Association between the dietary inflammatory index (DII) and serum inflammatory markers in healthy obese and non-obese individuals

Introduction  The dietary inflammatory index (DII) is a marker characterizing pro- or anti-inflammatory properties of a dietary pattern. A proinflammatory and therefore high DII is associated with a higher risk for obesity and several other non-communicable diseases. However, obesity itself is considered as being inflammatory and promoting chronic low-grade inflammation. We aimed to evaluate the association between the DII, anthropometric measurements and seven serum markers of inflammation in a healthy cohort.

Material and Methods  Within a lager clinical trial, a total of 11 obese participants (BMI: Md = 32.5 kg/m², IQR= 6.0) were identified. 22 sex and age matched non-obese controls (BMI: Md = 24.5 kg/m², IQR= 5.0) were included for this analysis. Food intake was assessed by the Vienna Food Record (VFR) and analyzed by the nutritional software nut.s, and the DII was calculated. Anthropometry and subcutaneous adipose tissue (SAT) were measured by standardized procedures applying an ultrasound method. The inflammation markers IL- 6, IL-8, IL-18, IL1-RA, TNF-α, IFN-α, and CRP were determined in serum by clinically established protocols.

Results  The DII was significantly higher in the obese group (p=0.031). Moreover, the inflammation marker IL-6 (p=0.04) and IL-18 (p=0.014) were significantly higher in the obese group. No differences were seen for the other inflammation markers. The DII did not correlate with any of the inflammatory markers, however, DII was significantly correlated with BMI (r_s(32)=0.421, p=0.016), SAT (r_s(32)=0.386, p=0.029) and abdominal fat (r_s(32)=0.404, p=0.022).

Conclusion  Our analyses revealed a more proinflammatory dietary pattern as well as higher IL-6 and IL-18 serum concentrations in the obese group. Further, a positive association of DII and BMI, total SAT and abdominal fat distribution was detected. Interestingly, despite a higher DII, only 2 of 7 inflammation markers were elevated in the obese cohort. Due to hypertrophying adipose tissue, the elevation of IL-6 and IL-18 are in line with the current literature, but the reason for the lack of higher plasma levels in TNF-α remains unknown. We hypothesize a missing systemic and only local secretion of TNF-α from adipose tissue in obese individuals, but further research is needed.

Publication History

Article published online:
26 May 2023