Nutrition Management and PKD
The best nutrition care for those with kidney disease is one that is personalized to your health goals, nutrition status, other health conditions, and blood and urine tests. And one new area of focus for personalization is the type of kidney disease – polycystic kidney disease (PKD) or chronic kidney disease (CKD). Most of the time when you look for nutrition information for kidney disease it is for information related to the CKD diet. Nutrition is important for those with PKD and the information has only recently begun to appear from research, lived experiences and on the internet.
A PKD diet can help to slow the growth of cysts, which helps to slow the decline in kidney function. A PKD diet can also help manage conditions like high blood pressure, metabolic acidosis, heart disease, and kidney stones. The diet for PKD is not the same as the diet for CKD. So, let’s break down some of the specific nutrition recommendations for PKD.
One of the first recommendations with PKD is to drink more water. Ideally it should be individualized and include things like your activity level or other health conditions. But a starting amount of 2-3L per day with PKD helps to lower the vasopressin hormone which is responsible for cyst growth and improve urine osmolarity, as a high urine osmolarity causes a release of vasopressin hormone which then impacts the growth of cysts with PKD. For more tips and tricks on managing your fluids with PKD, check out this blog post.
A common concern with drinking this volume of fluids is frequent urination. Try to space out your fluids and drink throughout the day and in the night when you wake to pee. As you make nutrition changes like reducing your sodium intake and drink adequate amounts of fluid your urine osmolarity will improve and frequent urination should reduce.
High sodium intake is associated with higher urine osmolality which can cause PKD to progress quicker due to increase cysts growth. Plus, higher sodium intake has also been associated with a greater decline in kidney function and increased risk of high blood pressure. Check out this previous blog post on high blood pressure and PKD.
The gold standard for measuring sodium intake is through a 24-hour urine collection. This test, in addition to your blood tests, can be completed by your nephrologist or healthcare team to help provide personalized nutrition recommendations. For nutrition, ideally aim for less than 2300 mg sodium per day. Using free technology like Cronometer or MyFitnessPal can help you track how much sodium you are consuming.
The amount and type of protein are a popular topic with PKD and things to consider when making nutrition changes. With PKD too much or too little protein can change the osmolarity of your urine. Again a 24-hour urine or working with a renal dietitian helps to determine how much protein you should be consuming. And with PKD it is often not a very low protein diet; this may be one of the biggest differences between PKD and CKD diets that we continue to learn about.
As for the type of protein, there is a lot of health benefits to plant-based proteins like managing kidney function and other conditions like high cholesterol and metabolic acidosis. Additionally, too much animal protein can lead to gout and increase your risk of kidney stones. Incorporating more plant-based proteins is a healthy approach with PKD. Try aiming for one meatless meal per week or per day and increase from there.
Another thing to consider with protein is when we consume it. Since our kidneys can only filter so much at a time, remember to spread out your protein throughout the day. This also helps to keep you full for longer.
You may be wondering what about keto diets? While there is promising research coming out about keto diets and PKD, there is no consensus statement currently. A keto diet puts you into nutritional ketosis and some concerns of safety and sustainability has been brought up. Whereas a low carbohydrate diet follows a carbohydrate restriction but chooses nutrient dense foods. The type of carbohydrate and the amounts you choose is still something to consider with PKD. If you choose to include carbohydrates aim for whole grains like whole grain bread, brown rice, barley, oatmeal instead of refined carbohydrates.
The link between heart disease and PKD is strong, so it is important to adopt a diet that helps to manage both. This may be choosing low fat dairy products, nuts, seeds, legumes, beans more often. If you include animal proteins aim for fatty fish like salmon, trout, or mackerel twice per week. And choosing unsaturated fat sources like olive oil or non-tropical oils for cooking. That is where diets like the Mediterranean Diet or DASH diet come into play for kidney health and heart health.
Potassium should be individualized based on your bloodwork. And many with PKD do not require a potassium restriction. Additionally, potassium that we get from vegetables, fruit, whole grains, and plant-based proteins is helpful at managing blood pressure.
Foods with added phosphorus should be avoided for anyone with kidney disease. It is important to read nutrition labels. Other phosphorus sources can be included in a PKD diet unless you are advised by your healthcare team otherwise.
Oxalates are a compound found in many foods but mainly from plant sources. Too much oxalate in the urine can lead to calcium oxalate kidney stones. With PKD it may be helpful to limit some of these foods (e.g. spinach, beets, oranges, raspberries, almonds) to help prevent kidney stones from forming. If you include oxalate foods in your diet pairing them with calcium helps to decrease their absorption in the gut preventing stones from forming. But stay tuned for future blog posts on this topic.
So, what’s next?
When making nutrition changes with PKD, start with these tips:
- Aim for half your plate in vegetables (choose low potassium or low oxalate if needed)
- Choose plant proteins more often (choose low oxalate if needed)
- If choosing to incorporate carbohydrates aim for whole grains more often
- Limit sodium by reading food labels, eating at home more often and cooking with herbs and spices
- Make water your beverage of choice
Additionally, speaking with your nephrologist or healthcare team for a 24-hour urine collection and working with a renal dietitian can help you determine a personalized nutrition plan that meets your needs.
If you have nutrition questions about PKD, reply to this email. Responses will be shared in a special upcoming blog post. If you are looking for healthcare support, check out ReferPKD to get access to local practitioners.
Written by: Emily Campbell, RD CDE MScFN is a Registered Dietitian and Certified Diabetes Educator with a Master’s Degree in Foods and Nutrition. Emily specializes in renal nutrition helping those with kidney disease overcome the confusing world of nutrition to promote health. Emily can be found at kidneynutrition.ca.