"Are nightshades actually inflammatory?"

"The popular claim that nightshades (tomatoes, peppers, eggplant, potatoes) cause inflammation is not supported by clinical evidence. This claim is based on the presence of alkaloids like solanine in these foods, which at very high doses in animal models can be irritating. At normal dietary doses in humans, there's no evidence that nightshade consumption raises inflammatory markers. For the vast majority of people, tomatoes and peppers are net anti-inflammatory due to their antioxidant and fiber content."

"Does sugar cause inflammation?"

"Excess sugar intake, particularly when it contributes to caloric surplus and fat gain, is associated with higher inflammatory markers. Visceral fat is pro-inflammatory. Whether sugar is directly inflammatory at typical doses (separate from its contribution to excess calories) is less clear. Some studies show that high-fructose corn syrup and excess fructose raise uric acid and CRP directly. But in the context of a balanced diet within caloric needs, moderate sugar doesn't clearly raise inflammatory markers in healthy people."

"What is the difference between CRP and IL-6 as inflammation markers?"

"IL-6 is a pro-inflammatory cytokine produced by immune cells, fat tissue, and other cell types. It's part of the inflammatory signaling cascade. CRP (C-reactive protein) is produced by the liver in response to IL-6. CRP is slower to rise and fall than IL-6 but is easier to measure in clinical settings. High-sensitivity CRP (hsCRP) below 1 mg/L is considered low cardiovascular risk. Both are used as markers of systemic inflammation, though neither is specific to any single condition."

"Do anti-inflammatory supplements work?"

"Curcumin (from turmeric) shows effects on inflammatory markers in clinical trials, but at doses far higher than typical food consumption, and absorption is poor without enhancement. Fish oil omega-3s have the strongest supplement evidence for reducing inflammatory markers, particularly triglycerides and certain cytokines. Most other marketed 'anti-inflammatory' supplements have weaker or more inconsistent evidence. Whole food sources are generally more effective than isolated supplements, partly because of synergistic effects from other compounds in the food."

Diet and Chronic Inflammation: What the Evidence Actually Shows

Quick Answer

Acute inflammation is a normal healing response. Chronic low-grade inflammation is different: it's a persistent, low-level immune activation that contributes to cardiovascular disease, insulin resistance, and other conditions. The Mediterranean dietary pattern consistently shows lower inflammatory markers (CRP, IL-6) in research. Ultra-processed food intake is associated with higher inflammation. Most individual food effects are real but smaller than the overall diet pattern effect.

The Science

Inflammation is not one thing. A sprained ankle inflaming overnight is different from the low, persistent immune activation that medical researchers link to heart disease and type 2 diabetes. Conflating them leads to confused thinking about diet and health.

The distinction matters before we get into the food evidence.

Acute vs. Chronic Inflammation

Acute inflammation is the body’s appropriate response to injury or infection. Blood vessels dilate, white blood cells flood the area, and cytokines coordinate tissue repair. It’s fast, intense, and resolves within days. Without it, wounds wouldn’t heal and infections would spread.

Chronic low-grade inflammation is different in kind, not just degree. It’s a persistent, smoldering immune activation at levels too low to cause obvious symptoms but high enough to contribute to arterial plaque, insulin receptor disruption, and tissue damage over years and decades.

The markers most commonly measured in research are C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). Chronic elevation of these markers correlates strongly with risk for cardiovascular disease, type 2 diabetes, and some cancers (Calder et al., 2011, British Journal of Nutrition).

How Food Affects the Inflammatory System

Food influences inflammation through several pathways.

Nutrient composition affects immune cell function directly. Omega-3 fatty acids compete with omega-6 fatty acids as substrates for inflammatory eicosanoid synthesis, shifting production toward less potent inflammatory mediators. This is the best-characterized single-nutrient anti-inflammatory mechanism (Calder, 2017, Biochemical Society Transactions).

Gut microbiome composition is another pathway. A microbiome fed by diverse fiber produces short-chain fatty acids that dampen NF-kB inflammatory signaling. Disrupted microbiomes produce more lipopolysaccharide (LPS), which activates innate immune pathways. This connection is detailed in the short-chain fatty acids guide.

