March 10, 2016 is World Kidney Day, which is a global awareness campaign, aimed at raising awareness of the importance of the kidneys in human health and longevity.
This campaign is a joint initiative of the International Society of Nephrology (ISN) and International Federation of Kidney Foundations (IFKF). The World Kidney Day campaign was first launched in 2006. Each year the campaign focuses on one theme. This year the theme is Kidney Disease & Children. Last year the focus was Kidney Health for All. In 2014, the focus was Chronic Kidney Disease (CKD) and Aging. Unlike heart diseases and cancer which appear with a bang, chronic kidney disease is a silent killer. It also represents a huge economic burden on the health care system. For example, in 2012 the United States Medicare system spent about $50 billion for the treatment of chronic kidney disease alone, excluding total kidney failure, kidney transplantation and other kidney diseases. Hence, let us discuss some facts about the kidney and kidney diseases, and why this campaign is important, and what can we do to protect our kidneys and enjoy a healthier and longer life.
Prevalence of Kidney Diseases: The prevalence of chronic kidney diseases is rising steadily all over the world, not just in the United States or the Western countries. According to USRDS (United States Renal Data System), there are 26 million (8.4% of the population) chronic kidney disease patients in the United States. No such systematically documented numbers are available for India. Various studies put the number of chronic kidney disease patients in India as 50 to 100 million (4% to 8% of the population). Experts warn that chronic kidney disease is spreading like a silent epidemic in India. The reasons are as follows. The two major contributors for chronic kidney disease are diabetes mellitus (sugar diabetes) and hypertension (high blood pressure). Uncontrolled blood sugar and/or blood pressure slowly damage the kidneys. Diabetes accounts for about 44%, and hypertension for about 27% of the chronic kidney disease incidence. Due to rapid changes in food and cultural habits, life styles and lack of sufficient physical activity the prevalence of both diabetes and hypertension are rising to epidemic proportions in India. Not only that, more and more young people are developing these two conditions, thus adversely impacting the productivity in the prime of their lives. Per capita productivity is significant determinant of the GDP of a country. Other causes of chronic kidney disease are polycystic kidney disease, excessive and/or long-term use of pain killers, etc. Another condition is kidney stones, which affects about 1 million people in the United States, most of whom are between 20 to 40 years of age. The exact prevalence of kidney stones in India is not known, but it may be comparable to that in other countries of the West.
What are the Functions of the Kidneys? Many people think that kidneys just produce urine, a waste product of metabolic activity in the body. That is only one aspect of kidney functions. Kidneys actually maintain the balance of water and salt in our body, without which other vital organs, such as brain, liver and lungs cannot function. This is exemplified in the fact that when kidneys fail, other organs, including liver and lung can fail. By maintaining the proper proportions of water and salt in the body, kidneys directly contribute to blood pressure regulation. Kidneys produce substances like endothelin and prostaglandins that regulate blood pressure and blood vessel function. Kidneys also produce erythropoietin, a hormone that stimulates the production of red blood cells in the bone marrow. In chronic kidney disease the production of erythropoietin is decreased. That is the reasons why chronic kidney disease patients develop anemia, and require treatment for it. Vitamin D is processed in the kidney to its active form, which helps in the deposition of calcium in the bones. Activation of vitamin D in the kidney is impaired in kidney disease patients, leading to loss of bone density and fractures. Thus, kidney is not just an excretory organ, but also a regulatory organ. Kidneys do an enormous work. Each day, they continuously filter the water and other small molecules from the blood and produce 180 liters of filtrate, i.e., about 47.4 gallons, enough to fill the 2.7 gas tanks of TATA Sumo Gold or 2.5 gas tanks of Ford Explorer. Of this total amount of water filtered every day, kidneys have to reabsorb or take back 179 liters (99.4%) into the blood. Now you can imagine what happens if kidneys fail to take back even 1% of filtered water. That will increase urine output from 1 liter a day to 2-3 liters. So, kidneys are very efficient. Not only that they have a large reserve capacity, which means a large amount of kidney tissue should become dysfunctional before one notices appreciable changes in the urine and body. That is why it is possible to donate one kidney and lead a healthy normal life with the remaining one kidney. These facts should make us realize that we should respect our kidneys and take care of them.
