Avoid These 7 Plant-Based Foods That Can Damage Your Kidneys

TRANSCRIPT

In recent years, many experts have suggested the benefits of a plant-based diet in reducing the strain on your kidneys (1, 2). But just because something is from a plant doesn’t mean it’s good for your kidneys, particularly if you have kidney disease. In reality, some plant-based foods can actually pose risks, and cutting back on them would bring lasting rewards.

Watch this video to learn 7 plant-based foods you should avoid to protect your kidneys.

Before we dive in, please note, all the information in this video is created by real people, thoroughly fact-checked, unbiased, and reviewed by qualified professionals.

7 Plant-Based Foods That Can Harm Your Kidneys

7. Seed Oils

Seed oils are plant-based cooking oils obtained from seeds. Examples are rice bran, canola, corn, cottonseed, grapeseed, soybean, sunflower, safflower, and peanut oils. These oils are promoted as valuable lipid sources due to their healthy fatty acid content and bioactive compounds (3). However, these oils have undergone extensive processing (including bleaching, refining, and heating) to extract and clean them before they can be used for cooking and baking (4). Refining can strip away essential nutrients like antioxidants and sometimes produce unwanted compounds (5). One example is trans fatty acids, one of the most harmful compounds for your kidneys and overall health (6, 7).

More concerning, seed oils can contribute to inflammation in the body due to their high omega-6 fatty acid content (8). Inflammation is the root cause behind a long list of health conditions like kidney disease, arthritis, heart disease, and diabetes (9). Small amounts of omega-6 fatty acids are necessary for your overall health. However, excessive consumption, typical in Western diets, can disrupt the balance between omega-6 and omega-3 fatty acids, leading to health problems such as kidney damage (8).

Fats are divided into saturated and unsaturated types. Unsaturated fats, found in oils like olive oil, are healthier, offering benefits such as improved cholesterol and heart health. Saturated fats, found in animal products and some plants like coconut, should be limited. Replacing saturated fats with unsaturated ones can minimize the harm caused by seed oils (10 , 11).

Opt for unrefined oils, such as extra-virgin olive oil, which retain more natural nutrients, flavor, and aroma. Because they are extracted using methods like cold pressing without high heat or chemicals, unrefined oils are tastier, healthier, more natural, and free from harmful additives (12, 13). This purity and nutrient retention support overall health, including kidney function.

6. Canned Vegetables/ Canned Soups

Canned soups and vegetables are commonly consumed because of their low cost and convenience. However, these foods typically contain high levels of sodium for preservation, which can be problematic for those with kidney disease (14, 15). When the kidneys are not functioning properly, they cannot effectively filter out excess sodium from the blood. This leads to a buildup of sodium, which can increase blood pressure and put additional strain on the kidneys (16, 17).

It is worth emphasizing that canned foods often contain added sugars or chemical additives. This is why individuals with kidney disease should avoid or limit canned foods, including canned vegetables. Instead, look for fresh or low-sodium alternatives (14, 15).

5. Chips and Pretzels

Baked chips, despite their reputation as a healthier alternative to the fried version, can still pose risks to kidney health. Baked chips are highly processed and low in fat, making it easy to overeat without feeling full. Pretzels are processed baked bread snacks, which can raise blood sugar levels and promote fat storage. These effects can contribute to kidney damage over time (18, 19, 20). Potato chips and pretzels are also low in essential nutrients like fiber and protein and can contribute to weight gain and obesity, potentially damaging your kidneys over time (18, 21).

Worse still, both chips and pretzels can contribute to high sodium intake, which can strain the kidneys by causing fluid retention and elevated blood pressure (22). High salt intake may worsen already existing kidney damage and increase the risk of cardiovascular complications like heart attacks and strokes (23, 24, 25). Try to moderate your intake of these foods in favor of healthier snack options to support kidney health.

4. Ketchup

Ketchup is made from tomatoes, which are high in potassium (26), and excessive potassium intake can be problematic for those with poor kidney function (7).

Also, ketchup is often high in added sugar and sodium, which can contribute to high blood pressure and strain on the kidneys (27). One tablespoon (17 grams) can contain 180 mg of sodium and 4 grams (1 teaspoon) of sugar (28, 29, 30). It’s best to choose options that are low in these ingredients, especially those that don’t include high fructose corn syrup (31). The sugar in ketchup, like high fructose corn syrup, can lead to obesity and insulin resistance, making kidney function worse (32, 33).

