Please feel free to forward it to your circle of friends. If you need to reprint, please contact backstage.
The number of words edited in this article is 397 1 word, and the estimated reading time is 12 minutes.
I told you the story of Sean Baker, who used to be a "Hercules". He is a doctor of medicine (Texas Tech University 200 1) and a plastic surgeon (Texas University 2006). He also loves sports and is an excellent athlete.
Shawn Baker, 52, has been eating steak, high-quality fat, water and sometimes eggs, seafood and cheese every day for more than two years.
Such a high-protein diet did not make him feel uncomfortable, but enjoyed it very much. He also benefited a lot from it. His body fat rate was low, his blood pressure was normal, C-reactive protein (an inflammatory indicator of the body) decreased, and all joint pains disappeared.
However, as you are worried, there has always been such a health legend, that is, "a high-protein diet will hurt the kidneys." Sean Baker was more or less skeptical in this process. After all, if it hurts the kidney, it is a very worthwhile thing. ...
So, when he was in the physical examination, he made a special renal function examination. Unexpectedly, the result made him very worried. It turns out that his blood urea nitrogen (BUN) is slightly higher than the standard value (2.9 ~ 7.5 mmol/L), which is a sign of kidney problems in the eyes of many people.
However, Sean Baker didn't stop eating the whole meat. Why? ①
First of all, we need to know, what is blood urea nitrogen (BUN) mentioned by Sean Baker? Blood urea nitrogen is the main by-product of protein, which is produced by the liver and filtered by the kidney.
Therefore, a person's blood urea nitrogen level is an important information to reveal the operation of liver and kidney.
However, what will lead to the increase of blood urea nitrogen? Common diseases such as infection, kidney disease, stress, drug abuse, pregnancy, burns, shock, aging and so on.
Another non-pathological reason is "high protein diet". To put it bluntly, you eat more meat.
Of course, blood urea nitrogen is not the only index to measure renal function, and there are many items, such as:
→ Serum creatinine (SCR) ②
Creatinine is the waste formed by the decomposition of creatine in muscle, and healthy kidneys will filter out creatinine and other wastes in blood.
When the kidney is damaged, the creatinine clearance rate is not so high, and the serum creatinine may increase.
However, the factors that lead to the increase of creatinine level are not only kidney problems, but also dehydration, high-protein diet and strenuous exercise.
The normal creatinine level is 0.9 ~ 1.3mg/dL in men and 0.6 ~1.65,438+0 mg/dl in women.
→ glomerular filtration rate (GFR)
Glomerular filtration rate is another index to know a person's renal function (about 125ml/min for normal adults), but it is not measured, but calculated according to serum creatinine, age, sex and weight.
It can determine the degree to which a person's kidneys filter blood, that is, the efficiency of your kidneys.
Based on Sean Baker's serum creatinine level (1.2 mg/dL), high glomerular filtration rate and his living conditions, it can be confirmed that the increase of blood urea nitrogen caused by high protein diet is not pathological, that is to say, his kidneys are very healthy.
In addition, Sean Baker also shared a calculation method, which is to calculate his own "creatine clearance value". The normal creatinine clearance rate of healthy women was 88–128 ml/min, and that of healthy men was 97–97–137 ml/min. His result was 165438+.
Sean Baker's calculation results, if you want to calculate, you can go to ③.
In fact, ShawnBaker is not the only one who has had a similar experience. Ken D Berry, MD (a family doctor and researcher certified by the American Academy of Family Physicians) once talked about this issue through video. ④
He mentioned that in order to get to the bottom of it, he tried a whole meat diet of 1 year, and there was no difference in renal function.
There is a clearer example in front of most people. If a high-protein diet is harmful to renal function, then everyone who adheres to the traditional bodybuilding method (high-protein diet) may die of renal failure.
And as far as scientific research is concerned, there is no reliable evidence that healthy people's kidneys will be damaged by a high-protein diet.
Many people say that a high-protein diet is harmful to the kidneys, based on the fact that many wastes produced by protein's metabolism are filtered by the kidneys. If the intake of protein is increased, it will obviously increase the workload of the kidney, and it will definitely damage the kidney after a long time.
It is true that high protein intake will increase the workload of the kidneys, but there is really no conclusive evidence of kidney damage.
→20 16 study: the intake of protein was 3-4 times of the daily recommended amount, and the kidney was not damaged.
Jose Antonio of the International Sports Nutrition Society (ISSN) led the randomized controlled study. The subjects were 14 men who had received resistance training. ⑤
The experiment lasted for 12 months, and participants consumed 2.5/kloc-0 to 3.32 grams of protein per kilogram per day (3-4 times the daily recommended amount).
The results showed that there were no adverse changes in renal function or other health indicators.
→ 2065438+2008 Meta-analysis: High protein intake in healthy adults does not damage the kidneys ⑥.
The researcher * * * reviewed 2 144 abstracts, of which 40 articles were reviewed in full, and after 28 analyses, the data of 1358 participants were involved.
The results showed that the intake of protein in healthy adults would not have adverse effects on renal function.
→20 18 intervention study: the high protein diet has no adverse effects on the subjects.
In this study, the researchers divided 355 male and female subjects with prediabetes into the following two different dietary groups: ⑦.
