Check the ingredients. Many brands add citric acid as a preservative, which spikes the acidity. Look for brands that use only tomatoes and salt.
When you're browsing the aisles, keep these keywords in mind to find the best options: buy canned low acid tomatoes
These are the gold standard. Grown in volcanic soil, they are naturally lower in acid and higher in sugar. Check the ingredients
Sold in sealed bricks rather than cans, these contain no added preservatives or citric acid. buy canned low acid tomatoes
Yellow canned varieties are almost always less acidic than their red counterparts.