Walnut intake and heart function in CARDIA adults
What it found
In 3,341 black and white adults followed for 25 years, walnut eaters had better measures of the heart's filling phase (diastolic function) than those who did not eat walnuts.
The study cannot prove that walnuts caused the difference.
What they found
Studies in people
Who ate walnuts
Walnut eaters were more likely to be female, white, and more educated. They also had smaller waists, lower diastolic blood pressure, and lower heart rates than non-eaters.
Diet quality
Walnut eaters had higher diet quality scores and ate more nuts, whole grains, fruit, vegetables, and legumes. They ate less refined grains, red and processed meat, and sugary foods.
Diastolic function
Walnut eaters had better values for several heart filling measures: lower A wave, higher E/A ratio, and higher septal and lateral e'. These differences remained after accounting for body mass index and diabetes.
Systolic function
There was no difference between walnut eaters and non-eaters in left ventricular mass index or in systolic function measures like ejection fraction and strain.
Blood pressure and heart rate
Walnut eaters had significantly lower diastolic blood pressure and heart rate, and marginally lower systolic blood pressure, than non-eaters.
What the authors conclude
“Compared to non-consumers, walnut consumption is associated with better diastolic dysfunction in young to middle-aged adults.”
Also in their conclusions
- They conclude that walnut consumption is associated with better diastolic function in young to middle-aged adults.
- They say their findings are in line with the health claim to include walnuts as part of usual dietary intake.
- They note that their findings are consistent with the 2015–20 Dietary Guidelines for Americans recommendation to consume a variety of protein sources, including nuts.
How it was done
The authors wanted to see whether walnut consumption is linked to the heart's structure and pumping and filling function, which are risk factors for heart failure. Previous studies had looked at heart disease and cholesterol, but not at these detailed heart measures.
They studied 3,341 participants from the CARDIA study, who were 18 to 30 years old at the start and followed for 25 years. Diet was asked about three times over 20 years, and heart structure and function were measured by ultrasound at year 25.
What it can’t tell you
- This was an observational study, so it can show a link between walnut eating and better heart function but cannot prove that walnuts caused the difference.
- The study relied on people reporting what they ate, which can be inaccurate.
- The participants were generally healthy, so the results may not apply to people with existing heart disease.
Who paid
- Funding
- Funded by NHLBI NIH HHS (from the PubMed record).
- Authors work at
- University of Minnesota, USA; University of Alabama at Birmingham, USA
The paper
- Title
- Walnut consumption and cardiac phenotypes: The Coronary Artery Risk Development in Young Adults (CARDIA) study
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Steffen LM, Yi SY, Duprez D, Zhou X, Shikany JM, Jacobs DR (2021). Walnut consumption and cardiac phenotypes: The Coronary Artery Risk Development in Young Adults (CARDIA) study. Nutrition, metabolism, and cardiovascular diseases. doi:10.1016/j.numecd.2020.09.001Free full textPubMed 33097410DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error