Anti-Inflammatory Diets: Strategies to Reduce Risk of Chronic Disease
Inflammation is not always bad
While we think of inflammation as harmful, it’s important to recognize that not all inflammation is bad. Inflammation is triggered as a short-term protective mechanism against infection and as a mechanism for healing from injury. Dietary factors can also trigger inflammation, and it is believed that chronic low-grade inflammation may drive metabolic disease such as obesity, diabetes, and cardiovascular disease.
One of the challenges in evaluating inflammation is assessing it. The inflammation that we are aware of often takes the form of swelling, redness, and/or pain. Inflammation at the cellular level is not perceptible to us as pain, and thus we rely on inflammatory markers in the blood such as C-Reactive Protein (CRP), a protein that indicates inflammation but does not differentiate between infections, injuries, etc.
Dietary factors that affect inflammation
The balance of omega-6 and omega-3 fatty acids appears to be critical in the production of inflammation. The omega-6 fatty acid arachidonic acid (AA) is the building block of inflammatory factors that stimulate inflammation. The omega-3 fatty acid eicosapentaenoic acid (EPA) is involved in the inhibition of inflammation.
To simplify the explanation, it’s sufficient to know that the hormone insulin activates the conversion of linoleic acid (the most commonly consumed form of omega-6 fatty acids) into arachidonic acid (AA). High levels of insulin (hyperinsulinemia) and insulin resistance are not only consequences of inflammation, but also cause inflammation, particularly in the fat cells.
The balance of omega-3 and omega-6 fatty acids is relevant
Omega-3 fatty acids help to inhibit the formation of AA, but our modern diet has created a significant imbalance of excess omega-6 compared to omega-3 fatty acids. The combination of high levels of insulin in with high levels of linoleic acid in our diet greatly increases the inflammatory pathway.
To summarize the roles of these fatty acids:
Omega-6 = pro-inflammatory
Omega-3 = anti-inflammatory
It appears that hunter-gatherers ate fats at a ratio of approximately 2:1 to 4:1, while the Inuit eating mostly omega-3-rich seafood were at a ratio of 1:4. Now, the omega-6 to omega-3 ratio in our modern diet is approximately 16:1. This dietary trend is even visible in human fat stores of linoleic acid over time.
The following food items appear to cause inflammation:
- Sugar – glucose, high-fructose corn syrup
- Refined carbohydrates
- Trans fats
- Vegetable/seed oils (see image)
- Excessive alcohol
- Processed meats
Research has shown that several popular diets are associated with reduced inflammation:
Though these dietary strategies cover a wide range of macronutrient compositions, the similarity among them is decreased intake of processed foods, which is likely the mechanism by which they decrease inflammation. As is often the case, it’s often a matter of what’s not being eaten.
Foods considered anti-inflammatory
Specific food items appear to have anti-inflammatory properties:
- Fruit – mangoes, deep-colored berries, e.g. cherries, grapes, etc.
- High-fat fruits – avocados and olives
- Olive oil
- Seafood, fatty fish – squid, crab, salmon, mackerel, anchovies, sardines, etc.
- Nuts and seeds – chia seeds, hemp seeds, walnuts
- Dark chocolate
- Spices – turmeric, fenugreek, cinnamon
- Green tea
- Red wine
Rather than trying to design a diet that is concentrated heavily on these particular foods, it is ultimately more important and more practical to simply know what foods NOT to eat.
There are certainly individual food intolerances and sensitivities that may contribute to inflammation, as well. Self-experimentation, often done by using elimination diets and reintroduction of potential culprits (i.e. the Scientific Method), can be used to uncover food sensitivities/intolerances.
What dietary interventions work best to reduce inflammation?
It appears that we have the best evidence for the following principles:
- Reduce omega-6 fatty acids, especially seed oils
- Consume omega-3 fatty acids
- Avoid sugar and refined carbs
- Eat colorful vegetables
- Stabilize insulin levels
Effect of other lifestyle factors
Outside of dietary factors, there are other lifestyle factors that can have significant impact on inflammation. It appears that sleep deprivation increases inflammation, while exercise decreases inflammation
Given that chronic inflammation is associated with development of chronic diseases such as obesity, diabetes, and cardiovascular disease, it is imperative to address a wide range of lifestyle factors in order to optimize health.