By Sheela Sinharoy
Tuesday’s minisymposium ‘Nutrition and Inflammation’ covered a wide range of topics and research designs from clinical, lab, and public health perspectives.
Starting with clinical research, Wendy Ward of Brock University (Canada) presented on associations of dietary intake with periodontal healing. She explained that 42% of adults in the US are affected by periodontal disease, which is characterized by inflammation of tissues around the teeth that can eventually lead to loss of alveolar bone. One treatment is the mechanical removal of bacteria below the gum line through sanative therapy. Dr. Ward’s group found that higher dietary intakes of fruits and vegetables, β-carotene, vitamin E, and α-linolenic acid were associated with greater healing following sanative therapy.
Taking a more public health-oriented perspective, Mercedes Sotos Prieto of Harvard University spoke about the development of a healthy lifestyle score (HLS) and its association with inflammatory markers among Puerto Rican adults in Boston. The HLS included five components: diet, physical activity, smoking, social network and support, and sleep. Dr. Sotos Prieto found that a 20-unit increase in the HLS was associated with a decrease in the inflammatory biomarkers IL-6 and TNF-α when adjusted for a number of covariates. These in turn were associated with obesity and hypertension but not with diabetes or heart disease.
Presentations from Yaw Addo and Leila Larson of Emory University also had clear public health implications. They looked at biomarkers of iron and vitamin A status, respectively, and their relationship with biomarkers of inflammation. First, Dr. Addo explained that transferrin receptor was strongly associated with α-1 acid glycoprotein (AGP) in women of reproductive age across six countries, though the magnitude of the association varied by country. Next, Ms. Larson showed that retinol binding protein (RBP) was significantly associated with both C-reactive protein (CRP) and AGP among preschool children in Liberia. Both of these analyses suggested that it may be important to account for inflammation, particularly with RBP, where adjusting for inflammation through linear regression decreased the prevalence of vitamin A deficiency by almost 20 percentage points.
Moving to lab studies, Marie-Caroline Michalski of the University of Lyon (France) presented research on the effects of dietary lipids on plasma endotoxins and lipopolysaccharides (LPS), which contribute to low-grade inflammation. She showed that in a sample of normal weight and obese men, ingestion of a higher-fat test meal led to postprandial endotoxemia only in obese subjects. Qiaozhu Su of the University of Nebraska then presented data showing that the cAMP responsive element binding protein H (CREBH), which is activated by the inflammatory cytokine TNF-α, induces expression of apolipoprotein B. This in turn increases secretion of very low density lipoproteins (VLDL) and may play a role in hepatic steatosis, hyperlipidemia, and insulin resistance. Finally, Sadiq Umar of Washington State University showed that thymoquinone, a compound derived from Nigella sativa, or black cumin, inhibits TNFα-induced production of the inflammatory cytokines IL-6 and IL-8 as well as the pro-inflammatory mediator ASK1.
Given the associations between inflammation and many chronic diseases, we will likely hear a great deal more about these topics in years to come.