Tomatoes are often considered a healthy and nutritious food, but if you’ve been researching what to eat with CKD, you might have come across confusing advice—some sources say tomatoes should be avoided altogether, while others don’t mention them at all. So, are tomatoes bad for your kidneys?
The good news? You don’t necessarily have to give up tomatoes completely (and for some people, you don’t have to give them up at all!) This blog post will help answer any questions you might have about tomatoes and help you understand how they can fit into a kidney-friendly diet.
Nutrients in tomatoes
Tomatoes are naturally low in calories, making them a great addition to a balanced diet without adding excess energy. They’re packed with vitamins, minerals, and antioxidants, offering several health benefits for people with CKD Stages 3 and 4:
- Vitamin C: Supports your immune system and helps your body absorb iron from plant-based foods.
- Folate: Helps your body make new cells, supporting overall health and healing.
- Vitamin K: Helps your blood clot properly when you get a cut and plays a role in keeping your bones strong.
- Lycopene: A powerful antioxidant that may help reduce inflammation and protect against heart disease, which is especially important for people with CKD.
- Fibre: Supports gut health and helps regulate blood sugar levels, which is essential if you have diabetes.
Do tomatoes have potassium?
While tomatoes have many health benefits, they do contain potassium. Potassium is a key mineral that helps your muscles and heart function properly. However, as kidney function declines, or when you are on certain medications, the kidneys may struggle to remove extra potassium from your blood. This can lead to raised potassium levels.
That being said, not everyone with CKD needs to follow a low-potassium diet, and therefore, not everyone needs to limit tomatoes in their diet. If you need to follow a low-potassium diet, your healthcare team would have told you so. There is NO advantage to being on a low-potassium diet when you don’t need to be.
Are tomatoes bad for kidneys?
We often hear people with CKD asking questions like this. It’s easy to fall into the habit of labelling foods as “good” or “bad”—especially when so much information online tells you what to avoid. We don’t believe in calling foods “bad” because this can make eating feel stressful and restrictive.
The truth is, rarely is a single food 100% off-limits if you have CKD. What matters most is portion size, balance and how food fits into your overall diet. Instead of thinking of foods as “good” or “bad,” we encourage you to ask:
✅ How can I include this in a way that supports my kidney health?
✅ Are there adjustments I can make to enjoy it safely?
✅ What are some great tasting alternatives if I need to limit it?
Taking this approach removes guilt from eating and helps you build a more positive, flexible relationship with food – because food should be enjoyable, not a source of stress!
So with that said, let’s help you decide whether you can eat tomatoes freely or whether you should limit them.
Who can eat tomatoes freely
✔ If your potassium levels are within the normal range and your healthcare team hasn’t advised you to limit potassium, you can enjoy tomatoes as part of a healthy diet.
Who should limit tomatoes
❌ If you have raised potassium levels or your doctor/dietitian has recommended a low-potassium diet (e.g. if you’re on medications that increase potassium levels), you may need to limit the amount of tomatoes you eat.
💡 Good news! Even if you need to watch your potassium, you don’t have to give up tomatoes completely. Keep reading to learn how you can still enjoy tomatoes in a kidney-friendly way.
We get asked a lot about tomatoes in our 1:1 consultations. If you would like to know more about what else you can eat that’s good for kidney health, why not book a FREE 15 minute enquiry call to chat with a kidney specialist dietitian to see how 1:1 support can help you.
Tomatoes and tomato products: How much potassium do they have?
Tomatoes come in many different forms, from fresh whole tomatoes to tomato-based products like ketchup and pasta sauces. The potassium content varies depending on how the tomatoes are processed.
Here’s a breakdown of common tomato products and how they fit into a kidney-friendly diet:
✅ Better choices (lower in potassium)
✔ Raw tomatoes: Fresh tomatoes have less potassium than ready-made tomato sauces. Enjoy them in moderation.
✔ Cherry tomatoes: A great option for portion control! About 7 cherry tomatoes contain the same amount of potassium as 1 medium-sized tomato.
✔ Tinned whole/chopped tomatoes: Can be included in small portions. Use 1 tin for 4 servings and drain the juice before cooking to reduce potassium. Tip: It’s easier to drain the juice with a tin of whole tomatoes.
✔ Homemade tomato sauce: Use 1 tin of chopped tomatoes for 4 portions, and mix with slow-cooked onions, garlic, some olive oil and oregano to create a delicious, kidney-friendly sauce.
🚫 Higher potassium tomato products (eat in moderation or avoid if needed)
❌ Tomato purée/paste: A very concentrated source of potassium. Best to avoid if you’re on a low-potassium diet – especially if you’re already using tomatoes in the dish.
❌ Tomato-based ready-made pasta sauces: Many store-bought sauces are high in potassium, salt and sugar. Instead, make your own (using the suggestion above!).
❌ Tomato ketchup: Can be eaten occasionally in small amounts (no more than 1 tablespoon) but look for lower-salt varieties.
❌ Sun-dried tomatoes: Very high in potassium, so use in tiny amounts. Avoid adding other tomato products to the same meal. Bonus tip: they are packed full of flavour so a small amount goes a long way.
❌ Tomato juice: A very concentrated source of potassium and usually high in salt! Best avoided if you need to limit potassium.
❌ Tomato soup: With tomatoes or tomato puree making up around 90%, this is a high-potassium dish and should be avoided.
Practical tips for enjoying tomatoes safely
If you love tomatoes, here are some kidney-friendly ways to include them in your diet without overloading on potassium:
- Stick to small portions: A few cherry tomatoes in a salad or a couple of slices in a sandwich can add flavour without too much potassium.