How to Take Care of Our Kidneys? Actually, this is not very difficult. It is simple, if we understand it properly. First, we need to drink enough clean water every day, so that our kidneys can flush the waste products efficiently. Imagine, what happens if there is no water in the flush tank in your toilet. Avoid drinking carbonated drinks and drinks containing fructose, which are not good for general health also. How much water to drink? This has been always a dilemma. There are no specific guidelines, and it varies depending on the weather conditions, and also from person to person, based on individual level of physical activity. As a simple rule, one must drink at least one glass (8 ounces or 250 ml) of water with each meal. There is a popular belief circulating in social media that one should drink 8 glasses of water 8 times a day (about 2 liters). Please do not fall into that trap. There is no scientific evidence for that. The food we eat contains at least 1 liter of water per day. In addition, water is produced in our bodies as a byproduct of metabolic activity. So, drinking excess amount of water causes sodium levels in the blood diluted and thus go down, a condition called hyponatremia. Hyponatremia is a serious condition as it may cause convulsions, landing the person in ICU (Intensive Care Unit). Hence, use prudence and drink wisely. Please remember, if our bodies require more water, then we will feel thirsty. No need to overload water, which is dangerous. Just a word of caution, this thirst mechanism may not work well in older people. Hence they need to ensure that they drink enough water, even if they do not feel thirsty. There is also a myth that drinking a large amount of water will help to lose body weight. People who drink more water also eat less food. But that is not the best way to reduce food consumption to lose weight.
Avoid junk foods and cut down on fast foods. Eat plenty of fruits and vegetables, and consume yogurt on daily basis. One should pay attention to salt intake. Too much salt in the food is not good. Salt is essential, but too much of it hurts the kidney by rising the blood pressure. So, watch out the large bag of chips or pickles or soups, and avoid consuming them on regular basis. The other food item that hurts the kidneys is eating too much meat, especially red meats. High consumption of protein results in production of high amount of nitrogenous waste products in the body, such as urea. The kidneys have to over work to eliminate these waste products, and if they have to do such hard work every day then they may fail, like any machine that is made to over work.
What about beverages? Alcohol can also damage the kidney, if taken in excessive amounts over long time. But before that can happen, the liver is damaged more. It is better to exercise moderation while consuming alcoholic drinks. Coffee and tea do not hurt the kidney, if taken in moderate amounts. Too much tea may increase urine flow, which is a common experience. Nicotine in the cigarettes causes retention of water in the body. So, smokers should not overload their bodies by drinking too much water.
There are a few pain relievers, such as ibuprofen and naproxen, which have the potential to damage the kidney over the time, due to the development of so called analgesic nephropathy. Analgesic nephropathy is a relatively common condition in the United States due to excessive or long-term consumption of over-the-counter pain relievers.
What if One is Diagnosed with Diabetes and/or High Blood Pressure? First thing, do not panic. As long as the blood sugar levels are controlled with proper diet, exercise and medications (in that order); and blood pressure is controlled by restriction of salt consumption, exercise and drugs (in that order), one can avoid kidney damage to a large extent. Proper control of blood sugar and blood pressure are known to slow down the damage to the kidney, so it can take a long time before the kidneys fail due to these two disease conditions. It should be realized that to control blood sugar or blood pressure, drugs alone are not enough. One has to pay attention to the food one eats, and do exercise on regular basis, at least 20-30 min, three times a week. Regular waling for a mile or two also helps. Avoid snacking between meals and mid-night snacks. Those with diabetes should check their hemoglobin A1c (HbA1c) levels once every three months and should ensure that the values are brought down to 6-7%. Unlike fasting blood sugar value, which is a single snapshot, HbA1c provides information about long-term control of blood sugar. Similarly, one has to check ones blood pressure on regular basis and ensure that it is within the normal limits. If one can achieve these two, and maintain them, one need not worry about chronic kidney disease for a long time. In fact, there are documented cases where persons diagnosed with diabetes or high blood pressure, and taken care of their health so much, they actually lived longer than those who did not have these two conditions. So, it is all about how much we care our own bodies and health.
Finally, please watch this short video about taking care of your kidneys:
Author: Prof. Bellamkonda K. Kishore, M.D., Ph.D., MBA