Inflammaging is the slow, low-grade rise in inflammation that tends to come with age, a term coined by immunologist Claudio Franceschi in 2000. It is usually tracked with blood markers such as C-reactive protein (CRP) and interleukin-6 (IL-6). Trials of Mediterranean-style eating have lowered these markers modestly. Whether that changes how people age is still an open question.
What is inflammaging?
Inflammation is the body's response to injury and infection. Short bursts of it are useful. Inflammaging describes something different: a mild, chronic inflammatory state that builds over decades.
Franceschi and colleagues named it "inflamm-aging" in a 2000 paper. They argued that aging brings a gradual loss of the ability to cope with stress, plus rising pro-inflammatory status (Franceschi et al., 2000). They saw it as the result of a lifetime of antigens and other stress.
Their explanation was evolutionary. Inflammation helps neutralize threats early in life. Late in life, a period evolution did not plan for, the same response may become harmful. The paper also noted a paradox: even healthy centenarians had higher levels of inflammatory proteins in their blood.
By 2014, the idea was mainstream. A summary from a US National Institute on Aging meeting described human aging as marked by chronic, low-grade inflammation. It also stated plainly that the precise causes of inflammaging, and whether it directly causes poor health, remain largely unknown (Franceschi and Campisi, 2014).
What causes inflammaging?
There is no single cause. A 2018 review listed several possible drivers (Ferrucci and Fabbri, 2018):
- genetic susceptibility
- central obesity (fat carried around the abdomen)
- a leakier gut lining and changes in gut bacteria
- senescent cells, which stop dividing but keep sending signals
- oxidative stress from aging mitochondria
- changes in immune cells and chronic infections
A 2019 perspective in Nature Medicine added lifestyle and environment. It named infections, physical inactivity, poor diet, environmental toxicants and psychological stress as factors that can promote chronic inflammation (Furman et al., 2019). Several of these are things you can change. Your genes and your age are not.
How is inflammaging measured?
There is no single test for inflammaging. Researchers usually measure a few proteins in the blood. Two come up in almost every diet study.
| Marker | What it is | What to keep in mind |
|---|---|---|
| C-reactive protein (CRP, or hs-CRP) | A protein made by the liver when inflammation is present. The high-sensitivity test detects the low levels seen in chronic, mild inflammation. | It rises sharply with a cold, an injury or a hard workout. One reading says little on its own. |
| Interleukin-6 (IL-6) | A signaling protein (cytokine) released by immune cells and fat tissue. It is one of the signals that tells the liver to make CRP. | Mostly a research test. It is not part of routine check-ups. |
| Others (IL-18, TNF-alpha, adhesion molecules) | Additional signals used in some trials. | Results vary from study to study and lab to lab. |
The 2018 review described inflammaging as elevated blood inflammatory markers that come with higher susceptibility to chronic illness, disability and frailty (Ferrucci and Fabbri, 2018). The same authors were careful. Whether lowering inflammation changes the course of most age-related problems is still debated. For a broader look at how inflammation works, see our guide to inflammation.
What do diet studies show about inflammatory markers?
Most of the evidence comes from Mediterranean-style eating patterns, studied against other diets. Here is what the main trials and reviews found.
| Study | Who and how long | What changed |
|---|---|---|
| Naples trial (Esposito et al., 2004) | 180 adults with metabolic syndrome, 2 years. Mediterranean-style diet vs a "prudent" low-fat diet. | hs-CRP and IL-6 were significantly lower in the Mediterranean group. That group also lost more weight (4.0 kg vs 1.2 kg). |
| PREDIMED substudy (Estruch et al., 2006) | 772 adults aged 55 to 80 at high cardiovascular risk, 3 months. Mediterranean diet with virgin olive oil or nuts vs low-fat advice. | The olive oil group's CRP fell by 0.54 mg/L compared with the low-fat group. |
| Meta-analysis of Mediterranean diet trials (Schwingshackl and Hoffmann, 2014) | 17 randomized trials, 2,300 people, at least 12 weeks each. | hs-CRP was 0.98 mg/L lower and IL-6 0.42 pg/mL lower than in control diets. |
| Meta-analysis of olive oil trials (Schwingshackl et al., 2015) | 30 randomized trials, 3,106 people. | CRP was 0.64 mg/L lower (15 trials) and IL-6 0.29 lower (7 trials) than in controls. |
| NU-AGE (Ghosh et al., 2020) | 612 older adults in five European countries, 1 year of a Mediterranean diet adapted for older people. | Gut bacteria that increased with diet adherence were linked to lower CRP and IL-17, and to markers of less frailty. |
The pattern is consistent. People eating a Mediterranean-style diet, with olive oil as the main fat, tend to show modestly lower CRP and IL-6 than people on comparison diets. The olive oil meta-analysis concluded that olive oil "might" have favorable effects on these markers, and it asked for a conservative reading of its results.
