Supermarket Diet Advice Improves DASH Adherence: SuperWIN Supermarket Diet Advice Improves DASH Adherence: SuperWIN

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 dieticians 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 low-density lipoprotein 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 American College of Cardiology (ACC) 2022 Scientific Session by Dylan Steen, MD, adjunct associate professor of medicine at the University of Cincinnati College of Medicine in Ohio.

“The SuperWIN study provides evidence for the benefit of delivering healthy-eating interventions at modern supermarkets and retail-based clinics,” 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,” he added.

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.

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 healthcare 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 ay 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 healthcare before.”

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,” she said.

In his presentation, 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,” he said.  

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 healthcare 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,” 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 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,” 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,” 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,” 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. BMI was reduced by 0.2, 0.4 and 0.8, respectively, but the between-group differences were not significant.

Steen noted that 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 healthcare utilization information will be available.

“We can the integrate retail-based healthcare information with traditional healthcare information. And we can start to look at downstream healthcare utilization and cost outcomes as well, which will be important as we start to think how to evolve the healthcare 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 healthcare system,” he added.  

Challenges Ahead

Handberg pointed out there would be challenges in reaching the underserved population who do not shop at the major supermarkets. “We need to figure out how to get partnerships across the whole spectrum of grocery stores.”

She also noted that 3 months (the duration of the study intervention) was not much time to change the eating habits of a family. “Interventions may have to be a bit more intensive to get the change in blood pressure and weight that we would want to see.”

She added that she hoped the major grocery store companies will see the opportunities in this approach. “Changing behavior is very complicated, and the key will be how to make people stick with the changes. But grocery stores are smart. They have got us going to their pharmacies, so getting us to see a dietitian is not that much of a stretch.”   

Moderator of the ACC late breaker session at which the study was presented, Pamela Morris, MD, from the Medical University of South Carolina, who is also ACC Annual Scientific Session chair, asked whether the approach could be sustained.  

“I am thinking back to the barber shop study of blood pressure treatment and to my knowledge those PharmDs are no longer in those barbershops, taking blood pressures, counseling patients, and prescribing antihypertensives. So is Kroger maintaining a long-term commitment to providing this education, or how can this be financed over the long term?” she asked.

Steen replied that he believed sustainability to be one of the key strengths of this model. “Retail-based healthcare is exploding in the US. The number of retail outlets offering a comprehensive list of services is going up all the time. These programs exist regardless of whether this trial was conducted or not.”

But Steen stressed that having an evidence base will be critically important.

“Validation is an enormous part of this evolution in retail-based healthcare — not only to figure out what works but also to engage payors and others in the process of supporting these interventions. I think the sustainability is there — it is sort of baked into the model — but research will be a huge part of cementing this in and helping us to understand what we should do.”

The study was funded by Kroger. Steen is a consultant for Sanofi and CEO of and co-founder of High Enroll LLC.  

American College of Cardiology (ACC) 2022 Scientific Session. Presented April 3, 2022.

For more from theheart.org | Medscape Cardiology, join us on  Twitter and Facebook