by William Lu Have you ever heard of the saying “Alkaline food is good, acidic food damages your health”? As people care more and more about their health nowadays, lots of health guidelines have emerged. Some are based on scientific evidence, and some are from people’s experience, but others seem to be logical and scientific but are actually false. Let’s look at the misleading concepts behind alkaline and acidic food. The ostensible theory appeals to partial scientific evidence and interprets it in the wrong way. The theory says that the body should maintain a mild alkaline condition in order to keep healthy. It says that food can be classified as acidic or alkaline. Generally, alkaline-forming foods include fruits and vegetables, and acid-forming foods include meat, fish, eggs, and grains. If the body becomes acidic, then the person will become ill, fatigued, depressed, or get cancer. To have a healthy life, we should eat more alkaline food and avoid acidic food. The theory attributes lots of people’s ailments to modern dietary habits which are full of acidic food. What’s wrong with this theory? To begin with, let’s look at what acid and alkaline really are. In chemistry, we know that a water molecule is H2O, made up of 2 hydrogen and 1 oxygen atom. In water, most of it remains H2O, but a small portion dissociates into H+ hydronium ion and OH- hydroxide ion. The concentration of H+and OH- is inversely proportional, that is to say, when the concentration of H+ becomes greater the concentration of OH- becomes smaller, and vice versa. In liquid, when H+ and OH- have exactly the same concentration, it is defined as neutral. When H+ is higher, then the liquid is acidic; when H+ is lower, then it is alkaline. We often use pH to indicate the acidity or alkalinity for convenience, which is inversely proportional to the concentration of H+. In 25 degrees Celsius, pH=7 for neutral liquid; pH below 7 is acidic, and pH above 7 is alkaline. Here are some examples to illustrate what the pH is of some common things in our daily life. When discussing the effect of food on our bodies, acidity is obtained by burning food into ashes and then dissolving the ashes into water and testing its pH. Generally speaking, those foods which contain minerals like potassium, calcium, magnesium, iron, and sodium, are alkaline, and those that contain sulfur, phosphorous, and chlorine are acidic. This method is based on the assumption that the digestion of food in our bodies is similar to burning food, so the product after digestion is similar to the ashes after burning; both of them have a similar effect on our body pH. The pH obtained from ashes is different from the pH from original food; for example, lemon juice pH=2, but its ashes are pH>9.
In fact, pH differs over different parts of our bodies. Normally, in the mouth, pH=6.5-7.5; in the stomach, pH=1.5-3.5; in intestines, pH=4.0-7.0; and in blood, pH=7.35-7.45. Therefore, to say the body should be mildly alkaline is very crude. It is surely necessary to keep pH levels within a certain range, for if the level is too acid or too alkaline – in the mouth, the stomach, or the intestines – we cannot digest food. In blood, the cells cannot function in the wrong pH and will die. In the mouth, if the pH is too acid (original pH, not ashes pH), teeth will erode and form cavities. However, don’t worry that the food will change the pH in our blood, because it is rigorously regulated by the buffer system of our bodies: when we breathe, we exhale carbon dioxide which is acidic, and our kidneys pass excessive acid or alkaline. Modern diets contain too much meat and starch and lack vegetables, which causes many diseases. Experts advise us to eat more vegetables, which is coincident with their being alkaline. This oversimplified but scientific sounding theory has become widely accepted. Though food can be classified as acidic or alkaline, it should not be used to judge whether it is healthy or unhealthy. Both meat and vegetables are important. It is not necessary to spend money on pills to adjust “body pH.” It is futile to identify and memorize the alkaline or acidity of particular foods; what we should do is to have a balanced diet, avoid too much oil, sugar, and salt. References https://en.wikipedia.org/wiki/PH www.shape.com/healthy-eating/diet-tips/ask-diet-doctor-alkaline-foods-vs-acidic-foods www.rense.com/1.mpicons/acidalka.htm a
0 Comments
Leave a Reply. |
Authors
The Taida Student Journal has been active since 1995 with an ever-changing roster of student journalists at NTU. Click the above link to read about the authors Archives
May 2024
|