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Seven walnuts a day for improved health, reduced CVD risk– US study

People who eat walnuts have a better heart disease risk profile than those who don’t, gain less weight, and enjoy more physical activity compared with non-walnut eaters, according to an analysis of data from the Coronary Artery Risk Development in Young Adults (CARDIA) study.

While nuts are generally considered important to a balanced diet, thanks to their high levels of protein, fibre, and healthy fats, walnuts, in particular, have been singled out by a team of scientists from the University of Minnesota, showing that they are among the healthiest nuts on the planet.

The study was published in the journal Nutrition, Metabolism & Cardiovascular Diseases.

Walnuts and ALA

Senior study author Lyn Steffen, PhD, MPH, professor of epidemiology and community health at the University of Minnesota School of Public Health, said the main objective was to determine if walnut consumers had a better diet pattern and better cardiovascular risk factor profile over 30 years of follow-up, compared with those who did not eat them.

She and her team used findings from the CARDIA study, which began during 1985-1986 with a group of more than 5 000 Caucasian and black men and women ages 18 to 30, and which is ongoing today.

The team examined data for 3 023 CARDIA participants that included 352 walnut eaters, 2 494 eaters of other nuts, and 177 non-nut eaters.

Upon examination of physical and clinical measurements after 30 years, they found walnut eaters showed a better heart disease risk profile, including: lower body mass index (BMI) waist circumference, blood pressure, and blood triglyceride levels.

The researchers also determined that walnut eaters followed a healthier overall diet, gained less weight, tested with a lower fasting blood glucose concentration, and self-reported more physical activity.

Steffen said the findings were not surprising because walnuts are an excellent source of plant n-3 fatty acids, more specifically alpha-linolenic acid (ALA) and other antioxidants.

“Other nuts are also nutritious and contain fatty acids and antioxidants, but do not contain ALA, plant-based n-3 fatty acids,” she said.

Although commonly considered to be a nut, walnuts are technically the seed of a fruit, and according to Lauren Pelehach Sepe, a clinical nutritionist at the Kellman Wellness Center in New York, are rich in healthy fats, antioxidants, as well as several essential minerals.

“Given their beneficial nutritional profile, walnuts are an important part of a healthy diet, as they provide a number of crucial health benefits,” she told MedicalNewsToday.

Sepe said walnuts offered more health benefits than other nuts because they contain the highest amount of omega-3 fatty acids – also known as n-3 fatty acids – of any nut, and cited a 2019 study showing that walnuts help provide cardiovascular benefits due to their impact on the gut microbiota.

“A healthy gut microbiome has been linked to reduced inflammation levels, which reduces your risk of cardiovascular disease, improves your lipid profile, decreases your risk of metabolic disease, as well as many other health benefits,” she added.

How many walnuts to eat daily?

Sepe said there is no exact answer to determine how many walnuts a person should eat daily to enjoy the health benefits outlined in the study.

However, she suggested about seven walnuts or 14 walnut halves, could provide benefits.

“They are easy to add to your daily diet, or you can have a larger serving several times a week. The goal is not so much a specific number, but to start including these and other nutrient-dense foods into your diet daily to confer maximum benefits.”

Study details

Association of nut consumption with CVD risk factors in young to middle-aged adults: The Coronary Artery Risk Development in Young Adults (CARDIA) study

So-Yun Yi, Lyn M. Steffen, Xia Zhou, James M. Shikany, David R. Jacobs Jr.

Published in Nutrition, Metabolism & Cardiovascular Diseases on 30 July 2022

Highlights

• Walnut and nut consumers had higher HEI2015 diet quality scores than those who do not consume nuts.
• Walnut consumers had a better CVD risk profile than other nut and no nut consumers.
• Our study findings support the health claim to include walnuts as part of a healthy diet.

Abstract

Background and aims
Few studies have examined long-term associations of walnut, other nut, and no nut consumption with cardiovascular disease (CVD) risk factors. Results from prospective studies with long-term follow-up can provide further evidence for dietary guideline messaging to consume nuts. Therefore, we examined the associations of walnut, other nut, and no nut consumption with diet quality and CVD risk factors over 30 years of follow-up.

Methods and results
Data were analysed from 3092 young adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Dietary intake, including walnuts and other nuts, was assessed 3 times over 20 years. CVD risk factors were measured at multiple exams. General linear regression evaluated the associations of walnut, other nut, and no nut consumption with CVD risk factors over 30 years (Y30) of follow-up. The 20-year cumulative mean intake of walnuts (0.74 oz/d), other nuts (1.6 oz/d), or no nut consumption was differentially associated with HEI-2015 and CVD risk factors by Y30. Generally, walnut consumers had significantly higher HEI-2015, lower body mass index, waist circumference, blood pressure, and triglyceride concentration, and gained less weight since baseline than other nut consumers (p ≤ 0.05 for all). Further, walnut consumers had lower fasting blood glucose than no nut consumers (p ≤ 0.05).

Conclusion
Study findings that walnut and other nut consumption was associated with better CVD risk factors and diet quality aligns with the 2020–2025 US. Dietary Guidelines for Americans recommendation to consume nuts, such as walnuts, within the context of a healthy diet.

 

MedicalNewsToday article – Walnuts linked to improved health, reduced risk of cardiovascular disease (Open access)

 

Nutrition, Metabolism & Cardiovascular Diseases article – Association of nut consumption with CVD risk factors in young to middle-aged adults: The Coronary Artery Risk Development in Young Adults (CARDIA) study (Open access)

See more from MedicalBrief archives:

 

Daily handful of walnuts modestly lowers ‘bad’ cholesterol — 2-year US study

 

Walnuts may help lower blood pressure for those at risk of heart disease

 

Eating nuts twice a week link to 17% lower CVD risk

 

Nuts improve colon cancer recurrence by 42%, mortality by 57%

 

Mediterranean diet + oil and nuts = better memory

 

 

 

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