High-protein Diets May Harm Your Kidneys

A high-protein diet is believed to be healthy. It is suggested that it keeps you fit, helps you to lose fat and to retain lean muscle mass. Avoiding carbohydrates and substituting them with proteins has become a leading dogma for all those who care for their looks and health.

Kamyar Kalantar-Zadeh, Holly M Kramer and Denis Fouque [1] now consider it necessary to question this belief and to put a tough warning label on our modern eating habits. “We may save calories, but we may also risk the health of our kidneys.” The promise of saving calories and losing weight is why a high-protein diet is very often recommended to people who suffer from diabetes or who are obese. But the crux of the matter is that these groups of people are especially vulnerable to the kidney-harming effects of a high protein intake. “A high-protein diet induces glomerular hyperfiltration, which, according to our current state of knowledge, may boost a pre-existing low-grade chronic kidney disease, which, by the way, is often prevalent in people with diabetes. It might even increase the risk of de novo kidney diseases”, explains Prof Fouque, past-chair of the European Renal Nutrition Working Group. “To put it in a nutshell: To recommend a high-protein diet to an overweight diabetes patient may indeed result in loss of weight, but also in a severe loss of kidney function. We want one, but we also get the other.”

In view of the rising number of people affected by type-2 diabetes, and the fact that at least 30% of patients with diabetes suffer from an underlying chronic kidney disease, the experts believe it is high time that the diabetes population and the general public are warned. “By advising people – especially those with a high risk for chronic kidney disease, namely patients with diabetes, obese people, people with a solitary kidney and probably even elderly people – to eat a protein-rich diet, we are ringing the death bell for their kidney health and bringing them a big step closer to needing renal replacement therapy”, says Fouque. This is the essence of the editorial by the three authors mentioned above, which has been published along with two new studies on that topic in the current issue of NDT. The analysis of a Dutch cohort [2] showed a strictly linear association between daily protein intake and decline in kidney function. The higher the intake, the faster the decline. The result of an epidemiological study conducted in South Korea [3] points to the same direction: Persons with the highest protein intake had a 1.3 higher risk of faster GFR loss. The finding itself is not new. Many previous studies have shown that a high-protein diet may harm kidney function, and this is why patients with a known early-stage chronic kidney disease are recommended a low-protein diet by their nephrologists. As long as it is unclear whether it makes any difference if the proteins are animal- or plant-based, the recommendation is to abstain in general from a high protein intake.

However, as Fouque and his colleagues point out, the problem are the people who have a mild chronic kidney disease which they are totally unaware of and who follow the trend of eating a protein-rich diet because they believe it is healthy. “These people do not know that they are taking the fast lane to irreversible kidney failure”. Prof Fouque and his ERA-EDTA colleagues want to start an information campaign and raise awareness for this problem among the general population. “It is essential that people know there is another side to high-protein diets, and that incipient kidney disease should always be excluded before one changes one eating habits and adopts a high-protein diet.”

Source: EurekAlert!

What Is a Renal Mass and What Is a Localized Renal Tumor?

One in four renal masses are benign. Smaller masses are more likely to be benign. Larger masses are more likely to be cancerous. Some tumors can be slow to grow while some can be aggressive. Aggressive tumors form, grow and spread very quickly.

Most diagnosed kidney growths are small and localized masses. Localized means that the tumor has not spread out from where it first started. Around 40% of kidney cancers are localized renal masses. Masses may be solid or cystic (having fluid). Most cystic masses are benign.

Where are the Kidneys and What are they for?

The kidneys are two bean-shaped organs near the middle of the back. There is one kidney below the rib cage on each side of the spine. Each kidney is about the size of a fist.Our kidneys’ main job is to filter the blood. The kidneys remove water and waste from our blood in the form of urine. Urine then leaves our body by way of the bladder and the urethra. As a filter, the kidneys:

  • Detoxify (clean) our blood
  • Balance fluids
  • Maintain electrolyte levels (e.g., sodium, potassium, calcium, magnesium, acid)
  • Remove waste (as urine)

The kidneys also make hormones that help to:

  • Keep blood pressure stable
  • Make red blood cells
  • Make bones stay strong

What do we Know about Kidney Cancers?

