Are Grits Good for Kidney Disease?

Grits can fit into a kidney-friendly diet, but whether they help or hurt depends on the type you choose, how you prepare them, and what else you pile on the plate. Plain grits are relatively low in potassium and moderate in phosphorus, which puts them in a reasonable position compared with many other starches. The more interesting story is what happens to grits’ minerals during processing and cooking, and how the broader dietary pattern they belong to has been linked to worse kidney outcomes in one large study.

The Phosphorus Question

Phosphorus control is one of the central dietary challenges when your kidneys aren’t filtering well. As kidney function declines, excess phosphorus accumulates in the blood and can contribute to bone disease and cardiovascular problems. This is where grits have a quiet advantage over many animal-based foods: the phosphorus in corn is mostly bound up in a compound called phytate, and phytate-bound phosphorus is harder for your body to absorb than the phosphorus in meat, dairy, or eggs.

That said, the advantage isn’t as large as renal dietitians once assumed. Older estimates suggested that only about 10 to 30 percent of phytate-bound phosphorus gets absorbed, but more recent evidence from human studies suggests the true figure is at least 50 percent. Food processing, gut bacteria that can break down phytate in the colon, and the colon’s own ability to absorb phosphorus all push that number higher than the textbook figure.¹ So while grits still deliver less absorbable phosphorus per gram than a piece of cheese or a chicken breast, the gap is narrower than many kidney-diet resources suggest.

How Nixtamalization Changes the Picture

Grits aren’t just ground raw corn. Traditional grits are made from hominy, which means the corn kernels have been soaked in an alkaline solution, usually lime water, in a process called nixtamalization. This ancient technique softens the hull, improves texture, and has some meaningful effects on nutrition: it increases the bioavailability of niacin, calcium, and iron, and it reduces certain contaminants and compounds that can interfere with nutrient absorption.²

For kidney patients, the relevant catch is this: nixtamalization also breaks down some of the phytate in corn. Since phytate is the very thing that keeps phosphorus from being fully absorbed, removing it can make the remaining phosphorus more available to your body. In other words, the processing that makes grits taste better and adds calcium may slightly undercut the phosphorus advantage that plant-based grains usually hold over animal foods. This doesn’t make grits a high-phosphorus hazard, but it’s worth knowing that they aren’t quite as “locked up” on the phosphorus front as, say, unprocessed whole wheat or brown rice.

The trade-off goes the other direction for food safety: nixtamalization reduces mycotoxins, which are mold-derived contaminants that corn is prone to. Some mycotoxins, particularly ochratoxin A and fumonisin B1, can damage kidney tissue directly.³ Grits’ traditional processing step essentially lowers the risk of those kidney-harming compounds before the product ever reaches your bowl.

The Southern Dietary Pattern Problem

Grits are deeply associated with Southern US cooking, and that association carries some nutritional baggage that has nothing to do with the grits themselves. A large cohort study tracking people with chronic kidney disease found that those whose diets most closely matched a “Southern” eating pattern had roughly 50 percent higher mortality risk compared with those who ate the least Southern-style food. Meanwhile, those who ate more plant-based foods had about 23 percent lower mortality risk.⁴

The Southern pattern in that study was defined by fried foods, organ meats, processed meats, sweetened beverages, and added fats alongside staples like grits. So the mortality signal isn’t coming from grits specifically. It’s coming from the full pattern. If you eat grits loaded with butter, cheese, bacon bits, and a side of sweet tea, the grits are the least of your kidney worries. If you eat them plain or topped with vegetables, you’re closer to the plant-based pattern that performed well in the same study. This distinction matters because some people hear “grits are bad for kidneys” and give up a food they enjoy, when the real culprit is everything they put on top of them.

Interestingly, neither the Southern nor the plant-based dietary pattern was associated with progression to end-stage kidney disease in that study. The mortality difference was real, but it didn’t translate into a clear link with needing dialysis or transplant. That suggests the harm from a Southern-style diet in CKD likely runs through cardiovascular and metabolic pathways rather than through direct kidney damage alone.

Resistant Starch and Kidney Health

One genuinely promising angle for grits involves resistant starch, a type of carbohydrate that passes through the small intestine without being digested and feeds beneficial bacteria in the colon. Corn is a natural source of resistant starch, and the amount increases when cooked grits are cooled and reheated, a process called retrogradation.

In chronic kidney disease, the gut microbiome shifts in unfavorable ways. Certain gut bacteria produce uremic toxins, compounds like indoxyl sulfate and p-cresol sulfate, that healthy kidneys would normally clear. When kidney function drops, these toxins build up and contribute to inflammation, cardiovascular damage, and further kidney deterioration. Resistant starch appears to partially counteract this. Animal studies and small human trials have shown that resistant starch supplementation reduces levels of these toxins. In hemodialysis patients, supplementation lowered both indoxyl sulfate and p-cresol sulfate levels.⁵

A meta-analysis of randomized controlled trials confirmed this direction: resistant starch supplementation significantly lowered indoxyl sulfate and blood urea nitrogen in CKD patients.⁶ The effect sizes were modest, but the consistency across trials suggests this is a real phenomenon, not a statistical fluke. The resistant starch in a typical bowl of grits is far less concentrated than what’s used in supplement form in these studies, so you shouldn’t expect a bowl of grits to act like a therapeutic dose. Still, it counts toward the broader goal of feeding your gut bacteria in a way that reduces toxin production.

