Unlock the Power of Tofu in Your Kidney Diet: Benefits, Easy Recipes & Essential Tips!

Chronic Kidney Disease (CKD) poses a significant global health challenge, characterized by the absence of curative treatments and high rates of morbidity and mortality. Nutrient therapies are recommended for intervention of kidney disease and complications. Malnutrition is a critical factor influencing clinical outcomes in CKD. As such, dietary recommendations often include high-quality, plant-based protein sources like soy products. However, adherence to these dietary guidelines among CKD patients is often low. A significant portion of patients with CKD do not consume soy foods, which could be mainly resulted from their misconception towards soy products delivered by medical workers or social media.

Understanding CKD and the Importance of Diet

Chronic kidney disease (CKD) is a major global health issue, with approximately 10% of adults worldwide are affected by some forms of CKD, which cause 1.2 million deaths and 28 million years of life lost annually. When kidneys are damaged and cannot function properly, fluid can build up in your body, and waste can accumulate in your blood. Following a kidney-friendly diet and avoiding or limiting certain foods can help decrease the accumulation of waste products in your blood, improve your kidney function, and prevent further damage. With CKD, the kidneys may have trouble keeping these nutrients at healthy levels.

Protein Needs in CKD

Since 1990s, supplement with high-quality dietary protein rather reducing protein intake has been highly recommended for patients with kidney diseases. The most common question that dietitians hear from patients diagnosed with CKD is, “What should I eat?” It can seem confusing when you hear or read different things. Renal (kidney) diets minimize the amount of waste in the blood and decrease the amount of work the kidneys do. Kidneys are your body’s filters. When you have chronic kidney disease (CKD), any stage of CKD, you lose the ability to get rid of nitrogenous protein waste from foods you eat or drink, and it starts to build up in your blood. This is called uremia. Symptoms of uremia include nausea, bad taste in the mouth, loss of appetite, and weakness. Protein comes from both animal sources - like beef, pork, poultry, eggs, fish, shellfish, and dairy - and plant sources, including beans, legumes, and tofu. Protein powder supplements are usually made from whey or soy and are not recommended on a low-protein diet.

If your tests show you have protein in your urine (proteinuria) or high blood urea levels (azotemia), or both, eating less protein becomes very important. Too much protein can irreversibly damage your kidneys. In general, for CKD stages 1 and 2, the current recommendation is to limit dietary protein to no more than 0.8 grams per kilogram of your ideal body weight. For example: if your ideal weight is 150 lbs or 68 kg, your protein needs are: 68 kg x 0.8 g/kg = 54 grams of protein or less per day. Once your glomerular filtration rate (GFR) starts to decline, it is better to get more plant-based proteins, as they break down to less urea than animal proteins. If you have CKD stages 3-5 (GFR 59 or lower), unfortunately, you will need to restrict your protein even more. Studies now show that limiting protein to 0.55-0.60 grams per kilogram of your body weight can delay decline in kidney function. For example, if your weight is 150 lbs or 68 kg, your protein needs are: 68 x 0.6 - 0.8 g/kg = 40-54 grams per day. This equals about 4-6 ounces of protein from animal or plant sources per day. If you are diabetic, 0.8-0.9 grams per kilogram of your ideal body weight is reasonable. Sometimes a doctor may prescribe keto acid analogues to meet protein requirements of very low-protein diets to prevent malnutrition. Protein exists in limited amounts in starchy foods and grains, so that needs to be accounted for as well. It may sound difficult and maybe unrealistic. However, a renal dietitian can help you plan out a diet that will work for your preferences and your lifestyle.

The Role of Soy Protein in CKD Diets

In the past decades, it had been prevailing that patient with CKD should not consumed soy products due to the skeptics on their nutrition significance. Currently, digestibility corrected amino acid score (DIAAS) is a worldwide acknowledged approach for determining protein quality and proteins with DIAAS equal to or higher than 75 are defined as high-quality according to Food and Agricultural Organization of the United Nations (FAO) DIAAS report. In recent years, with the confirmation of soy products as qualified sources of proteins, including soy foods as part of CKD patients’ dietary treatment could have clinical importance. Furthermore, soy protein consumption, when compared to animal protein consumption, showed remarkable effects on lowering serum creatinine (SCR) and serum phosphorus concentrations in pre-dialysis CKD patients.