Medium protein diet group: energy accounts for 15%.
High protein diet group: energy accounts for 25%
Among them, the high protein diet group can reach 1.6 g protein per kilogram. After 12 months, the researchers found that:
There is no difference between a moderate intake of protein and a large amount of every day, and there is no indication that a high-protein diet has a negative effect on the kidneys of participants.
As far as renal function is concerned, there is no difference between proper daily intake and high protein.
And interestingly, there are some signs that with the increase of protein intake, renal function will improve.
Yes, the saying that "eating protein hurts the kidney" has always been a myth, and there is no reliable evidence to confirm its establishment. It does not appear in bodybuilders who adhere to a high-protein diet, and there is no evidence in the general healthy population.
In fact, only people with kidney problems may have negative effects because of a high-protein diet. If your kidneys are healthy enough, eating more meat won't hurt them.
However, I think many people are more concerned about the question: If protein is not hurting the kidney, what is it?
Remember the news I once shared? The 8-year-old girl died of kidney cancer. The doctor told her the cause, and her father collapsed and cried: It's all my fault! 》)。
The girl's father is a pastry chef and brings some desserts to his children after work every day. At the age of 8, chubby Lili (a child's pseudonym) suddenly became thinner, complained of stomachache, and was taken to the hospital for diagnosis of advanced renal cancer.
Despite her best efforts, the doctor failed to save her life, and the reason why Lili got such a disease was that the doctor said that she had a lot to do with eating desserts every day.
Eating dessert leads to high blood sugar, which may not only lead to diabetes, but also the most likely behavior to hurt the kidney, but few people know this.
Now adhering to the concept of "eating meat hurts the kidney", many people simply have no time to pay attention to the high carbohydrates they eat (such as rice flour sugar, which will soon be converted into glucose when ingested, leading to an increase in blood sugar).
But in fact, it is clinically found that the biggest cause of end-stage renal disease is diabetes, and the proportion of diabetic patients suffering from renal disease is 1/3 (in other words, 1 person in every three diabetic patients has renal problems).
20 15 Reuters reported a Norwegian study, and scientists found that even those with hyperglycemia (people who have not yet developed diabetes) will increase the risk of kidney damage. ⑧
This is because the "erosion" of high blood sugar on the kidney is multi-level:
→ Renal vascular damage
The filtration system of the kidney is covered with many tiny blood vessels, and persistent hyperglycemia will constantly "impact" them, causing these blood vessels to become narrow or even blocked.
→ cause renal hypertension.
The disorder of glucose metabolism in local tissues of kidney will lead to the thickening of glomerular basement membrane and the accumulation of extracellular matrix, which may increase the blood pressure of glomerular capillaries and trigger renal hypertension, thus aggravating the damage to kidney.
→ invade the nerves of the body
Diabetes can also cause damage to the nervous system, which can transmit information in the brain and other parts of the body, including the bladder and kidneys.
→ aggravate inflammation in the body
Diabetes is a metabolic disease. People with this disease often have great inflammatory reaction and oxidative stress, which will accelerate the damage of renal endothelial cells, blood vessels and microcirculation.
In addition, fructose can cause similar damage to the liver and kidneys. Therefore, a suggestion to improve kidney health is to strictly control sugar intake.
It is worth mentioning that a low-carbon diet is not a high-calorie diet. It doesn't mean you eat meat three times a day. We low-carbon people have two meals at most, and many people have one meal a day. Because we have enough meat, we are not hungry at all.
Previous studies also found that after low carbon, the renal function of diabetic patients returned to health.
Recently, I had the opportunity to meet a foreign expert. I consulted Dr. Atkins' nurse, Ms. Jacqueline, on this issue.
Her answer is that eating more meat and some indicators such as urinary protein are rising. These are short-term phenomena, and the body will gradually adjust. It is recommended to check again after a while.
In fact, protein is very important to everyone. Unlike carbohydrates, protein is an essential nutrient for human body.
However, they use meat and eggs as carriers, and there are often controversies in recent years. The most concentrated one is the saying that "high protein hurts the kidney".
In this article, I talked about Shawn Baker, MD, who insisted on a "pure meat diet" (the diet contains animal protein and high-quality animal fat). He was worried at first, too. After examination, he found that blood urea nitrogen (BUN, the main by-product of protein, filtered by the kidney) was on the high side.
Ordinary people may immediately think of kidney damage. However, a non-pathological reason for the increase is that protein eats more food.
Comparing creatinine clearance rate, glomerular filtration rate and overall health status, the doctor confirmed that Sean Baker's kidneys were very healthy.
In fact, if "high protein hurts the kidney" is established, all athletes who adhere to the traditional bodybuilding method (high protein diet) may die of renal failure.
But such a thing did not happen, because this legend has always been a hypothesis, and in scientific research, there are constantly new discoveries to deny it.
Many people are concerned: if it is not high protein, what is kidney damage?
The first two causes of kidney injury are diabetes and hypertension, among which diabetes accounts for the highest proportion.
Reuters 20 15 reported a study that even without diabetes, if blood sugar remains high, it may increase the risk of kidney damage.
Therefore, to protect the kidneys, it may be more practical to control sugar intake than not to eat meat.