Submitted by Fiona Bellefeuille, Renal Dietitian
You have likely heard about the latest diet trends such as intermittent fasting, plant-based, Mediterranean, Keto and DASH diets. Maybe you have been wondering if it is safe to try one. The safety of popular diets is usually based on tests among individuals who are overweight or who have diabetes or heart disease. Unfortunately, not many of these diets have been tested on those with kidney disease.
Let’s look at some of these food trends in more detail to see if they are beneficial and safe.
Ketogenic Diet
Often referred to as the “keto diet”, this eating plan has been around for a very long time. First used as an effective treatment for epilepsy, it has now become a popular weight loss diet. The principle of this diet is to limit the carbohydrates that our bodies usually use for energy. With less carbohydrates, our body breaks down fat stores to make ketones to use as energy instead. The traditional ketogenic diet is very high in fat, low in carbohydrates and moderate in protein.
Some of the benefits include:
- Effective reduction of epileptic seizures
- Potential improvement of some cardiovascular risk factors (e.g., lower triglyceride levels)
- Better blood sugar control
- Weight loss (initially due to fluid loss)
Some of the risks include:
- Nutrient deficiencies due to a low intake of fruits, vegetables, and grains
- Constipation due to a low dietary fibre intake
- Liver issues as the liver works overtime to break down fat for energy
- Greater potential for increase in LDL (your bad cholesterol) and heart disease depending on the fat sources chosen
- Kidney strain if the intake of protein is higher than normal
- Kidney stones
- Low blood pressure
- Negative effect on the microbiome
- Keto flu, producing symptoms such as nausea, vomiting, headache, fatigue, and dizziness
- Low blood sugar for those with diabetes on glucose-lowering medications and/or insulin
- High blood potassium levels due to high potassium foods, such as avocado, coconut, and nuts
As you can see the long list of risks outweighs the list of benefits. Most studies looking at the effects of the ketogenic diet have been short term in duration. The long-term effects of following this diet are still unknown. The keto diet is not recommended for long-term health as the high fat content may increase the risk of heart disease. Studies that have compared weight loss for people following a keto diet with that of those following a low-calorie diet found the amount of weight loss to be equal after a year.
There is some early evidence related to the ketogenic diet and polycystic kidney disease (PKD). Animal studies have found that following a ketogenic diet has slowed cyst growth. Further studies in humans are required prior to this diet being recommended for those with the condition.
Intermittent Fasting
This is a diet where you restrict your eating to a shortened period and then fast for a period. An example would be eating between the hours of 11 am and 6 pm and then fasting from 6 pm to 11 am. There are many different types of intermittent fasting (IF): alternate day fasting, modified fasting, or restricted time fasting.
Advantages of following IF diets include:
- Weight loss due to consuming less food
- Improved blood sugars
Risks of following IF diets include:
- Low blood sugar if you have diabetes, especially if taking diabetes medications or insulin
- Nutritional deficiencies due to missed meals
- Dizziness, lightheadedness, mood swings, and fatigue
- Regain of weight if intermittent fasting is stopped
A systematic review of 40 studies found that IF is effective in promoting weight loss. However, other studies have found that intermittent fasting is no more effective in promoting weight loss than calorie restricted diets. Not enough research has been done and most has been completed in animal models. Small studies have had inconclusive results as to whether IF can slow the progression of kidney disease with some studies finding that IF increases glomerular filtration rate (GFR) and others finding it decreases GFR.
Plant-Based Diets
A plant-based diet (PBD) means eating mostly fruits, vegetables, whole grains, legumes, pulses, nuts, and healthy oils, and limiting animal foods like dairy products, eggs, meat, poultry, and fish. Generally, a PBD would involve preparing meals from scratch and avoiding processed foods, refined grains, and sugar sweetened drinks.
Advantages of following a PBD include:
- Decreased acidity in the body, putting less stress on the kidneys
- Slowed progression of kidney disease related to decreased acidity
- Prevention of development of kidney disease
- Decreased inflammation due to the antioxidants and increased fibre content
- Lower blood pressure
- Increased longevity
- Less constipation due to high fibre content
- Decrease in blood levels of phosphorous
Disadvantages of following a PBD:
- Elevated blood potassium levels due to higher potassium content
- Increase in risk of iron deficiency anemia
- Difficulty consuming adequate protein for those on dialysis
Commonly studied plant-based diets include the Mediterranean and the DASH diet.
