What Your Kidneys Do and How They Keep You Healthy

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You may not know it, but your kidneys play several important roles in keeping you healthy.

Located just below your rib cage, these fist-sized organs do everything from filtering waste to maintaining acid levels in your body.

“If you ask me as a nephrologist or a transplant nephrologist, I would say the kidney is the cleverest organ in the body,” says Karim Soliman, MD, a transplant nephrologist who serves as medical director of the UPMC Kidney and Pancreas Transplant Programs.

In this article, learn the important functions that the kidneys perform. Discover healthy hydration habits and other lifestyle changes that support kidney wellness.

What Do the Kidneys Do?

Your kidneys play several important roles. Here’s a snapshot.

They remove waste and excess fluid from the body

Your kidneys’ main role is filtering. They filter toxins and excess fluid from your body, producing urine (pee).

Unfiltered blood enters the kidneys through the renal artery. Each kidney has up to 1 million tiny filtering units called nephrons. One part of the nephron, called the glomerulus, filters the blood; another part, called the tubule, returns necessary substances to your blood.

The filtered blood leaves the kidneys and returns to your body through the renal vein. Waste and excess fluids exit your kidneys through the ureters and enter your bladder as urine.

Each day, your kidneys filter about 150 quarts of blood. Only 1 to 2 quarts become urine.

They help to control blood pressure

Your kidneys also play a vital role in managing your body’s blood pressure. They control fluid and sodium in the body. They also release hormones that can control how your blood vessels constrict or relax.

If your kidneys sense your blood pressure is too low, they release a hormone called renin. Renin helps convert angiotensin (a hormone produced by your liver) into angiotensin I. Angiotensin I then becomes angiotensin II, which tightens your blood vessels and raises your blood pressure.

Angiotensin II also stimulates the adrenal glands to produce aldosterone, a hormone that helps the kidneys retain salt and water. This also raises blood pressure. This process is known as the renin-angiotensin-aldosterone system (RAAS).

Meanwhile, if your blood pressure is too high, the kidneys can adapt by removing excess salt and fluids from the body through urine.

Your blood pressure and kidney wellness are strongly linked. Kidney disease can lead to high blood pressure (renal hypertension) or low blood pressure. Meanwhile, both high and low blood pressure can cause kidney damage.

They manage minerals

Through filtering and hormones, our kidneys also control our levels of minerals like:

• Calcium
• Phosphorous
• Potassium
• Sodium

This balance helps keep our bodies functioning normally.

They help keep bones healthy

You may have heard of the importance of vitamin D for bone health. But did you know how important your kidneys are for vitamin D?

Your kidneys activate the vitamin D you get from your diet and sunlight. In turn, vitamin D helps our bodies absorb calcium and phosphorus, keeping our bones healthy.

Kidney damage can affect your kidneys’ ability to activate vitamin D, which can lead to weaker bones.

They help make red blood cells

Your kidneys release a hormone called erythropoietin, or EPO. EPO signals the bone marrow to produce red blood cells.

Red blood cells play a vital role, carrying oxygen from the lungs throughout the body. They also help discard carbon dioxide.

Kidney damage affects your kidneys’ ability to release EPO. This, in turn, causes lower red blood cell production. A low red blood cell count is known as anemia.

They control the pH level in your body

Our body’s pH level measures the acidity in our body. A normal pH level for the body is between 7.35 and 7.45.

Your kidneys help keep the pH level normal by removing excess acid produced by cells and keeping the right amount of bases.

What Daily Habits Support Kidney Health?

If you’re wondering how to keep your kidneys healthy every day, you’re not alone. Living a healthy lifestyle can help protect your kidney function naturally and prevent kidney disease.

Try the following daily routines for kidney health.

Eat a healthy diet

What we put into our bodies affects all of our organs, including the kidneys. You should aim for a healthy diet that emphasizes:

• Fruits and vegetables.
• Lean protein sources.
• Low-fat dairy.
• Whole grains.