Body fat itself is inflammatory. Visceral adipose tissue secretes IL-6 and TNF-alpha. Dietary patterns that contribute to visceral fat accumulation are pro-inflammatory by that mechanism alone. This makes isolating direct food effects from indirect effects through body composition difficult in most observational studies.

What the Dietary Pattern Evidence Shows

The Mediterranean dietary pattern has the most consistent and strongest evidence for lowering inflammatory markers. The PREDIMED trial (Estruch et al., 2013, New England Journal of Medicine), a large randomized controlled trial, found that Mediterranean diet groups had significantly lower CRP, IL-6, and other inflammatory markers than control groups at follow-up, along with lower cardiovascular event rates.

The Mediterranean pattern is not a single food. It’s a combination: high in vegetables, fruits, whole grains, legumes, fish, olive oil, and nuts. Low in red meat and ultra-processed foods. This makes it difficult to attribute the effect to any single component.

Western dietary patterns (high in ultra-processed foods, refined grains, sugar, and saturated fat with low vegetables and fiber) consistently associate with higher inflammatory markers across observational studies. Whether this is causal or confounded by lifestyle and body composition is hard to fully separate, but the association is strong and consistent.

Ultra-processed food intake specifically, independent of nutrient composition, has been linked to higher CRP in several large cohort studies. The NOVA classification system groups these foods by level of industrial processing. Higher intake of NOVA Group 4 (ultra-processed) foods associates with higher inflammatory markers after controlling for obesity and other confounders (Minihane et al., 2015, British Journal of Nutrition). The mechanisms may include food additives, advanced glycation end products from high-heat processing, and displacement of anti-inflammatory whole foods.

Individual Foods: Where Evidence Is Strong vs. Speculative

Omega-3 fatty acids from fatty fish, walnuts, and flaxseed have the most consistent individual food evidence. EPA and DHA from fish directly compete with arachidonic acid (an omega-6) for conversion to eicosanoids, producing less inflammatory leukotrienes and prostaglandins.

Extra virgin olive oil contains oleocanthal, which inhibits COX-1 and COX-2 enzymes by a mechanism similar to ibuprofen, though at lower potency. Galland (2010, Nutrition in Clinical Practice) reviewed oleocanthal’s anti-inflammatory activity and noted significant effects at typical olive oil consumption levels.

Berries contain anthocyanins and other polyphenols that reduce NF-kB activity in cell culture and animal studies. Human evidence is more modest, showing reductions in CRP in some trials. The effect sizes are real but not large.

Specific spices like turmeric (curcumin) and ginger (gingerols) reduce inflammatory markers in clinical trials, but mainly at supplemental doses rather than typical cooking amounts.

The category of “inflammatory foods” as popularly described often includes things with very weak or nonexistent human evidence. Nightshades, seed oils broadly, and gluten in non-celiac individuals are common examples where popular claims outrun the research.

The Practical Limitation

Most inflammation-and-diet research measures biomarkers, not clinical outcomes. Lower CRP from a dietary change is a promising finding, not proof that the person will have fewer heart attacks. The gap between biomarker improvements and hard clinical outcomes matters, especially when evaluating dramatic claims about specific superfoods.

Dietary patterns remain the most actionable evidence. Not because individual foods are irrelevant, but because the pattern effect is larger, more consistent, and more studied than any single food effect.

This article is for educational purposes only. It’s not medical advice. Talk to your doctor or a registered dietitian before making significant changes to your diet.

What This Means for You

Focus on dietary patterns over individual 'anti-inflammatory foods.' A diet rich in vegetables, fruits, whole grains, legumes, fish, and olive oil with less ultra-processed food has the most consistent evidence for lowering inflammatory markers. Omega-3s (from fatty fish, walnuts, flaxseed) have the strongest individual food evidence. Reducing ultra-processed food intake may be the single most impactful dietary change for most people's inflammatory profile.