Read also: Healthy Tofu Recipes

Tofu: A Kidney-Friendly Superfood

Tofu is a nutrient-dense plant-based food that's low in phosphorus, potassium, and sodium, making it kidney-friendly. For people with kidney disease, tofu is a versatile, high-quality protein source. And it doesn’t contain the high levels of absorbable phosphorus and PRAL (potential renal acid load) found in many animal-based proteins. Since tofu is a minimally processed plant protein, it is easier on the kidneys. Tofu is safe to eat for all the following conditions and treatments:Chronic Kidney Disease (CKD)/Transplant, Hemodialysis (3 times/week), Daily Home and Nocturnal Hemodialysis/Peritoneal Dialysis and Kidney Stones

Why Tofu is Considered a Superfood

Tofu contains all the essential amino acids needed to build protein and provide your body with energy.Other reasons why tofu is a superfood include:

It is rich in minerals such as calcium and magnesium.
Tofu contains omega-3 and omega-6 healthy fats.
Due to its protein, fiber, and isoflavone content, tofu boasts potential health benefits.

Addressing Misconceptions About Soy Consumption in CKD

However, in clinics, there are still quite a few CKD patients, even some medical workers who are uncertain about or continue to misunderstand the importance of consuming soy products. A study demonstrated that although soy products have been classified as high-quality protein diets, knowledge and recognition of soy products in CKD patients has not been updated correspondingly.

In the survey, 488 (85.6%) patients were informed that CKD patients should have high-quality protein diets, while 82 (14.4%) patients were not. The results showed that, although the number of respondents in each subgroup varies greatly, more than 50% of respondents, which are 345 (84.8%) non-dialyzed, 116 (90.6%) peritoneal dialysis and 27 (77.1%) hemodialysis patients were informed that they should have high-quality protein diets. Interestingly, only 239 (41.9%) CKD patients answered yes to the question of whether soy products are good sources of high-quality proteins, and the rest patients answered either no (197, 34.6%) or no idea (134, 23.5%) in this question. In addition, to our surprise, more than 90% of respondents were affected by the notion that CKD patients should not eat soy products. These findings clearly demonstrate the urgent need for updated knowledge and guidance on soy foods in CKD patients for better dietary intervention.

Most (435, 76.3%) CKD patients received dietary treatment-related information from medical workers, and the information or suggestion delivered by medical workers may also indirectly influence two other sources, internet/TV (217, 38.1%) or other CKD patients/family members (170, 29.8%), in the survey. We also found that 204 (35.8%) patients showed no preference for soy foods, 325 (57%) patients stayed away from soy foods for healthy concerns, and 41 (7.2%) of them avoided soy products due to personal preference. For the specific group of patients with healthy concerns about soy foods (don’t dare to eat) (n = 325), the major reason is the development of clinical symptoms, such as proteinuria, hematuria, high blood uric acid, and high blood creatinine. Within this group, the concerns of 137 (42.2%) patients were resulted from previous misconception on soy foods conveyed by medical workers, which further emphasizes the significance of renewal of knowledge in medical workers during long-term treatment of the disease. In the survey, only 110 (19.3%) of CKD patients maintained their eating habits of soy products as before the diagnosis, while 305 (53.5%) of them consumed soy foods less frequently than before or occasionally. 113 (19.8%) of them stopped eating soy foods completely, and in contrast, 42 (7.4%) of them used soy products to replace all or part of dietary animal proteins.

