vegetarian diet for dogs with kidney disease

Dietary Guidelines for Dogs with Chronic Kidney Disease (CKD)

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The Vegetarian Diet and Chronic Kidney Disease

ByDaVita renal dietitian Chhaya Patel, MA, RD, CSR

What is a vegetarian?

A vegetarian is a person who follows a specific diet and has specific food choices which include plant foods. Vegetarians do not consume meat, but depending on what type of vegetarian they are, they may eat other products from animal sources.

Most vegetarians fall into one of the following categories:

• Lacto-vegetarians: Consumes dairy products and plant foods, but excludes eggs.
• Lacto-ovo vegetarians: Consumes eggs, dairy products and plant foods.
• Pesco-vegetarians: Eats fish in addition to eating plant foods, dairy products and eggs.
• Vegan: Consumes only plant foods and no animal products.

If youre a vegetarian, you dont have to start eating meat because you have chronic kidney disease (CKD)or have started dialysis. To combine your vegetarian lifestyle with a kidney diet, youll need to devise a meal plan to fit your nutritional needs. Here are some things your dietitian may help with for your new diet:

• Monitor your calorie intake so youre getting enough calories.
• Include vegetarian sources of proteinand calorie supplements when needed.
• Increase your phosphate bindersthat may be needed for meals and snacks.
• Suggest a lower potassiumdialysate for those on dialysis to control potassium levels.
• Adjust your diet as needed for acceptable urea clearances.
• Provide resources, recipes and renal education materials specific to your needs.

Food for a vegetarian, kidney-friendly diet

Vegetarian diets can meet the higher protein needs of a dialysis patient..

Protein-enriched foods for vegetarians on a kidney dietmay include:

• Meat analogs (meat substitutes such as soy burgers, tofu, hot dogs and deli slices)
• Soy products (tofu, tempeh)
• Beans and lentils
• Nuts and nut butters
• Eggs and egg substitutes
• Dairy products
• Grains

The protein and nutrient content can vary for tofu products, soymilks and meat analogs. Check product labels for the specific nutrient content per serving (such as protein, sodium, potassium, phosphorus, etc.). Powder and liquid protein supplements may be an option for patients with who are unable to meet their protein needs by food alone.

Benefits of being on a vegetarian diet with kidney disease

Plant protein sources have been shown to:

• Decrease protein in the urine (proteinuria)
• Slow the decline of glomerular filtration rate (GFR)and kidney blood flow
• Result in less kidney tissue damage when compared to animal proteins
• Reduce kidney cyst growth
• Improve lipid (blood fat) profile of the blood

Modifying the source of protein rather than restricting the amount of protein may be effective. Plant sources alone can provide high quality protein and adequate amounts of essential amino acids, if a variety of plant foods are consumed daily and energy needs are met.

Vegetarian diets may help slow down the progression of kidney diseasewithout compromising nutritional needs. High protein consumption has long been shown to potentially have harmful effects on the kidney in those with pre-existing kidney disease.

Iron, calcium, zinc, vitamin D and B12 should not be a concern for vegetarians on dialysis. The renal vitamin that is prescribed for hemodialysispatients should contain vitamin B12 and zinc. All dialysis patients are regularly evaluated and prescribed calcium, vitamin D and intravenous (IV) iron by their doctors if and when they need it.

Pitfalls of being on a vegetarian diet with kidney disease

While people in the earlier stages of kidney diseaseare generally told to limit protein intake, dialysis patients require more protein because of protein loss during dialysis and increased body needs. It is more difficult for vegetarian dialysis patients to consume enough protein and keep potassium and phosphorus controlled without using a protein supplementthis is especially true for those who are vegans, because no eggs or milk products are consumed.

Foods that cannot be eaten on a vegetarian, kidney-friendly diet

Vegetarians will need to limit certain foods with high amounts of sodium, phosphorus and potassium based on their kidney function and lab report, just like other chronic kidney disease patients.

