If you’ve come across information about a low phosphate diet for chronic kidney disease (CKD) while you’ve been trawling through the internet, you might be wondering: “Do I really need to follow one?”
This is a common question people with CKD have – and it’s no surprise. Phosphate isn’t often discussed by your healthcare team, and it’s not always clear when changes are necessary.
The truth is, not everyone with CKD needs a low phosphate diet. Whether you do depends on your blood test results and guidance from your healthcare team.
In this blog, we’ll take away the guesswork. You’ll learn:
- What phosphate is and why it matters in CKD
- How to know if your phosphate levels are high and when you may need to follow a low-phosphate diet
- Why phosphate additives are more of a problem than natural phosphate in foods
- Simple swaps and tips to keep meals enjoyable and balanced
By the end, you’ll understand when a low phosphate diet is truly needed — and the first steps you can take to keep your kidneys and bones healthy.
What is phosphate and why does it matter in CKD?
Phosphate is a mineral that’s naturally found in many of the foods you eat. Your body needs it for several important jobs: it helps keep your bones and teeth strong, gives you energy, and supports your muscles and nerves to work properly.
In people with healthy kidneys, any extra phosphate that the body doesn’t need is filtered out and removed in the urine. This keeps blood phosphate levels balanced. However, when you have CKD, your kidneys can’t get rid of phosphate as effectively. This means phosphate can build up in your blood — a condition called hyperphosphataemia. This is only usually seen when eGFR < 45 mls/min (KDOQI).
But here’s the tricky part: you can’t always feel when your phosphate is high. So how do you know if it’s a problem for you? Let’s look at how phosphate levels are checked and what signs to be aware of.
What are normal phosphate levels?
Phosphate is measured through a blood test, and normal levels typically range between 0.8 – 1.5 mmol/L (millimoles per litre). Normal ranges may vary slightly between laboratories, so you will need to check your results against the normal range on your blood test results.
Because symptoms often only appear at more advanced stages of kidney disease, it’s important NOT to rely on how you feel to know if your phosphate levels are high. Therefore, regular blood tests to monitor phosphate levels are important, as raised levels can occur without noticeable symptoms.
Symptoms of high phosphate
Potential symptoms can include:
- Itchy & dry skin that doesn’t seem to go away. In addition to treating the high phosphate levels (see below), moisturising regularly with emollient creams, taking cool or lukewarm baths or showers and using unscented skin products may help. In severe cases, your healthcare team may recommend a medication for itching.
- Bone weakness & pain occurs as phosphate levels trigger the release of parathyroid hormone (PTH) which pulls calcium out of the bone. Over time, this can increase the risk of fractures.
- Brittle nails
- Calcium deposits in blood vessels and soft tissue with persistent high phosphate levels, which increases the risk of heart disease.
If you have high blood phosphate levels, you may require treatment for this, such as a low phosphate diet and medication. However, it is important to note that a one-off high or low result doesn’t always mean something is wrong, but consistent imbalances need to be addressed.
How to lower phosphate levels?
The good news is that if you have been advised that you have raised blood phosphate levels, there are ways to manage high phosphate and protect your health. Treatment usually focuses on two main areas:
1. Diet – Reducing foods that contribute to phosphate levels
Since phosphate comes from the food you eat, diet changes are usually the first step. Some foods naturally contain phosphate, while others have phosphate added during processing in the form of additives.
Added phosphates in the form of phosphate additives are absorbed more easily by the body, so they tend to have a bigger impact on blood levels. So learning how to spot these and limiting the amount of processed foods containing these can make a real difference.
2. Medication – Phosphate binders
Sometimes diet alone isn’t enough. In these cases, your healthcare team may prescribe phosphate binders. These are tablets you take with meals to “bind” to the phosphate in your food, stopping some of it from being absorbed into your blood.
- Common examples include Renacet (calcium acetate), Renvela (sevelamer carbonate), Calcichew (calcium carbonate), Fosrenol (lanthanum carbonate) & Renagel (sevelamer hydrochloride)
- They only work if taken at the same time as food
- They don’t replace diet changes, but work alongside them
- You may be prescribed one of the above or a combination
If you would like support with a kidney-friendly diet, why not book a FREE 15 minute enquiry call with an experienced kidney dietitian, to find out how 1:1 support could help you.
Does everyone with CKD Stage 3 and 4 need a low phosphate diet?
It’s important to know that not everyone with CKD Stage 3 or 4 needs to lower the amount of phosphate in their diet. Whether you need to make changes depends on your blood test results and the advice of your healthcare team.
However, as one helpful step in the management of high phosphate levels is to cut back on processed foods, reducing these is a healthy choice even if your phosphate levels are currently in range.
Low phosphate diet
Foods containing phosphate additives
One of the biggest sources of phosphate in modern diets isn’t natural foods – it’s additives. These are forms of phosphate that manufacturers add to processed foods to improve texture, flavour, or shelf life. As these are highly absorbed by the body (more than phosphate found naturally in foods), this should be the first step when following a low phosphate diet.