Kidney and renal pelvis cancers are the 12th leading cause of cancer death in the U.S. Kidney cancer is 9th on the list of the 10 most common types of cancer. Almost all of the kidney cancers in the U.S. are renal cell carcinomas (RCC). These cancers form in the lining of the small tubes in the kidney.

Doctors are able to diagnose kidney cancer earlier because of better testing. Kidney cancer is more common in men than women. More men than women die from the disease. Kidney cancer is more common in African Americans, American Indians and Alaskan Native people. You can get kidney cancer at any age. But, it is more common in older people (those greater than 75 years old).

There will be more than 73,000 new cases of kidney cancer in the U.S. in 2019. Of those cases, nearly 15,000 people will likely die from the disease. The earlier the cancer is diagnosed-the better the chances of survival. The five-year survival rate for all kidney cancers is about 74%. If the cancer spreads over the body, then this rate falls to about 12%. The five-year survival for localized kidney and renal pelvis cancer is 92.5%.

Around the world, over 300,000 people get kidney cancer each year. Half of those people will die from the disease. But, less people are dying each year from the disease.

Types of Renal Tumors

Renal tumors are grouped by where they start growing and by their structure. The main classes of tumors are:

  • Renal Cell Carcinomas (RCC). These are the most common malignant kidney tumors. They are found in the lining of the small tubes in the kidney. RCC may form as a single tumor within a kidney. It can also form two or more tumors in one kidney.
  • Benign renal tumors. There are about 9 different types of tumors in this class. Some can grow quite large. But most are non-cancerous and do not spread to other organs.
  • Wilms tumor. Wilms tumors almost always are found in children and are rarely found in adults.


Over half of renal tumors are found by chance and may have no symptoms. They often are found when your doctor is doing a test for other health problems. Tumors found in this way are more likely localized to the kidney. These types of tumors have good outcomes. Most renal masses have no symptoms in the early stages. But, if there are symptoms, they will most likely be:

  • Hematuria (blood in urine)
  • Flank pain between the ribs and hips
  • Low back pain on one side (not caused by injury) and that does not go away
  • Loss of appetite
  • Weight loss not caused by dieting
  • Fever not caused by an infection and that does not go away
  • Anemia (low red blood cell count)


Doctors do not know what causes kidney cancer. But, they do know there are certain risk factors that increase your chance of getting kidney cancer. They are:

  • Smoking (male smokers have a higher risk than female smokers)
  • Drinking a lot of alcohol
  • Obesity, poor diet
  • Family history of high blood pressure
  • Being on kidney dialysis
  • Workplace exposure to chlorinated chemicals
  • Heredity (some kidney cancers are found in multiple family members)

How can you lessen the risk for kidney cancer?

Some actions may help to reduce the risk of kidney tumors:

  • Stop smoking
  • Limit alcohol intake
  • Eat fruits and vegetables like broccoli, brussel sprouts, cabbage, collard greens and kale
  • Add fatty fish into your diet such as salmon, tuna and sardines
  • Maintain a healthy diet
  • Exercise regularly, it will help prevent obesity and hypertension


There are no routine lab tests to find kidney cancer. Often tumors are found during genetic screening or when you see a doctor about another problem. If your doctor thinks you have a kidney tumor, he/she might send you to see a urologist. A urologist is a doctor who specializes in the genitourinary system. When you see your urologist, they will ask you questions about your symptoms and health. They will give you a physical exam, order lab tests and may take pictures of your body.

Some common tests and procedures for renal tumors

Your doctor may use many tests and procedures to make a diagnosis. Here are some that you might expect:

  • Physical exam and history is when your healthcare provider checks your body and asks you questions about your health and family. He/she will check for lumps or any other unusual signs. Your health habits, past illnesses and treatments will also be discussed.
  • Basic or complete metabolic panel (CMP), also called a blood chemistry, is used to evaluate organ function and check for certain conditions.
  • Complete Blood Count (CBC) checks for certain substances. If amounts are higher or lower than normal, that may be a sign of disease.
  • Urinalysis checks for infection, blood and protein in your urine.
  • Kidney function tests check how well the kidneys are working. They show if the kidneys are getting rid of waste the right way.
  • Ultrasounds take pictures of your kidneys and organs.

