2026-09-29
4. rwine-daily-r2-04 · controlled trial
   In four separate studies we observed that absorption was 2- to 3-fold higher from white wine containing a low concentration of polyphenols than from two red wines containing a 10-fold higher concentration of polyphenols...Our findings indicate that the inhibitory effect of phenolic compounds in red wine is unlikely to affect iron balance significantly.
   Am J Clin Nutr, 1995 · checked 2026-09-29
5. rwine-daily-r2-09 · RCT
   After a meal of turkey meat cutlets, plasma MDA levels increased by 160 nM (P<0.0001); after (B) there was a 75% reduction in the absorption of MDA (P<0.0001). However, after (C), the elevation of plasma MDA was completely prevented (P<0.0001).
   FASEB J, 2008 · checked 2026-09-29
6. rwine-daily-r2-01 · RCT
   After 2 years, no significant progression in carotid-TPV was observed (water, -1.4 (17.0) mm3, CI (-2.7, 5.5), white-wine, -1.2 (16.9) mm3, CI (-3.8, 6.2), red wine, -1.3 (17.6) mm3, CI (-3.4, 6.0; p = 0.9 between groups)).
   Eur J Clin Nutr, 2018 · checked 2026-09-29
7. rwine-daily-r2-02 · RCT
   After 6 months of intervention, the average 24-h BP did not differ between the wine and water groups.
   Am J Hypertens, 2016 · checked 2026-09-29
8. rwine-daily-r2-13 · agency fact sheet
   Even moderate alcohol consumption of 240 ml (8 fluid ounces) red wine per day or 80 ml (2.7 fluid ounces) vodka per day for 2 weeks can significantly decrease serum folate concentrations in healthy men, although not to levels below the cutoff for folate adequacy of 3 ng/ml [35].
   NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals · checked 2026-09-29
9. rwine-daily-r2-05 · RCT
   Cisapride AUC and C(max) with red wine were 115% (difference not statistically significant) and 107% (difference not statistically significant), respectively, of those with water...However, even this amount of red wine may cause a marked interaction similar to that for grapefruit juice in individuals with a preexisting high intestinal CYP3A4 content.
   Clin Pharmacol Ther, 2001 · checked 2026-09-29
10. rwine-daily-r2-06 · RCT
    Nine subjects demonstrated a significant fall in peak flow in one or more challenges. In all cases the most severe reaction was observed after the wine with high SO2 content.
    J Allergy Clin Immunol, 1986 · checked 2026-09-29
11. rwine-daily-r2-14 · agency guidance
    There is no known safe amount of alcohol use during pregnancy. ... All types of alcohol can be harmful, including red or white wine, beer, and liquor.
    US CDC, About Alcohol Use During Pregnancy · checked 2026-09-29
12. sf-alclim-r1-redwine-1 · agency advice
    The Dietary Guidelines for Americans recommends that adults of legal drinking age (21 or older) should not drink alcohol or drink in moderation if they choose to drink alcohol...Moderate alcohol use is: For men—two drinks or less in a day. For women—one drink or less in a day...You shouldn't drink at all, even in moderation, if you: Are younger than 21. Are pregnant or might be pregnant...Even low levels of alcohol use (less than 1 drink per day) can raise the risk of certain cancers.
    CDC, About Moderate Alcohol Use · checked 2026-10-08
13. sf-alcmed-r5-3 · agency advice
    Monoamine oxidase inhibitors (MAOIs), such as tranylcypromine and phenelzine, when combined with alcohol, may result in serious heart-related side effects. Risk for dangerously high blood pressure is increased when MAOIs are mixed with tyramine, a byproduct found in beer and red wine
    NIAAA, Harmful Interactions: Mixing Alcohol with Medicines (brochure, revised 2014) · checked 2026-10-08
14. rwine-daily-r2-07 · RCT
    This study showed that 8 weeks of RWP supplementation did not improve insulin sensitivity in 29 obese volunteers.
    Diabetes Obes Metab, 2018 · checked 2026-09-29
15. rwine-daily-r2-08 · RCT
    However, no reduction in lipid peroxidation was observed following red or white wine consumption, suggesting that any protective effects of wine drinking on cardiovascular disease are unlikely to be related to inhibition of lipid oxidation.
    Free Radic Biol Med, 2001 · checked 2026-09-29
16. rwine-daily-r2-10 · network meta-analysis
    CONCLUSIONS: The consumption of soft cola, coffee, black tea, grape juice, and red wine, as well as the consumption of a totally unrestricted diet, do not have a significant influence on the effectiveness of bleaching as compared to a white diet regimen.
    J Dent, 2025 · checked 2026-09-29
17. rwine-daily-r2-12 · regulatory decision
    POL-HC-7784 Polyphenols derived from red wine Total red wine polyphenols help vascular functions that contribute to a healthy cardiovascular system. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7784, snapshot 2026-09-21 · checked 2026-09-29
18. rwine-daily-r2-11 · cohort
    Upon further classification of alcoholic beverages, our analysis revealed that red wine, champagne plus white wine, beer, spirits, and fortified wine presented a U-shaped relationship with the risk of all-cause mortality and CKD.
    Medicine (Baltimore), 2024 · checked 2026-09-29