Reference
Monge A, Stern D, Cortés-Valencia A, Catzín-Kuhlmann A, Lajous M, Denova-Gutiérrez, E. Avocado consumption is associated with a reduction in hypertension incidence in Mexican women. Br J Nutr. 2023;129(11):1976-1983.
Study Objective
To assess the association of avocado consumption with the incidence of hypertension in the Mexican Teachers’ Cohort
Key Takeaway
Eating 2.5 or more avocados each week is associated with a lower incidence of hypertension in an all-female study population (Mexican Teachers’ Cohort).
Design
Observational-analytic study
Participants
This study included female teachers from 12 states in Mexico. All participants were women aged more than 25 years (mean age 41.9 ± 7.1 years) who were free from hypertension, cardiovascular disease, and cancer at the beginning of the study. The study population was approximately 13% postmenopausal, 78% premenopausal, and 9% classified as unknown.
The first phase of data collection started in 2006 with 27,979 participants from 2 Mexican states. The second phase of data collection continued between 2008 to 2010 with 87,334 participants from 10 additional Mexican states.
Participants responded to a baseline questionnaire that gathered information regarding sociodemographics; reproductive health; lifestyle (physical activity, tobacco use, diet); and medical history.
Investigators for the larger MCT study distributed follow-up questionnaires every 3 to 4 years, updating medical history and lifestyle risk factors. This study used the first follow-up questionnaire, which went out between 2011 and 2013 and which had an 83% response rate.
Participants were excluded from the results of this study for the following reasons:
- They had prevalent hypertension (n=340)
- They reported daily caloric intake of under 500 calories (n=9,670)
- They completed less than 50% of the semi-quantitative food frequency questionnaire (FFQ, n=3,598)
- The staple-food section was incomplete (n=4,654)
- They reported myocardial infarction, stroke, or cancer (n=2,036)
- They were pregnant at baseline (n=1,080)
- They did not complete the follow-up questionnaire (n=543)
After the exclusions, the final number of female participants in the analysis was 67,383.
Study Parameters Assessed
This is the subjective and objective data collected.
Dietary assessment guidelines
During a 1-year period, each participant was asked to complete a 140-question semi-quantitative FFQ. This FFQ was a record for a 4-day period. This 4-day period was requested during each season, for a total of 4 times per year.
Avocado consumption was categorized as the frequency of 1 serving (one-half an avocado), and results were grouped into the following categories: <1/month, 2–3/month, 1/week, 2–4/week, and 5+/week.
Hypertension
Hypertension incidents were evaluated by baseline and follow-up questionnaires. Participants who were given a diagnosis by a clinician and received treatment were confirmed. The validity of the self-diagnosis of hypertension was confirmed using a random subsample of hypertension patients taking a structured interview process.
The Healthy Eating Index 2015 (HEI-2015 score) was calculated using the frequency of consumption of items from the FFQ.
The model was adjusted for the following covariates:
- Socioeconomic status, measured based on internet access in the home and types of insurance for serious health conditions (public, private, other).
- Ethnicity, defined based on indigenous language spoken by the parents or woman.
- Family history of hypertension if reported by parents, siblings, or children.
- Menopause, defined as no period for 12 months, surgical, or over the age of 51.
Type 2 diabetes, which was self-reported by treatment, was not adjusted for in the covariates model since it did not change the result (P=0.01).
Primary Outcome
The association of avocado consumption with the risk of developing hypertension in a population that eats avocados as part of their normal diet
Key Findings
Women who had higher avocado consumption also had other health-imparting characteristics. Specifically, they:
- were less likely to be obese,
- were more likely to have a high-quality diet based on the HEI score,
- were not current smokers, and
- were more likely to have internet in the home, be physically active, and take multivitamins.
Along with a higher-quality diet, there were increased levels of monounsaturated fatty acids (MUFA) and fiber intake in those who ate higher amounts of avocado.
Participants with the highest levels of avocado intake had higher overall intakes of magnesium and potassium as well.
After adjusting for covariates, women who ate 5+ servings (2.5+ avocados/week) had a 17% lower rate of hypertension than those who ate fewer servings (P=0.01).
Transparency
- The American Institute for Cancer Research Grant 05B047
- Consejo Nacional de Ciencia y Tecnología (CONACyT) Grant S0008-2009-1:000000000115312.
Practice Implications & Limitations
The risk of developing hypertension can often be reduced or even eliminated through lifestyle medicine, including dietary and physical activity changes. The results of this observational study show that regular avocado consumption reduced hypertension incidence by 17% when compared to people who did not consume avocados or who consumed low amounts.
It is important to note that this study was conducted with women only, making the data interpretation for possible benefits from avocado consumption stronger for this population. However, it is not clear from this study whether such an association exists for men. Further studies are needed to determine if such extrapolation can be made.
Avocados are rich in several phytonutrients that could be providing the protective effects for heart disease, including antioxidants, MUFAs, and phytosterols. These dietary components are known to improve lipid profiles in the bloodstream. A 2019 systematic review found consistency in the research that supplementation with phytosterols reduces systolic and diastolic blood pressure in patients with high cholesterol levels,1 though the authors concede that doses used in phytosterol supplement studies far exceed the amounts found in avocado consumption.
However, it is not clear from this study whether such an association exists for men.
Avocados have been shown to contain 4 to 6 grams of fiber per half avocado, which contributes to a high-fiber diet. Women who eat 25 grams of fiber per day have been shown to have a lower associated cardiac disease risk,2 including lower blood pressure.3
Avocados are a good source of magnesium and potassium. Both of these nutrients support the cardiovascular system, and deficiencies are associated with a higher risk of hypertension.4
It is worth noting that the group that ate the highest amount of avocados tended to have other advantageous characteristics, such as internet in the home, more physical activity, and higher consumption of multivitamins. They were also less likely to be obese. We can use the activity and multivitamin usage associated with less risk in this study to bolster the strength of our recommendations.
When working with women who have cardiovascular disease in general and hypertension specifically, diet change is a baseline therapy. Clinically, as we draft our dietary advice for the patient, perhaps we should, based on this study, consider adding half an avocado 5 times a week to a heart-healthy diet.
