As a renal dietitian, this one kills me! It’s one of the main reasons why a diabetic diet and renal diet seem to be so contradicting. If you have kidney disease and have been told that you can’t eat whole grains, keep reading!
What’s the difference between whole grains and white grains?
Whole grains contain 3 layers: bran, endosperm, and germ. Most of the nutrients present in the grain (fiber, B vitamins, iron, zinc, magnesium, phytonutrients) are located in the germ. When grains are highly processed, the bran and germ are removed. This processing lowers the potassium and phosphorus content, but also removes the important nutrients listed above (1).
Now let’s think about this…Diabetes is the number one cause of Chronic Kidney Disease. When someone has Diabetes, they are recommended to consume minimally processed, high fiber, whole grains over refined, processed, white grains. When someone with Diabetes finds out they have kidney disease, they sometimes receive outdated advice to switch to more processed, lower fiber, white grain products. How does this even make sense and why was it ever recommended?
The renal diet used to solely focus on single nutrients (ex: phosphorus, potassium, sodium). Practitioners forgot how people actually eat. We eat whole foods, composed of many different nutrients. To say one can no longer have whole grains because one nutrient (potassium) is too high fails to take into account the other nutrients (fiber, vitamins, minerals, phytochemicals) that are also present in the food and protective for the kidneys.
Key points to consider:
- Fiber is essential to gut health, digestion, and prevention of chronic diseases. Fiber helps form/bulk stool and prevent constipation. Some potassium is excreted in the stool. So, someone with a low fiber diet is more at risk of constipation and therefore could suffer from decreased elimination of potassium.
- Phosphorus in plant foods (like whole grains) are absorbed less than 50% due to the phytates in plants (2). For this reason, there is really no need to stress over the phosphorus in whole grains. The phosphorus in animal products or processed foods are absorbed at a much higher rate and should actually be what someone limits in their renal diet.
- If we look at the potassium content of whole grain vs white grain products, the difference is not significant enough to warrant switching from whole grain to white products. Yes, white grain products contain anywhere from 40-160 mg less potassium per serving, but there are many whole grains that are still less than 200 mg/serving which categorize them as “low potassium” (barley, bulgur, wild rice, brown rice, millet, farro, oats).
So, can someone on a renal diet eat whole grains?
The answer is YES! You can choose to eat white grains if you prefer that, but there is no reason someone on a renal diet can’t eat whole grains. It is even beneficial to choose whole grains over white grains!
If you need to be more mindful of potassium, that’s where choosing lower potassium whole grains and controlling the portion comes into play. Make sure you work with a specialized renal dietitian so they can help you learn what your nutrient needs are.
If you’re looking for exact kidney nutrition info (potassium, phosphorus, PRAL, protein, etc) for different whole grains, check out my Plant Based E-Guide which includes this detailed nutrition info for over 300 different whole, plant foods!
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