Adding small handful of walnuts to diet reduces nutrient deficiencies

Adding just 1 oz of walnuts to the diets of children and adults who typically do not eat any nuts was associated with significant improvements in healthy index eating scores, a recent study showed.

Krisha Thiagarajah, PhD, MS, a senior lecturer of nutrition at Indiana University School of Public Health-Bloomington, and colleagues wrote in Nutrients that under-consuming calcium, fiber, potassium and vitamin D is a public health concern in the United States, but adjusting eating patterns to increase dairy product, fruits, nut, vegetables and whole grain intake can help people hit the recommended targets and achieve healthier diets.

“While nut consumption is already promoted in the Dietary Guidelines for Americans as part of a healthy dietary pattern, consumers are often not eating enough alongside whole grains, fruit and vegetables,” Thiagarajah said in a press release.

So, Thiagarajah and colleagues conducted a diet modeling study to better understand “how adding a handful of walnuts to the typical U.S. diet could change intakes in nutrients of public health concern identified by the 2020-2025 U.S. Dietary Guidelines for Americans, including potassium, dietary fiber and magnesium,” Thiagarajah said in the release.

For the study, the researchers analyzed data from the National Health and Nutrition Examination Survey. They used the Healthy Eating Index-2015 (HEI-2015) to measure participants’ diet quality and modeled the impact of adding 1 oz of walnuts to the diets of people who do not typically eat nuts, “a simple change that consumers could likely make,” according to the researchers.

The analysis included 7,757 “no-nut consumers” who were aged at least 4 years. No-nut consumers tended to be Hispanic or Black, younger and had a household income of less than $20,000.

The researchers then examined the percentages of people with consumption above the adequate intake values for fiber and potassium and intakes below the estimated average requirement (EAR) values for calcium, folate, magnesium and vitamin E.

Thiagarajah and colleagues found that adding 1 oz — or 28.35 g — of walnuts to one’s diet significantly improved HEI scores in both children and adults. For adults, the scores improved from 52.4 (95% CI, 51-53.8) to 59.2 (95% CI, 58-60.5). For children, the scores jumped from 49.1 (95% CI, 48-50.4) to 58.5 (95% CI, 57.5-59.6).

Specifically, the researchers found significant increases in two HEI components for every age and sex group: the ratio of saturated to unsaturated fatty acids and plant and seafood proteins. However, they also noted that “additional dietary strategies remain necessary to encourage healthy dietary intake and improve overall health.”

They also found that, for adults, the addition of walnuts increased the percentage of people above the adequate intake of potassium — 22.8% vs. 26.5% — and significantly reduced the percentages of adults with intakes below the EAR for folate and magnesium — 49.2% vs. 40.6% and 69.6% vs. 52%, respectively. They observed a similar trend among children.

“Underconsumption of nutritious foods like walnuts as part of a balanced diet can result in nutrient inadequacies. When added in the diet, walnuts lead to small nutrition wins for the whole family,” Thiagarajah said in the release.

Thiagarajah told Healio that “well-designed randomized clinical trials are needed” to confirm the positive nutritional impact with walnut consumption. But, in the meantime, primary care physicians should know that “adding a handful of walnuts to the diet of children and adults who do not normally eat nuts can improve nutrient intake and diet quality.”

References:

• Adding just a small handful of walnuts can have dietary benefits for the whole family. https://www.eurekalert.org/news-releases/977453. Published Jan. 25, 2023. Accessed Feb. 1, 2023.
• Spence LA, et al. Nutrients. 2023;doi:10.3390/nu15020258.