Most of us think about body fat in terms of what we can see around our waist or hips. But fat can also accumulate in organs, including the pancreas, which helps regulate blood sugar. New research suggests that what we eat may influence how much fat builds up there.
In an 18-month study published in The American Journal of Clinical Nutrition, people following a plant-rich version of the Mediterranean diet experienced greater reductions in pancreatic fat than those following a traditional Mediterranean diet or standard healthy eating advice. The findings offer another clue about how dietary patterns may influence metabolic health beyond changes in body weight.
Researchers examined data from nearly 300 adults participating in the DIRECT-PLUS clinical trial in Israel. Participants were assigned to one of three groups: standard healthy eating guidelines, a calorie-reduced Mediterranean diet or a green Mediterranean diet that placed greater emphasis on plant foods.
Both Mediterranean groups included walnuts, while the green Mediterranean group also consumed green tea and Mankai, a small aquatic plant, and ate less red and processed meat. All three groups received exercise support.
Using MRI scans, researchers measured the amount of fat in participants' pancreases at the beginning and end of the study.
After 18 months, pancreatic fat had decreased by an average of 14% in the green Mediterranean group, compared with 6.7% in the traditional Mediterranean group and less than 1% in the group following standard dietary guidelines.
The greater reduction in the green Mediterranean group remained significant even after researchers accounted for weight loss and changes in abdominal fat. That suggests the difference may not be explained entirely by losing weight.
Why does pancreatic fat matter?
The pancreas produces insulin, the hormone that helps the body regulate blood sugar. Excess fat in the pancreas has been linked to problems with how the body uses insulin, although scientists are still working to understand that relationship.
In this study, participants who lost more pancreatic fat also tended to show improvements in insulin resistance, a condition in which the body doesn't respond to insulin as effectively as it should.
However, the researchers couldn't establish that losing pancreatic fat directly caused those improvements. Results involving longer-term blood sugar levels were also less clear.
The researchers found that participants who ate more walnuts and Mankai tended to experience greater reductions in pancreatic fat. But those foods weren't tested independently, so it's unclear whether they played a special role or were simply part of an overall eating pattern associated with better results.
There are also limitations to consider. This was a follow-up analysis of an existing clinical trial rather than a study designed specifically to test pancreatic fat loss. Most participants were middle-aged men, and researchers haven't established what amount of pancreatic fat should be considered unhealthy.
Still, the findings add an interesting dimension to what we know about Mediterranean-style eating. Previous research has linked these dietary patterns to better metabolic health, and this study suggests they may also influence fat stored in an organ that plays an important role in blood sugar regulation.
The study was supported by the German Research Foundation, including funding through Germany's Excellence Strategy. Co-author Matthias Blüher disclosed receiving consulting and speaking fees from several pharmaceutical companies, including Eli Lilly, Novo Nordisk and AstraZeneca.