Basic nutrition

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The alkaline diet is an alternative medical nutrition theory and has been known since around 1913.

Sulfur in reducing amino acids ( methionine and cysteine ) is produced in the body of sulfuric acid , which the urine is excreted and this consequently acidified. While (acute) acidosis (too low blood pH ) is a recognized (often intensive care) clinical picture, supporters of the alkaline diet also deny completely healthy people the ability to regulate their acid-base balance through the kidneys (so-called " chronic acidosis "). To prove this, urine pH tests are sometimes carried out, although a low urinary pH is an expression of a functioning acid excretion. So that the body does not become "acidic", the proportion of base-forming foods must be increased; as a dietary supplement are for citrate ( "base powder") propagated. While the formation of acid in a protein-rich diet can be explained physiologically , in alternative medicine many foods and luxury foods that appear or are actually unhealthy are labeled as acid-forming even without such a reason .

Proof of effectiveness has never been provided, and there is no plausible mechanism of action. Professional organizations and consumer protection see no advantages for a person with a normal diet.

theory

Basic assumptions and their evidence

The reason for the alkaline diet is the hypothesis that the body is "acidified" by too many acid-producing components in the food of the usual "civilized diet", which brings the acid-base balance of the body into a health-damaging imbalance. Such “chronic acidosis ” (not to be confused with acidosis , in which the usual pH value of the blood is below 7.35) has harmful consequences in the long term, which manifest themselves in the form of various diseases and chronic ailments, such as the Examples include gout , osteoarthritis , rheumatic diseases , neurodermatitis , osteoporosis , muscle pain, chronic fatigue, sleep disorders, cardiac arrhythmias , allergies and cancer .

The above-mentioned consequences of a diet-related acidification corresponding to this hypothesis are justified by the fact that the excess acids in the body, which are mainly stored in the connective tissue , contain basic minerals in the body, e.g. B. would bind to itself from the bones and form salts , which ultimately lead, among other things, to demineralization of the bone tissue . In addition, the resulting salts and also the acids themselves are deposited in cells and tissues, especially in the connective tissue of all organs. An alkaline diet prevents such pathological processes. It can also cure existing diseases.

The clinical pictures of acute acidosis and, on the contrary, alkalosis are known in evidence-based medicine and occur only briefly in healthy people. The body regulates the acid-base balance independently. Excess acids are the kidneys excreted , during exhalation is carbon dioxide excreted; The sweat also contains acids, as does the excreted feces . Persistent acidosis is only known in metabolic diseases such as diabetes mellitus and functional disorders of the kidneys. If too many acids are permanently in the blood under these circumstances, calcium is broken down from the bones to compensate for this after a while , which can promote osteoporosis .

The concept of basic nutrition does not mean the acute acidosis of the (arterial) blood, which is referred to as blood acidosis , nor the uric acid level, but an alleged chronic acidosis of the body tissue. Since it is diet-related, it has also been referred to as alimentary chronic tissue acidosis for several years ( Latin alimentum , food). It is assumed that even healthy people cannot excrete excess acids in the long term, which has a disease-promoting effect.

history

The thesis that an imbalance of acids and bases in the body causes disease was probably first put forward by Francis de la Boe Sylvius in the 17th century, at that time still related to the "humors" according to the ideas of humoral pathology . The recommendation was to treat the patients accordingly with acids or with alkalis. At the beginning of the 20th century, Howard Hay and Franz Xaver Mayr first took up this theory. Mayr used the saying “the acid is the ultimate cell poison”.

The hypotheses about acidification of the body became popular at the beginning of the 20th century and were represented by several diet founders, including Howard Hay ( food combining ), Maximilian Bircher-Benner and Are Waerland ( Waerland food ). The Swedish biochemist Ragnar Berg has determined the alleged acid and base content in many foods by analyzing the ashes after burning. He equated cations with bases and anions with acids. These findings correlated with the urine values ​​determined after predominantly plant-based and predominantly meat-based food. Berg then formulated the theory of excess acid in the body, which could ultimately even lead to "acid death", since he associated ketoacidosis in diabetics with hyperacidity.

This theory was taken up by Bircher-Benner: "If the acid excess grows so high that the food bases are no longer sufficient (...) the organism gradually gets into acidic distress, until acidosis, a state of life-threatening acid poisoning, sets in." Bircher-Benner also made uric acid responsible for the development of cancer . Otto Warburg observed that cancer cells ferment glucose instead of burning it, so that the tumor acidifies its surroundings with lactic acid ( Warburg effect ). Supporters of the alkaline diet, on the other hand, like to claim that Warburg identified acidification as the cause of tumor growth.

In 1927 a book by the American journalist and health food advocate Alfred McCann was published in German under the title Kultursiechtum und Säuretod , in which the hyperacidity theory is also represented. A quote:

"We know that the meat diet acidifies the blood and that man's only means of defense against the attacks of diseases is based on the normal alkalinity of the blood."

Because the acids are excreted through the kidneys, McCann described meat eaters as "kidney killers".

Food

The base-forming foods mentioned include, for example, potatoes , vegetables , lettuce, fruit and dried fruits . The acid-forming foods mentioned include protein sources such as meat , sausage , fish , cheese , eggs .

Sugar is often mentioned as acidifying, but it is neutral. Whole grain flour is often called base-forming, but has an acid-forming effect like white flour. Coffee is often mentioned as acidifying, but has a slightly alkaline effect.

