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From healthy nutrition, a virus does not care anything
Translated from Dutch. View the original post
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Healthy food reduces the risk of all kinds of diseases, writes Martijn Katan. But you don't prevent a corona with it.
Eat healthy, that keeps your resistance up. That's the only corona advice no one seems to doubt. But is it true? Healthy eating and drinking reduces the risk of myocardial infarction, obesity, diabetes and other diseases, but does it also help against infectious diseases such as corona?
A person's resistance to infection by bacteria and viruses may be defective. That's a serious problem. Defects in the immune system that provides our resistance occur, for example, in AIDS, after radiation or chemotherapy, and in children with congenital malformations of the immune system. You also often hear that your resistance is affected by what you eat. The Food Center says: 'by eating healthy. . . your body is better able to fight pathogenic bacteria and viruses. 'What kind of research has been done and are the results convincing?
Many studies have been done on the effect of nutrition and dietary supplements on components of the immune system. Such effects are studied in the test tube, in experimental animals or in volunteers. That's very feasible, you give people a nutrient or supplement, for example fish oil or a vitamin pill, you take blood and you measure what has changed in some of the thousands of types of cells and proteins involved in the immune system..
Resistance is not measurable
But with that you do not know yet whether the diet or supplement really protects against infectious diseases. Resistance is not measurable and can be expressed in a number, it is above all a word that feels good. We don't have enough insight into the immune system to understand exactly which components need to change in what way to protect us from a particular infection. Before that, it is necessary to examine the occurrence of the infectious disease itself.
This applies equally to food as with medicines and vaccines. A vaccine can show promising effects in the test tube and in laboratory animals, it can increase the amount of antibodies to corona in the blood in volunteers and show beneficial effects on white blood cells.
But then the research is only halfway through; we do not yet know if the vaccine will prevent corona. This requires experiments in which large groups of people receive the vaccine or a fake injection (placebo). These experiments are now running; in a few months or years, we will know which of the dozens of vaccines under investigation fewer people have fallen ill by corona in the vaccine group than in the placebo group. This was often disappointing in the past with vaccines and medicines for other diseases, many of which were ultimately ineffective or had too many side effects. A noose for the manufacturer, because then the drug does not come on the market.
A favorable exception
For public health, it is very important to find out whether nutrition affects the risk of infectious diseases. However, relatively few such studies appear in the top medical journals. A favorable exception was a study by Judith Graat in the group of Kok in Wageningen. They gave six hundred elderly people vitamins or a fake pill for a year and investigated how much flu or cold they were getting. The outcome was that vitamins did not help. The research appeared in the top medical journal JAMA. Ten years before, Canadian researcher Ranjit Chandra had published in another top magazine, The Lancet, that vitamins and minerals did reduce respiratory infections in the elderly. Why did he find anything else? Because he scamed the place and made up his results. His publications were withdrawn and the substantiation of the effect of nutrition on infections received a sensitive blow.
One possible reason why studies on nutrition and infectious diseases rarely appear in top journals is that they are often not about the occurrence of the disease itself but about effects on white blood cells. This preference may be because they can be done more quickly; a study of blood cells takes weeks or months while a study with disease as a result takes years.
Everything in the risk scale
There may also be something else to play. A researcher may have built a scientific career based on promising effects of nutrition or supplements on blood cells or proteins in the test tube, in laboratory animals or in the blood of volunteers. A study with real disease outcomes would put all that at risk; the outcome of such a final experiment is often disappointing, as with medicines. Hence perhaps not all nutritionists are eager to test whether healthier eating really prevents infectious diseases. That's why we still don't know.
Healthy diet reduces the risk of all kinds of diseases, from strokes to tooth decay. Those who have eaten and drank healthy for years have strengthened their condition and indirectly improved their chances of surviving coronary infection. But don't think that by filling your supermarket cart with healthy food, you can prevent infectious diseases such as corona.
Eat healthy, that keeps your resistance up. That's the only corona advice no one seems to doubt. But is it true? Healthy eating and drinking reduces the risk of myocardial infarction, obesity, diabetes and other diseases, but does it also help against infectious diseases such as corona?
A person's resistance to infection by bacteria and viruses may be defective. That's a serious problem. Defects in the immune system that provides our resistance occur, for example, in AIDS, after radiation or chemotherapy, and in children with congenital malformations of the immune system. You also often hear that your resistance is affected by what you eat. The Food Center says: 'by eating healthy. . . your body is better able to fight pathogenic bacteria and viruses. 'What kind of research has been done and are the results convincing?
Many studies have been done on the effect of nutrition and dietary supplements on components of the immune system. Such effects are studied in the test tube, in experimental animals or in volunteers. That's very feasible, you give people a nutrient or supplement, for example fish oil or a vitamin pill, you take blood and you measure what has changed in some of the thousands of types of cells and proteins involved in the immune system..
Resistance is not measurable
But with that you do not know yet whether the diet or supplement really protects against infectious diseases. Resistance is not measurable and can be expressed in a number, it is above all a word that feels good. We don't have enough insight into the immune system to understand exactly which components need to change in what way to protect us from a particular infection. Before that, it is necessary to examine the occurrence of the infectious disease itself.
This applies equally to food as with medicines and vaccines. A vaccine can show promising effects in the test tube and in laboratory animals, it can increase the amount of antibodies to corona in the blood in volunteers and show beneficial effects on white blood cells.
But then the research is only halfway through; we do not yet know if the vaccine will prevent corona. This requires experiments in which large groups of people receive the vaccine or a fake injection (placebo). These experiments are now running; in a few months or years, we will know which of the dozens of vaccines under investigation fewer people have fallen ill by corona in the vaccine group than in the placebo group. This was often disappointing in the past with vaccines and medicines for other diseases, many of which were ultimately ineffective or had too many side effects. A noose for the manufacturer, because then the drug does not come on the market.
A favorable exception
For public health, it is very important to find out whether nutrition affects the risk of infectious diseases. However, relatively few such studies appear in the top medical journals. A favorable exception was a study by Judith Graat in the group of Kok in Wageningen. They gave six hundred elderly people vitamins or a fake pill for a year and investigated how much flu or cold they were getting. The outcome was that vitamins did not help. The research appeared in the top medical journal JAMA. Ten years before, Canadian researcher Ranjit Chandra had published in another top magazine, The Lancet, that vitamins and minerals did reduce respiratory infections in the elderly. Why did he find anything else? Because he scamed the place and made up his results. His publications were withdrawn and the substantiation of the effect of nutrition on infections received a sensitive blow.
One possible reason why studies on nutrition and infectious diseases rarely appear in top journals is that they are often not about the occurrence of the disease itself but about effects on white blood cells. This preference may be because they can be done more quickly; a study of blood cells takes weeks or months while a study with disease as a result takes years.
Everything in the risk scale
There may also be something else to play. A researcher may have built a scientific career based on promising effects of nutrition or supplements on blood cells or proteins in the test tube, in laboratory animals or in the blood of volunteers. A study with real disease outcomes would put all that at risk; the outcome of such a final experiment is often disappointing, as with medicines. Hence perhaps not all nutritionists are eager to test whether healthier eating really prevents infectious diseases. That's why we still don't know.
Healthy diet reduces the risk of all kinds of diseases, from strokes to tooth decay. Those who have eaten and drank healthy for years have strengthened their condition and indirectly improved their chances of surviving coronary infection. But don't think that by filling your supermarket cart with healthy food, you can prevent infectious diseases such as corona.
Martijn Katan is biochemist and emeritus professor of nutrition at the Vrije Universiteit Amsterdam. For sources and figures see mkatan.nl.
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