The latest critique from the ISFAR considers a study that looks at the affect of alcohol consumption on health through metabolic and biochemical mechanisms

The latest critique from the ISFAR considers a study that looks at the affect of alcohol consumption on health through metabolic and biochemical mechanisms

A large study from Australia, which included a high percentage of current or former alcohol abusers, related alcohol consumption with a variety of metabolic and biologic parameters that relate to health. Included were markers of lipid function, inflammation, glucose metabolism, and liver function.

As expected, there was a linear increase in HDL-cholesterol with increasing alcohol intake; somewhat surprisingly, there was a linear decrease in insulin levels with increasing alcohol consumption (which may relate to the typical finding of a significantly lower risk of diabetes mellitus among moderate drinkers).

Essentially, all of the other factors showed a 'J-shaped' or 'U-shaped' relation with alcohol: namely, a decrease of risk with small to moderate amounts of alcohol and an increase with larger intake. 

In their association with alcohol, the lowest (most favourable) values of parameters varied by the measure: lowest triglycerides at about one to two drinks per day, lowest CRP at about one drink per day, lowest blood sugar and lowest alkaline phosphatase values at one to three drinks per day.

Adverse effects on liver enzymes, blood glucose, and inflammatory markers showed a threshold level of intake that varied somewhat by marker. For example, reported non-drinkers had higher values of CRP, triglycerides, and alkaline phosphatase; among drinkers, significant increases were seen only in consumers of 40 or more drinks per week. Unfortunately, the investigators did not report on the pattern of drinking, which usually shows preferable results from the regular, moderate intake of alcohol with no binge drinking.

The key findings of the study can be summarised as favourable effects of moderate alcohol intake on HDL-cholesterol and insulin levels, and for most other factors (including liver enzymes, triglycerides, blood glucose, and the inflammatory marker CRP), a 'J-shaped' relation: lower values with light drinking and higher values with larger amounts of alcohol. For most of these, there was either no effect or a favourable effect until alcohol intake exceeded a “threshold value”, at which heavier drinking began to show adverse effects.

Forum reviewers agreed with the conclusion of the authors: “The pattern of potentially beneficial effects of alcohol on HDL-C and insulin increasing progressively as consumption increases, whereas the negative effects show thresholds, is consistent with net U- or J-shaped effects of alcohol on health.”

While actual health outcomes were not evaluated in this study, overall it provides strong support for the results of most prospective epidemiologic studies that show lower rates of cardiovascular and other diseases among light-to-moderate drinkers than among abstainers or heavy drinkers.

To read the full critique, click here.

These critiques are released with the permission of ISFAR.