The following table according to Vormann gives the so-called PRAL value ( potential renal acid load ) in the unit milliequivalent per 100 g. A negative value means basic, a positive value means acidic. The values ​​agree well with the acid exposure in 24-hour urine.

Food PRAL value in meq / 100 g
Whole Wheat Buckwheat 2.42
Wholegrain oat 7.90
Whole grain millet 2.46
Potatoes −6.14
Rice , natural 8.03
Rice, peeled 3.82
Whole grain rye 4.67
Rye flour type 650 3.52
Whole Wheat Wheat 6.71
Wheat flour type 405 4.98
Grain sprouts 1.73
Peas 1.69
Peas, sprouted, fresh 1.17
Peas, dried 1.26
lenses 4.81
Lentils, sprouted, fresh 2.69
Soybeans −9.07
Tofu , fresh 2.60
Tofu, firm 0.33
Apple −2.36
banana −7.46
orange −3.17
Raisins −11.94
fennel −9.77
cucumber −2.30
carrot −5.17
tomato −4.17
spinach −12.1
Chicken egg 9.96
Yogurt , 3.5% fat −0.37
kefir 0.34
Cow's milk 0.06
whey −1.88
Emmentaler 21.54
Gruyere 20.35
cottage cheese 8.43
Mozzarella 11.50
Quark 8.86
Lyons 4.85
turkey 11.13
Beef , roast, fresh 10.44
Pork , roast, fresh 8.69

The PRAL value can be estimated using the following formula:

PRAL / [meq] = 0.49 × protein / [g] + 0.037 × phosphorus / [mg] - 0.021 × potassium / [mg] - 0.026 × magnesium / [mg] - 0.013 × calcium / [mg]

Evaluation and criticism

  • The suitability as a permanent form of nutrition is controversial.
  • The effectiveness of the alkaline diet in preventing diseases has not been proven, apart from the side effects of an overall healthier diet.
  • There is neither scientifically recognized evidence for the hyperacidity theory nor a plausible mechanism of action.
  • The Hessian consumer center describes basic nutrition and corresponding dietary supplements as superfluous. In their statement it says: "The natural buffer systems of the body, a balanced diet with plenty of vegetables and fruit, moderately animal-based foods, plenty of drinking and exercise protect sufficiently against acidity."
  • From a statement by the German Nutrition Society : “A base-excess diet has no verifiable health benefits. Over-acidification of the body is not to be feared in healthy people, as buffer systems keep the acid-base level in the blood and tissue constant. Acidosis (hyperacidity) can occur, for example. B. come with a metabolic imbalance in diabetes mellitus. "
  • An acidic pH of urine is primarily a proof that the kidneys excrete excess actually acids. It fluctuates constantly throughout the day. This value is not a reliable indicator that the body is over-acidic; the pH value of the blood would have to be determined for this.
  • Attributing very different diseases and symptoms in principle monocausally to the diet does not correspond to the current state of knowledge of medicine and nutritional science.
  • Alkaline food supplements (NEM) were rated by the consumer magazine Öko-Test as "unsatisfactory" at best, and most as "unsatisfactory". This is due to the lack of benefit for healthy consumers, the overdosed ingredients and an inadequate declaration.
  • There is no risk of bone fractures in old age due to supposed hyperacidity. Two meta-reviews that were examined show that a so-called acidic diet has no negative effects on the bones.

literature

  • Philippe-Gaston Besson: Dynamic life through acid-base balance. Waldthausen Verlag, 1997.
  • H. Knophius: acid-base balance. Verlag Graefe & Unzer, 2003.
  • E.-M. Kraske: acid-base balance. Verlag Graefe & Unzer, 1999.
  • Hans-Helmut Martin and Stefan Weigt: Do we eat sour? In: UGB-Forum 6, 2005, pp. 296-299. (pdf 93 kB)
  • Christian Rummel: Ragnar Berg. Life and work of the Swedish nutrition researcher and founder of the basic diet. With a foreword by Gundolf Keil . Publishing house Peter Lang, Frankfurt am Main / Bern / Vienna / Oxford / New York 2003 (= European University Papers, Series VII, Department B: History of Medicine. Volume 10). At the same time medical dissertation Dresden 2001.

Web links

Individual evidence

  1. a b Vormann, Jürgen. Acid-base balance: the compass for more vitality and well-being. Gräfe and Unzer, 3rd edition, 2018.
  2. Hans Krautstein: How much acid can humans tolerate? Schrot & Korn September 1999, accessed August 13, 2012.
  3. a b c d Deutschlandfunk Kultur; Andrea Fock and Udo Pollmer: The history of the basic diet , accessed on March 23, 2018
  4. Thomas Remer, Triantafillia Dimitriou, Friedrich Manz: Dietary potential renal acid load and renal net acid excretion in healthy, free-living children and adolescents. In: The American Journal of Clinical Nutrition. 77, 2003, p. 1255, doi : 10.1093 / ajcn / 77.5.1255 .
  5. Business with "acidification" by food - consumer advice center Hessen clears up ( Memento of October 8, 2007 in the Internet Archive ) August 8, 2006
  6. Öko-Test destroys basic NEM . In: DAZ.online . February 9, 2015 ( deutsche-apotheker-zeitung.de [accessed October 2, 2018]).
  7. Nicola Kuhrt: Expensive nonsense with basic products. In: MedWatch . August 27, 2019, accessed January 16, 2020 .