The Alkaline Diet Does It Work?


The alkaline diet, also known as the acid-alkaline diet or alkaline ash diet is mainly based on the idea that the food we eat can modify the acidity of our body (ie, the pH value).

The fundamental point of this diet is to replace acid-rich foods with alkaline foods. Some people believe that this diet is really miraculous and that it provides exceptional results, being able to help prevent and cure different diseases, including cancer.

How does the alkaline diet work?

Normally, when we metabolize food and extract energy from it, we are actually burning it, although in a slow and controlled way. During combustion, the food leaves residues in the form of ash, which can be acidic, alkaline or neutral.

The defenders of this diet proclaim that according to the type of ashes that have been formed, the acidity of our organism can be modified. Apparently, the acid ashes would make us more vulnerable to different diseases, while the alkaline ones are considered as protective. Therefore, the more alkaline foods consumed, we should have better health.

What foods make up the alkaline diet?

There are three groups of foods that are considered as acid, alkaline or neutral:

Acids: Meat, poultry, fish, dairy products, eggs, cereals and alcohol.

Neutral: Natural fats starch and sugars.

Alkaline: Fruit, vegetables, legumes and nuts.

The main components of the food that create an acidic environment would be protein, phosphate and sulfur, while alkaline foods would have as main components calcium, magnesium and potassium (Remer and Manz, 1995).

What are the normal pH levels?

The pH value is basically the measure to determine if a component is acidic or alkaline. To determine this, the following criteria are followed:

  • 0-7 is acid.
  • 7 are neutral.
  • 7-14 is alkaline

Some people argue that the pH of the urine should be measured from the test strip test, being the most appropriate that its value is 7 or less than 7. However, the pH value varies greatly in our own body and some parts will be more alkaline than others, or vice versa, so there is no fixed value for the whole body.

For example, the stomach contains hydrochloric acid and this gives the pH a value between 2 and 3.5, that is to say very acid, since it needs to decompose the food. On the other hand, human blood is always slightly alkaline, with a pH value between 7.35-7.45.

Does the food change the pH of the blood?

If the blood pH levels drop it could be a sign that we have a problem and therefore we would need to consult a doctor, but this would only happen as a result of certain diseases, and it has absolutely nothing to do with what we have eaten. .

To prevent the pH of our blood from falling too much, our body has a series of mechanisms to regulate it. These mechanisms are known as acid-base homeostasis and make it practically impossible for external causes to change blood pH, also including food.

Does the food change the pH of the urine?

In contrast, feeding it can change and l value pH of urine, although there seems to be too important for our body (Bonjour, 2013). Urine is one of the main means by which our body regulates the pH of the blood. Therefore, if we eat a food with a high acid content our body will be responsible for excreting the acid produced through the urine.

Therefore, the pH of urine is of no value when it comes to determining the general pH level of our body and it is not a reliable indicator to know what our state of health is.

Do acidic foods cause osteoporosis?

The osteoporosis is a degenerative bone disorder characterized by decreased bone mineral content. It is quite common in women who have gone through menopause and may increase the risk of fractures.

Many proponents of the alkaline diet point out that our body takes alkaline minerals from the bones to buffer the effect of the acidic foods we consume and maintain a constant pH. That is, a diet based on processed foods like the one that follows a large part of the population would cause a loss of bone mineral density.

This theory does not take into account that our kidneys produce bicarbonate ions that neutralize the acids in our blood and regulate our pH, so it would not make sense to point to acids as the main cause of osteoporosis (Koeppen, 2009).

Thanks to the excretory system and the respiratory system we can control our pH , since the bicarbonate ions together with the acids in the blood form carbon dioxide (which we expel through respiration) and water (which we urinate), what we maintain the acid-base balance of our organism.

Another factor that ignores this theory is that it ignores one of the main causes of osteoporosis:  the loss of collagen in bones (Saito and Marumo, 2010), which is paradoxically related to low levels of orthosilic acid and ascorbic acid , which We get through vitamin C (Rondanelli, Opizzi, Perna and Faliva, 2013).

There is also no relationship between a high acid content in the diet and bone density or the risk of fractures or between the pH of urine and bone health (McLean et al., 2011, Pedone et al., 2010; Fenton et al. ., 2010).

Moreover, it seems that high-protein diets  are related to better bone health and have little impact on the levels of calcium in our body (Promislow, Goodman-Gruen, Slymen and Barrett-Connor, 2002, Fenton, Tough, Lyon , Eliasziw and Hanley, 2011). The reasons why this seems to be the case is due to the increase in calcium retention and the activation of the hormone IGF-1, which stimulates muscle and bone repair (Bonjour, 2005, Fenton, Lyon, Eliasziw, Tough and Hanley, 2009).

Therefore, we can see that our bones are not involved in the process that causes osteoporosis in the body and that diets composed of foods with high acid content not only do not harm our bone health, but could improve it.

Do acidic foods cause cancer?

Some theories maintain that cancer can only appear in an acidic environment and that it could therefore be treated and even cured thanks to an alkaline diet. However, this theory can be disassembled for two reasons:

  1. The blood pH can never be modified by feeding.
  2. Even if the pH of blood or other tissues is altered, cancer cells will not develop more easily. In fact, cancer usually develops in organic tissues with a slightly alkaline pH of 7.4 (Martínez-Zaquilán et al., 1996).

It is true that tumors grow more rapidly in an acid environment, but the acidic environment is not responsible for the appearance of cancer, rather it is the cancer itself that creates an acidic environment, which in turn causes the tumor to grow at higher speed (Moellering et al., 2008). Therefore, there is no relationship between following a diet high in acid and cancer.


The alkaline diet is quite healthy compared to other diets, as it encourages the consumption of fruit, vegetables, legumes and nuts and completely restricts junk food.

However, there is no evidence that the creation of an alkaline environment in the body is conducive to better health. In fact, acids are some of the key components to have a healthy organism, such as amino acids and fatty acids.

Therefore, it is advisable to keep the best that this diet provides (consumption of natural foods and restriction of processed foods) but without avoiding foods high in protein since, although they raise the pH of urine, they are essential for full health.

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