Be kind to your kidneys

By Theresa Anderson, R.D., L.D., registered dietitian, Providence Nutrition Services.

You probably think about what’s for dinner far more often than you think about how your kidneys are doing. But what you eat can affect your kidneys in profound ways. If you have diabetes (the No. 1 cause of kidney failure), high blood pressure (the No. 2 cause) or other conditions that increase your chances of kidney problems, the way you eat can make a drastic difference in the quality of your life. Being aware of your mealtime habits can potentially prevent long-term complications such as kidney disease and dependence on kidney dialysis.

During National Diabetes Month, I’d like to put in a plug for thinking about your kidneys a little more often – especially when you’re thinking about what’s for dinner. As Terry Davis, M.D., pointed out in last month’s To Your Health, “Most of the things that lead to chronic kidney disease and kidney failure are things that we do, often unwittingly, to ourselves.” (If you missed his article, read it here.) The way we eat is high on that list – we can accelerate kidney decline or slow it down, depending on our dietary choices.

The following suggestions can reduce the risk of developing kidney disease altogether. Some of them may sound like the common-sense advice you’ve heard before for reducing your risk of all kinds of health problems, but these tips are especially effective in preserving kidney health. Note: Although these recommendations are based on many of the same strategies that dietitians employ to preserve kidney function in people with kidney disease, people who have been diagnosed with kidney disease should consult a dietitian for an individualized plan tailored to their unique health condition. However, if your kidneys are in good working order, these tips can go a long way toward helping you keep them that way.

Eat to beat blood sugar spikes

If you have diabetes, good blood sugar control is crucial to preserving your kidney function. Researchers are finding that it isn’t necessarily the pre-meal blood sugar that causes the most kidney damage – it’s the highest blood sugar spikes, whenever they occur. For many people, that’s an hour or two after meals. I tell my patients with diabetes that if they are trying to avoid kidney disease – and they should be – they need to be sure that their blood sugar is great all the time, not just right before a meal.

Spend a couple of days tracking your blood sugar at random times – for example, two hours after a meal, and after eating certain foods or large meals – and find out when your levels are highest. Blood sugars that routinely rise higher than 180 can lead to many more health complications, including kidney disease. If you find that your blood sugar is spiking higher than you thought, try these eating strategies to reduce dangerous spikes:

  • Avoid huge meals: eat smaller meals three to six times a day.
  • Don’t skip meals: eat on a regular schedule, including breakfast.
  • Eat balanced meals: include protein, fiber-containing carbohydrates and healthy fats at each meal.
  • Use the plate method: Fill half your plate with vegetables, and use the rest for a small portion of protein and a half or full cup of starch (especially high-fiber sources) – this makes meal planning easy and will do great things for your blood sugar control, as well as your blood pressure.
  • Avoid sweet beverages: sodas, fruit juices and sugary energy drinks can cause an immediate spike.
  • Limit or avoid concentrated sweets such as cookies, cakes and candy.
  • Move after meals: Take five or 10 minutes to walk – or to do any kind of movement – after meals. This has been shown to help prevent blood sugar spikes.
  • Control your weight: Going on crash diets is not recommended; following the tips I just outlined, and adding a little regular exercise, is a better way.

Eat to beat high blood pressure

High blood pressure and diabetes are responsible for more than two-thirds of all cases of kidney failure in the United States. To keep your blood pressure in a normal range, watch your weight, take medications as prescribed, and follow a diet that focuses on:

  • Vegetables and fruits
  • Low-fat or fat-free dairy products
  • More fresh, whole foods, and fewer processed foods
  • Foods that are low in salt and sodium

In addition, use alcohol only moderately or not at all. Moderate use is defined as one drink per day for women and one to two drinks per day for men – more than that can raise blood pressure. One drink is equivalent to either 12 ounces of beer or wine cooler, 8 to 9 ounces of malt liquor, 5 ounces of wine (less if it’s fortified), or 1.5 ounces of 80-proof hard liquor.

Don’t overdo it on protein

While protein is important for building your muscles and bones, diets that emphasize huge amounts of protein are hard on the kidneys and can lead to kidney failure – even if you have no other risk factors for kidney disease. To maintain healthy kidneys, eat reasonable amounts of protein and divide it evenly throughout the day. What’s a reasonable amount for you? See the Dietary Guidelines for Americans.

If you have been diagnosed with chronic kidney disease, do not try to restrict protein further without guidance from a dietitian. Protein restriction can be a great kidney-preserving strategy for some, but it needs to be guided and monitored carefully by a dietitian to avoid the serious risk of malnutrition and other health problems.

Go easy on supplements

Taking high doses of some nutritional supplements can be toxic to the kidneys. Chinese herbs, colon cleansers and some alternative medicines can cause problems. Even vitamin D, usually thought of as a good thing, can burden the kidneys in mega-doses. Make sure that your doctor is aware of the type and dosage of every supplement you take.

Avoid dehydration

Acute dehydration, which can occur under extreme heat or physical exertion, can cause acute kidney failure – the kind that comes on suddenly and seriously. But a lifetime pattern of drinking less water than your body needs also can cause chronic kidney disease – the more gradual damage and decline of the kidneys that eventually progresses to kidney failure. Avoid both kinds by hydrating well and evenly throughout the day. Drinking eight cups of water throughout the day is a good general guideline for most people. In hot weather, or when engaging in strenuous physical activity, you may need to drink more.

Get help from experts

As a dietitian, I have seen how powerfully food – and water – can affect kidney function. Many chronic kidney disease patients have been able to delay dialysis for years, largely by making changes in their diets. Nutritional intervention is recognized as being so effective in delaying dialysis and preventing other problems for people with kidney disease that it is one of only two nutrition benefits that are covered by Medicare.

Ideally, of course, it’s always preferable to prevent diseases in the first place. If you are at risk for kidney disease and you do not know your GFR (a measure of how well your kidneys are working), learn about it and find out what yours is. If you are having trouble managing diabetes or high blood pressure, ask your doctor to connect you with Providence resources that can help you get these under control. And the next time you’re thinking about what’s for dinner, think about your kidneys, and feed them well.