Imaging Tests:

  • CT scan (CAT scan or computed tomography) and MRI (magnetic resonance imaging) are useful for diagnosing and staging renal masses. They can show which kidney is affected, whether the cancer has spread and if other glands or organs are involved.
  • Chest x-rays help to find out what stage your cancer is. A mass in your chest usually suggests your tumor has spread.
  • Bone scans may be done if you have bone pain or neurologic (nerve) symptoms.
  • Renal mass biopsy may be done to find out what type of tumor you may have. A biopsy is when cells or tiny parts of an organ are removed and studied. A pathologist views the sample under a microscope. The biopsy will show if the tumor started in another part of your body or if it started in the kidney. A biopsy may also tell if there is an infection, such as an abscess. It can help find cancer and make better treatment choices.

Source : Urology Care Foundation

Healthy Plant-based Diet (but Not Plant-based Junk Food) May Protect Kidneys

Lisa Rapaport wrote . . . . . . . . .

While a healthy-plant based diet is tied to a lower risk of kidney disease, people who fill their plates with starchy, sugary vegetarian fare may actually increase their risk of kidney damage, a new study suggests.

Researchers examined data on eating habits and kidney function for 14,686 middle-aged adults, following half of them for at least 24 years. Overall, 4,343 participants developed chronic kidney disease.

People who most closely adhered to a diet of healthy plant-based foods were 14 percent less likely to develop kidney disease than individuals who rarely ate these foods, the study found.

At the same time, participants who consumed the greatest amount of unhealthy vegetarian foods were 11 percent more likely to develop kidney disease than people who ate the smallest amounts of these foods.

“Relatively higher intakes of healthful plant foods and relatively lower intakes of less healthful plant foods and animal foods are associated with favorable kidney outcomes,” said senior study author Casey Rebholz of the Johns Hopkins Bloomberg School of Public Health in Baltimore.

“We believe that healthful plant foods played an important role because higher consumption of healthful plant foods were associated with a lower risk of kidney disease and slower decline in kidney function when the consumption of less healthful plant foods and animal foods were held constant,” Rebholz said by email.

A healthy plant-based diet includes whole grain foods; fruits like apples, pears, and oranges; veggies like dark, leafy greens, sweet potatoes, and broccoli; nuts and natural peanut butter; and legumes like string beans and lentils.

Study participants who had the healthiest plant-based diets consumed an average of nine to ten servings a day of these foods. These individuals were more likely to be women, white, older, high school graduates, and physically active.

An unhealthy plant-based diet may limit meat but load up on potatoes. This type of diet might also include juice instead of whole fruit, sodas and sugary drinks, and lots of candy, cake and chocolate.

Participants who had the least healthy plant-based diets consumed an average of seven servings a day of these foods. They were more likely to be men, younger, sedentary, and drink more alcohol.

The association between plant-based diets and chronic kidney risk was especially pronounced for people with a normal weight at the start of the study, researchers report in the Clinical Journal of the American Society of Nephrology.

The study wasn’t a controlled experiment designed to prove that certain eating patterns directly contribute to kidney disease.

One limitation of the study is that researchers relied on participants to accurately recall what they ate and drank, which can lead to measurement errors, the study authors note. Researchers also may not have had a complete picture of long-term eating habits.

Still, it’s possible eating more fruits and vegetables may make it easier for the kidneys to rid the body of toxins, said Dr. Michal Melamed of Albert Einstein College of Medicine and Montefiore Medical Center in Bronx, New York. Fruits and vegetables have less acid, putting less demand on the kidneys than meats which have a lot of acid.

“It could also be that the people who eat more fruits and vegetables also do other things, such as exercise more, get more sleep, or in general have a healthier lifestyle and that is the reason why this association is seen,” Melamed, who wasn’t involved in the study, said by email. “In general, multiple studies have shown that eating a lot of processed meats and red meats is probably not good for people, not just for their kidney health but also for the heart.”