Ketchup also has lots of phosphorus, which isn’t good for individuals with kidney issues. Too much phosphorus can cause problems since damaged kidneys struggle to filter it out (34).

It’s important to avoid other store-bought condiments that might cause similar adverse effects. This includes salad dressing, BBQ sauce, and soy sauce, as they often contain high levels of sodium, sugars, or chemical additives. Rather than topping your favorite summer dishes with these condiments, consider using salsa. Choose fresh, salt-free salsa from the store, or make your own at home (31).

3. Instant noodles

Instant noodles are precooked, dried noodles that are popular worldwide due to their convenience, long shelf life, variety of flavors, and reasonable cost. However, they are often criticized for being unhealthy due to their high sodium, carbohydrate, and trans fat content and lack of essential nutrients like fiber, vitamins, and minerals.

In 2017, Nutrition Research and Practice published a study involving 3,397 college students in Seoul, aged 18-29. The study aimed to understand how eating instant noodles affects heart and metabolic health. They found frequent instant noodle intake was linked to elevated levels of blood triglycerides and sugars and increased blood pressure. These effects can potentially cause diseases that lead to kidney damage (35).

Instant noodles are a perfect example of ultra-processed foods (UPFs), which can damage kidney function. UPFs are typically high in calories, refined carbohydrates, sugar, salt, chemical additives, and trans fats and low in dietary fiber and essential nutrients.

A 2022 study published in the American Journal of Kidney Diseases analyzed data from the Atherosclerosis Risk in Communities (ARIC) study, a major research initiative conducted in the United States. This study involved 14,679 middle-aged adults without kidney disease at baseline. After analyzing, the researchers found that each additional serving of ultra-processed foods, including canned soup, was linked to a 5% higher risk of chronic kidney disease (CKD). These findings highlight the potential harm of canned soup and other ultra-processed foods on kidney health (36). A study conducted in Korea found that people consuming the most UPFs had a higher prevalence of CKD. The results demonstrated that every 6.6% increase in UPF consumption was linked with a 6% higher prevalence of CKD. This association may be due to the harmful ingredients found in UPFs, such as hydrogenated oils and chemical additives, which can cause oxidative stress and inflammation (37).

Frequent consumption of instant noodles can harm the kidneys due to their high phosphorus content, which can raise serum phosphorus levels. Elevated serum phosphorus is linked to increased mortality and cardiovascular events (38). Efforts are being made to address these concerns and develop healthier versions. In Malaysia, for example, researchers have explored the use of composite flours incorporating locally available ingredients like seaweed powder to improve the nutritional value and quality of instant noodles while reducing dependence on imported wheat flour (39).

2. Frozen Meals

Pre-packaged vegan/vegetarian frozen meals frequently contain lots of salt, potassium, and phosphorus, which can be bad for patients with kidney disease. Excess salt and other preservatives are often added to make these meals taste better and last longer (40, 41).

Moreover, excessive potassium intake can be problematic for individuals with compromised kidney function, as mentioned earlier, because the kidneys struggle to properly regulate potassium levels in the blood. However, plant based diets in kidney disease have been shown to be beneficial, as the potassium in fresh whole plants are paired with fiber, which prevents its absorption. Talk with your dietician about the right plant-based diet for you (40, 42).

Similarly, additives containing phosphorus in processed frozen foods can contribute to elevated phosphorus levels in the blood (43), potentially leading to bone and heart complications in those with kidney disease (44).

Therefore, frozen meals are generally not a good choice for people concerned about kidney health, especially if consumed regularly (45).

To make frozen meals less harmful to kidney health, choose those with lower sodium and reduced potassium and phosphorus content. This involves carefully reading labels and selecting products with minimal processed ingredients.

A better option is to prepare homemade meals using fresh whole-food ingredients, allowing for greater control over nutrient intake. Try cooking large batches of kidney-friendly vegetarian or vegan dishes and freezing individual portions for later consumption. By prioritizing fresh, whole foods and mindful meal planning, you can enjoy a kidney-friendly diet while minimizing potential harm (45).