Sodium restriction for vegetarians with kidney disease

Sodium in some vegetarian foods can be high. The foods high in sodium are usually processed, commercially-produced plant proteins. To reduce sodium intake, the use of high-sodium foods such as meat analogs, salted nuts, miso, frozen entrees, marinated tofu products, savory snacks and meals in a cup should be limited.

Phosphate restriction for vegetarians with kidney disease

Legumes, nuts and seeds will need to be limited for people with CKD, if high potassium and phosphorus levels become an issue. Consumption of a vegetarian diet may require an increase in the number of phosphate binders for patients in end stage renal disease (ESRD) or on dialysis.

Potassium restriction for vegetarians with kidney disease

Fruits and vegetables are the primary source of potassium and may need to be limited for vegetarians with CKD. Selecting the lowest potassium fruits and vegetables over higher potassium choices can help keep potassium levels down. Other foods high in potassium that vegetarians may use are soybeans, textured vegetable protein (TVP), soy nuts, soy flour, natto (soybean paste) and wasabi. Potassium amounts will need to be modified and levels monitored carefully by your renal dietitian.

Protein restriction for vegetarians with kidney disease

The quality of vegan protein sources is a concern for dietitians working with vegetarian patients. Renal dietitians recommend an acceptable soy-based product for vegetarian dialysis patients. Meat analogs are a significant source of protein. Look at nutrition labels for sodium content. In addition, the quality of protein is determined not only by the source of the protein, but also by the mixture of vegetable protein sources throughout the day. This means a meal plan for a vegetarian dialysis patient only needs to include foods from all the vegetarian food groups to meet recommended protein needs.

Beans and nuts are considered too high in potassium and phosphorus to be incorporated into a kidney diet. But with careful dietary planning with your dietitian, certain ones can be included in the vegetarian meal plan.

Menu items for a vegetarian, kidney-friendly diet

DaVita.com features delicious recipes for those that are vegetarian. Visit DaVita.com/Recipesand go to the Browse Tags section. Click on All tags and then Vegetarian, you will see a list of all the vegetarian recipes on the website. Here is a sample of kidney-friendly vegetarian recipes:

Breakfast

Lunch

Snack

Dinner

Dessert

The impact of a vegetarian diet on chronic kidney disease (CKD) progression a systematic review

Four RCTs with a total of 346 participants were included in this systematic review. In two largest RCTs, eGFR was reported to increase following a change to a vegetarian diet (P=0.01 and P=0.001). Another two reported no significant differences between the experimental and control groups, and these were associated with a high risk of bias in terms of missing data outcome, or the randomization process. The clinical application of a vegetarian diet in CKD prevention may be compared to a low-protein conventional diet (0.6-0.8g/kg/day of proteins), due to its naturally low protein character [17] and positive impact on eGFR [17, 18] along with a decreased urinary albumin exertion [20]. In fact, the implemented bias assessment might discredit the aforementioned studies, due to the change in standards over the last 20 years. Therefore, introducing a time criterion for the trials may be the most appropriate solution. Moreover, the study groups in both trials were relatively small, involving no more than 17 patients, which also could have affected the final results. A study strictly comparing the difference between a low protein vegetarian diet and a low protein conventional meat diet was considered biased, thus, the values demonstrated in the study were not significant [19]. Only two studies [17, 18] were assessed, having a low overall risk of bias, and these constituted the basis for the conclusions. There was a significant difference between the lacto-ovo-vegetarian diet (VD) and the Mediterranean diet (MD) with a mean difference of 4.2 mL/min/1.73m2 (P<0.001) in final eGFR. However, considering the eGFR at baseline (0.5 ml/min/1.73m2), the relative final difference is 4.7 ml/min/1.73m2. An increase of 3.4 ml/min/1.73m was observed between the initial and final eGFR in the VD group, indicating a positive effect of the diet on eGFR (17). In contrast, among patients following the Mediterranean diet, a decrease in glomerular filtration rate of 1.3 ml/min/1.73m2 was observed. It should be noted that in this study the vegetarian diet was compared to the Mediterranean diet. The Mediterranean diet is high in vegetables and low in protein. It seems promising to conduct a study that will compare the vegetarian diet with the usual diet. In the second study, the authors compared a very low protein (KD) vegetarian diet supplemented with ketoanalogs with a standard low protein (LPD) diet. Glomerular filtration rate decreased in both groups. The KD diet caused a smaller reduction in eGFR than LPD, the difference in eGFR decrease was 4.2 ml/min/1.73m. Although the eGFR was lower at the end of the study in both study groups, the KD diet helped minimize the decline in filtration function (18).

