Something I hear all the time: you need to consume less acidic foods and liquids.
Water is marketed and sold as alkaline at stores everywhere (at a substantial cost increase) and wellness influencers sell books, workshops, and supplements to help people change their diets to be more alkaline.
These recommendations are promoted under the guise of remedying medical issue.
People spend thousands of dollars on water ionizer machines to raise the pH of water and make it more alkaline. Yes, you can get your very own Kangen (or similar) machine for a bargain at $5500!
The alkaline diet is one of many trendy diets that claims to improve your health, help you lose weight and even fight cancer.
The alkaline diet has been a constant and pervasive trend. It is based on the notion that that cancers grow in an acidic environment, and proponents claim that eating a diet high in alkaline foods will create an internal environment that discourages the development of cancer. Advocates say: it’s just science!
But is it really? NO. The reality is, there is no science behind these claims.
Let’s first talk about what acidity/alkalinity mean and the pH scale:
pH is a scale we use to measure the acidity or alkalinity of a substance. The actual calculation relates to how many hydrogen ions are present in a substance or environment (hydrogen ions contribute to the acidity of substances). It is inversely proportional to that value, and is logarithmic. The scale ranges from 0-14. 7 is considered neutral. Less than 7 is considered acidic, greater than 7 is considered basic/alkaline.
The logic proponents use is that things you eat can change pH of your body. Some believe that changing the body’s pH levels can improve your health and help you lose weight or even prevent cancer.
But there’s no way the foods you eat can alter the pH level of your blood. The body’s pH is a very tightly regulated system. If you change your diet, you may see changes in the pH of your saliva or urine because these are waste products, but there’s no way you could ever eat enough that it really impacts your blood pH or other organ systems.
Our blood pH is constantly maintained at 7.4 (a range of 7.36 - 7.44) - if it were to change in either direction, we would die, or at the very least, be in critical medical condition and need emergency interventions.
The alkaline diet promotes the false idea that it is possible to change blood pH with diet. This is untrue, and major changes in blood pH could even be life-threatening. It is possible to change the pH of urine and saliva with diet. However, when the pH of these fluids changes, the pH of blood remains the same.
How are we able to maintain that pH if we change what we are eating?Buffer systems!
Our body is an amazing example of homeostasis - the ability to maintain a state of equilibrium (physical, chemical, etc). This enables us to function optimally, and includes things like temperature, fluid balance (and electrolytes), and pH!
To maintain homeostasis - we need buffer systems. Buffer systems do exactly what the word sounds like - they buffer things. In physiology, these are substances and solutions that resist changes in pH even if you are consuming things that are well above or below the pH of our blood. Our complex organ systems do this for us.
Broadly, we have (3) main buffer systems in our bodies that ensure the pH of our blood is tightly regulated:
1) the carbonic acid bicarbonate buffer system
2) the phosphate buffer system
3) protein buffer systems
Our lungs, kidneys, and excretory organs (yep, that includes your bladder and the urine that is excreted!) ensure that we maintain this pH balance of 7.4 in our blood.
Some unresolved animal health issues that require urgent review
The carbonic acid bicarbonate buffer system operates via the lungs and kidneys.
When we inhale, we breathe in oxygen (along with other molecules in the air), and we exhale carbon dioxide. The exhalation of CO2 is what allows us to regulate the pH of our bodies (and get rid of excess acid). When our bodies have a build-up of acid, our lungs will exhale more CO2 as a waste product to offload it. Similarly, our kidneys will excrete excess acid in our urine through similar buffer systems. Kidneys are constantly filtering our blood, sensing levels of acid and salts in our bodies, and excreting (through urine) waste products that would affect homeostasis.
The phosphate buffer system operates within all of the cells of your body. It regulates the intracellular fluids of our bodies to ensure our cells operate normally, particularly in our renal (kidney) tubules.
The phosphate buffer system operates in the internal fluids of all cells. Dihydrogen phosphate ions scavenge excess acid and hydrogen phosphate scavenge excess base (alkali) to ensure a consistent pH within all of your cells. If additional base is present (OH-) they are neutralized by the dihydrogen phosphate. If additional acid is present (H+), they are neutralized by hydrogen phosphate ion. Anything that is in excess will be excreted by the kidneys to the bladder and passed out as urine.
