Kidney Disease & Health Archive

Ask the doctor

Q. I read that the death rate from COVID-19 is going down, but that people who recover from the infection still can remain sick for a long time. Is that true?

A. It is true, but we don't yet know how big the problem is: COVID-19 has been with us for only a year, and there hasn't been enough time to know the long-term effects.

Surprising factors influence urine color and odor including food and medication

Many things can alter the look and smell of your urine. When should you be concerned?

Nearly six and a half cups — that's how much urine the average person produces a day, usually in four to eight trips to the toilet. The ritual is so routine that most of us pay little attention to our urine — that is, unless it happens to look or smell different than usual.

Urinary bleeding can be dramatic and frightening, prompting an appropriate call to your doctor. But sometimes the call travels in the other direction; many people are surprised and alarmed to get a call from their doctors reporting that the urine that looked clear in the specimen jar actually contains red blood cells (RBCs). Either way, blood in the urine, known technically as hematuria, requires medical evaluation. Although the results are often reassuring, hematuria is a warning symptom that you should never ignore.

Blood can enter the urine from any place in the urinary tract. So the first step in understanding hematuria is to understand your anatomy.

On call

Q. When should I worry about changes in the color of my urine? What color is considered healthy?

A. If a person is well hydrated, the normal color of urine is a pale yellow. Someone who drinks large amounts of fluid or takes diuretics (water pills) can have almost clear-looking urine. A dark yellow color may indicate a need to increase your fluid intake.

What is the test?

By filling your bladder with a liquid dye that shows up on x-rays, your doctor can watch the motion of your bladder as it fills and empties and can see if your urine splashes backwards toward your kidneys as the bladder muscle squeezes. This kind of test can help your doctor to better understand problems with repeated urinary tract infections or problems involving damage to the kidneys. It can also be useful for evaluating urine leakage problems.

How do I prepare for the test?

Tell your doctor before the test if you have ever had an allergic reaction to x-ray dye (IV contrast dye). Also let your doctor know if there is any chance you are pregnant.

What Is It?

A kidney transplant is surgery in which a person who has permanent kidney failure receives a healthy kidney from another person. This single, healthy kidney takes on the workload of both of the person's failed kidneys. The failed kidneys usually are left in place. The new kidney is added to the abdomen.

The new kidney can come from a living or dead donor. A living donor is often a close blood relative of the person who receives the new kidney (the recipient). However, in certain cases, a recipient's spouse or friend can be a kidney donor. Most people are born with two kidneys, but really need only one of them: the second kidney is like an "insurance policy". Therefore, there is little risk in a living donor giving up one of his or her two kidneys.

A substance called trimethylamine N-oxide, which is produced when your body digests red meat, may raise the risk of cardiovascular problems.

Experts used to think that red meat raised your risk of heart disease simply because it was high in saturated fat. But today that picture has gotten more complicated thanks to the discovery of a metabolite — a substance produced during digestion and metabolism — called trimethylamine N-oxide, or TMAO.

According to a news article published June 11 in JAMA, three recent analyses have linked high blood levels of TMAO with a higher risk for both cardiovascular disease and early death from any cause. In one of those studies, researchers found that people with higher levels of TMAO in their blood may have more than twice the risk of heart attack, stroke, or other serious cardiovascular problems, compared with people who have lower levels. Other studies have found links between high TMAO levels and heart failure and chronic kidney disease.

Kidney stones strike twice as many men as women, but there are simple ways to stop their formation.

 Image: © pixologicstudio/Getty Images

If you've ever passed a kidney stone, you will never forget it, and you'll do anything to avoid it again. If you haven't, here is what you could expect: unbearable pain centered in your mid- to lower back that often comes in waves for 20 minutes to an hour at a time, until the tiny stones finally pass out of the body through your urine.

Unfortunately, as you age, the odds of getting kidney stones tends to rise. "Kidney stones are more common in men than in women, and in about half of people who have had one, kidney stones strike again within 10 to 15 years without preventive measures," says Dr. Brian Eisner, co-director of the Kidney Stone Program at Harvard-affiliated Massachusetts General Hospital.

Research we're watching

 Image: © wildpixel/Thinkstock

Can a high-tech water bottle help prevent painful kidney stones? The National Institutes of Health is hoping to find out. As many as one in every 11 people in the United States today has experienced a painful kidney stone. Kidney stones, a condition also referred to as nephrolithiasis or urolithiasis, are hard deposits that form inside the kidneys. They can be as small as a grain of sand or the size of a marble or larger. Symptoms of a stone include excruciating pain, interrupted urine flow, or bleeding inside the urinary tract. In short, kidney stones are definitely something you want to avoid. One way to keep stones from developing is to drink lots of water. The problem is, people who have had a stone often don't drink enough water to prevent new ones from forming, even when they're told how important it is to stay hydrated.

This trial, which will enroll 1,642 people, is trying to change that by using a "smart" water bottle that not only encourages people to drink a target amount of water each day, but also tracks their consumption using an app. People in the test group who reach their daily fluid intake targets will get financial incentives. Health coaches will provide added support to help participants achieve their goals. The findings could shed new light on how to get people to change their behavior to prevent this common and painful condition. For more information on the trial or to see if you qualify, visit www.health.harvard.edu/push.

Ask the doctors

Q. My bad cholesterol has been rising, and my doctor suggested that I start taking a statin. I've read that red yeast rice has many of the cholesterol-lowering benefits of a statin, and I would rather go the natural route. However, I recently heard on a newscast that red yeast rice can have adverse effects on the kidneys. Is it still safe for me to take this supplement?

A. It's true that red yeast rice, which contains monacolin K, a chemical that's identical to the active ingredient in the cholesterol-lowering drug lovastatin (Mevacor), may reduce your LDL (bad) cholesterol and lower your total cholesterol. However, an independent analysis of a dozen 600-milligram (mg) capsules of red yeast rice products conducted a few years ago found that the actual monacolin K content varied widely — from 0.1 mg to 10.9 mg. (The lowest dose of lovastatin is 20 mg.) In addition, one-third of the products were contaminated with a potentially toxic compound called citrinin, which can damage the kidneys. The Food and Drug Administration (FDA) has blocked the sale of red yeast rice supplements that contain enough of the active ingredient to make them as effective as lovastatin because they haven't undergone the drug approval process. Unlike FDA-approved drugs, supplements can be sold without proof of effectiveness and purity.