Compared with CKD patients older than 60 years, higher percentage of younger patients considered soy products belong to high-quality protein, suggesting that clinicians should pay more attention to older patients when delivering the updated dietary education, because aging is also one of the risk factors accelerating the progression of kidney disease. Besides, the highest percentage of patients answering yes to the question was found in the group of peritoneal dialysis. This could be because peritoneal dialysis patients need to perform the procedures by themselves at home, they therefore could contact physicians more frequently and have better chance in receiving updated information of soy products. Another potential explanation is that operation of the procedures encouraged patients in this group to follow current progress in CKD treatment closely. Among all the patients who did not dare to eat soy products (n = 325), peritoneal dialysis patients have a higher proportion than other CKD patients. Regarding to this result, peritoneal dialysis patients might be more cautious in intaking soy foods, because they may have symptoms, such as proteinuria, high blood creatinine, and fatigue, but at the same time, they had to perform the dialysis procedures by themselves at home. With the uncertainties of how their diseases would develop and effects of soy products, they could be more skeptic on soy foods than other patients.

In our results, although 85.6% of the included CKD patients have heard that controlling of kidney disease requires high-quality protein diets, but only 41.9% of patients knew that soy products belong to high-quality protein foods, and up to 90.4% of patients have ever heard that they should not eat soy products. From the analysis of subgroups, although higher percentage of peritoneal dialysis patients knew that soy products are a good source of high-quality proteins, the proportion of this group that did not dare to eat soy products is as high as 68.8%. To some extent, this reflects the CKD patients’ uncertainty and misconception of intaking soy products and high-quality protein diets. Besides, 57% of the respondents did not dare to eat soy products, which may also imply that this concept significantly limits the choices of foods in CKD patients who are vegetarian or consume soy products regularly. In terms of sources of knowledge about consumption of soy products, our results confirmed that 76.3% of patients obtained related knowledge from medical workers, and 42.2% of patients who did not dare to eat soy products were advised by medical staff. Due to the long-term course of the disease, some patients may learn about the necessity of limiting soy products consumption from medical workers in early years and have retained this conception since then. In addition, although there are many ways to acquire information in this digital world, suggestions from medical staff, especially physicians and nurses, are still the most reliable for patients. The results from this self-administered questionnaire study suggest that significant numbers of CKD patients, especially those over 60, are not being directed by current understanding of high-quality protein diets, which could be essential for maintenance of kidney functions.

Incorporating Tofu into a Kidney-Friendly Diet

Making tofu taste delicious is all about preparation and seasoning. Wrap in paper towels or kitchen towels: Place a clean kitchen towel or several layers of paper towels on a flat surface (or cutting board). Put the block of tofu on top of the towels. Add weight: Place a heavy object on top of the tofu to apply pressure. This could be a plate, a cutting board, or a baking sheet. Press for 10-20 Minutes: Allow the tofu to press for 10-20 minutes.

Tofu Preparation Tips

Tofu on its own does not have much flavor, but it takes up other flavors of the dish. Marinating or seasoning brings both sweet and savory flavors to tofu.You can find tofu in different varieties and consistencies:

Bulk or individually packaged
Soft tofu is lower in fat and is good for use in salad dressings, sauces, and desserts
Firm tofu is good for stir-frying, baking, and grilling
Tempeh is tofu that has been fermented. It has more texture and a more nutty, meaty flavor.
Tofu blocks should be rinsed before use.
You can refrigerate your tofu for up to 3-5 days by submerging it in water in an airtight container and changing the water daily to keep it fresh. You can also freeze tofu in its original packaging for about 5 months

Seven Easy Ways to Use Tofu

Tofu is a soy product that is very versatile and can be cooked in a variety of ways as a meat substitute for many different dishes. You can add it to stir-fry dishes, smoothies, soups, sauces, desserts, and more.

Tofu aioli: Blend soft tofu, olive oil, garlic, and lemon juice into a sauce.
Tofu breakfast scramble: Use firm tofu instead of eggs; spice up the flavor and color by mixing in some cumin, Dijon mustard, and turmeric.
Marinated tofu: Firm tofu can be used to replace meat in just about any dish; drain, cube, marinate and bake it.
Grilled tofu: Use extra firm tofu; cook on a lightly greased grill until heated and grill marks show.
Sandwiches and wraps: Cut marinated firm tofu into thin slices and use it in sandwiches and wraps.
Soups: Use plain cubed firm tofu in soup recipes.
Desserts and smoothies: Blend soft tofu, cocoa powder, vanilla, raspberries, and honey into a smooth, low-phosphorus chocolate pudding or smoothie.