The Mediterranean diet is an eating pattern typically followed by those living in Mediterranean regions. This diet has consistently shown beneficial effects on heart disease, diabetes, and longevity. It is high in fish, fruit, vegetables, unrefined grains, legumes, nuts, and olive oil and lower in protein and dairy than a typical North American diet. There is a minimal intake of red meat and processed food. The lower protein content and increase in fruits and vegetables decreases acidity in the body and consequently puts less stress on the kidneys. The higher fibre and antioxidant content of this diet have been shown to reduce inflammation and decrease mortality. Studies have determined that the Mediterranean diet may both prevent people from getting kidney disease and slow the progression in those with the condition. One study found that individuals who followed a Mediterranean diet post kidney transplant had better kidney function outcomes.
The DASH diet is rich in fruits, vegetables, low-fat dairy foods, whole grains, fish, poultry, and nuts. It restricts unhealthy foods that are high in sodium (salt), sugar, red meats, and unhealthy fats. It was first studied as a diet to lower blood pressure, but further research has shown this food plan can also improve insulin resistance, decrease bad cholesterol levels, and promote weight loss. The DASH diet has also been found to lower the risk of developing kidney disease, slow the progression of the condition, and reduce the formation of kidney stones.
Everyone has unique and individual needs when it comes to nutrition. No one diet or eating pattern can be recommended for everyone with kidney disease. When modifying your eating patterns, it is important to adopt healthy changes that you can maintain. You are encouraged to consult with your doctor and a registered dietitian before changing the way you eat. They can help you do so in a safe and healthy manner.
References
Ketosis Ameliorates Renal Cyst Growth in Polycystic Kidney Disease
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Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Seimon RV, Roekenes JA, Zibellini J, Zhu B, Gibson AA, Hills AP, Wood RE, King NA, Byrne NM, Sainsbury A. Mol Cell Endocrinol. 2015 Dec 15;418:153-72
Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. Trepanowski JF, Kroeger CM, Barnosky A, Klempel MC, Bhutani S, Hoddy KK, Gabel K, Freels S, Rigdon J, Rood J, Ravussin E. JAMA Internal Medicine. 2017 May 1.
Healthy Dietary Patterns and Incidence of CKD; A Meta-Analysis of Cohort Studies
Katrina E. Bach, Jaimon T. Kelly, Suetonia C. Palmer, Saman Khalesi, Giovanni F. M. Strippoli and Katrina L. Campbell. CJASN October 2019, 14 (10) 1441-1449
Fruit and Vegetable Treatment of Chronic Kidney Disease-Related Metabolic Acidosis Reduces Cardiovascular Risk Better than Sodium Bicarbonate. Nimrit Goraya, Yolanda Munoz-Maldonado, Jan Simoni, Donald E Wesson. Am J Nephrol 2019;49(6):438-448
The Associations of Plant Protein Intake With All-Cause Mortality in CKD
Xiaorui Chen, Guo Wei, Thunder Jalili, Julie Metos, Ajay Giri, Monique E Cho, Robert Boucher, Tom Greene, Srinivasan Beddhu. Am J Kidney Dis. 2016 Mar;67(3):423-30
Mediterranean diet as the diet of choice for patients with chronic kidney disease
Philippe Chauveau, Michel Aparicio, Vincenzo Bellizzi, Katrina Campbell, Xu Hong, Lina Johansson, Anne Kolko, Pablo Molina, Siren Sezer, Christoph Wanner, Pieter M Ter Wee, Daniel Teta, Denis Fouque, Juan J Carrero. Nephrol Dial Transplant. 2018 May 1;33(5):725-735
Adequacy of Plant-Based Proteins in Chronic Kidney Disease Shivam Joshi, MD Sanjeev Shah, MD Kamyar Kalantar-Zadeh, MD. Journal of renal Nutrition: Volume 29, issue 2, P112-117, March 1, 2019.
Adherence to the Mediterranean Diet is Associated With Renal Function Among Healthy Adults: The ATTICA Study. ChristinaChrysohoou, Demosthenes B.Panagiotakos, Christos Pitsavos, JohnSkoumas, AkisZeimbekis, Christina-MariaKastorini, ChristodoulosStefanadis. Journal of Renal Nutrition. Volume 20, Issue 3, May 2010, Pages 176-184