Increased Intake of Healthy Plant-Based Foods Attenuated Overall Blood Pressure

by | Nov 2, 2020 | 2020, Blood Pressure, Cardiovascular Health, Fiber

Halima Phelps, DC, ND. This study found that higher consumption of total fiber, particularly insoluble fiber, was associated with lower blood pressure (BP), which may be attributable to an inverse association between insoluble fiber and BP.

fruits and vegetablesHypertension (HTN), a worldwide problem, is a major culprit for cardiovascular disease 3.  Many cases are preventable. Dietary intake can significantly affect the prevention or development of HTN. For example, high quantities of refined carbohydrates and alcohol and imbalances with sodium and potassium intake may all be associated risk factors for HTN 1, 2. Furthermore, (though fiber type may matter), a 2015 study cites a cohort study where higher total dietary fiber consumption decreased the chance of developing HTN; and another study revealed that supplementation with fiber decreased BP in active HTN 3.

In this cross-sectional INTERnational study on MAcro/micronutrients and BP (INTERMAP), an assessment of 4,680 men and women, 40-59 years old with different ethnicities spanning the United Kingdom, United States, Japan and China were examined to determine whether a healthy plant-based diet would positively affect BP. This diet requires the intake of fresh vegetables and fruits as the main dietary food source, and small amounts or no meat is consumed. Healthy plants provide crucial elements including antioxidants, soluble and insoluble fibers, vitamins, potassium and unsaturated fatty acids. Their primary consumption shows a relationship with decreased risk of harm to the cardiovascular system 4. Unfortunately, many non-organic and non-grass-fed meats are injected with added hormones and/or cooked with excessive fat and sodium, which can potentially cause adverse effects on the body. Nonetheless, pure meats are a good, important source of vital protein and nutrients which could be lacking in some vegan and vegetarian diets. Meat was not eliminated for the majority of participants, but it was not given a positive score here.

Healthy plant foods were distinguished from unhealthy ones and from meats using a graded plant-based diet index (PDI). Healthy plant foods were given a score in the healthy plant-based diet index (hPDI) which was also contingent on the individual countries’ dietary guidelines, and unhealthy plant-based foods [such as foods containing refined sugars and juices] and meats [including dairy] were classified in an unhealthy plant-based diet index (uPDI). 24-hour dietary recalls were used to measure PDI’s and assessed via INTERMAP.  24-hour urinary samples were obtained to measure sodium vs. potassium wastes. BP was measured eight times within four visits.

Results revealed a significant difference in BP readings based on diet. There was no significant difference in participants who simply consumed a PDI, but an hPDI showed a decrease in both systolic and diastolic BP readings. Systolic BP revealed a -0.82 mm Hg drop (95% CI: -1.32 to -0.49), and diastolic revealed a -0.49 mm Hg drop (95% CI: -0.91 to 0.28); lifestyle and dietary modifications were performed to final measurements. This supported the hypothesis that not only maximizing vegetable and fruit consumption was important, but the healthy plant-based diet brought about change in BP. Contrariwise, participants who consumed a higher uPDI showed a +0.77 mm Hg increase in systolic BP readings overall (95% CI: 0.30 to 1.20); and for Western participants, a higher uPDI also revealed an increase in diastolic BP readings at 0.48 mm Hg (95% CI: 0.14 to 0.93). All of these results were separate from BMI and urinary sodium and potassium values.

The added detriment of a uPDI on diastolic BP solely for Westerners may have reflected the relationship present in a 2011 study’s finding wherein a high intake of sugars and sugared-drinks affected obesity and heart disease; lowering the intake of such over 18 months helped lower BP 2. Future considerations should include a diet diary as a 24-hour dietary recall was a limitation. The potential lack of vital nutrients in vegan or vegetarian diets should also be addressed; along with benefits of organic and grass-fed meats and essential nutrients provided thereby.

Source: Aljuraiban G, Chan Q, Gibson R for the INTERMAP Research Group, et al Association between plant-based diets and blood pressure in the INTERMAP study BMJ Nutrition, Prevention & Health 2020;bmjnph-2020-000077. doi: 10.1136/bmjnph-2020-000077

© The Authors 2015

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Posted November 2, 2020.

Halima Phelps, BA, AA, PBT, is a graduate of the University of Wisconsin Parkside. She graduated in 2014 with a bachelor of arts in Spanish and a biology minor. She is currently a student staff member in the department of postgraduate education and completing a medical degree at the National University of Health Sciences in Lombard, IL.

References:

  1. Villegas R, Liu S, Gao Y-T, et al. Prospective study of dietary carbohydrates, glycemic index, glycemic load, and incidence of type 2 diabetes mellitus in middle-aged Chinese women. Arch Intern Med 2007;167:2310–6.
  2. Brown IJ, Stamler J, Van Horn L, et al. Sugar-Sweetened beverage, sugar intake of individuals, and their blood pressure: International study of macro/micronutrients and blood pressure. Hypertension 2011;57:695–701.
  3. Aljuraiban GS, Griep LMO, Chan Q, et al. Total, insoluble and soluble dietary fibre intake in relation to blood pressure: the INTERMAP Study – CORRIGENDUM. Br J Nutr 2015;114:1534.
  4. Aljuraiban G, Chan Q, Gibson R for the INTERMAP Research Group, et al Association between plant-based diets and blood pressure in the INTERMAP study BMJ Nutrition, Prevention & Health 2020;bmjnph-2020-000077. doi: 10.1136/bmjnph-2020-000077