Posted on March 25 2018
Our kidneys work around the clock filtering waste products out of our blood stream. In a 24 hour period they process up to 150 quarts of blood and produce one to two quarts of urine wastewater every day. In this chapter from his book How Not To Die, Dr. Michael Greger discusses what impairs kidney function, ultimately resulting in kidney failure and death for almost 50,000 Americans every year. But the more startling statistic is that in a national survey, less than half of all Americans tested had normal kidney function, and about a third of all Americans over the age of 64 suffer from Chronic Kidney Disease (CKD). Perhaps even more frightening than that statistic is that 75% of these sufferers don’t even know they have CKD because most people with this disease have no symptoms. And between 1990 and 2010 kidney disease was found to be one of the causes of death that increased the fastest among all such diseases. What is going on?
Most kidney disease is characterized by gradual loss of function over time. The other confounding factor is that because kidney malfunction is so damaging to some other parts of the body, 95% of the people with kidney disease die from other diseases exacerbated by failing kidneys before they reach end-stage kidney failure. For example, patients with kidney disease are one hundred times more likely to die from heart disease than individuals with normally functioning kidneys.
But, if kidneys fail, we can always get a new transplant, right? Well, unfortunately, kidney donors are in short supply, and if you are therefore forced to go on dialysis (where a machine filters your blood for you) your life expectancy is less than three years. Not good.
So, let’s focus on how to avoid getting kidney disease in the first place. Healthy kidneys work hard to retain proteins and other vital nutrients for our blood supply from what we consume while filtering out toxic and other useless wastes into our urine. When kidneys start to leak protein into our urine it is a sign that they are not functioning properly. Researchers at Harvard University followed thousands of healthy women, their diets and their kidney function for more than a decade and found that three specific dietary components were associated with signs of declining kidney function: animal protein, animal fat, and cholesterol. Plant protein appears to be handled differently than animal protein by the kidneys. High animal protein intake induces a state of hyperfiltration in the kidneys, making the kidneys work much harder. Plant protein causes no such stress on the kidneys. In a 2014 six-month, double-blind, randomized, placebo-controlled clinical trial (the “gold standard” of scientific studies) it was found that plant protein helped to preserve kidney function.
The reason for the different effects of animal versus plant protein on the kidneys is because animal protein causes hyperfiltration, inflammation and increased acid formation in the kidneys. Within hours of eating tuna, for example, your kidney filtration rate can increase by 36%. No such increases are caused by plant protein. Seafood is also the most powerful cause of increased acid load in the kidneys, followed by pork, then poultry, cheese, beef and eggs. Animal proteins cause more acid to form in the kidneys because they have higher levels of sulfur-containing amino acids which ultimately results in the creation of sulfuric acid. Fruits and vegetables are the opposite, they are base forming, which helps to neutralize acids in our kidneys. Higher dietary acid is associated with significantly higher risk of protein leakage into the urine, an indicator of kidney damage.
To counteract the negative effects of acid formation, the kidneys produce ammonia (which is a base) to help neutralize the acid. However, over the long term, if the kidneys are forced to continually produce ammonia to constantly counteract acid formation from animal proteins, all the extra ammonia in the kidneys can have its own toxic effect. So, you can help your kidneys function normally by consuming less animal proteins and more plant-based proteins.
Reducing your consumption of animal protein can also help you to avoid kidney stones, which are caused by the crystallization of hard minerals or uric acid in the kidneys due to very high levels in your kidneys. Approximately one in eleven of all Americans will suffer from kidney stones. Vegetables are the best reducer of acid in the kidneys, followed by fruit and then beans. Uric acid stones can in some cases be completely dissolved away by a combination of eating more fruits and vegetables, restricting animal protein and salt intake, and drinking at least ten glasses of fluid a day.
Reducing your consumption of animal proteins can also help to reduce elevated phosphorus levels in the blood which can cause damage to blood vessels as well as accelerate aging and bone loss. Too much phosphorus in the body can come from the phosphate in animal-based foods, which is more readily absorbed by the blood stream than phosphorus from plants, which is called phytate. But the most significant source of phosphates is not that which is naturally occurring in animal proteins, but rather the phosphates which are artificially added to meat to improve its color, add “water weight” to increase its cost, and to reduce the liquid that would normally seep from meat as it aged. In the United States, eleven different types of phosphate salts are allowed to be injected into meat and poultry (a practice that has long been banned in Europe). However, producers are not required to disclose whether they have injected additives like phosphate salts. Phosphates are hard to avoid in the grocery store meat section. One survey found that 90% of all chicken products contained phosphate additives.
Finally, let’s focus on nitrites and nitrosamines, which are carcinogenic and cause kidney cancer. Nitrates are found in both animal and plant-based foods. In digestion, the body converts nitrates to nitrites but they only become harmful if they are then turned into nitrosamines and nitrosamides. To do that, amines and amides must be present, which are found in abundance in animal products. The transformation of nitrites into nitrosamines and nitrosamides can occur in the meat itself or in your stomach during digestion, but antioxidants found naturally in plant-based foods tend to block the formation of these carcinogens in the body.
Compounding these natural sources of nitrosamines and nitrosamides is the fact that processed and cured meats have added nitrites to retain color and to prevent the growth of botulism bacteria. A study done by the National Institutes of Health and the AARP of more than 500,000 Americans concluded that, as one example, 20% of heart disease deaths among American women could be averted if those who consumed the most processed meats (ham, bacon, salami, hot dogs, and sausages) cut their consumption down to no more than a half strip of bacon per day. It is best to eliminate these items from your daily menu.
So, to reduce your risk of kidney damage, kidney failure, kidney stones, or kidney cancer, try reducing your consumption of meat and dairy products (especially processed meats) and increase your consumption of plant-based foods. Juice Plus capsules and Complete protein shake mix (available at Objects of Desire Artful Living) are both easy and convenient ways of helping you do so. Stay healthy. It is hard to live artfully when you are suffering from kidney disease.