Why Acid Load Matters

Your kidneys play a central role in maintaining your body’s acid-base balance, and when they’re compromised, excess dietary acid can accelerate kidney function decline. Grains in general, including corn-based products like grits, are acid-producing foods. The metabolic byproducts of digesting grains contribute a net acid load to your system. By contrast, fruits and vegetables are alkaline-producing: research has shown that a fruit-and-vegetable-heavy diet produces roughly 60 percent less net acid than a standard diet, even when protein intake stays the same.⁷

This doesn’t mean grits are an acid bomb. Their acid contribution is modest per serving. But if grits are your primary starch at multiple meals, without balancing them with fruits and vegetables, the cumulative acid load can matter. The practical takeaway is simple: pair grits with produce. A serving of grits alongside sautéed greens or sliced tomatoes accomplishes both goals, keeping the starch portion reasonable while adding alkaline-producing counterbalance. For CKD patients in later stages who are actively managing metabolic acidosis, this kind of meal-level thinking can complement whatever bicarbonate supplementation their doctor has recommended.

Potassium and Preparation Tips

One of grits’ clearest selling points for kidney patients is their low potassium content. A standard cooked serving of plain grits contains far less potassium than popular alternatives like baked potatoes, sweet potatoes, or brown rice. For people in later stages of CKD who need to limit potassium, grits are one of the safer starch options available.

If you want to lower the mineral content further, soaking is an effective technique. Research on various food groups has shown that soaking grains reduces potassium by 40 to 49 percent and phosphorus by 30 to 39 percent.⁸ For grits, you can soak the dry grits in water for several hours, drain the water, then cook as usual with fresh water. This leaches out a meaningful fraction of the minerals you’re trying to avoid. The texture may soften slightly, but the difference is minor.

Beyond soaking, the biggest preparation variable is what you add. Here’s where kidney patients need to be disciplined:

Cheese and butter: These add phosphorus, sodium, and saturated fat. If you must add cheese, use a small amount and choose a lower-phosphorus variety.
Instant packets: Pre-flavored instant grits often contain sodium phosphate additives, which are far more absorbable than the natural phosphorus in corn. Additive phosphates can be absorbed at close to 100 percent, erasing the bioavailability advantage of plant-based phosphorus entirely. Always check the ingredient list for anything with “phosphate” in the name.
Salt: Plain grits are naturally low in sodium. Adding salt at the stove or table quickly turns them into a high-sodium food, which contributes to fluid retention and high blood pressure, both of which worsen kidney disease.

Stone-ground or regular grits with minimal added ingredients are the safest choice. The ingredient list should ideally be one word: corn.

Instant Versus Stone-Ground Grits

Not all grits are created equal, and the processing differences go beyond texture. Instant grits have been pre-cooked and dehydrated, which speeds up preparation but also changes the nutritional profile. The pre-cooking process degrades more of the phytate, which means the remaining phosphorus is more bioavailable. Instant grits are also more likely to contain added sodium and phosphate-based additives used as stabilizers and flavor enhancers.

Stone-ground grits retain more of the whole corn kernel, including the germ and hull, which means they have more fiber and resistant starch. They also retain more phytate, keeping their phosphorus in a less absorbable form. The trade-off is cooking time: stone-ground grits take 20 to 45 minutes on the stove, compared with a few minutes for instant varieties. For kidney patients who have the time, stone-ground grits are the better option on almost every metric that matters, including lower sodium, more fiber, more resistant starch, and less absorbable phosphorus.

Quick grits fall somewhere between instant and stone-ground. They’ve been ground finer and partially processed, which cuts cooking time to about five minutes. They’re a reasonable middle ground if stone-ground isn’t practical for your morning routine. Just read the label carefully. Some brands add salt or enrichment minerals that kidney patients don’t need.

Corn Mycotoxins and Kidney Safety

Corn is one of the crops most susceptible to mycotoxin contamination, and this is worth mentioning for people whose kidneys are already vulnerable. Ochratoxin A and fumonisin B1 are among the mycotoxins found in corn products, and both have documented kidney-damaging properties. In some regions, chronic low-level mycotoxin exposure has been linked to a specific pattern of kidney disease in both livestock and humans.³

In practice, the risk from commercially produced grits in the United States and Europe is low. Food safety regulations set limits on mycotoxin levels in grain products, and the nixtamalization process used to produce hominy grits further reduces mycotoxin concentrations.² The concern is more relevant for people who consume large quantities of corn products sourced from regions with less stringent grain safety oversight, or who use home-ground corn that hasn’t been tested. If you’re eating grits daily, buying from a reputable brand that meets national food safety standards is a simple way to minimize any residual mycotoxin exposure.

Putting Grits in Context with Other Starches

If you’re choosing a starch for a kidney-friendly meal, grits compare favorably on several fronts. White rice is similarly low in potassium and phosphorus, but it lacks the resistant starch content of grits, especially stone-ground or cooled-and-reheated grits. Oatmeal is higher in both phosphorus and potassium. Potatoes are notoriously high in potassium unless extensively soaked and boiled, and even then they remain higher than grits. Bread varies enormously depending on whether it’s white or whole wheat and whether phosphate additives are present, but many commercial breads contain added phosphates that grits avoid entirely.

Where grits fall short is the acid-load comparison. Starches from plant sources like potatoes and sweet potatoes are closer to neutral or mildly alkaline, while grain-based starches including grits are mildly acid-producing. For people managing metabolic acidosis in advanced CKD, this trade-off may tip the balance toward root vegetables prepared with proper potassium reduction techniques. For earlier stages, the acid contribution from grits is modest enough that balancing with a vegetable side dish handles the issue.

The biggest variable isn’t which starch you pick. It’s what the rest of your plate looks like. A meal built around plain grits, sautéed vegetables, and a small portion of plant or lean animal protein hits the targets that kidney dietitians generally recommend: controlled phosphorus and potassium, moderate protein, low sodium, and reasonable acid balance. A meal of cheese grits with bacon and a biscuit gets you the Southern dietary pattern linked to worse outcomes, and no amount of starch-swapping fixes that broader problem.