A diet rich in whole grains, fiber, fish and n-3 polyunsaturated fatty acids (PUFAs) may reduce the risk of death from all causes in adults with type 2 diabetes (T2D), according to a systematic review and a meta-analysis synthesizing all available evidence, presented at this year’s European Association for the Study of Diabetes (EASD) annual meeting in Stockholm, Sweden (September 19-23).
“There are some dietary recommendations and guidelines for people with type 2 diabetes, but most are either not evidence-based or are derived from general population studies,” says author Dr. Janett Barbaresko of the German Diabetes Center in Düsseldorf, Germany. “Our rigorous evaluation of the best currently available evidence indicates with reasonable certainty that eating a diet high in whole grains, fiber, fish and PUFAs, as well as eating more vegetables and plant-based protein, may help people with type 2 diabetes to live longer.”
However, the researchers point out that the limited evidence regarding other dietary factors, including dietary habits, foods such as dairy, meat, and tea, and micronutrients such as caffeine and vitamin D, underscores the need for more robust and comprehensive studies to better understand the impact of different dietary factors on the progression of T2D.
People with T2D are more prone to circulatory disease, dementia, cancer, and bone fractures. And despite a growing number of effective drugs, lifestyle modifications – such as exercise and diet – remain the cornerstone of treatment.
However, little is known about diet and the prevention of illness and death in people living with T2DM. A few studies have assessed the association between specific dietary factors such as Mediterranean diet or vegetable consumption on all-cause mortality in T2DM, but the relationship with different dietary factors has not been comprehensively summarized.
To find out more, German researchers conducted a systematic review of 107 prospective observational studies that looked at all dietary factors (i.e. dietary patterns, foods and food groups, macronutrients [carbohydrates, fats, protein] and micronutrients [minerals and vitamins] secondary plant compounds [e.g., polyphenols]and supplements [e.g., vitamin E, magnesium]) and the risk of death from all causes in adults (aged 18 years or older) with T2DM, through June 2022.
A total of 72 studies were included in 45 meta-analyses comparing the effects of high versus low intake and to assess the dose-response relationship between dietary factors and death from all causes, over an average of 10 years. The number of participants included in the meta-analyses ranged from 1,073 to 84,816. The certainty of the evidence was assessed to determine the confidence in the meta-conclusions .
Analyzes revealed that there was moderate certainty of evidence for a protective association between consumption of whole grains, fiber, fish, n-3 PUFAs and death from any cause. Adding one serving (20g/day) of whole grains from foods such as brown bread and rice or breakfast cereals was associated with a reduction of about 16%. Each serving per week of increased fish consumption was associated with a 5% lower risk of death.
Similarly, an additional intake of 5 g per day of dietary fiber (equivalent to one medium pear or two shredded wheat) and a 0.1 g per day increase in n-3 PUFAs were associated with a reduced risk of death every combined causes: 14% and 13%% lower, respectively. The body does not produce n-3 fatty acids naturally, so good sources include fish, vegetable oil, nuts (especially walnuts), flax seeds and flaxseed oil, and vegetables to leaves.
Lower-certainty evidence also suggests that consuming large amounts of vegetables and plant-based protein may be beneficial. A daily increase of 100 g of vegetables and 10 g of plant proteins such as nuts, tofu, beans, lentils and peas was associated with a 12% and 9% lower risk of death, respectively.
Possible beneficial effects of these foods include their link to favorable changes in blood pressure, cholesterol, blood sugar and anti-inflammatory effects, which may help reduce the risk of comorbidities such as cardiovascular disease and cancer. .
In contrast, high consumption of eggs and dietary cholesterol were associated with an increased risk of death from any cause. A 10 g per day increase in egg consumption (equivalent to two medium eggs per week) was associated with a 5% increased risk of death, while adding 300 mg of dietary cholesterol per day was linked to a 19% increase.
For other dietary factors, no association was found and/or the evidence was very uncertain, including: dietary habits such as Mediterranean diet and low-carb, high-protein diet; foods, including nuts, dairy products, meat, sugar and sweets; macronutrients, including carbohydrates and micronutrients such as caffeine and vitamin D.
“Further research is needed to provide stronger and more comprehensive evidence on different dietary factors and the progression of diabetes,” says Dr Sabrina Schlesinger from the German Diabetes Center in Düsseldorf and the German Center for Diabetes Research (DZD) at Munich-Neuherberg (partner in Düsseldorf), who conducted the study. “But if people with type 2 diabetes are able to add a few servings of whole grains, fiber, fish, vegetable oils and vegetables to their weekly diet, our findings suggest this could be an easy way out. and low risk of possibly improving their outcome.”
The authors note that the study is observational and therefore does not prove that people with T2D who eat a diet rich in whole grains, fiber, fish and n-3 PUFAs will live longer. On the contrary, it shows an association. They also note that the small number of studies in many meta-analyses may limit the conclusions that can be drawn.
For interviews with the authors of the report, please contact Dr. Olaf Spörkel at the Press Office of the German Diabetes Center, Düsseldorf, Germany E) [email protected] T) +49 211 3382-507
Alternate contact in the EASD press room: Tony Kirby T) + 44(0)7834 385827 E) [email protected]
Notes to Editors:
 The certainty of the evidence was assessed using the GRADE approach which considers risk of within-study bias, inconsistency, indirectness and imprecision between studies, publication bias, magnitude of effect and dose-response relationship. High certainty of the evidence indicates that there is a high degree of confidence in the estimate of the effect and further research is unlikely to change the estimate of the effect, while moderate certainty of the evidence indicates confidence in the estimate of effect and that further studies may change the estimate of effect. Low certainty of evidence indicates low confidence in the estimate of effect and it is likely that further studies will change the estimate of effect, and very low certainty of evidence indicates that there are meta- very limited and uncertain evidence available.
The German Diabetes Center is funded by the German Federal Ministry of Health and the Ministry of Science and Culture of the state of North Rhine-Westphalia. The study was partly funded by the German Center for Diabetes Research (DZD). The funders had no role in the design of the study or in the collection, analysis and interpretation of the data.
The authors declare no conflict of interest.
This press release is based on Oral Presentation 1 to the European Association for the Study of Diabetes (EASD). All accepted abstracts have been carefully reviewed by the conference selection committee. There is no complete article at this stage, but the authors are happy to answer your questions. The research was submitted to a medical journal for publication. As this is an oral presentation, there is no poster with this presentation.
Conflict of Interest Statement
The authors declare no conflict of interest.