Excessive coffee consumption increases the likelihood of hypertension in genetically predisposed people
August 21, 2019
By Karina Toledo | Agência FAPESP – The habitual consumption of more than three cups of coffee per day leads to an up to fourfold increase in the likelihood of developing high blood pressure in people who are genetically predisposed to the condition, according to a study conducted by the University of São Paulo (USP) in Brazil and published in the journal Clinical Nutrition.
The study, which was supported by FAPESP, was based on data for 533 subjects interviewed as part of the São Paulo City Health Survey (ISA-Capital 2008), a cross-sectional population-based survey conducted in 2008-09 throughout the municipality’s urban area. Coffee drinking did not correlate significantly with high blood pressure in people who consumed three or fewer cups per day.
“Our findings highlight the importance of moderating coffee consumption to prevent the development of high blood pressure, especially for people with a genetic predisposition to this cardiovascular risk factor,” Andreia Machado Miranda, first author of the article, told Agência FAPESP. Miranda is a postdoctoral researcher in the Nutrition Department of USP’s School of Public Health (FSP-USP).
High blood pressure was defined as systolic pressure of 140 mmHg or higher and a diastolic pressure of 90 mmHg or higher. In a previous study, using data from ISA-Capital 2008, Miranda found that moderate coffee consumption (one to three cups per day) has a beneficial effect on some cardiovascular risk factors, especially blood pressure and blood levels of homocysteine, an amino acid associated with alterations in blood vessels, heart attack and stroke. This prior study did not include genetic data.
“In the latest study, we decided to see whether coffee consumption influenced blood pressure in individuals with genetic factors that predisposed them to hypertension,” Miranda said.
A questionnaire answered by 2,691 individuals aged 12 years or more provided demographic information (age, sex, ethnicity, income, schooling, etc.) and lifestyle data (diet, physical activity, smoking, drug use, etc.). In addition, 750 of these participants donated a blood sample for biochemical and DNA analysis (genotyping), completed two 24-hour dietary recalls, and had their anthropometric data and blood pressure measured.
The study conducted by Miranda et al. at FSP-USP selected a representative sample of 533 older adults for further genetic analysis. The selection criteria included daily coffee intake and whether they had genetic variants considered risk factors for high blood pressure.
The researchers focused on four genetic polymorphisms (common DNA sequence variations) found in previous genome-wide association surveys to be related to a predisposition to high blood pressure. The four polymorphisms (blood pressure risk alleles) were CYP1A1/CYP1A2 (rs2470893, rs2472297), CPLX3/ULK3 (rs6495122), and MTHFR (rs17367504).
They created a genetic risk score on a scale ranging from 0 to 8. Homozygous, heterozygous dominant and homozygous recessive subjects scored 0 (no risk alleles), 1 (one risk allele) and 2 (two risk alleles), respectively, per polymorphism. Each subject’s final score was the sum of the risk alleles for all four polymorphisms.
Daily coffee intake was divided into three categories: less than 1 cup (50 mL) per day, 1-3 cups per day, and more than 3 cups per day.
“We analyzed the associations among these three factors: the genetic risk score, coffee intake, and blood pressure. Using a statistical method called multiple logistic regression, we adjusted for other variables that could influence the results, such as age, sex, ethnicity, tobacco and alcohol use, body mass index, physical activity, and the use of anti-hypertensive medication, among others,” Miranda explained.
The statistical analyses showed that the higher an individual’s genetic risk score and coffee intake, the higher the probability of developing high blood pressure. Subjects with higher scores who consumed more than three cups of coffee per day were four times more likely to have high blood pressure than people without the genetic predisposition.
“Most people have no idea whether they’re predisposed to develop high blood pressure. To determine this, they would have to sequence and analyze their genome. Ideally, everyone should consume a moderate amount of coffee, as the evidence shows it’s good for the heart,” Miranda said, adding that moderate coffee intake can help prevent coronary artery calcification, according to recent research.
This effect derives from the action of polyphenols, bioactive compounds that are abundant in coffee. Chlorogenic acid is believed to account for the beneficial effect of coffee on blood pressure, while caffeine notoriously tends to raise it.
According to the latest recommendations of the American Heart Association (AHA), in healthy individuals, the moderate consumption of coffee does not increase the risk of heart disease and is not associated with long-term detrimental effects on health.
Miranda’s PhD research advisor was Dirce Marchioni, a professor at FSP-USP. Her postdoctoral research, which is ongoing with FAPESP’s support, focuses on evaluating the effects of coffee consumption on patients with cardiovascular disease, especially acute coronary syndrome, a condition caused by the blockage of blood flow to the heart via the coronary arteries.
The group plan to undertake a four-year follow-up study of 1,085 patients treated for acute heart attack or unstable angina at the University of São Paulo’s teaching hospital (HU-USP) and included in the cohort of the ERICO longitudinal survey (the acronym stands for acute coronary syndrome registration strategy).
“The idea is to estimate the influence of coffee consumption on these patients’ survival over the years,” Miranda said.
For Marchioni, the research conducted for Miranda’s PhD produced important results. “Coffee is known to contribute significantly to polyphenol intake. Polyphenols are bioactive compounds and have been associated with various health benefits. When we investigated coffee consumption and its association with specific conditions, we found that moderate consumption can be beneficial and can therefore be part of a normal diet. Excessive consumption should, of course, be avoided,” she said.
The article “The association between genetic risk score and blood pressure is modified by coffee consumption: Gene-diet interaction analysis in a population-based study” (doi: https://doi.org/10.1016/j.clnu.2018.07.033) by Andreia Machado Miranda, Josiane Steluti, Marina Maintinguer Norde, Regina Mara Fisberg and Dirce Maria Marchioni can be retrieved from: www.sciencedirect.com/science/article/pii/S0261561418312469.
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