Effect of a diet based on the dietary guidelines for americans on inflammation markers in women at risk for cardiometabolic disease: results of a randomized, controlled trial

Authors: KRISHNAN, SRIDEVI - University Of California, Davis; Freytag, Tammy; Jiang, Xiaowen; SCHUSTER, GERTRUD - University Of California, Davis; Woodhouse, Leslie; Keim, Nancy; Stephensen, Charles

Submitted to: BMC Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Eating a healthy diet is important for minimizing the risk of developing chronic inflammatory disease. It is an open question, however, as to what impact a change in diet will have in the short term on markers of inflammation associated with chronic inflammatory diseases. In the present randomized, controlled dietary intervention trial a healthy diet based on the Dietary Guidelines for Americans was compared to a more typical US dietary pattern for their ability to affect markers of inflammation, immune activation and tissue remodeling (which is a normal process). The study involved 44 overweight or obese women who were provided with a complete diet during this 8 wk controlled feeding study during which their pre-study body weight was maintained. The study measured 13 plasma markers of inflammation and immune activation, three markers of tissue remodeling, and the production of seven cytokines produced by white blood cells isolated and maintained in culture. One marker of inflammation, the plasma acute phase protein serum amyloid A (SAA) was significantly decreased by the Dietary Guidelines dietary intervention relative to the typical American control diet, suggesting an anti-inflammatory benefit for this dietary pattern. In addition, one marker of tissue remodeling, matrix metalloproteinase-3 (MMP-3), was increased by the same diet. Whether this increase signals a similar anti-inflammatory benefit to the diet is not as clear. However, MMP-3 production in adipose tissue is decreased during the development of obesity, thus this increase may signal beneficial changes in adipose tissue depots as this represents a modest change toward more “normal” levels. In summary, consumption of a healthy diet for 8 wk by overweight and obese women at risk of chronic disease development lowered the inflammatory profile in plasma, suggesting a short-term benefit from this dietary intervention.

Technical Abstract: : Background: Inflammation is closely associated with onset and progression of chronic cardiometabolic diseases. Epidemiological studies strongly support the association between dietary pattern and inflammatory status, suggesting that diet can modulate systemic inflammation. Randomized controlled trials evaluating specific diet patterns provide contrasting evidence. Some studies suggest a beneficial effect of healthy diet patterns, yet other studies report no effect. Objective: To evaluate the effect of a diet pattern based on the Dietary Guidelines for Americans (DGA), in a controlled feeding setting, on plasma markers of inflammation and on cytokine production by peripheral blood mononuclear cells (PBMC). Design: Women (n=44) with one or more risk factors of metabolic syndrome and BMI between 25.2-39.8kg/m2 completed an 8-wk controlled feeding study. They were randomized to either a group following a diet based on the DGA 2010 (DGA), or a group given a ‘typical American diet’ (TAD), based largely on a Western diet pattern. By design, women maintained their body weight. Fasting plasma and PBMC were collected at wk 0 (baseline) and at wk 8 (post-intervention). Plasma markers of inflammation and PBMC cytokines were measured at both time points. One-way ANCOVA was used to evaluate if the diet had a significant effect on concentrations of these inflammatory markers. Results: Serum amyloid A (SAA) in plasma was significantly reduced following an 8 wk exposure to the DGA diet compared to TAD (p = 0.04), while matrix metalloproteinase 3 (MMP3) was elevated (p = 0.014). Conclusions: The acute-phase protein SAA was reduced following an 8-wk DGA based dietary pattern, and MMP3, sometimes called the ‘anti-adipogenic’ factor, was elevated. Diet pattern, in particular the DGA, independent of change in body weight, imparts anti-inflammatory immune modulating properties.