Shaun Ward MSc ANutr
What Is The Alkaline Diet
The Alkaline Diet aims to create an ‘alkaline state’ within the body, as opposed to an acidic state caused by traditional western diets.
This is supposedly achieved by replacing acid-forming foods (meat, dairy, eggs, processed food) with alkaline-forming fruits and vegetables.
These dietary changes are claimed to lower the pH levels in the body, which is a scientific measure of acidity or alkalinity, to create a healthier physiological environment that is free not only of harmful acids but also disease.
Proponents of the program also state that it can prevent and treat a large range of health conditions, and even stop major diseases such as osteoporosis and cancer.
This hypothesis is, in part, due to the fact that modern-day eating programs produce twice the amount of acid in the body compared to pre-agricultural diets, where rates of these diseases are reported to be dramatically less than today. 
What Foods Can You Eat You The Alkaline Diet?
On the Alkaline Diet, it is recommended that over 70% of the food consumed should be sourced from alkaline-forming foods. This includes nearly all vegetables apart from pickled vegetables and sauerkraut.
Therefore, an emphasis is placed on green leafy vegetables such as:
- Root vegetables.
- Alkaline-forming fruits (lime, lemon, avocado, cherries, watermelon, bananas).
Banned Foods List
As a general rule of thumb, you'll want to limit or completely avoid consumption of the following foodstuffs:
- Anything containing soy.
- Anything with added sugar.
- Corn syrup.
- Red meat.
- White meat.
The Theory Behind The Diet
When foods are metabolized, there is always some degree of residue that is not needed for energy or health purposes - known as metabolic waste.
These metabolic waste products can be defined as either alkaline or acidic, depending on their pH value.
It is from this physiological component that the analysis of metabolic waste was explored, and some health enthusiasts speculated the benefits of minimizing acidic waste.
It has been mentioned that high amounts of acidic waste products from food would inevitably cause blood pH values to become acidic. In similar fashion, switching to more plant-based products would raise blood pH levels and create an alkaline environment in the blood.
Based on the ‘acid-ash hypothesis’, excessively acidic diets result in a number of negative health effects, whereas alkaline diets are deemed protective.
Do Foods Produce Different Amounts of Acid?
Yes. Omnivorous diets have shown to produce considerably greater amounts of endogenous acid production compared to vegetarian diets.
The reason for this is that omnivorous diets contain more high-protein foods, particularly those which are considerably high in phosphate and sulfur.
These sulfur-containing amino acids, methionine and cysteine, are oxidized into sulfuric acid which is an acid-producing waste product.
Unlike this, fruits and vegetables are mostly alkaline-producing foods as their metabolic waste products are organic precursors such as citrate and succinate.
Can Acid-Producing Foods Change Blood pH?
This question is crucial because unless these acid-forming foods result in a real physiological difference in blood pH, it is highly unlikely they will impact health.
Scientific research concludes that the human body has a well-established and tightly controlled system in which acids produced from the ingestion of food are rapidly buffered and excreted .
Specifically, the kidneys produce bicarbonate ions that are capable of neutralizing harmful acids in the blood . This process allows for a metabolic regulation of blood pH that inhibits any significant fluctuations in acidity.
Persistent ingestion of acid-forming diets may indeed cause very minor decreases in blood pH, but the metabolic buffering system does not allow for pH values to fluctuate outside of the normal physiological range. Any small fluctuations within the normal physiological range are described as diet-induced acidosis – not to be confused with acidaemia.
The interaction between bicarbonate ions and acids also allows for the acids to be easily excreted through the urine or via breathing.
Overall, the systemic balance of net acid production versus excretion remains neutral.
Only when these metabolic compensatory measures fail does diet-induced acidosis lead to serious cases such as acidaemia - marked by an abnormally high concentration of hydrogen ions in a person's blood.
Do Acid-Forming Foods Cause Cancer?
Acidic environments are a well-known factor associated with cancer progression.
In turn, it is logical to think that lower pH levels (more acidic) outside of cells will promote the growth potential of cancer cells.