Recipe: Sesame Greens with Tofu

Serving size: 4 servings per recipe

Ingredients* 4 cups (about ¾ pound) mixed greens (lettuce, collard, beet, etc.)

1 tablespoon olive oil
1 cup onions, sliced thin
1 teaspoon curry powder
1 tablespoon low-sodium soy sauce
½ cup unseasoned rice vinegar
8 ounces firm tofu, cut into cutes
½ teaspoon sesame oil
1 teaspoon sesame seeds

Instructions1. Cut greens into 2-inch-long shreds. Remove hard stems if needed.

Drain tofu and pat dry with a paper towel.
Heat oil in wok or sauté pan.
Sauté tofu for 3 to 5 minutes until golden. Set aside.
Sauté onions until translucent, about 2 minutes.
Sprinkle curry over onions and add sugar and greens. Cover.
Reduce heat and let greens steam in their own juice until tender, 3-5 minutes. Stir halfway through cooking. Don’t overcook or the greens will turn darker.
Add soy sauce and vinegar, and heat to boiling.
When the sauce is slightly thickened, remove it from the heat and add the tofu.
Garnish with sesame oil and seeds.

Other Dietary Considerations for CKD

If you have kidney disease, it’s important to watch your intake of sodium, potassium, and phosphorus. Foods that contain high amounts include cola, brown rice, bananas, processed meats, and dried fruits.

Foods to Limit or Avoid

Dark-Colored Sodas: Dark-colored sodas should be avoided on a renal diet, as they contain phosphorus in its additive form, which is highly absorbable by the human body.
Avocados: Consider avoiding avocados on a renal diet if a doctor or dietitian has advised you to lower your potassium intake.
Canned Foods: Canned foods are often high in sodium. Avoiding, limiting, or buying low sodium varieties is likely the best to reduce your overall sodium consumption.
Whole Wheat Bread: White bread is typically recommended over whole wheat bread on a renal diet due to its lower phosphorus and potassium levels. All bread contains sodium, so it’s best to compare food labels and choose a lower-sodium variety.
Brown Rice: Brown rice has a high content of phosphorus and potassium and will likely need to be portion-controlled or limited on a renal diet. White rice, bulgur, buckwheat, and couscous are all good alternatives.
Bananas: Bananas are a rich source of potassium and may need to be limited on a renal diet. Pineapple is a kidney-friendly fruit, as it contains much less potassium than certain other tropical fruits.
Dairy Products: Dairy products contain high amounts of phosphorus, potassium, and protein and should be limited to a renal diet. Despite milk’s high calcium content, its phosphorus content may weaken bones in those with kidney disease.
Oranges and Orange Juice: Oranges and orange juice are high in potassium and should be limited to a renal diet. Try grapes, apples, cranberries, or their juices instead.
Processed Meats: Processed meats are high in salt and protein and should be consumed in moderation on a renal diet.
Pickles, Processed Olives, and Relish: Pickles, processed olives, and relish are high in sodium and should be limited on a renal diet.
Apricots: Apricots are a high potassium food that should be avoided on a renal diet. They offer over 400 mg per 1 cup (165 g) raw and over 1,500 mg per 1 cup (130 g) dried.
Potatoes and Sweet Potatoes: Potatoes and sweet potatoes are high-potassium vegetables. Boiling or double-cooking potatoes can significantly reduce their potassium content.
Tomatoes: Tomatoes are another high-potassium fruit that should likely be limited on a renal diet.
Processed Foods: Packaged, instant, and premade meals are highly processed items that can contain very large amounts of sodium and lack nutrients. It’s best to limit these foods on a renal diet.
Leafy Green Vegetables: Leafy green vegetables like Swiss chard, spinach, and beet greens are full of potassium, especially when served cooked. Although their serving sizes become smaller when cooked, their potassium contents remain the same.
Dried Fruits: Nutrients are concentrated when fruits are dried. Therefore, the potassium content is very high in dried fruits, so they should be avoided on a renal diet.

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