Acid or alkaline, how does it work?

Lemon juice is said to be a healthy drink with potential beneficial properties. It is particularly popular in the alternative health community due to its supposed alkalizing effects. However, lemon juice has an unmistakably low pH and should therefore be considered acidic, not alkaline. This article examines why some people consider lemon juice to be alkalizing, despite its acidic pH, and what this means for your body.

What is pH?

When talking about acidic or alkalizing foods, it is important to understand the concept of pH. Simply put, pH is a measure of the acidity or alkalinity of a solution on a scale of 0 to 14. A pH of 7 is considered neutral. Any pH value below 7 is considered acidic, and any pH value above 7 is considered alkaline. On the pH scale, the difference between two adjacent numbers represents a tenfold difference in acidity. For example, a pH of 5 is 10 times more acidic than a pH of 6 and 100 times more acidic than a pH of 7.

Because they contain a high amount of citric acid, lemons have an acidic pH. Lemon juice has a pH between 2 and 3, which means it is 10,000 to 100,000 times more acidic than water.

The supposed benefits of alkalizing foods

The alkaline diet has grown in popularity in recent years. It is based on the principle that the foods you eat can alter your body’s pH. To set the record straight, there is no evidence to support the alkaline diet. According to research, the foods you eat have very little effect on your blood pH.

However, the alkaline diet classifies foods into three groups:

Acidifying foods: meat, poultry, fish, dairy products, eggs and alcohol.
Neutral foods: natural fats, starches and sugars.
Alkalizing foods: fruits, nuts, legumes and vegetables.
Proponents of this diet believe that eating large amounts of acid-forming foods can make your body’s pH more acidic, which increases your susceptibility to disease.

For example, many believe that your body steals alkaline calcium from your bones to compensate for the acidifying effects of the foods you eat. Some also believe that cancer only develops in acidic environments and that you can prevent or even cure it if you follow an alkaline diet. Followers of this diet therefore try to improve their health and reduce the risk of disease by limiting acidifying foods and favoring alkalizing foods.

Why is lemon juice considered alkalizing despite its acidic pH?

Whether a food has an acidic or alkaline effect on the body has little to do with the pH of that food before it is digested. Rather, it depends on whether acidic or alkaline byproducts are created after the food is digested and processed by your body. One method of estimating what type of by-product a food will produce is the technique of “ash analysis”. In this method, food is burned in the laboratory to simulate digestion. The pH of their ashes is used to classify foods as acidic or alkaline. Ash analysis is the reason why foods are sometimes said to produce acidic or alkaline “ash”. However, because ash analysis is an imprecise estimate, scientists now prefer to use a different formula that ranks foods according to their potential kidney acid load (PRAL). The PRAL of a particular food is the amount of acid expected to reach the kidneys after the body has metabolized that food.

In general, the kidneys keep the pH of the blood constant by eliminating excess acid or alkali through the urine. Acidic nutrients such as protein, phosphorus, and sulfur increase the amount of acid the kidneys have to filter out. Meats and grains, which tend to contain these nutrients, therefore receive a positive PRAL score. In contrast, fruits and vegetables are rich in alkaline nutrients such as potassium, calcium, and magnesium. These reduce the amount of acid the kidneys have to filter out and therefore get a negative PRAL score.

Like other fruits, lemon juice produces alkaline byproducts once it has been metabolized. It therefore has a negative PRAL score. This is why some people consider lemon juice to be alkaline, even though it has an acidic pH before being digested.

Lemon juice can alkalize your urine but not your blood.

Many alkaline diet proponents use pH test strips to check the alkalinity of their urine. They think it helps them determine how alkaline their body really is.
What they don’t realize is that while lemon juice can make your urine pH more alkaline, it doesn’t have the same effect on your blood pH.

According to research reviews published in 2013 and 2012, the foods you eat have a very limited effect on your blood pH. Some much older studies have estimated that you would need to eat the equivalent of 8 kg of oranges, which have a similar alkalizing potential to lemons, in one sitting to raise your blood pH by just 0.2.

Foods have such limited effects on the pH of your blood because your body needs to maintain pH levels between 7.35 and 7.45 for your cells to function properly. If your blood pH values ​​fall outside this range, you have a condition called metabolic acidosis or alkalosis, which can be very dangerous if left untreated. However, this rarely happens because your body is very good at keeping your blood pH values ​​from falling outside the normal range. One of the ways to keep levels constant is to use your kidneys to filter out excess acids in your urine.

This is why your urine may become more acidic a few hours after eating a large steak, or less acidic after eating a diet high in alkalizing foods. However, while the acidity of your urine may vary depending on the foods you eat, the pH of your blood remains constant. So while drinking lemon juice can make your urine more alkaline, it’s unlikely to have an effect on your blood pH.

Does the pH of food matter?

Proponents of the alkaline diet seem to believe that the foods you eat can affect your health by influencing the pH of your blood. They generally claim that alkalizing foods prevent bone loss and can prevent cancer. However, as discussed above, this theory completely ignores the role your kidneys play in regulating your blood’s pH, among other methods your body uses to maintain pH.

Also, contrary to popular belief, many leading reviews have concluded that acid-forming diets have no impact on calcium levels in the body. In fact, several studies link diets high in protein, which are thought to be acidifying, to healthier bones.

As for the effects some people believe acid-forming foods have on cancer, studies show that there is no direct link between the amount of acid-forming foods you eat and your risk of developing the disease. Nevertheless, an alkaline diet may have health benefits for some people. For example, people with kidney disease generally need to limit their protein intake. Consuming an alkaline diet may slightly reduce this need.

It may also reduce the risk of kidney stones in people prone to developing them. However, more research on these purported benefits is needed before any solid conclusions can be drawn.

Other Benefits of Lemon Juice

Although it has very little alkalizing effect on the blood, regular consumption of lemon juice may have several other beneficial health effects. For example, lemon juice is rich in vitamin C, a powerful antioxidant that helps keep the immune system strong and prevent and fight disease. 30ml of lemon juice covers about 13% of your daily vitamin C needs.

Also, drinking a drink rich in vitamin C, such as lemon water, with meals can help increase the absorption of certain minerals, including iron. Lemon juice also contains small amounts of antioxidants that may help reduce the risk of heart disease by strengthening blood vessels, reducing inflammation and preventing plaque buildup. Also, some research suggests that regular consumption of lemon juice may help prevent the formation of certain types of kidney stones.

In summary

Lemon juice has an acidic pH before being digested. However, once metabolized by the body, it produces alkaline byproducts. These alkaline byproducts can make your urine more alkaline but have very little effect on your blood pH. Therefore, the health benefits that lemon juice may offer are unlikely to come from its purported alkalizing effect.

* Presse Santé strives to transmit health knowledge in a language accessible to all. In NO CASE, the information given can not replace the advice of a health professional.

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