This page about tomatoes and gout was last reviewed or updated on 24 November 2015
In centuries before the 20th, tomatoes were considered poisonous in many countries. Actually it wasn’t the tomatoes, but the tomato plant’s leaves. These days there are gout sufferers who think that tomatoes trigger gout attacks.
In fact a lot of gout sufferers think they cause gout attacks, although studies have shown that tomato juice and sauce usually do not raise uric acid, or not by very much. In one that raised it by 0.77 mg/dL (46 umol/L - a decent amount), it was tomato sauce that was tested. Tomatoes themselves, (not juice, sauce etc), have even lowered uric acid by 0.17 mg/dL.(10 umol/L) in a small number of young women.
In other words there is no trial pattern of tomatoes or derivatives raising uric acid by good amount and consistently.
So,just as it is hard to see why tomatoes were once thought poisonous, it’s also hard to see why tomatoes cause gout.....when you examine their ingredients.
Tomatoes and uric acid To raise uric acid over the years, a food must be high or moderate in purines. Or high in the carbohydrates and sugars (which are a carbohydrate) that can lead to gout over time through the insulin resistance route. Or cause dehydration, a body state that can trigger a gout attack. Caffeine, and especially alcohol, do this but tomatoes are around 90% water.
But tomatoes are very low purine, and don't have many net carbs, (total carb grams minus the grams of fibre/fiber). This is the carbs number that matters. And if you prefer a low calorie/low fat diet they aren’t high in calories. If you eat more alkaline foods to alkalise (alkalize) the body in the hope of expelling more uric acid, note the pH of tomatoes (below). So their nutrition profile makes them one of the good gout diet foods, whichever kind of diet you attempt.
100 grams of raw red tomatoes, uncooked. GI is the Glycemic Index. On the GI, low is good, medium is not bad, high is poor.
Fibre (fiber): 1.2g.
Net carbs: 2.7g.
pH: Raw, uncooked tomatoes are alkalising (alkalizing). If cooked, they become mildly acidic in the body once metabolized.
Other ingredients good for gout: Potassium 237 mg per 100 grams.
Furthermore, a very large study of men who got gout found that the purines in fruits and vegetables (even high purine ones) do not raise the risk of gout. It was purines in other foods that do. So unless there’s something else in tomatoes, it’s hard to see why they cause gout attacks.
They are of course a food (in the
nightshades family) to which many are allergic. And because they have an
acidic effect when cooked, it's possible that tomatoes themselves
might cause a
more acidic body which could mean less uric acid is expelled. (i.e. the
opposite of the alkalinity to dilute more uric acid argument). But most
gout sufferers, those who do not attempt an alkaline body solution, will
be eating many acidic foods. So it's hard to see only tomatoes causing
higher body acidity,unless you eat a lot without anything else.
Moreover, in a study of the effects of alkaline and acidic foods, 26 women who raised their urine pH, raised their uric acid excretion - a positive event in gout treatment - with a more alkaline diet. They ate 120 grams (4.23 ounces) a day of tomatoes whilst they did this.
Cooking tomatoes releases their lycopene, which is promoted as good for many health conditions, although I don't think it has any effect on the gout problem.
Nevertheless many gout sufferers think tomatoes cause gout flares. If any reader is convinced tomatoes are bad for gout and caused their gout attack, perhaps because you ate cooked tomatoes a few times before your gout attack, we'd love to hear from you. Please tell us your story about tomatoes and gout using our contact us form.
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