Eating Almonds May Help Improve the Heart and Nervous System’s Responses to Mental Stress: Study
Mental stress is among the psychosocial factors thought to contribute to cardiovascular disease (CVD) risk. Heart rate variability (HRV), a measure of the fluctuation in time intervals between consecutive heartbeats, is an important indicator of the cardiovascular system’s response to stress and it is thought that lifestyle factors including physical activity and diet might impact HRV. Higher HRV represents greater adaptability of the heart in response to environmental and psychological challenges, while low HRV is linked to cardiovascular disease and sudden cardiac death.
As part of a recent clinical trial, researchers at King’s College London measured HRV in participants undergoing a mental stress challenge and saw improved measures of HRV in participants who had been replacing typical snacks with almonds over a six-week period. The study[1] was funded by the Almond Board of California.
This new research finding was part of the ATTIS study, a 6-week randomized control, parallel-arm trial, where participants with above average cardiovascular disease risk consumed a daily snack of almonds or a calorie-matched control snack providing 20% of each participants’ estimated daily energy needs.
In this study, researchers measured participants’ real-time heart rate (HR) and heart rate variability (HRV) at rest (lying down for 5-minute periods) and during a Stroop test (in which participants were asked to read colored words i.e. say “red” in a green font) to simulate short period of mental stress.
During acute mental stress, participants in the almond group showed better heart rate regulation compared to the control group, indicated by statistically significant differences in high frequency power, which specifically evaluates beat-to-beat intervals (a measure of HRV).
“This study shows that the simple dietary strategy of swapping almonds for typical snacks may bolster resilience to the adverse cardiovascular effects of mental stress by improving regulation of heart rate. We found that the stress-induced reduction in heart rate variability was lessened in the almond group compared to control following the dietary intervention, which indicates a cardiovascular health benefit. It is useful to think of having a higher HRV as the heart being able to switch gears faster in response to demands on the body, which means more cardiac resilience and flexibility during periods of stress. In the long term, this is beneficial for cardiovascular health,” said Dr. Wendy Hall, PhD, co-principal investigator (together with Dr. Sarah Berry, PhD) and Reader in Nutritional Sciences at King’s College London.
The research suggests that eating almonds in place of typical snacks may diminish the drop in HRV that occurs during mental stress, thereby improving cardiac function. This dietary strategy has the potential to increase cardiovascular resilience to mental stress, along with other heart health benefits of consuming almonds such as lowering LDL-cholesterol and improving the function of blood vessels.
“These results are particularly timely given the heightened levels of stress many of us are experiencing, alongside increased snacking, from working at home.,” said Dr Sarah Berry, PhD, King’s College London.
This new study was part of the ATTIS trial. A recently published paper from ATTIS also examined the role of almond eating on LDL-cholesterol levels and endothelium-dependent vasodialation (measured through flow meditated dilation, or FMD), which is a predictor of cardiovascular disease risk
Commenting on the results of the study, Sheela Krishnaswamy, Nutrition and Wellness Consultant commented, “The results of this study are very promising, and relevant especially now when several Indians are experiencing high levels of stress due to the current pandemic. This research suggests that revising one’s dietary strategy to include almonds can increase cardiovascular resilience to mental stress in addition to reducing LDL-cholesterol and improving endothelial function of the blood vessels (as shown in other studies) – thereby improving cardiac risk factors. Simply by replacing unwholesome snacks with almonds, people who are suffering from CVD or are at risk, can make a healthy difference to their lives.”
Years of heart health research – including a systematic review and meta-analysis[2] – support the inclusion of almonds in heart healthy eating plans. Both ATTIS studies included measures that had never before been evaluated in clinical research trials including almonds. Although additional studies are needed to confirm these findings, the improvements in HRV and FMD suggest that almonds provide heart health benefits in a variety of ways. Almonds provide fiber (12.5 / 3.5 g per 100g / 28g serving) and 15 essential nutrients including (per 100g / 28g serving): magnesium (270 / 76 mg), potassium (733 / 205 mg), and vitamin E (25.6 / 7.2 mg).
