Nutritional Pearls: Fruits and Vegetables Are Good for Your Heart
Answer: Incorporating more fruits and vegetables into any diet is beneficial.
A study1 released in 2014 assessed the impact of eating fruits and vegetables that are high in flavonoids (a particular type of antioxidant) on what I called the "clinical precursors" of heart disease: biomarkers of inflammation as well as arterial elasticity and vascular reactivity.
While the research was inconclusive for the 150 men and women as a group, the authors noted that those men who began the study at higher risk for heart disease improved their biomarkers far more than the women in the group or those men who were not already at higher risk.
Today's research is somewhat similar, in that it looks at fruit and vegetable intake's effects on 3 biomarkers of subclinical cardiac damage in people without diagnosed heart disease.
The Research
This study made use of blood specimens gathered from a study that took place in the mid-90's. It originally included over 450 men and women recruited from 4 different locations in the United States.2
The participants were randomly assigned to follow 1 of 3 diets: a control diet "typical of what many Americans eat"; a diet similar to the typical American diet, but with more fruits and vegetables and fewer snacks and sweets (the "fruit and vegetable diet"); or the DASH diet.
The study lasted only 8 weeks, but the participants were provided all of their meals: 1 meal each weekday, either lunch or dinner, was consumed in the lab, while all other meals were provided in coolers to be consumed at home. The participants' meals were designed to maintain their weight and provide about the same amount of sodium regardless of which diet they were on.
The participants kept records of any non-study foods or drinks they consumed as well as any salt they might add to the provided foods. At the start and end of the study the participants' blood was drawn and frozen for later use in other studies (such as today's).
Unfortunately, only 3 of the 4 original locations provided their stored specimens for today's research, meaning only 326 of the original 450+ participants had specimens to analyze.
The authors looked specifically at 3 biomarkers: high-sensitivity troponin I [hs-cTnI], which is associated with subclinical cardiac damage; N-terminal pro–B-type natriuretic peptide [NT-proBNP], which is associated with cardiac strain; and high-sensitivity C-reactive protein [hs-CRP], which is associated with inflammation.
The Results
Given its reputation as a diet good for heart disease in general and blood pressure specifically, you might assume that those on the DASH diet would show the most improvement in their scores.
Not so!
Compared to the control diet, both the fruit and vegetable diet and the DASH diet improved both hs-cTnI (the marker of cardiac damage) and NT-proBNP (the marker of cardiac strain) by the same amounts. The levels of hs-CRP (the marker of inflammation) did not change regardless of which diet the participant was on.
The authors state "we believe these findings strengthen recommendations for the DASH diet" as well as fruits and vegetables in general. I would contend that this research demonstrates the critical impact of fruits and vegetables on any diet—not just the DASH diet.
What’ the Take Home?
Eat more fruits and vegetables. That's it.
Choose your favorite fruit for snacks. Keep them around the house so you can grab something when you get a craving.
References:
- Macready AL, George TW, Chong MF, et al. Flavonoid-rich fruit and vegetables improve microvascular reactivity and inflammatory status in men at risk of cardiovascular disease--FLAVURS: a randomized controlled trial. Am J Clin Nutr 2014 Mar;99(3):479-89. doi: 10.3945/ajcn.113.074237
- Juraschek SP, Kovell LC, Appel LJ, et al. Associations between dietary patterns and subclinical cardiac injury: an observational analysis from the DASH trial. Published online June 16, 2020. Ann Intern Med. doi:10.7326/M20-0336