Effect of Mediterranean diet combined with healthy food boxes on blood glucose levels of people with type 2 diabetes and low socioeconomic status: a randomized controlled trial

The prevalence of type 2 diabetes (T2D) continues to rise. In the Netherlands,
it is estimated that 1,2 million people are currently affected by T2D, which is
expected to grow to 1,4 million by 2040. In the European region, approximately
60 million people live with diabetes, making it one of the leading causes of
death and disability.

Unhealthy diets and physical inactivity can lead to an increase in overweight
and obesity, especially among socioeconomically disadvantaged communities. In
addition, people with low socio-economic status (SES) are more likely to
develop T2D. One reason for this could be the financial aspect of food.
Research done in the Netherlands found an inverse association between energy
density and the costs of food items. Energy-dense, nutritionally depleted food
products, such as refined grains, added sugar, and fats, cost significantly
less than nutrient-dense foods.

Nowadays, several dietary interventions have been shown to be effective for
patients with T2D, including the Mediterranean diet. This diet is characterized
by a high intake of vegetables, fruits, legumes, whole grains, nuts, fish, and
olive oil, which has been associated with several health benefits. Intake of
products rich in fibers, mono- and poly-saturated fatty acids, vitamins,
probiotics, antioxidants, and low-glycaemic foods can decrease inflammation and
insulin resistance and improve glycaemic control in diabetes patients. For
dietary treatment to be successful in people with T2D, individual
responsibility and intrinsic motivation for change are critical enablers.
However, increasing costs of healthy products, such as those recommended in the
Mediterranean diet, pose a barrier to maintaining healthy dietary patterns,
especially among patients experiencing food or financial insecurity. To support
patients in overcoming these barriers, a growing body of evidence is examining
the use of food as a medical prescription to improve access to fresh produce.

Several product interventions have shown a positive association between
providing food via incentives such as food vouchers or boxes and positive
health outcomes. A systematic review and meta-analysis by Haslam et al. (2023)
lists HbA1c improvement, weight reduction, reduction of systolic blood
pressure, increased health index scores, and increased vegetables and fruit
servings as the primary outcomes. Bhat et al. (2021) point out that despite
possible positive outcomes such as increased fruit and vegetable consumption,
decreased BMI and HbA1c, most of the studies were designed in
quasi-experimental (pre/post) interventions without a control group. Randomized
control trials investigating the effect of healthy food prescriptions on diet
quality and cardiovascular risk factors among T2D patients are lacking,
especially in Europe.

Primary Objective: What is the difference in the effectiveness of the Food
Pharmacy Program in glycaemic regulation compared to nutrition coaching
performed by dieticians after three months in overweight adults with type 2
diabetes?

Secondary Objectives:
1. What is the difference in weight loss, waist circumference, cardiovascular
risk factors, and diabetic medication usage between FPP and nutrition coaching
after three months in overweight adults with type 2 diabetes?
2. What is the difference in fruit and vegetable consumption between the
intervention and control groups?
3. What is the difference in the quality of life, treatment satisfaction,
compliance, and adherence between the intervention and control groups?

The above-presented objectives will be answered by conducting a randomized
controlled pilot study in which eligible T2D patients will be randomized to
either the control or intervention group.

Both groups will be recommended to follow the Mediterranean diet. Participants
in the intervention group will receive weekly whole plant-based food boxes
supplied from local farms in the South Holland region for 12 weeks.
Additionally, during the intervention, patients will be asked to participate in
two health facilitated by a dietician and two culinary medicine workshops
facilitated by a trained chef. Additionally, at baseline, week 4 and week 12
of the intervention, patients will receive coaching sessions with a dietician.

The control group participants will receive three coaching sessions with a
dietician (usual care) at baseline, week 4 and week 12, provided under the
reimbursement scheme of the basic insurance package in the Netherlands.

The burden and risks associated with participation in the study are considered
to be low. The participants will benefit from the intervention by receiving
food boxes and professional support to help them improve their health. All
participants will be asked to attend the standard visits at the doctor's office
to collect the cardiovascular risk factors and perform anthropometric
measurements at the dietician's office. Participants of the intervention group
are asked to pick up weekly boxes in Rotterdam South and attend health and
cooking workshops, which will require time investment.