Tomato juice is a high-potassium drink. A single 8-ounce cup of canned tomato juice contains 527 mg of potassium, which covers about 11% of the recommended daily intake of 4,700 mg for most adults. That puts it ahead of a banana and makes it one of the more potassium-dense beverages you can pour from a can.
How Tomato Juice Compares to Other High-Potassium Foods
Bananas get all the credit as the go-to potassium food, but a medium banana contains about 451 mg of potassium. One cup of tomato juice beats that by roughly 75 mg, and you can drink it faster than you can peel a banana. A medium baked potato with the skin still on delivers over 900 mg, making it one of the highest single-food sources available. But for a beverage, tomato juice is hard to beat.
The potassium in tomato juice is also more concentrated than in whole raw tomatoes simply because juicing packs more tomato into each serving. One or two slices of raw tomato contain far less potassium than a full cup of juice, which is made from several tomatoes’ worth of pulp. If your goal is to increase potassium intake without eating large volumes of food, tomato juice is an efficient choice.
What Potassium Actually Does for You
Potassium is an electrolyte that helps your muscles contract, your nerves fire, and your heart maintain a steady rhythm. One of its most practical benefits is its relationship with sodium: potassium helps your kidneys flush excess sodium out through urine, which can lower blood pressure. Most adults in the U.S. fall well short of the 4,700 mg daily target, so adding a glass of tomato juice to your routine can meaningfully close that gap.
That said, tomato juice, especially canned varieties, often comes with a significant amount of added sodium. A standard 8-ounce serving can contain 600 mg or more of sodium, which partially offsets the blood-pressure benefits of the potassium. Low-sodium versions are widely available and typically cut that number by more than half. If you’re drinking tomato juice specifically for the potassium, the low-sodium option is the smarter pick.
When High Potassium Is a Concern
For most people, getting more potassium from food is a good thing. But for those with kidney disease, the picture changes. Healthy kidneys filter excess potassium out of the blood efficiently. When kidney function declines, potassium can build up to dangerous levels, a condition called hyperkalemia, which affects heart rhythm and can be life-threatening.
The National Kidney Foundation notes that how much potassium you can safely eat depends on your stage of kidney disease or the type of dialysis you receive. Tomato products, including juice, are commonly flagged on renal diet lists because of their potassium density. If you’re managing kidney disease, the amount of tomato juice that’s safe for you is specific to your lab results and your care team’s guidance, not a one-size-fits-all number.
Getting the Most From Your Glass
Not all tomato-based juices are identical. Vegetable juice blends that use tomato as a base may have slightly different potassium levels depending on what other vegetables are added. Pure 100% tomato juice consistently delivers around 527 mg per cup, so check the nutrition label if you’re tracking your intake closely. Some brands fortify their juice with additional potassium, pushing the number higher.
Tomato juice works well as part of a broader strategy to hit your daily potassium target. Pairing it with other potassium-rich foods like beans, sweet potatoes, spinach, and yogurt throughout the day makes it easier to reach 4,700 mg without relying on any single source. One glass of tomato juice at breakfast gets you roughly a tenth of the way there before you’ve picked up a fork.