Your kidneys work hard. They maintain fluid equilibrium in the body, they produce hormones and they filter blood, removing waste and other impurities and excreting them through the urinary system. They produce blood cells as well as control blood pressure. Keeping them healthy is key, and a glass of wine might help with that.
A team of researchers at Johns Hopkins University in Baltimore has found a link between moderate consumption of alcohol and a reduced chance of developing chronic kidney disease (CKD). "We found that a moderate amount of alcohol consumption (up to 1 glass per day for women and up to 2 glasses per day for men) was associated with lower risk of chronic kidney disease compared with little to no consumption of alcohol," Emily Hu, lead author and a PhD candidate at Johns Hopkins, told Wine Spectator in an email.
CKD compromises normal kidney functions, allowing excess fluids, toxins and minerals to remain in the body. The disease puts patients at risk of developing high blood pressure, heart disease and diabetes. CKD affects an estimated 30 million adults in the U.S., according to the Centers for Disease Control and Prevention (CDC).
The new study, published in the Journal of Renal Nutrition, collected and analyzed data on more than 12,600 participants, black and white men and women aged 45 to 64 years, who were tracked over the course of 24 years. Using questionnaires on eating habits, the researchers separated the participants into groups based on amounts of alcohol consumed: never drinkers, former drinkers, those who consume less than or equal to 1 drink per week, 2 to 7 drinks per week, 8 to 14 drinks per week and 15 drinks or more per week.
Over the course of the 24 years, 3,664 of the participants developed CKD. But there was a surprising result when investigating the alcohol habits of those that didn't develop CKD.
Compared to participants who had never drank alcohol, those who consumed less than or equal to 1 drink per week had a 12 percent lower risk of developing CKD. Those who had 2 to 7 drinks per week had a 20 percent lower risk and those who consumed 15 drinks or more per week had a 23 percent lower risk. Participants who drank a moderate 8 to 14 drinks per week enjoyed the biggest risk reduction in CKD—a 29 percent lower risk of CKD than never drinkers.
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Heavy drinking showed a decreased benefit, however. "There was a linear decrease in CKD risk from 1 drink per week to 10 drinks per week," the authors write. "For alcohol consumption between 10 drinks per week and 20 drinks per week, there was still a reduced risk of CKD, but the association started to approach the null. For alcohol consumption greater than 20 drinks per week, the association was no longer statistically significant."
The researchers write that the moderate drinkers in the group tended to be male, white, and had higher levels of education and income. They say that further studies are needed to examine whether any of those factors play a role.
"There are limitations in our study that must be acknowledged. First, alcohol consumption was self-reported, which is subject to reporting bias and may have been underreported," the authors write. "A strength of our study was the large community-based population with a relatively large number of kidney events and therefore enough power to detect significant associations. Our population includes both men and women and blacks and whites, allowing generalizability to other populations. Our study also had a lengthy follow-up time, with a median of 24 years, which is longer than previous studies."
The scientists theorize that alcohol's impact on reducing the risk of CKD are similar to how it lowers the risk of coronary heart disease. Past research has found that low levels of HDL cholesterol (aka “good cholesterol”) are often found in people with impaired kidney function. Moderate alcohol consumption has been linked with high levels of HDL.
But before you go buy that case of Merlot to protect your kidneys, keep in mind that preliminary studies on the role of alcohol and disease reduction don't tell a complete story. The researchers conclude the study on a cautionary note: Consuming 1 to 2 drinks per day may not appear to be detrimental to kidney health, but their findings should not be used as a reason to begin an alcohol habit. The study is positive news for those that already drink moderately—1 drink per day for women and 2 for men—but further research is needed.