N-3 fatty acids

Marine n-3 polyunsaturated fatty acids (PUFAs) and seafood intakes have been shown to decrease the risk of metabolic syndrome (MetS), whereas data on related MetS burden in China remain absent. We hypothesize that low marine n-3 PUFAs and seafood consumption are a significant contributor to the burden of MetS in China. The time trend of marine n-3 PUFAs consumption and seafood was evaluated based on the China Health and Nutrition Survey. We used the comparative risk assessment method to estimate the population attributable fraction of MetS cases attributable to the low marine n-3 PUFAs and seafood consumption. We also projected the intakes of marine n-3 PUFAs and seafood and the related MetS burden from 2011 to 2031. The overall intakes of marine n-3 PUFAs (40.4 mg/day) and seafood (32.6 g/day) were far below the optimal level in 2011. The low intakes of marine n-3 PUFAs and seafood were estimated to be responsible for 8.1% and 2.2% of the MetS burden, accounting for 17.0 and 4.6 million MetS cases, respectively, according to the International Diabetes Federation definition in 2011. Although marine n-3 PUFAs and seafood intakes are projected to increase for the next 20 years, the intake levels would still be inadequate and are expected to contribute to 11.3 (marine n-3 PUFAs) and 2.2 (seafood) million MetS cases in 2031. Dietary guidelines should continue to highlight increasing marine n-3 PUFAs and seafood consumption to reduce the MetS burden in China.

Cancer is a major health concern in persons with type 2 diabetes (T2D). Diet plays an important role in progression of diabetes and cancer. We aimed to systematically summarize the evidence on diet and cancer in individuals with T2D.

PubMed and Web of Science were searched until August 2023 and followed up via PubMed alert until December 2024. Prospective studies investigating any dietary factor in association with cancer in individuals with T2D were eligible.

We identified 68 studies and conducted 20 meta-analyses. A general low-carbohydrate diet was not associated with cancer outcomes, whereas an inverse association was found for vegetable-based low-carbohydrate diet (HR per 5 points [95 % CI]: 0.90 [0.84, 0.97]; n = 2). We found indications of lower cancer incidence for higher adherence to Dietary Approaches to Stop Hypertension diet, (Alternate) Healthy Eating Index, higher intakes of n-3 fatty acids (0.73 [0.55, 0.98]; n = 2) and higher serum vitamin D (0.95 [0.93, 0.97]; n = 2), as well as a positive association for serum manganese concentrations (1.44 [1.11, 1.87]; n = 2), rated with low to very low certainty of evidence.

So far, the certainty of evidence is very limited due to the small numbers of primary studies. There is an indication of a possible association between diet and cancer risk among persons with T2D, but further well-designed prospective cohort studies are warranted.