However, it is important to note that the extracellular acidity in which cancer cells thrive is mostly generated by the tumor cells themselves as opposed to any metabolic waste products.
In other words, it is not the acidic environment that creates the cancer, but the cancer that creates the acidic environment.
Any minor and brief variation in blood acidity from metabolic waste products are not significant enough to impact on cancer growth to any measurable degree.
This is crucial to distinguish the misconceptions behind some claims made by advocates of the diet.
To add to this, scientific reviews conclude there is limited evidence to suggest that diet-induced acidosis is sufficient enough to increase the risk of cancer .
Do Acid-Forming Foods Cause Bone Loss?
The idea that acid-forming foods cause bone loss stems from the theory that it is necessary to leach calcium phosphate from bones in order to neutralize pH levels in the blood.
These theories were furthered by studies that claimed dietary acid loads are detrimental to bone mass .
Firstly, it is also crucial to remember that the buffering process is achieved from bicarbonate ion stores in the pancreas – not calcium phosphate from bone.
Bone does not seem an important source to stabilize bicarbonate stores in both theory and experimental data .
In addition, studies making these claims were conducted in patients with chronic kidney malfunction, or who were administered large amounts of ammonium chloride – an acidic compound. In turn, these studies purposely induced supraphysiological levels of acidity by using artificial supplementation, or unhealthy patients who were not able to excrete an acidic substance.
In healthy individuals, natural minor alterations in blood pH do cause bone issues or osteoporosis .
Do Alkaline-Forming Foods Maintain Bone Health?
Although acidic forms may not be detrimental to bone health, alkaline-forming foods such as most fruit and vegetables can improve bone health. However, assuming that fruit and vegetables are beneficial to bone health, such a positive influence would be mediated by mechanisms other than those related to their alkalinizing potential, such as their nutrient and phytonutrient composition.
A number of trials have shown that bone loss can be reversed by the addition of an alkaline-forming substance, such as potassium, by reducing the rate of bone break down and improving bone composition . Plant foods high in calcium, magnesium, and potassium seem to have the largest effects on bone health.
Potentially, these minerals are the ones most needed for the optimal functioning of the bodies internal buffering systems.
Is The Alkaline Diet Useful For Losing Weight?
It potentially could help you shed some weight, but that's not what it's designed to do by its creators.
The Alkaline diet is not a program that's intended to help followers lose weight; it does not impose any sort of caloric restriction on the follower; you can technically eat as much of the approved foods as you want (though that's obviously not advisable).
In order to use it for the purposes of losing weight, the dieter will need to modify it by capping their daily caloric intake below their total daily energy expenditure number (though we do not recommend this).
Always Run The Diet Schedule & Approved Foods Past A Doctor If You Have Any Health Conditions Before Starting Diet!
It's unlikely that this diet will be suitable for everyone. If you have any sort of underlying medical condition(s), we highly advise that you speak with a healthcare professional to gain their approval first.
Is The Alkaline Diet Healthy?
Even though the fundamental concept of it is wrong, the alkaline diet still represents a very healthy diet that encourages high consumption of fruits, vegetables, and other plant foods, while restricting the intake of processed junk foods.
Due to this, the health benefits will be similar to that seen by the Vegan Diet, Mediterranean Diet, and the DASH diet.
It is noted that the Alkaline diet may also have a specific dietary use for individuals with chronic kidney disease in an attempt to avoid unnecessary use of this organ .
The Bottom Line
The Alkaline Diet aims to create an alkaline state within the body, as opposed to an acidic state caused by traditional western diets.
It was hypothesized that high amounts of acidic byproducts from food would cause blood pH values to become acidic and potentially lead to diseases such as cancer.
However, scientific reviews conclude there is limited evidence to suggest that diet-induced acidosis is sufficient enough to increase the risk of cancer.
This is because the kidneys produce bicarbonate ions that are capable of neutralizing harmful acids in the blood. This process allows for a tightly controlled regulation of blood pH that inhibits any large fluctuations in acidity.
Overall, the alkaline diet can be labeled as a very healthy diet that is based on unprocessed plants foods. However, the benefits of it have nothing to do with lowering the amount of acids in the body.