1. Chocolate Bars / Energy Bars

While cocoa contains phenolic antioxidants and flavonoids that can help support the function of your blood vessels, chocolate bars should be consumed with caution. Chocolate bars have high levels of saturated fats and added sugar. These components contribute to high blood sugar, high blood pressure, and weight gain, which are common triggers for kidney disease (21, 46).

Chocolate bars and energy bars are also considered UPFs, which are linked with an increased risk of CKD and worsened complications in patients with CKD. As mentioned earlier, UPFs are typically high in energy, low in nutritional value, and contain additives that may be harmful to kidney health (47).

Energy bars, often consumed for replenishing electrolytes lost during exercise, can pose significant dangers to kidney health. Similar to energy drinks, they often contain high amounts of sugar to provide a quick energy boost. Also, the combination of high sugar and other additives in energy bars leads to conditions that can cumulatively strain the kidneys. Thus, long-term consumption of energy bars can accelerate kidney damage (25, 48, 49).

Therefore, it is essential to minimize your consumption of these processed bars and consider fresh fruits and other healthier alternatives.

Are Your Kidneys Damaged?

Healthy kidneys filter about half a cup of blood each minute, getting rid of waste and excess water to produce urine. The urine travels from the kidneys to the bladder through two thin, muscular tubes called ureters, one on each side of the bladder. The bladder serves as a reservoir, temporarily storing the urine. Together, the kidneys, ureters, and bladder make up the urinary system (50).

When your kidneys are damaged, waste and fluid build up. Over time, this can lead to kidney disease and kidney failure, which can be either acute or chronic. Acute kidney failure is usually short-term and reversible, while chronic kidney failure is a long-term condition that is progressive (51).

Symptoms of kidney damage can include nausea, vomiting, fatigue, sleep problems, changes in urination, decreased mental sharpness, muscle cramps, swelling of feet and ankles, itchy skin, and high blood pressure. These signs might not manifest until irreversible damage has occurred due to the kidneys’ ability to compensate for lost function (52, 53, 54).

Kidney problems can cause anemia and bone and mineral disorders, such as hyperkalemia, which can be deadly. Additionally, kidney failure can heighten the risk of heart disease or stroke (55).

Without treatment, kidney failure is fatal. Doctors rely on biomarkers like creatinine levels, glomerular filtration rate (GFR), and protein in the urine to assess kidney function. Newer biomarkers such as kidney injury molecule and neutrophil gelatinase-associated lipocalin show promise for early detection of kidney damage (56).

Triggers for kidney disease include high blood pressure, high blood sugar, and high blood cholesterol levels (57, 58, 59). The increased force from high blood pressure injures the filtering units of the kidneys (60). Elevated blood sugar from diabetes can cause damage to small blood vessels in the kidneys, which harms the filters (61, 62). Additionally, cholesterol forms plaques along the artery walls, blocking blood flow to the kidneys, which impairs their function and also causes protein loss in the urine (21, 46, 59). Other diseases and environmental factors can also contribute to kidney damage (55, 63). Obesity increases the risk of chronic kidney disease (CKD) by lowering urine pH, causing chronic inflammation, and disrupting fat metabolism. It also worsens high blood pressure, insulin resistance, and glucose intolerance, further raising the CKD risk (64, 65).

Summary

Conclusion

While CKD can be caused by various factors, including diabetes and high blood pressure, dietary choices play a significant role. This video has highlighted some plant-based foods to avoid, emphasizing the importance of opting for less processed alternatives.

The one thing all of these foods have in common is that they are processed. From seed oils to flavored instant oatmeal, many processed foods contain additives that can worsen kidney disease. To maintain healthy kidneys, swap out high-sodium condiments like ketchup for homemade sauces with fresh herbs.

Opt for antioxidant-rich fruits and vegetables, choose lean proteins with less saturated fat, and stay hydrated with water. By prioritizing whole, nutrient-rich foods and limiting processed options, you can support your kidneys and prevent pre-existing kidney conditions from getting worse.

Remember, consulting with a healthcare professional is necessary, especially if you have an existing kidney condition. Your doctor and registered dietitian can provide personalized guidance to help you make informed dietary choices and maintain optimal kidney health.