One month without alcohol measurably changed insulin, blood pressure and cancer markers

The premise of a month off alcohol is that the body recovers. A prospective study in BMJ Open put that premise to a controlled test in moderate-to-heavy drinkers, and found measurable improvements across metabolism, blood pressure and two proteins linked to cancer — changes that did not appear in a comparison group that kept drinking [s1].

The study

Researchers recruited healthy adults based on their own intention either to abstain from alcohol for one month or to carry on drinking [s1]. To qualify, participants had to be drinking more than 64 g of alcohol a week for men or 48 g for women at baseline, and anyone with known liver disease or alcohol dependence was excluded [s1]. The abstinence group comprised 94 people, the control group 47 [s1].

These were not light drinkers. Baseline consumption in the abstinence group averaged 258.2 g of alcohol a week — roughly 26 UK units, or well over a bottle of wine's worth of alcohol every few days [s1]. The primary outcome was change in insulin resistance, measured by the HOMA score, with weight, blood pressure, liver function and two growth factors tracked as secondary outcomes [s1].

What changed

In the group that stopped, the reductions were substantial and statistically clear. Insulin resistance fell by a median of 25.9% [s1]. Systolic blood pressure dropped 6.6% and diastolic 6.3% [s1]. Weight fell 1.5% [s1]. Two circulating growth factors implicated in cancer development moved most of all: vascular endothelial growth factor (VEGF) fell 41.8% and epidermal growth factor (EGF) fell 73.9% [s1]. Every one of these changes was significant at p<0.001 [s1].

The spread within the abstinence group was wide, which is worth stating alongside the medians. The interquartile range for the fall in insulin resistance ran from a 48.6% drop to a slight 0.3% rise, and for EGF from an 86.1% drop to a 36.4% drop [s1]. Not everyone responded to the same degree, and a minority barely moved on some measures — averages of this kind describe a group, not a guarantee for any one person [s1].

The comparison is what gives the numbers weight. In the control group, which continued its usual drinking, none of these measures changed significantly [s1]. And the improvements in the abstinence group were not explained by people also eating better, exercising more or quitting smoking — the analysis adjusted for those, and they did not account for the effect [s1].

Why the growth-factor result is the interesting one

The metabolic improvements are unsurprising in direction, if notable in size. The growth-factor findings are the study's real contribution. VEGF and EGF are involved in the blood-vessel formation and cell proliferation that tumours exploit, and their sharp fall on abstinence is, the authors argue, biological support for the idea that alcohol's link to cancer is causal rather than coincidental [s1].

That link is not hypothetical at the population level. A Lancet Oncology analysis attributed 741,300 new cancer cases worldwide in 2020 to alcohol, with a dose-response pattern that extends down into light drinking [s3]. The BMJ Open study offers a plausible mechanism at the individual level for how reducing intake might reduce that risk, though it did not measure cancer itself [s1].

The blood-pressure change fits the wider evidence

The 6.6% fall in systolic pressure also aligns with what causal-inference studies of alcohol and blood pressure show. A dose-response meta-analysis of 23 cohort studies found an almost linear rise in hypertension risk with intake, supporting a causal relationship rather than mere association [s2]. A drop in blood pressure when drinking stops is the expected other side of that curve [s2].

The limits, which are real

This was an observational study, not a randomised trial: people chose their group, and self-selection can bias who ends up where [s1]. It was conducted at a single centre, the sample was modest, and the participants were moderate-to-heavy drinkers, so the size of the changes should not be assumed to apply to light drinkers, who have less to reverse [s1]. One month is also a snapshot; the study cannot say whether the improvements persist, or whether they return if drinking resumes [s1].

What it does establish is a clean before-and-after contrast against a control group: in people who were drinking well above guideline levels, a single month without alcohol produced real, measurable shifts in the markers that track metabolic and cancer risk [s1]. This article describes what the study found; it is not medical advice.

Sources

• Short-term abstinence from alcohol and changes in cardiovascular risk factors, liver function tests and cancer-related growth factors — BMJ Open, 2018-05-05
• Alcohol Intake and Risk of Hypertension: A Dose-Response Meta-Analysis of Nonexperimental Cohort Studies — Hypertension, 2024-06-12
• Global burden of cancer in 2020 attributable to alcohol consumption: a population-based study — The Lancet Oncology, 2021-07-30