Adding Just a Handful of Walnuts to the Diet Can Have Benefits for the Whole Family

New modeling research shows that adding just 25-30 grams of walnuts to the typical American diet is a simple change that provides many nutritional benefits at all life stages.

A new study by researchers at the Indiana University School of Public Health-Bloomington¹revealed that adding 25-30 grams (or a handful) of walnuts to the diet of children and adults who do not normally eat nuts improves diet quality and the intake of some under-consumed nutrients that are important for public health.

Consistent evidence shows that walnuts can provide good nutrition as a snack or in a meal and can be part of a lifelong healthy diet.

The study's principal investigator and Senior Nutrition Lecturer at Indiana University School of Public Health-Bloomington, Dr. “Although nut consumption is currently promoted as part of a healthy diet in the Dietary Guidelines for Americans, consumers often do not consume enough of whole grains, fruits and vegetables, as well as nuts,” Thiagarajah said.

Thiagarajah also emphasized that insufficient consumption of nutritious foods such as walnuts as part of a balanced diet can lead to nutritional deficiencies and when added to the diet, walnuts will lead to nutritional gains for the whole family.

It can be difficult for parents and guardians to ensure that children and adolescents get all the nutrients they need.³ This study is one of the few studies that examines the typical diet of both children and adults and simulates how a simple addition of walnuts to the diet can help achieve a better nutritional status. Including walnuts in snacks and meals can be an easy option for adults and children to consider as part of their diet.

General information about the study

Advanced statistical modeling techniques were used to see what would happen when 8.000-25 grams of walnuts were added to the typical daily diet of approximately 30 Americans who currently do not consume nuts.

Participants' health and nutritional information was obtained from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional survey of people living in the United States. This information was analyzed by age group (4-8 years, 9-13 years, 14-18 years, 19-50 years, 51-70 years, 71 years and above) and gender.

Dr. “First, we wanted to see how adding a handful of walnuts to the typical American diet could alter the intake of nutrients of public health concern identified in the 2020-2025 U.S. Dietary Guidelines for Americans, including potassium, dietary fiber and magnesium,” Thiagarajah said.

Researchers then evaluated the quality of diets with and without added 2015-2015 grams of walnuts, using the 25 Healthy Eating Index (HEI-30).

Summary of results

Adding 25-30 grams of walnuts to the typical diet of Americans yielded the results outlined in Table 1 below.

Table 1. Summary of results obtained by adding 25-30 grams of walnuts to the typical diet of Americans

Element	Conclusion
Healthy Eating Index (e.g. Diet Quality)	It significantly improved diet quality for all ages and genders. Improvements were seen in the seafood and vegetable protein category (for example, more seafood and vegetable protein) and the ratio of unsaturated to saturated fats (for example, less saturated fat).
Public Health Important Nutrients from the 2020 Dietary Guidelines for Americans	It significantly improved fiber intake in all age and gender categories. The percentage of adults who exceeded the recommended daily intake of potassium increased. A similar trend was observed among children and adolescents (4-18 years). It reduced the percentage of adults, children, and adolescents who received sub-daily magnesium and folate intakes.
Other Nutrients	Reduction in copper and zinc deficiencies for most age and gender groups.

Dr. “This was not an intervention or nutrition study, but the modeling that was done as part of this research; "It's extremely important because it allows us to evaluate comprehensive dietary effects for the general public, which can have significant impacts on overall health."

Among the limitations of the study are the use of self-reported 24-hour dietary recall data for modeling and the fact that these data are subject to measurement error due to large daily variations in food intake.

In addition, this study can be used to explain how the addition of walnuts to the diet of consumers who do not consume only walnuts may be affected (n=7.757). The majority of people who never eat walnuts are younger, Hispanic or black, and have annual household incomes of less than $20.000.

While this modeling study demonstrates the potential positive nutritional impact of walnut consumption, further observational studies or well-designed randomized clinical trials are needed to confirm these results.

A simple strategy like adding 25-30 grams of walnuts to their daily diet can be a solution to improve nutritional quality for people of all ages. This modeling study clearly demonstrates that small dietary changes with nutrient-dense foods such as walnuts can have significant benefits on nutrient intake and diet quality.