Keto and Chronic Kidney Disease
A keto diet can harm your kidneys, as you may have heard your doctor warn. Protein is essential， However, many experts say that high protein can damage the kidneys and that people with chronic kidney disease should eat less protein. So the question is, is keto therapy a high-egg diet? Does it damage kidney health?
What is Chronic Kidney Disease?
Diabetes, high blood pressure, and atherosclerosis (hardening of the arteries) are all familiar diseases, but you may not know that they are also the main diseases that cause chronic kidney disease.
Chronic kidney disease, also known as CKD, is now a global public health burden. The global prevalence of chronic kidney disease (CKD) is 8-16% and increasing. Chronic kidney disease is a precursor to many diseases. Although the symptoms are less severe, it can increase the risk of heart disease and stroke, and in severe cases, even develop into kidney failure.
CKD manifests clinically as a decrease in glomerular filtration rate (GFR) and an increase in urinary protein excretion. Damage to renal tubular cells and proximal tubular cells leads to urinary protein loss, which in turn induces apoptosis of tubular cells, leading to tubular atrophy and even renal failure.
Chronic kidney disease is also associated with many complications, including increased cardiovascular mortality, acute kidney injury, cognitive decline, mineral loss, anemia, and fractures.
The Relationship Between Nutrition and Kidney Disease
Different nutrients have different effects on kidney health, and people with CKD may need to control specific components of their diet to maintain the balance of electrolytes, minerals, and body fluids in the body.
Protein
Protein is one of the most essential nutrients, necessary to maintain body tissues, certain hormones, and antibodies, and is involved in transporting essential molecules within the body. However, for patients with kidney disease, too much protein can become a burden on the kidneys. Because of their reduced glomerular function, too much protein can lead to a buildup of waste products in the blood. On the other hand, protein intake should not be too low as it may lead to problems in basic physiological activities and affect bone formation and muscle synthesis.
Minerals Calcium and Phosphorus
Calcium and phosphorus are not usually talked about together. People are familiar with the importance of calcium in the bones, but they rarely hear about phosphorus. However, in people with CKD, the balance of calcium and phosphorus is very important. Calcium and phosphorus are key to preventing osteoporosis. In addition, calcium is involved in cell signaling, wound coagulation, muscle activity (contraction), and nerve function; while phosphorus is involved in pH balance and energy production. Under normal conditions, calcium and phosphorus are generally in equilibrium. As kidney function deteriorates, protein is lost in the urine along with calcium, resulting in elevated phosphorus levels in the blood and thus weakened bones.
For people with CKD, it is important to either supplement calcium with adequate food or limit phosphorus intake. However, foods rich in phosphorus are usually also rich in calcium, so limiting phosphorus intake requires separate calcium and vitamin D, and vitamin K2 supplements.
Sodium-potassium Balance
Sodium-potassium balance is an important aspect of kidney function, which is also key to how the kidneys affect blood pressure. This is why people with hypertension are usually on a low-salt or low-sodium diet. Sodium is usually in the form of salt (sodium chloride), but many salt substitutes contain potassium along with controlled sodium, which regulates the sodium-potassium balance.
If kidney function is impaired, sodium levels can be poorly regulated. Excess sodium can lead to fluid accumulation, swelling, increased blood pressure, and heart load. sodium intake is also lower in people with CKD, but be aware that potassium replacement sodium products can lead to high potassium (hyperkalemia) and may also lead to abnormal and dangerous heart rhythms.
The Relationship Between Acidic Blood and Acidic Urine
When Dr. Thomas Weimbs presented his theory, he mentioned the importance of acidic blood and acidic urine, which are important indicators of kidney health.
Metabolic Acidosis
What is metabolic acidosis? Acidosis occurs when the kidneys and lungs are unable to maintain the body’s pH balance, and body fluids contain too much acid. This is because many processes in the body produce acid, and this is usually caused by decreased kidney function. This is why people with damaged kidneys are more likely to develop acidosis. Metabolic acidosis consists mainly of the accumulation of acid and the loss of bases. For example, diabetic acidosis, lactic acidosis, and renal tubular acidosis are due to the accumulation of acid, while hyperchloremic acidosis is due to the loss of sodium bicarbonate. Metabolic acidosis is a common manifestation of CKD, which in turn worsens as acid accumulates and renal function decreases.
What Are the Effects of Low Urine PH?
People with metabolic acidosis are usually very sick and are often admitted to the emergency room. A low urine PH, a test included in routine urinalysis and often used to assess the risk of kidney stones, can reflect the amount of acid in food and kidney function. Studies have found that people with impaired kidney function or kidney disease may have a lower urine PH. Not only kidney disease, but several other conditions can also exhibit lower urine pH and often end up complicating kidney disease as well. Examples include hyperglycemia and diabetes.
The Relationship Between Protein, Calories, and Kidney Health
Nephrologists often recommend that patients with CKD limit their protein intake, especially in the third stage of kidney disease progression and beyond. Does protein affect kidney function?
Too Much Protein Can Worsen CKD
We all agree that protein is a particularly good nutrient and should not impair organ function. However, for patients with severe kidney disease, too much protein can indeed impair kidney function. First, protein is a highly complex macromolecule that may induce vasodilatation of the afferent small renal arteries, glomerular hypertension, and hyperfiltration, all of which can exacerbate CKD. in addition, the accumulation of the end products of protein breakdown (such as p-cresol sulfate, indole sulfate, and trimethylamine) can exacerbate the risk of uremia. In addition, protein intake is not constant at different stages of kidney disease. For example, in stages 1-2 of CKD, protein is not a big issue, however, from stage 3 onwards, protein should be appropriately restricted.
Keto Diet = High Protein = High Calories?
Does a keto diet, which also consumes a lot of protein, exacerbate the symptoms of CKD? This question should be discussed seriously. If you have learned about the keto diet, you should know that the core of the keto diet is low in carbohydrates, while eating more good fats, mainly to maintain adequate energy and satiety. There is often a moderate requirement for protein intake, which should even be minimized to avoid the production of sugar xenobiotics.
CKD usually requires less than 0.6-0.8g/kg/day, which means that for a 60 kg adult, the daily protein intake should preferably not exceed 40g. 1g of protein does not mean 1g of meat, beef, chicken, fish, shrimp, and pork almost, every 1 tael contains about 7g of protein, while eggs only less than 5g.
Keto damage to the kidneys is easy, as long as there is an excess of protein or calories, for patients with advanced diabetes, there may be damage. If a kidney patient is on keto, protein and total calories must be strictly controlled and supplemented with adequate nutrients. Studies have found that low-calorie, moderate protein ketosis is a safe and effective approach to kidney health.