You’ll often find phosphate additives in:
- Colas and other dark fizzy drinks
- Processed meats such as ham, bacon, sausages, and deli meats
- Processed cheese
- Ready meals
- Packaged snacks
- Bakery items like cakes, pastries, baking mixes and some breads
The problem with these additives is that they are absorbed much more easily by the body compared to natural sources of phosphate. This means they can quickly raise your phosphate levels, even if you don’t eat large amounts.
A simple tip is to check food labels: look out for words containing “phos” (such as phosphate, phosphoric acid, pyrophosphate) in the ingredients list or for the following E-numbers:
- E338: Phosphoric acid (found in cola and fizzy drinks)
- E339: Sodium phosphates (used in processed cheese, meats, and bakery products)
- E340: Potassium phosphates (in processed meats and instant products)
- E341: Calcium phosphates (in baking mixes)
- E343: Magnesium phosphates (used in drinks and supplements)
- E450: Diphosphates (in baked goods, processed meats)
- E451: Triphosphates (in meat and seafood products)
- E452: Polyphosphates (in processed cheese, meats, ready meals)
Cutting back on foods with phosphate additives is one of the most effective ways to reduce phosphate in your diet, and we recommend you start with this if you have been advised to follow a low phosphate diet.
High phosphate foods
In addition to added phosphate, phosphate is also found naturally in some foods. However, you don’t always need to cut these out completely. Furthermore, if you are moderating your protein intake, you are likely to be naturally consuming less phosphate anyway, as many high-phosphate foods are also high in protein. What matters is portion size and balance. For most people with CKD, it’s about choosing smaller amounts and making smart swaps rather than giving these foods up entirely.
Here are some common high-phosphate foods and kidney-friendly alternatives:
1. Meats & Fish
| Higher in phosphate | Swap for |
|---|---|
| Processed meats, eg burgers, sausages, chicken nuggets | Small portions (palm-sized) of fresh beef, lamb, chicken, turkey |
| Organ meats | White fish such as cod or haddock |
| Shellfish eg crab, scallops | Tinned or fresh tuna |
| Some oily fish with very fine bones, eg sardines, white bait | Oily fish such as salmon. A portion of oily fish is still recommended every week for omega-3 fatty acids to protect your heart. |
💡Tip: Make your own burgers with fresh mince (chicken or beef). You can even substitute half the mince with pulses to lower the protein and phosphate content.
2. Milk & milk products
| Higher in phosphate | Swap for |
|---|---|
| Cow’s milk | Plant-based milks |
| Tinned milk | Plant-based milks |
| Hard cheeses (cheddar, parmesan) | Softer cheeses like cream cheese or cottage cheese |
| Yoghurt | Small portions of natural yoghurt |
| Milky puddings | Small portions of natural yoghurt |
| Note: A small amount of cow’s milk can still be used in tea/coffee and cereal (no more than 200 mls/day). |
💡Tip: Check labels on plant-based milks – many contain additives.
3. Baked goods & cereals
| Higher in phosphate | Swap for |
|---|---|
| Shop-bought cakes and pastries containing baking powder | Baked goods without baking powder |
| Bran-based cereals | Cereals such as Weetabix, Shredded Wheat, Shreddies, Multigrain Hoops or Malt Wheats |
| Cereals with large amounts of nuts and seeds | Cereals such as Weetabix, Shredded Wheat, Shreddies, Multigrain Hoops or Malt Wheats |
💡Tip: If buying shop cakes or pastries, look at the ingredient list for both phosphate additives and raising agents such as baking powder. If baking at home, a good alternative to 1 tsp of baking powder is to use ½ a teaspoon of bicarbonate of soda mixed with ½ tsp of cream of tartar.
4. Snacks
| Higher in phosphate | Swap for |
|---|---|
| Chocolate | Small amounts of dark chocolate |
| Snack & cereal bars | Homemade snack bars |
| Large amounts of nuts & nut butters | Unsalted popcorn |
| Rice cakes |
💡Tip: You can still enjoy nut butters sparingly – a thin spread on toast or unsalted crackers goes a long way.
5. Drinks
| Higher in phosphate | Swap for |
|---|---|
| Cola | Water |
| Beer | Flavoured water |
| Hot chocolate made with milk | Squash |
| Some energy drinks | Tea |
| Herbal teas |
💡Tip: If you enjoy fizzy drinks, choose a no-sugar/diet light coloured fizzy drink such as lemonade or orangeade.
Key takeaways
Managing phosphate is an important part of protecting both your kidneys and your bones. But remember, a low phosphate diet is not necessary for everyone with CKD. Changes are usually only needed if your blood tests show high phosphate levels and your healthcare team advises it.
If you do need to take action, start with the basics:
✅ Cut down on phosphate additives – the easiest and most effective first step
✅ Choose lower-phosphate food swaps to keep meals enjoyable and balanced
✅ Watch your portion sizes of high-phosphate foods – balance matters more than cutting everything out
✅ Monitor your phosphate levels
✅ Take phosphate binders appropriately with meals if prescribed
Your blood results are the best guide to whether changes are needed. That’s why it’s so important to check your results regularly and talk to your healthcare team before making big changes to your diet.
Want to understand all your blood results better?
Download our free guide on understanding blood results to learn what they mean and how you can take control of your kidney health.