The available scientific sources provide data highlighting other benefits of a vegetarian diet in patients with chronic kidney disease. The crucial aspect is a lower systolic pressure observed in vegetarians, which may have a protective effect not only in terms of the kidneys, but also for the heart. Another vital factor is an anti-inflammatory effects of a plant based diet, which may reduce oxidative stress, protecting against renal injury [22]. Vegetarian diet provides a diversity of a gut microbiome preventing from dysbiosis and low grade inflammation. It can be achieved by the high fiber and vitamin content which increase the bowel transit, preventing from the production of uremic toxins and of reactive oxygen species (ROS) [23]. Vegetarian diet was found to have an anti-inflammatory effect through higher consumption of fruits and vegetables which contain more antioxidative vitamins such as vitamin C, E and beta-carotene [24]. Vegetarians have higher plasma ascorbic acid as well as lower concentration of uric acid and hsCRP [25]. Thanks to this, they have lower risk of developing cardiovascular disease or stroke. Moreover, vegetarians have been found to have lower HO-1 (heme-oxygenase-1) a marker indicating protective properties against oxidative stress [26]. That constitutes a significant factors in view of the cardiovascular health and the atherosclerosis risk in renal patients. Hyperkalemia, in turn, appears to be a limitation for the prevention of CKD in this group of patients. However, the aforementioned risk is low in patients in stage 4 of CKD, therefore, a vegetarian diet constitutes a safe option for this group [10]. Recent research on the population of CKD patients in stage 45 indicated that effects of a very low-protein diet supplemented with ketoanalogues (sVLPD) seem to be as effective as a standard low-protein diet (LPD), with no significant difference in the risk of renal death (P=0.28) end stage renal disease (ESRD) (P=0.51), or cardiovascular events (P=0.2). This provides a new perspective on the idea of the ketoanalogue use in delaying the progression of CKD [27]. In addition to its positive impact on the physical health, a vegetarian diet is considered to positively affect the quality of life (QoL), which comprises several domains, such as physical, social, environmental and psychological. In each of these, vegetarianism plays a vital role in influencing well-being [12]. Although a vegetarian diet seems beneficial, the treatment should be consulted with the dietician to avoid a potential nutritional deficiency.

Although not many RCTs were found, an interesting cohort trial including patients diagnosed with diabetes is worth mentioning. According to a multivariable logistic regression analysis of a cross-sectional study, vegan and ovo-lacto vegetarian diets were found to be less associated with CKD (vegan 0.87, 0.75 to 0.97, P=0.018; ovo-lacto vegetarian: 0.84, 0.770.88, P<0.001) [28]. Among the patients with a diagnosed T2DM, the risk of CKD was even lower (OR: 0.68, 95% (CI): 0.57 0.82) in a lacto-ovo vegetarian group as well as (OR 0.68, 95% CI: 0.490.94) in the vegan subjects [29]. Moreover, proteinuria was more frequent in the control group (27.7 vs. 21.7% as compared to vegans, and 20.5% in a lacto-ovo vegetarian group, P<0.001) [29].

Strengths and limitations

This systematic review bears certain limitations. Only papers in English were included in the review, no publications translated into English, or studies published in other languages were considered in the review process, which may lead to language bias. The availability of relevant studies was also a major limitation of this systematic review, as only four studies met the inclusion criteria. The studies analyzed were found to be heterogeneous in various aspects. There were clinical and methodological differences between studies, such as different inclusion criteria, variability in results due to administered medications, and most significantly - different study designs which may have affected the study results. Another factor was the changing risk of bias. Furthermore, the methods of measuring GFR varied between the studies. In terms of the strengths of this systematic review, the risk of bias was assessed using ROB2 tool in the case of each study.