- Choose fresh over concentrated: Fresh tomatoes have less potassium than ready-made tomato sauces and purées.
- Balance your meal: If you eat tomatoes, pair them with lower-potassium foods to keep your potassium intake in check.
- Drain tinned whole/chopped tomatoes: Rinse and drain before cooking to remove some of the potassium.
- Dilute sauces: Mix tomatoes with low-potassium ingredients like onion, red pepper, carrots and garlic to stretch the portion and add more flavour.
A kidney-friendly tomato-style soup recipe (and some extra meal suggestions!)
Since tomatoes are so versatile, you’ll likely find them in many of your favourite dishes (and we don’t want you to miss out!). Here’s how to make them more kidney-friendly without losing their distinct taste!
Roasted Red Pepper Soup - A kidney-friendly alternative to a classic tomato soup
Serves 2
Traditional tomato soup is off the table for many with CKD due to its high potassium content – that’s where this roasted red pepper soup comes in! A warm, comforting and lower-potassium alternative that’s still packed with flavour.
Red peppers offer the same vibrant colour and satisfying tang as tomatoes, but with a gentler potassium load – making them a smart swap if you’ve been advised to limit potassium. This version also uses no added salt, a splash of heart-healthy rapeseed oil, and is finished with a swirl of pesto and crème fraîche for richness. It’s ideal for batch cooking and easy to freeze, so you can enjoy it anytime.
Ingredients
- 3 large red bell peppers, chopped
- 2 garlic cloves
- 1/2 tbsp rapeseed oil
- 1/2 yellow onion, finely chopped
- 2 sun-dried tomatoes
- 300 mls very low salt or zero salt vegetable stock
- 1 tbsp pesto
- 1 tbsp full-fat crème fraîche
Method
1. Preheat oven to 200°C (180°C Fan/Gas Mark 6).
2. Roast the peppers and garlic: Place chopped red peppers and whole garlic cloves on a baking tray. Drizzle with half of the oil and season with black pepper if desired. Roast in the oven for around 40 minutes until slightly charred.
3. Sauté the onion: Meanwhile, heat the remaining oil in a pan and sauté the chopped onion until soft.
4. Combine ingredients: Add the roasted peppers, garlic, sun-dried tomatoes and prepared stock to the pan. Simmer gently for 10 minutes.
5. Blend: Turn off the heat and carefully blend the mixture until smooth using a blender.
6. Finish and serve: Ladle the soup into bowls and swirl in the pesto and crème fraîche.
Serving suggestion
Pair with a slice of wholegrain bread or homemade bread for a filling and balanced lunch.
Storage
- Keeps in the fridge for up to 2 days.
- Can be frozen for up to 3 months.
🍝 Lower-Potassium Marinara Sauce – A Savvy Swap for Pasta Lovers
Tomato-based sauces are a go-to in many kitchens, but they can be surprisingly high in potassium so this simple lower-potassium marinara sauce keeps all the Italian-inspired flavour without overloading your kidneys.
✔ Use 1 tin of chopped tomatoes for 4 portions.
✔ Add onion, garlic, olive oil, and oregano for flavour.
✔ Mix in carrot purée to reduce potassium and add natural sweetness.
🍕 Kidney-friendly pizza - Keep the flavour, ditch the excess potassium
Craving pizza? You don’t have to miss out. Making pizza at home is a brilliant way to keep your meals delicious and kidney-friendly. By using a small amount of tomato on the base and choosing lower salt, lower potassium toppings, you can enjoy this classic dish without worry.
✔ Use a small amount of chopped fresh or tinned tomatoes on the base.
✔ Skip tomatoes altogether with a tomato-free pizza topping such as bechamel sauce.
✔ Choose lower salt, lower potassium toppings, such as:
- Cheese: Mozzarella or ricotta (lower in potassium and phosphate).
- Protein: Shredded chicken, fresh ground beef, or tuna.
- Veggies: Peppers, onions and sweetcorn (low potassium)
Key takeaways
Tomatoes can still be part of a kidney-friendly diet so you can still enjoy the flavours you love without stress or guilt.
Here’s what to remember:
✅ Tomatoes contain potassium, but not everyone with CKD needs a low-potassium diet. Always follow the advice from your healthcare team.
✅ Portion control matters – you can enjoy tomatoes in small amounts, especially if you choose fresh or less concentrated forms.
✅ Fresh, cherry, and tinned (drained) tomatoes are generally lower in potassium and more suitable for a kidney-friendly diet than tomato paste/purée or prepared tomato sauces.
✅ Making your own sauces by combining small portions of tomatoes with kidney-friendly ingredients like onion, garlic, red pepper, and carrot is a great way to enjoy the flavour of tomatoes without as much potassium.
✅ You don’t need to give up your favourite tomato-based meals – with a few simple swaps and adjustments, you can enjoy them in a kidney-friendly way.
Take the Guesswork Out of Kidney-Friendly Eating!
If you’re looking for more low-potassium meal ideas, our CKD Stage 4 – 7 Day Meal Plan is designed to make eating easy, delicious and stress-free. It includes:
🍽️ Kidney-friendly recipes tailored for CKD Stage 4
🍽️ Portion guidance to help you safely enjoy your favourite foods
🍽️ Balanced meal plans to support kidney health without feeling restricted
👉 Click here to buy your CKD Stage 4 – 7 Day Meal Plan today and enjoy food without worry!
