Consumers want to know which foods quell inflammation to help them manage pain from arthritis, lessen the symptoms of asthma and reduce their chances of developing type 2 diabetes or having a heart attack.
There’s some good news for consumers. Research suggests that different dietary patterns can increase or decrease levels of various inflammatory markers in the blood. However, headlines claiming that this food or that food affects chronic inflammation are often premature, over generalized, based on pre-clinical research, not considering the total diet, and confusing to consumers. This post takes a brief look at the roles of dietary fat on the inflammatory response.
Writing in Advances in Nutrition, Kevin L. Fritsche of the University of Missouri summarizes current thoughts about the science of dietary fatty acids and inflammation. Here are a few key takeaways.
- Dietary fat is likely linked to inflammation via the microbiota. According to a rodent study with 72 percent of total energy derived from fat, a high-fat meal caused the translocation of lipopolysaccharide (LPS), an endotoxin and component of the cell walls of all gram-negative bacteria. LPS is a strong stimulus of the inflammatory system. Some researchers also believe that various foods contain endotoxins, and that dietary fats aid their absorption.
- Various saturated fats directly stimulate inflammatory gene expression. Lauric acid (12:0) appears to have the greatest potency, and myristic (14:0) and stearic (18:0) have little proinflammatory activity.
- Some researchers have claimed that linoleic acid (LA), the predominant omega-6 fatty acid in the diet, is proinflammatory because it can be metabolized to bioactive eicosanoids associated with inflammation and chronic disease. However, a systematic review of 15 studies did not identify a single study in which higher intakes of LA led to greater concentrations of inflammatory markers. More often, a higher intake of LA was associated with lower inflammatory status in healthy adults. Additionally, pro-inflammatory compounds trigger resolution and bring tissues back to health, so LA is also responsible for an anti-inflammatory response.
- Omega-3 fatty acids appear to have anti-inflammatory activity, as they are precursors for pro-resolving, anti-inflammatory lipid mediators. Additionally, as part of the cell membranes, these fatty acids may play a role in immune cell signaling.
Of course, there are a host of other dietary factors that may either boost or inhibit the inflammatory response. They too may exert effects through the microbiota. Gut microbes metabolize various food remnants and may free up or produce health-protective compounds. As registered dietitian nutritionists, we often understand what consumers do not: Diet as a whole — over individual foods and nutrients — plays an important role in modifying inflammation and diseases of inflammatory states. Shivappa et al. have developed and researched a population-based dietary inflammatory index (DII). They’ve identified many components of an anti-inflammatory diet, including dietary fiber, tea, herbs, spices, garlic and foods with a variety of phytonutrients. In general, diets with a plant slant (and at an appropriate calorie level) appear to exert anti-inflammatory effects. Take a look at their paper in Public Health Nutrition to see how they’ve weighted various foods and food components, including various types of fatty acids.