People who received personalized nutrition education in a series of sessions at their regular grocery store significantly improved adherence to a healthy diet, in a new “first-of-its-kind” study in which scientific researchers partnered with a large supermarket company.
In the SuperWIN study, participants were given individualized advice from supermarket-based dietitians using data on their own buying habits recorded on their supermarket loyalty cards. This was associated with an increased adherence to the DASH (Dietary Approaches to Stop Hypertension) diet, which emphasizes vegetables, fruits and whole grains while limiting foods that are high in saturated fat, sugar, and sodium and has been shown to lower blood pressure and LDL cholesterol.
One group of patients also received additional education about healthy eating and meal planning through online technologies, and this group showed even better adherence to the DASH diet.
The study was presented at the annual scientific sessions of the American College of Cardiology by Dylan Steen, MD, adjunct associate professor of medicine at the University of Cincinnati.
“The SuperWIN study provides evidence for the benefit of delivering healthy-eating interventions at modern supermarkets and retail-based clinics,” Dr. Steen said. “It demonstrates the efficacy of dietary interventions harnessing the physical environment of the supermarket, the retail-based dietitians working within the store, and the purchasing data captured on the store’s loyalty cards.”
The study was conducted in partnership with Kroger, the largest supermarket chain in the United States, which also operates a large chain of pharmacies and health clinics.
Dr. Steen said the study was addressing one of the biggest public health problems – unhealthy eating – with an innovative approach. “We need to think about how we can extend the reach of modern health care systems into communities and better deliver services right where people are; meet them where they live,” he said at an ACC press conference.
Commenting on the study at the press conference, Eileen Handberg, PhD, professor of medicine at University of Florida, Gainesville, and immediate past chair of the ACC Cardiovascular Care Team Council, said: “I am amazingly excited about this. There is so much potential here. We have never really taken advantage of the current explosion in retail-based health care before.”
Dr. Handberg suggested the study had major implications for the primary prevention of cardiovascular disease. “Little kids go shopping with their parents, so you have the ability here to change behavior from children on up if you can change the dynamic of the choices they make in the grocery store.”
In his presentation, Dr. Steen noted that, despite many longstanding guidelines on healthy eating, about 75% of Americans still have a poor-quality diet. This trial was conducted to see if a new approach could improve that situation. “If we change the environment in which we deliver dietary education, we can make a difference.”
The SuperWIN trial was conducted in 13 Kroger stores in Ohio and Kentucky. The study enrolled 267 people with at least one cardiovascular risk factor from a primary care network who regularly shopped at one of the study stores. All participants also had to be willing to follow the DASH diet, which was taught at each educational session in the trial.
All participants received one “enhanced” medical nutrition therapy that was guided by the individual’s own dietary intake analytics.
They were then randomly assigned to one of three arms. The control group received no further education. The strategy 1 group received six additional teaching sessions in the supermarket aisles over a 3-month period. Each session was guided by updated individualized purchasing data provided to the dietitian and the participant.
The strategy 2 group received the same six additional teaching sessions as strategy 1, but they also had some additional teaching on healthy eating and meal planning from a variety of online shopping tools, and nutrition and health care apps.
“The supermarket analytics were automatically collected so the dietitians could tell what each person liked to eat, how much of each product they were buying and how much they were spending,” Dr. Steen explained.
COVID hit halfway through the trial, and 20 participants were withdrawn for their own safety as they could no longer visit the stores, but the trial continued with the rest of the participants with enhanced safety precautions. The overall analysis cohort was 247 participants.
The average age of the participants was mid-50s, around 70% were female, and most did not have a history of cardiovascular disease.
Eating habits were assessed by three 24-hour dietary recalls assessed at the start of the study and at 3 and 6 months. The DASH score, which is a measure of adherence to the DASH diet, was calculated from this information. The score can range from 0 to 90, with an increased score showing increased adherence.
In one analysis, the researchers compared the DASH scores from the two intervention groups together with the control group, and in a second analysis they compared the scores in the strategy 2 group with those in the strategy 1 group.
Before the pandemic there was “near 100%” attendance for the six visits over the 3-month study period, which Dr. Steen said he thought was “remarkable.” During the pandemic, attendance came down to around 80%.
Results showed that the DASH score increased in all three groups at 3 months, with stepwise increases corresponding to the intensity of the intervention. DASH scores increased by 5.8 points in the control group, by 8.6 points in the strategy 1 group, and by 12.4 points in the strategy 2 group.
DASH scores significantly differed between the two intervention groups and the control group (P = .02). “This shows that purchasing data–guided in-store tours do increase the efficacy of dietary education,” Dr. Steen said.
The difference in scores between the strategy 1 and strategy 2 groups was also significant (P = .01). “This shows online enhancements increase adherence to the DASH diet even further,” Dr. Steen commented
By 6 months, the scores had dropped off a little but were still increased from baseline: by 4.4 points in the control group, 6.6 points in the strategy 1 group, and 8.4 points in the strategy 2 group. “There was again a stepwise increase as the intervention intensified, but there was no longer a significant difference between the interventions and control,” Dr. Steen noted.
Secondary endpoints included blood pressure and body mass index. Systolic blood pressure decreased slightly in all three groups: by 2.8 mm Hg in the control group, 6.6 mm Hg in the strategy 1 group, and 5.7 mm Hg in the strategy 2 group. Body mass index was reduced by 0.2, 0.4 and 0.8, respectively, but the between-group differences were not significant.
Dr. Steen said this is the first study of its kind to date in which scientific researchers collaborated with a large supermarket chain. He explained they also involved a primary care network so that health care utilization information will be available.
“We can the integrate retail-based health care information with traditional health care information. And we can start to look at downstream health care utilization and cost outcomes as well, which will be important as we start to think how to evolve the health care system,” he commented. “The hope is that we can get more scientists working with more retailers to really drive the evidence to shape the evolution of our health care system.”