Limit your intake of saturated and trans fats, sodium, and added sugars. These can cause conditions like high blood pressure and diabetes, which are risk factors for kidney disease. Also limit ultra-processed foods, as those are often high in sodium, added sugars, and unhealthy fats.

Stay hydrated

Proper hydration helps preserve our kidney function. It helps the kidneys remove waste, control blood pressure, and balance electrolytes. It also helps prevent kidney stones and urinary tract infections (UTIs).

There’s no one-size-fits-all recommendation for how much you should drink in one day. But your urine color can be a good indicator. Light yellow to clear urine is a good sign; darker yellow to light brown indicates you need to drink more fluids.

Other simple hydration tips that support kidney health include:

• Drink water, unsweetened fruit drinks, low-fat dairy, nondairy milks, and low-sodium broth.
• Limit or avoid alcohol, soda pop, and sugar-sweetened drinks, such as sweetened coffee and energy drinks.

Get moving

Physical activity is good for your whole body, including the kidneys. A good weekly goal to aim for is:

• At least 150 minutes of moderate-intensity cardio exercise.
• Or at least 75 minutes of vigorous-intensity cardio exercise.
• Or a combination of the two.

You should also add at least two muscle-strengthening exercises per week. If you’re unsure about what exercises to try, talk to your primary care provider (PCP).

Maintain a healthy weight

Being overweight or obese is a risk factor for kidney disease. It’s important to take steps to keep your weight in a healthy range.

Diet, exercise, and other factors can help you manage your weight. Talk to your PCP about whether your weight is in a healthy range and how you can manage it.

Get enough sleep

Poor sleep may raise your risk of kidney disease. It can also raise your risk of other diseases that are risk factors for kidney disease.

Adults should aim for between seven and eight hours of sleep per night.

Quit smoking

Smoking is very harmful to the kidneys. It raises blood pressure and affects your kidneys’ filtering ability. It increases your risk of chronic kidney disease, kidney cancer, and kidney failure.

Smoking can also raise your risk of numerous other diseases. If you smoke, quitting can help your kidneys and many other organs. Talk to your PCP about how to quit.

Limit (or avoid) alcohol

Alcohol raises blood pressure and cholesterol and can cause weight gain. These are all risk factors for kidney disease.

It’s important to drink alcohol in moderation. That means no more than one drink per day for women and no more than two for men.

Manage stress

Stress can cause changes in the body, including spikes in blood pressure and blood sugar. Temporary stress is natural and common. But over time, increased stress can lead to problems like kidney disease.

If you have chronic stress, it’s important to find relief. Try finding a relaxing activity like gardening or cooking. You could also take up yoga or meditation. Talk to your PCP about stress-relief techniques.

Manage your health conditions

Many diseases are risk factors for kidney problems, including:

• Diabetes.
• Heart disease.
• High blood pressure.
• High cholesterol.
• Obesity.

If you have any of these conditions, managing them can help limit long-term damage to your kidneys and other organs.

Limit NSAIDs

Chronic or long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) can raise your risk of kidney damage. That includes medicines like:

• Aspirin
• Ibuprofen
• Naproxen

Temporary use of these drugs to relieve pain and other symptoms is generally OK. But chronic or long-term use can damage your kidneys.

When taking NSAIDs, take them as directed and stop once your symptoms resolve.

When Should I Call a Doctor About Kidney Health Concerns?

It can be hard to tell if you have kidney problems, especially in their earliest stages. But you should talk to your PCP if you have any of the following warning signs:

• Changes in urination (such as peeing more or less often, bloody or foamy urine).
• Dry, itchy skin.
• Extreme tiredness.
• Extreme weakness.
• Headaches.
• Muscle cramps.
• Nausea/lost appetite.
• Puffiness around the eyes.
• Sleeping problems.
• Swollen feet or ankles.
• Trouble concentrating.
• Unexplained weight loss.
• UTIs or kidney stones.

These can be signs of kidney disease or other health problems. It’s important to seek care as soon as possible.