Why You Shouldn’t Avoid Whole Grains If You Have CKD

I recently shared an instagram post on the topic of CKD & whole grains. It contains some pretty useful information if I do say so myself!

But I have a lot more to say about whole grains. So here I am. This is what we’ll cover in this post:

  • Myths floating around online (and in doctor’s office!) about whole grains and kidney disease
  • The new recommendations regarding whole grains and kidney disease
  • A couple caveats when choosing whole grains items
  • Whole grain breads I recommend as a kidney dietitian

Let’s dive in!

What Doctor Google will tell you

Do an online search for “CKD diet” or “kidney disease diet” and you’ll often come across lists that state to choose following foods:

  • white bread and flour tortillas
  • Italian or sourdough bread
  • corn or rice cereals
  • cream of wheat
  • white rice
  • refined flour pasta noodles
  • rice noodles

Just to clarify before we move on – there is nothing wrong with choosing these types of foods. Personally, sourdough bread is one of my favorite things in the whole world, and I love a tofu/vegetable stir-fry tossed with nice noodles. But you don’t need to LIMIT yourself to these types of grains when you have kidney disease!

This is information you’ll find online, though. The very first Google search result for “kidney disease diet” links to a reputable organization that does lots of wonderful work on behalf of people with kidney disease, yet their nutrition information is outdated and probably leading lots of people astray:

As seen online, from a top google search about kidney disease diets. The advice about colas is solid. As for nuts and seeds... we can expand on that in another post!

What you often see online is guidance to limit whole grain foods because they contain a mineral called phosphorus. For people with kidney disease, phosphorus can be dangerous as kidney function declines. Healthy kidneys filter phosphorus out of the blood and then excrete it via urine. But damaged kidneys don’t filter it out, so it builds up in the blood. Over time, this can lead to calcifications – hard deposits that make themselves at home in the soft tissues of the body such as muscles, blood vessels, and the heart. High phosphorus levels in the blood can also lead to weakened bones, increasing a person’s risk for fractures.

The facts that a) whole grains contain phosphorus and b) phosphorus is not great for the kidneys have created a nutrition paradox, whereby people with kidney disease are frequently told that they need to limit whole grains – the exact opposite of what people are typically told about grains and healthy diets.

Doctors learned this same information about kidneys and phosphorus in their medical school nutrition curriculum. But unlike renal dietitians, doctors aren’t necessarily required to complete CEUs on kidney nutrition-related topics, so it’s possible they aren’t aware of the updated information – or, maybe they just aren’t comfortable conveying information that differs from what was the practice standard for a long time.

Regrettably, in my early days as a dietitian, I myself helped perpetuate the idea that whole grains were bad for people with kidney disease. I found a handout I made circa 2014 when I worked at a hospital and needed CKD diet information to share with patients – and yup, it suggested to choose white bread instead of wheat 🙃

Gah! I’m sorry to any patients I shared this information with, early in my career, before I set out on my journey to become a kidney nutrition expert. But now, I’m clearing this up, once and for all.

The NEW way to look at whole grains + the renal diet

The important thing to consider with foods that contain phosphorus is that there are 3 different types of phosphorus:

  • Added/artificial phosphorus
  • Animal phosphorus
  • Plant phosphorus

The difference here is that plant and animal foods, straight from the ground/farm, naturally contain some phosphorus. This is called “organic phosphorus.” On the flip side, processed foods (such as colas, “enhanced” meats, flavored waters, many shelf stable breads, packaged pastry or snack items) typically contain some artificial, added phosphorus as a food additive. This is called “inorganic phosphorus.”

Inorganic or added phosphorus is not added to enhance the nutritional content of these foods – rather, it’s there as a food additive. As a food additive, phosphorus can do many things – improve texture, prevent separation of ingredients, and promote longer shelf lives, to name a few. The bad news is that this artificial phosphorus is 100% absorbed by the body, and as we discussed above, too much phosphorus in the blood can be a BIG problem for people with kidney disease.

What about the phosphorus in animal and plant foods? Natural phosphorus is absorbed by the body to a lesser extent. About 40-60% of the phosphorus found in animals foods (such as unenhanced meats, milk, and cheese) is absorbed. Phosphorus in plant foods is stored by a compound called phytates, which makes much of the phosphorus inaccessible for us humans to absorb/digest into the GI tract. Only about a third of plant-based phosphorus is actually absorbed by the body. Only a third!

This means – for example – if the nutrition label for a whole wheat bread (without any artificial phosphorus added) lists 200 mg of phosphorus per serving, we really only get ~66 mg of phosphorus from it. That is a BIG difference. And that’s BIG news for people with kidney disease!

Some caveats to consider

I hope you are feeling excited about starting to include more whole grains in your diet! 🎉 Brown rice, oatmeal, and whole wheat breads are excellent foods to keep on hand in your kidney friendly pantry! But wait… before heading to the store and grabbing just any whole wheat bread off the shelf, there ARE a couple other things about bread in particular to keep in mind.

  1. The first thing to consider is that whole grain items such as breads (and tortillas, crackers, flavored oatmeal packets, etc) can still have ADDED phosphorus on the ingredient list as well. This means in addition to the NATURAL, organic phosphorus found in the whole grains, the food manufacturer might have added additional, artificial phosphorus for one of the reasons addressed above – improved shelf life, improved texture, etc. It’s important to look at the ingredient label and watch out for ingredients containing “phos” – for example: polyphosphate, tricalcium phosphate, hexametaphosphate, trisodium phosphate. This is not a comprehensive list – just know an ingredient containing phos means, well, there is definitely some added, artificial phosphorus in the food.
    Ingredients in a popular brand of bread
  2. Next point of consideration: whole grain foods such as breads can still contain a lot of sodium. Sodium is another mineral to be mindful about when you have kidney disease. In general, about 1500-2000 mg a day is recommended, but speak with your doctor or dietitian for individualized recommendations.

Good whole grain options for kidney disease to look for next time you're at the store

By the way… I’m NOT about to peace out now and just leave you alone to scour the labels of every item in the bread aisle at the store! Here are a few breads I like that meet the criteria I’ve laid out about, to help get you started:

Don’t forget to consider fresh-baked breads from a local bakery, or from the bakery section of the grocery store. These are less likely to contain added phos than most ones you’ll find in the bread aisle of the store. These breads may or may not have a nutrition facts label (something to think about when limiting dietary sodium…), but they should at least list the ingredients.
 
I hope this information leaves you breathing breaths of relief and feeling free to continue choosing whole grains in your diet! Foods like whole grain breads, brown rice, and oatmeal are RICH in fiber, healthy B-vitamins, and have proven associations with good heart health. Don’t let the fear of phosphorus keep you away from these nutrient-dense foods!   — Kate, Your Kidney Dietitian

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