Source: Reuters

Study: Drinking Caffeinated Soft Drinks While Exercising in Hot Weather May Increase the Risk of Kidney Disease

The study is published ahead of print in the American Journal of Physiology — Regulatory, Integrative and Comparative Physiology.

A research team from the University at Buffalo in New York studied healthy adults in a laboratory environment that mimicked working at an agricultural site on a hot day (95 degrees Fahrenheit). The volunteers completed an hour-long exercise cycle consisting of a 30-minute treadmill workout followed by three different five-minute lifting, dexterity and sledgehammer swinging activities. After 45 minutes of exercise, the volunteers rested for 15 minutes in the same room while drinking 16 ounces of either a high-fructose, caffeinated soft drink or water. After the break, they repeated the cycle three more times for a total of four hours. Before leaving the laboratory, the volunteers were given more of their assigned beverage to drink before consuming any further fluids. The volume was either 1 liter or a volume equal to 115 percent of their body weight lost through sweating, if that amount was greater. The researchers measured the participants’ core body temperature, heart rate, blood pressure, body weight and markers of kidney injury before, immediately after and 24 hours after each trial. All volunteers participated in both soft drink and water trials separated by at least seven days.

The research team found higher levels of creatinine in the blood and a lower glomerular filtration rate — markers for kidney injury — after the soft drink trial. These temporary changes did not occur when the participants drank water. In addition, the participants’ blood levels of vasopressin, an anti-diuretic hormone that raises blood pressure, was higher and they were mildly dehydrated during and after the soft drink trial. “The consumption of soft drinks during and following exercise in the heat does not rehydrate,” the researchers explained. “Thus, consuming soft drinks as a rehydration beverage during exercise in the heat may not be ideal. Further work will need to discern the long-term effects of soft drink consumption during exercise in the heat, and its relation to the risk of [kidney disease].”

Source: The American Physiological Society

Kidney Disease Risk Tied to Sugar-Sweetened Drinks

People who drink lots of sugar-sweetened drinks may be putting themselves at a heightened risk for kidney disease, a new study suggests.

The study of more than 3,000 black men and women in Mississippi found that those who consumed the most soda, sweetened fruit drinks and water had a 61 percent increased risk of developing chronic kidney disease.

That water was included in the increased risk surprised the researchers. It’s possible, however, that participants reported drinking a variety of types of water, including flavored and sweetened water. Unfortunately, that information was not included in the Jackson Heart Study, which was used for the project.

Specifically, the researchers looked at beverage consumption as reported in a questionnaire given at the start of the study in 2000 to 2004. Participants were followed from 2009 to 2013.

“There is a lack of comprehensive information on the health implications of the wide range of beverage options that are available in the food supply,” said lead study author Casey Rebholz.

Rebholz is an epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

“In particular, there is limited information on which types of beverages and patterns of beverages are associated with kidney disease risk in particular,” she added.

And while the study found an association between sugary drink consumption and kidney disease, it couldn’t prove a cause-and-effect relationship.

The study findings were published online Dec. 27 in the Clinical Journal of the American Society of Nephrology.

In an accompanying journal editorial, Dr. Holly Kramer and David Shoham of Loyola University in Chicago said the findings have public health implications.

Although a few U.S. cities have reduced consumption of sugar-sweetened beverages by imposing taxes on them, others have resisted these efforts, the editorial noted.

“This cultural resistance to reducing sugar-sweetened beverage consumption can be compared to the cultural resistance to smoking cessation during the 1960s after the Surgeon General report was released. During the 1960s, tobacco use was viewed as a social choice and not a medical or social public health problem,” Kramer and Shoham wrote.

In another editorial, a kidney disease patient, Duane Sunwold, said he changed his eating and drinking habits to put his disease in remission. He’s a chef who offers recommendations to other kidney disease patients who are seeking to cut back on sugar-sweetened drinks.

Source: HealthDay

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