Are tomatoes acidic? (the PARC index)

In this blog post, we will answer the following question: Are tomatoes acidic? We will turn to science, especially to the PARC index, in order to establish the acidity of the tomato. We will also provide you with great tips to reduce tomato sauce acidity. 

Are tomatoes acidic?

Are tomatoes really acidic or is this a common myth? Let’s find out. Traditional Chinese Medicine, which for centuries has considered food to be medicine in its own right, has always said that tomatoes are not acidifying but that they could partly become acidifying for certain organisms, depending on the gastric juices secreted and the level of hydrochloric acid in the stomach.

However, there is no recognized way, even if it is not perfect, to measure whether food has an acidifying or alkalizing effect (alkalizing is more often used) in the body.

This method is called the PARC index, which means: Potential Acid Renal Charge.

From a urinalysis, it is determined whether the minerals found are mostly acidic or mostly alkaline (ie basic). It also depends on one’s metabolism of course.

  • An acidifying food will have a PARC index greater than zero.
  • An alkalizing food will have an index less than zero.
  • An index equal to zero corresponds to neutral foods.

What about our tomatoes? index of -3.71 (average)

  • Lemon, raspberry, raw cucumber: between -2 and -3
  • Melon, raw carrot, potato, lettuce: between -5 and -6
  • Avocado: -8.19 and turmeric: -46!
  • In contrast, the index for brown rice is 1.05.
  • That of a fried egg is 7.88.
  • A prime rib of 11.16 and roast chicken of … 15.44
  • Brie cheese: 11 

These calculations, which vary, are obviously only orders of magnitude.

But we may better understand why, among other things, vegetarians are much less prone to colon cancer than meat-eaters. And they’re much less prone to overweight and cellulite as well.

Detected by the taste receptors of the tongue, the acidity brings liveliness to food. You find it markedly in lemon, vinegar, underripe fruits… and this flavor automatically makes you salivate!

If you like the acidity in tomatoes, go for round tomatoes or cherry tomatoes, the latter being both sour and sweet.

On the contrary, if you are running away from the acidic flavor, choose heart tomatoes instead.

 When cooking, a pinch of sugar will soften the acidity of the tomatoes: think about it!

 So that your tomatoes do not become acidifying:

  • buy them ripe as much as possible
  • buy them as unprocessed, as much as possible
  • eat them fresh, without processing (in cans, jars, tubes!)
  • avoid eating them cooked, as they can become extremely acidifying. Even if in recent years studies have shown that lycopene in tomatoes, a powerful anticancer, is better absorbed when cooked.

Other FAQs about Tomatoes which you may be interested in.

How do you peel a tomato?

Are canned tomatoes already cooked?

Can You Eat Raw Green Tomatoes?

How to remove acidity from tomato sauce?

Tomato sauce is widely used in many cooking recipes. But when you prepare it at home, it can be too acidic. Here are our tips for removing acidity from the tomato sauce.

For pizzas, pasta, rice, meat, fish … tomato sauce is undoubtedly one of the most used sauces to accompany dishes in the kitchen. And it’s even better homemade. But did you know that if you crush your tomatoes, your sauce is likely to be sour? Indeed, once broken, the seeds of the tomato release all their acidity. If that happens, don’t panic! 

Use sugar, carrots, or dates to reduce the acidity from the tomato sauce.

You are preparing a tomato sauce for your arrabbiata penne or your margarita pizza, and like any good cook, you taste your work. But there, woe! You wince because your tomato sauce is too sour. Don’t worry, it happens even to the best. To rectify this inconvenience, add sugar to your tomato and too acidic preparations. Indeed, the sugar takes over the acidity and neutralizes it. 

But be careful not to use too much, at the risk of having a tomato sauce with a taste too sweet. Depending on the amount of your sauce, add a piece of sugar, or two to your preparation.

If you are not consuming sugar, there are other, more healthy alternatives. If it is too acidic, add a whole carrot (or two, depending on the amount of sauce) to your tomato sauce preparation. The carrot is sweet, so letting it boil with the preparation will release this sugar which will neutralize the acidity of the tomato. 

Note that a straight, hard, orange-colored carrot will be sweeter than a slightly older carrot. Likewise, the sugar level will be higher if the carrot comes from a bunch that has retained its greenery.

You can also add half a date (or a whole date, depending on the amount of sauce). It is also sweet, it will have the same role as the carrot in your preparation.

Baking soda to remove the acidity from the tomato sauce

Practical in the kitchen, in the garden, for the maintenance of the house, it also has health benefits and it contributes to animal hygiene … baking soda is our best friend!

This handyman powder neutralizes the acidity of foods with an overly acidic pH that your stomach might not take well, and which is not very palatable. Whether it’s tomato sauce, fruit coulis, or jams, you can reduce the acidity with a little baking soda. Just add a pinch or two to the tomatoes while cooking or while reducing the sauce, and voila!

The bottom line 

So, are tomatoes acidic? 

The truth is, even though the PARC index shows that tomatoes are not acidic, many people believe that this product, especially tomato sauce, is high in acidity and can cause heartburn. 

This is why we provided you with the simplest tips to neutralize the acidity in tomato sauce, and remember: moderation is the key in everything!


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.