High intake of plant-based foods associated with lower blood pressure | Columnists


One if my friends from college recently became a vegetarian. It has helped him with his weight loss goals among other aspects of his health.

I, on the other hand, have remained an omnivore, meaning that I will eat just about anything available. I have tried to give up meat a few times. But I have not been a successful vegetarian for more than a few months before climbing back on the meat wagon.

Some researchers’ work suggests that I may need to make some adjustments in my diet.

As my blood pressure has creeped up at times, I have chosen to avoid medications in favor of other interventions, like exercise, weight control and adequate sleep. These actions have managed my blood pressure pretty well. But a new study suggests another natural therapy, flavanols.

A high intake of dietary flavanols, compounds found in plant-based foods, appears to be associated with lower systolic and diastolic blood pressure.

Unfortunately, it is not all great news since the study did not show a statistically significant association between biomarkers of flavanol intake and cardiovascular disease (CVD) incidence or death rate.

Flavan-3-ols (flavanols) are a major class of dietary bioactive chemicals commonly found in pome fruits, especially apples and pears, as well as berries, cocoa-derived products, red wine and leafy greens, although tea is a great source as well.

The study included a large group of older members of England’s general population. The English are known for their tea drinking, which made the population ideal for investigating the impact of flavanols.

For the study, the investigators developed two nutritional biomarkers to estimate flavan-3-ol intake. The investigators then collected non-fasting urine samples and blood pressure data for 24,152 participants with 55% women. They were divided into those with low or high biomarker concentrations based on the urine samples.

The researchers considered various factors, including age, body mass index, smoking status, physical activity, baseline health and family history. They calculated the estimated differences in systolic and diastolic blood pressure in men and women between low (10th percentile) and high (90th percentile) biomarker concentrations.

Results showed that participants with the highest 10% of flavanol intake had a blood pressure on average 1-3 mm Hg lower than those with the lowest 10% of intake.

The reduction in blood pressure from high flavanol intake is similar to what could be achieved with dietary interventions such as the Mediterranean diet, which emphasizes fresh fruits and vegetables, or the low-salt Dietary Approaches to Stop Hypertension (DASH) diet.

The specific molecular mechanisms underlying the cardiovascular effects of flavanols remain unclear. However, research suggests flavanols can affect immune function and remodeling of the vascular structures.

The investigators found only a weak correlation between the biomarker results and self-reported food intake. This supports the idea that self-reporting does not work well for compounds like flavanols since there is much variability in food composition. For example, one cup of tea can have a wide range of flavanol levels depending on the source of the tea leaves and how it is prepared.

The researchers also examined CVD events, such as stroke and death rate, over an average follow-up of 19.5 years, but found no significant link between these outcomes and flavanol intake.

Whether supplements could boost flavanol to levels that could reduce CVD risk is unclear. However, the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) may provide some answers. This clinical trial is examining whether 600 mg/day of cocoa supplements or a common multivitamin reduce the risk of developing heart disease, stroke, and cancer over five years.

In addition to cutting back on sodium and decreasing body weight, increasing flavanol intake appears to be another factor in keeping systolic and diastolic blood pressure at or below the recommended 120/80.

In addition to blood pressure effect, the literature suggests flavonoids have antioxidant and anti-inflammatory effects. Eating more plant-based foods, including fruits, vegetables, whole grains, legumes and nuts also fits well with American Heart Association current dietary recommendations.

Although I am not ready to become a vegetarian like my friend, I will try to consider flavanol content more seriously from now on. For example, a cup of tea might be pleasant right now, or perhaps a glass of red wine.

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