We went into this comparison assuming one of the three would turn out to be the salt bomb of the dip shelf. It does not work out that way.
Normalized to the same 30-gram scoop, the three generic dips land at 92, 103 and 128 milligrams of sodium — a spread of 36 milligrams across the entire category. In the terms the label uses, that is 4.0 to 5.7 percent of the Daily Value, and the Food and Drug Administration's own rule of thumb in its guidance on sodium in your diet is that 5 percent or less of the Daily Value per serving counts as low, while 20 percent or more counts as high. All three dips are sitting essentially on that low line, against a daily reference of less than 2,300 milligrams.
There is a small irony in the order. Hummus, the dip most often waved through as the healthy pick, is the highest of the three per scoop. Tzatziki, which tastes the saltiest to most palates because the salt sits on the surface of a cold, tangy base, is the lowest.
Where the Categories Do Separate
Sodium per scoop is a dead end. Sodium per gram of protein is not.
Divide one by the other and guacamole carries 176 milligrams of sodium for every gram of protein it delivers, against 55 for hummus and 59 for tzatziki — roughly a threefold gap, and the only computation in this dataset that produces a decisive ranking. Because it is a ratio, it holds at any serving size, so it does not care whose tub declares 28 grams and whose declares 33.
What it means in practice is straightforward. If a scoop of dip is doing a job in your day beyond flavor, guacamole is asking you to spend the most sodium for the least return on that job. If the scoop is there purely because it tastes good, the ratio is beside the point and the raw number — about a twentieth of a day's sodium — is the only one that matters.