Tomatoes and gout show up together constantly in patient conversation, but rarely with an actual study attached. One does exist.
Researchers led by Tanya Flynn tested the claim directly in 2015. Their findings landed somewhere between dismissal and confirmation.
This guide covers that study in full, including the real numbers behind it. It also covers what official gout diet guidance actually says about tomatoes, since the two do not fully agree.
The short version
A 2015 study in BMC Musculoskeletal Disorders found a real, measurable link. Higher tomato intake tracked with higher serum urate levels across thousands of participants.
The effect was small on an individual level, though. One extra weekly serving of tomato raised serum urate by about 0.66 micromoles per liter on average.
Meanwhile, official gout diet guidance does not list tomatoes among purine rich foods to avoid. Harvard Health points elsewhere instead. Shellfish, organ meats, and beer remain the real dietary heavyweights.
The study behind the claim
Flynn and colleagues published their findings in BMC Musculoskeletal Disorders in 2015. The paper carries the title “Positive association of tomato consumption with serum urate.”
Their New Zealand gout cohort included 2,051 people with clinically diagnosed gout. Participants came from Maori, Pacific Island, European, and other ancestries.
About 20 percent of that group named tomatoes as a personal gout trigger. That made tomatoes the fourth most commonly reported trigger food.
Seafood ranked first at 65 percent. Alcohol followed at 52 percent, then red meat at 39 percent, then tomatoes.
Testing the claim against real data
Self reported triggers are one thing. The researchers wanted a biological test, so they turned to three separate United States cohort studies.
Combined, those three studies covered 12,720 participants of European ancestry. Each had existing dietary data and blood urate measurements on file.
The researchers ran a combined meta analysis across all three cohorts together. Higher tomato consumption tracked with higher serum urate levels, and the result held up statistically.
The association measured about 0.66 micromoles per liter of added serum urate per additional weekly tomato serving. That result carried a p value of 0.006, well past the threshold researchers use to call a finding real.
The effect showed up in both men and women. It ran somewhat stronger in men specifically.
Two proposed mechanisms
The study authors offered two possible explanations, and neither is a household name. Both come from actual chemistry in the tomato itself.
The first involves phenolic acid compounds naturally present in tomatoes. The authors propose these compounds interfere with the kidney’s organic anion transporters. That transporter system is what normally clears uric acid from the blood.
The second involves glutamate, an amino acid tomatoes contain in high amounts. The authors describe glutamate as capable of acting as a nitrogen donor in the body’s purine synthesis pathway. That donor role effectively feeds the very process that produces urate.
Neither mechanism has been proven through a controlled trial yet. Both are grounded in real tomato chemistry rather than speculation, which is a meaningfully different starting point.
What official gout diet guidance says instead
Harvard Health’s patient guidance on reducing gout risk names shellfish, sardines, and anchovies as carrying the highest purine loads. Red meat follows on that same list.
Tomatoes do not appear anywhere on it. Vegetables in general get framed as part of the recommended eating pattern, not a food group to restrict.
MedlinePlus lists a similar set of high purine foods tied to elevated uric acid. Liver, anchovies, mackerel, red meat, shellfish, dried beans and peas, and beer all appear on that list.
Tomatoes are absent there too. The official guidance and the tomato specific study are not exactly contradicting each other. They are simply not telling the same story with the same emphasis.
Why purine content is not the real story here
Gout diet advice traditionally centers on purine content, since purines break down into uric acid directly. Tomatoes are a low purine food by that standard measure.
That is precisely what makes this study notable. The Flynn team’s proposed mechanisms do not run through the traditional purine pathway at all.
Phenolic compounds and glutamate work through different routes entirely, one blocking excretion and one feeding synthesis. A food can carry real risk for some gout patients without fitting the standard high purine warning label.
What this means in practice
A modest, real, population level association is not the same thing as a guaranteed personal trigger. Averages describe groups, not individuals.
Many gout patients report tomatoes as a trigger. The biology now offers a plausible reason why that might be true for at least some of them. Others with gout eat tomatoes regularly without any noticeable flare.
Tracking personal flares against actual intake remains the most reliable way to know where an individual stands. A food and symptom log over several weeks reveals patterns that population averages cannot.
For anyone with frequent flares who also notices a tomato pattern, testing a temporary reduction is worth trying. It is a reasonable, low cost experiment. Do it alongside a doctor’s broader gout management plan, not as a replacement for one.
Frequently asked questions
Do tomatoes actually cause gout?
No single food causes gout on its own. A 2015 study found a real statistical association between tomato consumption and higher serum urate levels. That is different from proof that tomatoes trigger attacks in every patient.
Are tomatoes high in purines?
No, tomatoes are considered a low purine food. The proposed link to gout in recent research runs through different compounds entirely. Phenolic acids and glutamate drive it instead, not traditional purine content.
Why do so many gout patients blame tomatoes?
About 20 percent of gout patients in a 2015 New Zealand study named tomatoes as a personal trigger. That ranked fourth behind seafood, alcohol, and red meat. Researchers found a real biological association that lends some support to those reports.
Should I avoid tomatoes if I have gout?
Official dietary guidance from sources like Harvard Health does not list tomatoes among foods to avoid for gout. Anyone who notices a personal pattern between tomato intake and flares can reasonably test cutting back. Doing so with a doctor’s input is the safer route.
What foods actually carry the highest gout risk?
Shellfish, organ meats like liver, anchovies, mackerel, red meat, and beer carry the most consistent purine related risk. Official medical guidance is consistent on this point. Those foods remain the primary dietary targets in most gout management plans.
The bottom line: tomatoes and gout share a real, published statistical link. That link does not run through the purine pathway most gout advice focuses on. The 2015 Flynn study found a small, consistent rise in serum urate tied to tomato intake. Phenolic compounds and glutamate appear to drive it, not purine content. Official guidance still centers on shellfish, organ meats, red meat, and beer as the primary dietary risks. For the broader picture on tomatoes and health concerns, see our are tomatoes bad for you guide. For the full case on tomato health benefits, see our tomato health benefits guide.
SOURCES
Flynn, Cadzow, Dalbeth, Jones, Stamp, Harre Hindmarsh, Todd, Walker, Topless, and Merriman: Positive Association of Tomato Consumption With Serum Urate: Support for Tomato Consumption as an Anecdotal Trigger of Gout Flares. BMC Musculoskeletal Disorders, 2015. https://link.springer.com/article/10.1186/s12891-015-0661-8
Harvard Health Publishing, Harvard Medical School: Lifestyle Changes to Reduce the Risk of Gout Attacks. https://www.health.harvard.edu/pain/lifestyle-changes-to-reduce-the-risk-of-gout-attacks
MedlinePlus, National Library of Medicine: Gout. https://medlineplus.gov/gout.html
MedlinePlus, National Library of Medicine: Uric Acid – Blood Test. https://medlineplus.gov/ency/article/003476.htm