How to Preserve Residual Renal Function

Chronic kidney disease (CKD) is irreversible, but for many patients, especially those in the disease’s early stages, it may be possible to stop its progress and preserve residual renal function: the kidneys’ remaining ability to remove toxins and extra fluid from your body. No matter how advanced your kidney disease may be, it is crucial that you work with your nephrologist to ensure that you are doing everything possible to protect your kidney function. Doing so in the early stages of CKD may help you avoid painful and expensive measures like dialysis and transplants; doing so after you’ve begun dialysis may improve your quality of life and make your treatments more effective.

Part 1 - Preserving Residual Renal Function through Diet

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→ Talk to your nephrologist about your diet. Always check with your specialist about your diet. If your chronic kidney disease has reached the final stage (a condition known as end stage renal failure, or ESRF, when you require dialysis or a transplant to survive) or if you have other major health concerns, you may need more specific dietary guidelines. Follow your doctor’s instructions.

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→ Limit your salt intake. Too much sodium can elevate your blood pressure, causing hypertension, and you need a healthy blood pressure to preserve your kidney function. Bypass the salt shaker whenever possible, and, in addition:

→ Choose fresh or frozen vegetables rather than canned. Canned foods are high in sodium. If you do use canned vegetables, rinse them under running water to remove as much of the salt as possible.

→ Avoid salty snacks, frozen meals, and processed lunch meats.

→ Replace salt with a salt substitute and/or lemon or other seasonings, but check with your nephrologist first: some salt substitutes are too high in potassium.

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→ Reduce your fat intake. Keeping your fat consumption in check will improve your cholesterol levels, helping your arteries stay clear so that more blood can reach your kidneys. Choose lean meats, trim excess fat, and remove any skin; bake, roast, stew, grill or broil these meats rather than frying them. Additionally:

→ Use egg whites rather than using whole eggs.

→ Choose low-fat or fat-free dairy products whenever possible.

→ Buy low-fat or fat-free mayonnaise and salad dressings.

→ Replace fats like butter and vegetable oil with healthier fats like olive oil and canola oil, or use non-stick cooking spray instead.

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→ Consume moderate amounts of protein. Excess protein can strain your kidneys unnecessarily, but you do need some protein – ideally about 1 gram (0.04 oz) of protein per kilogram of your body weight. In general, aim for moderate portions of protein rich foods like fish and meat.

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→ Minimize your consumption of potassium-rich foods. Some patients need to avoid foods high in potassium: talk to your nephrologist to see if you fall into this category. If so, avoid bananas, apricots, white beans, spinach, yogurt, salmon, mushrooms, and other potassium-rich foods. Excess potassium in your body can increase the risk of cardiac arrhythmia and sudden death.

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→ Watch your phosphorus intake. Excess phosphorus in the body can cause calcium reabsorption from bone, leading to fractures. In patients with kidney dysfunction, phosphorus levels are already elevated, so avoid eating too many phosphorus-rich foods, like milk, cheese, nuts, and sodas.

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→ Ask your doctor about calcium and vitamin D supplements. Patients with chronic kidney disease often experience calcium loss and low vitamin D production. Calcium and vitamin D are crucial to bone formation, so ask your doctor whether you should take them in supplement form.

→ Calcium supplementation can be especially critical, since you need calcium but, at the same time, need to avoid consuming too much of some of the best calcium sources – milk and cheese – because they are also high in phosphorus.

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→ Lower your overall calorie intake. Even when eating healthy foods, patients with kidney disease need to practice portion control and limit their daily calorie consumption. Read nutrition labels carefully, and stick to the suggested serving size. And don’t eat mindlessly: eat slowly, pay attention to how much you are consuming, and stop as soon as you no longer feel hungry.

→ Keep in mind that it can take 20 minutes or more for your brain to register that you feel full. Eating slowly and listening to your body can prevent you from consuming excess food.

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→ Drink about one liter of water per day. Talk to your doctor to be sure what’s safest for you, but in general, patients with chronic kidney disease need to limit water intake to about a liter per day, depending on how much swelling they experience.

Part 2 - Preserving Residual Renal Function with Other Lifestyle Changes

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→ Exercise. Staying active will help you control your blood pressure and your body weight; if you have diabetes, exercise will also help you manage it. You don’t need to join a gym or do anything fancy: even just walking can be excellent, low-impact exercise. Talk to your doctor about the right exercise plan for you, and consider asking for a referral to a physical therapist, especially if exercise is new for you: this person can help you create an exercise program with your particular health needs in mind.

→ Start slowly. To begin, try exercising for 15-20 minutes three days a week; once you can do that, work up to 30 minutes five days a week.

→ Stretch before and after exercise. Careful stretching warms your muscles, increases blood flow, and minimizes cramping.

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→ Stop smoking. Smoking is unhealthy for everyone, but for people trying to preserve residual renal function, quitting is crucial to slowing the progression of kidney damage and maintaining a healthy blood pressure.

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→ Maintain a healthy weight. Being overweight or obese places increased strain on your kidneys. Work with your doctor to determine your ideal weight, and strive to stay at or near it. The diet and exercise suggestions offered here will help you do that.

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→ Avoid nephrotoxicity. Nephrotoxicity happens when your kidneys are exposed to a medication that may be toxic to the kidney cells, resulting in serious health consequences. Talk to your doctor about all medications you may be taking, and discuss alternatives. Some drugs known to be nephrotoxic include:

→ Cyclosporines (immunosuppressant drugs used to prevent organ rejection and treat severe rheumatoid arthritis and severe psoriasis). Brand names include Gengraf, Neoral, and SandImmune.

→ Aminoglycosides (antibiotics used to treat bacterial infections). Brand names include Gentamicin, Streptomycin, and Tobramycin.

→ Chemotherapy medications (drugs used to treat cancerous tumors). Brand names include Cisplatin and Ifosfamide.

→ NSAIDs (drugs, including over-the-counter drugs, used to treat inflammation, pain, and fever). Brand names include Advil, Motrin, Ibuprofen, and Nuprin.

→ Some herbal preparations, including Chinese herbal preparations with wild ginger and aristolochic acids.

→ Contrast dyes (dyes containing iodine, which are used in diagnostic procedures like CT scans).

Part 3 - Preserving Renal Function with Medication

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→ Control your blood pressure. If diet and exercise are not sufficient to keep you from developing hypertension, your doctor may prescribe medications.

→ The most effective drugs are Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). Aside from reducing blood pressure, ACEIs and ARBs prevent protein loss in urine and consequently swelling of the body. These drugs can also be prescribed for diabetes-induced renal disease.

TIPS

→ Stages of chronic kidney disease are calculated from the glomerular filtration rate (GFR), which is a measure of how well your kidneys seem to be working. A normal GFR is greater than 90. If you have a GFR greater than 30, you may be able to preserve kidney function without dialysis. Even if your GFR is less than 30, though, you will benefit from attempting to preserve any residual renal function.