The authors of this paper test the hypothesis that overall diet quality influences associations between alcohol consumption and the risk of hypertension, based on data from a study in the USA (NHANES) and two studies in China. In general, their designation of a “high-quality” diet for Chinese was one with greater amounts of fruit, vegetables, and beans, while for Caucasians and Hispanics it was one with more whole grains, fruit, vegetables and nuts; “low-quality” diets were mainly those with higher intakes of red meat products. For comparisons with abstainers, subjects reporting < 7 drinks/week for total alcohol were categorized as light and those reporting 7-21 drinks/week categorized as moderate drinkers, with those reporting more referred to as heavy drinkers.
The paper concludes that light alcohol consumption among subjects with a high-quality diet was significantly associated with a decreased risk of hypertension in Caucasians, and the risk of hypertension was not significantly increased with increasing alcohol consumption in Caucasians, Chinese, and Hispanics. On the contrary, in context of a diet calculated to be low quality the risk of hypertension was significantly increased in a linear fashion with increasing alcohol consumption in all groups except African Americans.
Forum reviewers considered this to be a generally well-done and interesting study, but had concern that the authors may not have adjusted adequately for a factor strongly related to diet quality: socio-economic status. The authors included in their analyses whether or not subjects had a high school diploma, but no adjustments were made for occupation, income, or other important indices of deprivation, which may be important since lower SES subjects have consistently been shown to have poorer diets. Thus, we are unsure whether or not it is the diet solely that is the reason that alcohol consumption was found to be associated with lower, higher, or no effect depending on the type of diet. Further, no results are shown indicating whether or not there were differences if the beverage consumed was beer, wine, or spirits, and there was insufficient data on the pattern of drinking. The authors begin their abstract saying that ‘Alcohol is commonly consumed around mealtimes,’ but apparently do not have any data on whether the beverage was consumed with or without food for the present analyses.” All of these factors may modify how alcohol affects the risk of developing hypertension.
Finally, some Forum members were uneasy with the term “quality of diet”, based on the inclusion or exclusion of certain foods, which may be very important to taste. Said one member, we trust that diets recommended as being of “high quality” are not those whose savor has been removed.
Reference: Jiang W, Meng X, Hou W, Wu X, Wang W, Wang M, Chu X, Wang P, Sun C, Han T, Li Y. Impact of overall diet quality on association between alcohol consumption and risk of hypertension: evidence from two national surveys with multiple ethnics. Eur J Clin Nutr 2020; doi.org/10.1038/s41430-020-00708-1.