Doctors Are Begging You to Avoid Walnuts If You've Ever Suffered From This Common Medical Issue
When it comes to, uh, “getting your digestive system moving” in the morning, fighting inflammation, improving brain health and lowering your risk for disease, walnuts are a great go-to. So, when choosing what to eat for breakfast, consider adding walnuts to oatmeal or making a coffee shop treat with walnuts. As perhaps the “gold standard” of healthy nuts, dare we say…go nuts with walnuts?
Doctors agree that walnuts are packed with benefits, noting they're high in alphalinolenic acid (ALA), a food high in omega-3s and that they include anti-inflammatory effects. “By decreasing inflammation, it supports the health of several systems in your body, including the cardiovascular, gastrointestinal and endocrine systems,” says Dr. Chidozie Odigwe, DO, a nephrologist specializing in kidney health. “It decreases your risk for heart disease…Walnuts promote gut and brain health, and its anti-inflammatory ability seems to also decrease a person’s risk for cancer.”
Dr. Jennie Stanford, MD an obesity medicine physician, adds that the omega-3 fatty acid can improve cholesterol, and the antioxidants can reduce oxidative stress. In addition, she says, walnuts contain fiber (which helps the gut microbiome) and contribute to cognitive functioning.
However, walnuts can be dangerous for a certain population—in fact, one that about 1 in 7 adults fall into, and as many as 9 in 10 don’t know they do—and we aren’t talking about nut allergies.
Rather, we're talking about people with kidney disease. Signs of kidney disease include peeing more often, dry skin, bloody or foamy urine, muscle cramps and swollen feet. If you notice these signs, book an appointment with a healthcare provider ASAP. They can conduct blood work and urine tests, which are the only ways to know if you have kidney disease, according to Dr. Odigwe.
Why Walnuts Aren’t a Great Snack for People With Kidney Disease
First, Dr. Odigwe wants to clarify that not all kidney disease patients need to avoid or limit walnuts. “Only advanced-stage chronic kidney disease (CKD) patients (as well as dialysis patients) will need to focus on limiting (if not completely avoiding) walnut consumption,” he says.
Interestingly—and unfortunately—walnuts are high in two nutrients that can be toxic if consumed in high amounts. The nutrients in question? Phosphorus and potassium.
Even if not consumed in high amounts, the kidneys in people with CKD can't process the potassium and phosphorus well, which is where the problem lies. “The key point here is that the kidney helps to keep our phosphorus and potassium levels in check; however, advanced CKD and dialysis patients, unfortunately, don’t have that luxury and are thus at a high risk of having excessively high levels of these two elements (i.e. hyperphosphatemia and hyperkalemia),” Dr. Odigwe explains.
That’s only one of the concerns. “Walnuts (and their almond cousins) also contain oxalates, which may precipitate kidney stones if eaten in large amounts,” Dr. Stanford says. “CKD patients should pay close attention to their diet to help control their disease.”
But again, other than this specific population, walnuts are a smart snack or salad throw-in. Dr. Odigwe recommends them to everyone else since “the benefits of walnuts are so vast.”
Other Foods and Drinks For CKD and Dialysis Patients To Avoid or Limit
Doctors often recommend a kidney-friendly diet, or renal diet, to patients who have CKD and/or are on dialysis. In part, this means avoiding or significantly cutting down on highly salted foods, highly sugared foods, processed foods and highly sugary drinks, according to Dr. Odigwe.
Some sodas are more damaging than others, though. Dr. Odigwe adds a fun and helpful fact to note: “Colored sodas (Fanta, Pepsi, Coca-Cola, Dr. Pepper) have a higher amount of phosphorus compared to Sprite and 7Up.” So, if and when you opt for a soda, grabbing a clear one is your safest bet.
Dr. Stanford also encourages limiting foods high in potassium (bananas, citrus, spinach, avocados, tomatoes) and foods high in phosphorus (dark sodas, organ meats, dairy products)—which, again, are otherwise nutritious options.
Dr. Odigwe adds that diabetes and high blood pressure can lead to CKD. Along those lines, Dr. Stanford suggests patients “be mindful of sodium intake to promote healthy blood pressure control and fluid balance.”
Hearing you have to cut out or limit some foods and drinks that might be your favorites—like Diet Coke, avocados and chips—can be hard. Further, you may have experienced the phenomenon of wanting to do something more because you were told you couldn’t or shouldn’t. If this is the case for you, working with an anti-diet dietitian or intuitive eating counselor who specializes in chronic diseases can help you handle the change.
Related: Can You Manage Your Diabetes With Intuitive Eating? Top RDs Weigh In
Other Ways to Get the Benefits That Walnuts Offer
With walnuts having so many nutrients, how can CKD and dialysis patients get those health benefits?
First, let’s be clear that walnuts aren’t necessarily completely off the table (pun intended). Dr. Odigwe says portion control is key. “The more advanced your kidney disease is, the more imperative it will be to have to limit or avoid walnut consumption.”
To play it safe, though, Dr. Stanford says to focus on other nutrient-dense foods, like those high in polyphenols, antioxidants or omega-3 fatty acids. Some examples are berries, apples, grapes, bell peppers, squashes, green beans, fatty fish, flaxseeds and chia seeds.
Nailing down what exactly this looks like in practice—how much is too much?—is an individualized process, so don’t do it alone. “Patients who have CKD should work closely with their doctor and dietitian to establish a personalized diet plan to improve their overall health and help control CKD,” Dr. Stanford says.
Remember: Hope is not lost. While some tasty foods are best avoided or limited, other yummy, nutritious foods are still on the menu.
Up Next:
Related: The Common Habit That Could Be Damaging Your Kidneys, According to a Nephrologist
Sources
Dr. Chidozie Odigwe, DO, nephrologist
Dr. Jennie Stanford, MD, an obesity medicine physician
Chronic Kidney Disease in the United States, 2023, Center for Disease Control and Prevention (CDC)
10 Signs You May Have Kidney Disease, National Kidney Foundation
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