We cover the trial behind much of this research in what the PREDIMED trials really proved. For the evidence on high-phenolic oil specifically, see high-phenolic olive oil and inflammation.
What are the limits of this evidence?
This is where a lot of writing on inflammaging goes too far. Five cautions are worth keeping in mind.
Markers are not outcomes. A lower CRP is a change in a blood test. It is not proof that someone will age more slowly or feel better. No trial has shown that a diet, or any single food, slows inflammaging itself.
The results vary a lot. In the 2014 meta-analysis, the statistical measure of disagreement between trials (I²) was 91% for hs-CRP. That means the trials disagreed a great deal on how big the effect was.
Weight loss muddies the picture. In the Naples trial, the Mediterranean group lost about three times as much weight. Losing abdominal fat can lower inflammatory markers on its own. It is hard to separate the food from the weight change.
Diets differ in many ways at once. A Mediterranean diet adds olive oil, but also vegetables, legumes, nuts, fish and fiber. It usually removes processed food and some red meat. Trials cannot say which part matters most.
Single tests mislead. CRP swings with short-term illness and exercise. A single high reading in someone who just had a cold tells you very little about chronic inflammation.
What can you do about inflammaging after 40?
The honest answer is that the most useful steps are the ordinary ones. The factors named in the research are inactivity, poor diet, excess abdominal fat, smoking, chronic stress and infections. All of them are worth addressing for many reasons, not just inflammation.
On the food side, the pattern with the most data looks like this:
- Make extra virgin olive oil your main added fat, in place of butter or margarine.
- Eat vegetables and legumes most days, and fruit and nuts often.
- Choose whole grains over refined ones.
- Eat fish more often than processed or red meat.
- Keep sweets, sugary drinks and ultra-processed snacks occasional.
None of this needs to be strict to be useful. A simple Greek village salad dressed with olive oil covers several of these at once. For the full eating pattern, see our pillar guide, eating for longevity after 40.
If you want to know where you stand, ask your doctor whether an hs-CRP test makes sense for you. Repeat it when you are well, and read it alongside your other results.
If you use olive oil daily, our Pomoni High-Phenolic Olive Oil is an early-harvest Greek oil measured at 635 mg/kg total polyphenols by HPLC.
Sources
- Franceschi C, Bonafè M, Valensin S, et al. Inflamm-aging: an evolutionary perspective on immunosenescence. Annals of the New York Academy of Sciences. 2000;908:244–254. doi.org/10.1111/j.1749-6632.2000.tb06651.x
- Franceschi C, Campisi J. Chronic inflammation (inflammaging) and its potential contribution to age-associated diseases. Journals of Gerontology Series A. 2014;69(Suppl 1):S4–S9. doi.org/10.1093/gerona/glu057
- Ferrucci L, Fabbri E. Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty. Nature Reviews Cardiology. 2018;15(9):505–522. doi.org/10.1038/s41569-018-0064-2
- Furman D, Campisi J, Verdin E, et al. Chronic inflammation in the etiology of disease across the life span. Nature Medicine. 2019;25(12):1822–1832. doi.org/10.1038/s41591-019-0675-0
- Esposito K, Marfella R, Ciotola M, et al. Effect of a Mediterranean-style diet on endothelial dysfunction and markers of vascular inflammation in the metabolic syndrome: a randomized trial. JAMA. 2004;292(12):1440–1446. doi.org/10.1001/jama.292.12.1440
- Estruch R, Martínez-González MA, Corella D, et al. Effects of a Mediterranean-style diet on cardiovascular risk factors: a randomized trial. Annals of Internal Medicine. 2006;145(1):1–11. doi.org/10.7326/0003-4819-145-1-200607040-00004
- Schwingshackl L, Hoffmann G. Mediterranean dietary pattern, inflammation and endothelial function: a systematic review and meta-analysis of intervention trials. Nutrition, Metabolism and Cardiovascular Diseases. 2014;24(9):929–939. doi.org/10.1016/j.numecd.2014.03.003
- Schwingshackl L, Christoph M, Hoffmann G. Effects of olive oil on markers of inflammation and endothelial function: a systematic review and meta-analysis. Nutrients. 2015;7(9):7651–7675. doi.org/10.3390/nu7095356
- Ghosh TS, Rampelli S, Jeffery IB, et al. Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across five European countries. Gut. 2020;69(7):1218–1228. doi.org/10.1136/gutjnl-2019-319654
