Background Evidence from studies investigating biomarkers of saturated fatty acids (SFAs) suggests
that specific SFAs with different chain lengths may have different metabolic effects
and impact on health, including the type 2 diabetes (T2D) development. We aimed to
quantify existing evidence in a systematic review and dose-response meta-analysis
on the association between biomarkers of total and specific SFAs and the incidence
of T2 D from prospective observational studies.
Methods The systematic literature search was conducted in PubMed and Web of Science by two
independent investigators up to August.2020. Summarised relative risks (SRR) and 95 %
confidence interval (95 % CI) were estimated using random effects models.
Results Ten articles, including 24 cohorts were identified. Total SFAs were associated with
an increased T2 D risk (per 3 %mol: 1.17(1.03; 1.33)). For the odd-chain and the very
long-chain SFAs a reduced T2 D incidence was observed. The SRR (95 % CI) per 0.1 %mol
ranged from 0.74(0.56; 0.97) for arachidic acid to 0.90(0.83; 0.98) for behenic acid.
For even-chain SFAs, the T2 D incidence was increased (palmitic acid per 1 %mol of
total FAs: 1.10(1.04; 1.16). No association was found between myristic acid, stearic
acid and the T2 D incidence.
Conclusions Our results indicate that specific SFAs are differently associated with the T2 D
risk. Total and even-chain SFAs were associated with increased, whereas odd-chain
and very long-chain SFAs were associated with decreased T2 D incidence. The results
suggest a reconsideration of current dietary recommendations on total SFAs as a homogeneous
group. More precise recommendations on specific types and sources of SFAs are needed.
