Garlic Consumption Associated with Lower All-Cause Mortality Risk

by | Jul 22, 2019 | 2019, Antioxidants, Cardiovascular Health, Garlic

Written by Angeline A. De Leon, Staff Writer. Garlic consumption revealed an inverse association between garlic consumption and all-cause mortality in a group of 27,437 community-dwelling older Chinese adults.

One of the most common cooking ingredients used throughout the world, garlic is also considered a functional food 1. In vitro and in vivo studies have documented the protective effects of garlic against cardiovascular disease and various kinds of cancer 2-4, and evidence from randomized controlled trials support the benefits of garlic supplementation for hypertension 5. Garlic has also been used to lower cholesterol and glucose 6,7, and in general, has been utilized as an antibacterial and immune-boosting agent 8. Studies suggest that the protective, antioxidant effects of garlic are due to the organosulfur compounds (OSCs) it contains 1. OSCs demonstrate the ability to reduce reactive oxygen species (ROS) concentrations, which is associated with anti-aging effects 9. While consumption of garlic has been found to be associated with lower mortality risk in younger healthy subjects 10, no such evidence has been reported for older adults. A recent study 11 published by Shi and colleagues (2019), therefore, examined the relationship of dietary garlic intake with all-cause mortality in a group of oldest-old individuals living in China.

A longitudinal population-based cohort study was conducted with a group of 27,437 community-dwelling older adults (mean age = 92.9 years) living in different provinces of China. At baseline, participants completed physical examination measurements, as well as a brief food frequency questionnaire assessing garlic consumption during the present time and retrospectively, at the age of 60 years old. Mortality was assessed from baseline to the date of death, 3 years post-baseline, or loss of follow-up, whichever occurred first.

Overall, among the 27,437 participants, 15.9% reported frequently consuming garlic (5 or more times per week), with a trend of decreasing garlic intake with age (17.6% by octogenarians and 15% by nonagenarians, and centenarians). At the time of follow-up, 22,321 deaths were documented, however, participants who reported more frequently consuming garlic had a longer median survival time, relative to those who consumed garlic occasionally (1-4 times per week) or rarely (less than once per week) (3.2 vs. 3.0 and 2.7 years, respectively, p < 0.001). Greater garlic consumption was associated with lower all-cause mortality: adjusted hazard ratio (HR) for mortality was 0.92 (0.89 to 0.94) for occasional consumers and 0.89 (0.85 to 0.92) for frequent consumers, relative to rare consumers at baseline. Compared to those who rarely consumed garlic at the age of 60 years old, the HR for occasional consumers was 0.96 (0.93 to 0.98) and 0.78 (0.75 to 0.82) for frequent consumers at the age of 60. Subgroup analysis revealed an inverse association between all-cause mortality and garlic consumption at baseline or at age 60 that was more robust for octogenarians and nonagenarians (p for interactions = 0.018 and < 0.001).

Researchers conclude that habitual consumption of garlic is inversely associated with overall mortality in oldest-old (80 years and older) individuals. This protective effect, hypothesized to be related to garlic’s potent antioxidant properties, was evident when garlic was consumed five or more times per week and was seen to result in an 11% decrease in risk of mortality. This association was true for octogenarians, nonagenarians, and centenarians studied in the present trial. Several study limitations, however, should be considered when interpreting results, namely, the fact that quantity of garlic consumption was not recorded; the form of garlic (raw, cooked, processed) consumed was not taken into account; and the collection of data on garlic consumption at the age of 60 is susceptible to recall bias. Nonetheless, findings verify the favorable role of garlic in supporting human longevity. Additional studies are needed to establish the dose-response relationship between garlic intake and mortality rates for specific conditions, such as cancer and cardiovascular disease.

Source: Shi X, Lv Y, Mao C, et al. Garlic consumption and all-cause mortality among Chinese oldest-old individuals: a population-based cohort study. Nutrients. 2019; 11: 1504. DOI: 10.3390/nu11071504.

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Posted July 22, 2019.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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