According to two new studies from Asia and one from the US, higher blood levels of long-chain omega-3 fatty acids from marine sources as well as those derived from plants are associated with lower risk of diabetes.
One study evaluated the association of fish and shellfish consumption with the incidence of type 2 diabetes (T2D) in two large, population based, prospective studies of middle aged women and men: the Shanghai Women’s Health study (SWHS) and the Shanghai Men’s Health Study (SMHS), conducted in Shanghai, China (1). The research was based on the postulation that long-chain omega-3 fatty acids (FAs), mainly found in fish, influence the development of T2D. The assessment of the dietary intake was made through an in-person interview by a validated food frequency questionnaire at the beginning of the study and again at the first follow-up survey for both SWHS and SMHS. For the calculation of n-3 FAs consumption, the researchers used the Chinese Food Composition Tables. The findings showed that higher intakes of fish and shellfish and long-chain fatty acids were associated with a lower risk of T2D among women.
The World Health Organisation (WHO) is reporting that over 220 million people globally are affected by diabetes and that the consequences of this disease cause 3.4 million deaths every year – predicting that this number will double between 2005 and 2030. Therefore, prevention is an urgent matter of health worldwide.
In the Cardiovascular Health Study (CHS), a population-based, longitudinal study in the US, data from 3,088 men and women of 65 years and older were prospectively analysed (2). They authors used biomarkers to measure n-3 FAs in plasma phospholipids. 204 incidences of diabetes cases occurred in this cohort. The results revealed that both omega-3 FAs originating from marine and plant sources were associated with a lower risk of diabetes. In conclusion, however, no association was observed for intakes of omega-3 FAs, but the individuals with the highest plasma concentrations of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) and alpha linolenic acid (ALA) had a lower risk of diabetes.
Furthermore, a population-based prospective cohort investigating > 63,000 Chinese men and women in Singapore, the Singapore Chinese Health Study (SCHS), suggested that consumption of ALA was associated with a decreased risk of diabetes (3). Scientists commented that a good trial using ALA would is lacking so far but the chance of a protective effect merits more attention.