Certain proteins can bind excess acid or base and neutralize it through protein buffering.
For example, hemoglobin is a protein in our red blood cells that can help bind acids in the blood, removing the acid before it changes the blood's pH.
Measuring urine an an indicator of “alkalinity” of your body is not appropriate.
Proponents of the alkaline diet suggest that people monitor the pH of their urine to ensure that it is alkaline (over 7) and not acidic (below 7).
This is not an appropriate metric because urine is a waste product. The pH of urine will vary widely depending on what the homeostatic processes in your body are doing - so it provides no indication as to what’s going on ‘inside’ your body.
It’s also important to note that pH varies within your body based on compartment and function. While some parts are acidic, others are alkaline — there is no universal pH level (other than in your blood). Your stomach is loaded with hydrochloric acid, giving it a pH of 2–3.5, which is highly acidic. This acidity is necessary to break down food. On the other hand, human blood is always slightly alkaline, with a pH of 7.36–7.44.
Blood pH is a true indicator of health state.
When your blood pH falls out of the normal range, it can be fatal if left untreated. However, this only happens during certain disease states, such as ketoacidosis caused by diabetes, starvation, or alcohol intake.
There are four main ways in which blood pH can change (and these are all dangerous and due to legitimate medical conditions):
Metabolic acidosis: This occurs due to reduced bicarbonate or increased acid levels.
Respiratory acidosis: This occurs when the body removes less carbon dioxide than usual.
Metabolic alkalosis: This occurs due to increased bicarbonate or reduced acid levels.
Respiratory alkalosis: This occurs when the body removes more carbon dioxide than usual.
We don’t WANT these things to happen in our body, because they would be an indication of a serious medical issue.
Ok, so the alkaline diet itself:
According to the diet, certain food groups are considered acidic, alkaline, or neutral:
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Acidic: meat, poultry, fish, dairy, eggs, grains, alcohol
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Neutral: natural fats, starches, and sugars
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Alkaline: fruits, nuts, legumes, and vegetables
Paradoxically, lemons and other acidic foods with a very low pH range are considered to be alkalizing on the diet. The ‘thinking’ is that they cause the body to produce alkalizing byproducts after they’re metabolized. But lemon juice is unlikely to do much beyond adding flavor to your beverage or meal. The assignment of these foods to these groups is also somewhat arbitrary, and comes down to the marketing of another fad diet.
Remember: proponents of this diet are not using scientific data behind these recommendations.
More importantly, as soon as you eat anything, it ends up in your stomach, with a pH of ~ 2.5 (extremely acidic) in order for you to properly digest. So nothing you eat is traversing your body beyond that point at the pH it entered your body.
So-called “acid-producing foods” like meat, eggs and dairy are supposed to be avoided on the alkaline diet. That’s because these foods are claimed to create an acidic environment in our bodies, allowing conditions like cancer, osteoporosis and obesity to take root.
The alkaline diet has science-y rules sprinkled in that make it seem legitimate, but the tenets of this diet skirt around basic facts about human physiology. This is unfortunately true for a lot of ‘pseudoscience’ claims that have taken root in society, particularly around nutrition.
The food we eat and water we drink has virtually no impact on our blood’s pH — that’s tightly regulated by our lungs and kidneys.
The purported health benefits of the alkaline diet have been studied by scientists, and there’s little evidence to actually support this way of eating.
The diet is based on a 100-year-old scientific theory called the acid-ash hypothesis, originally associated with osteoporosis research. The idea behind it is that the foods we eat leave behind a chemical residue — or ash — in our bodies that’s either alkaline, neutral or acidic. Put simply, the theory states that a buildup of alkaline ash makes your blood more alkaline and has a protective effect. Acidic ash has a harmful effect, whereas neutral ash has no effect.
Proponents of the diet often use the example of osteoporosis since it’s thought that acidic byproducts force our body to leach alkaline minerals like calcium from our bones to correct this imbalance. But there is no evidence that shows the acid-ash hypothesis plays a role in causing osteoporosis or other poor health outcomes.
Many studies have attempted to draw a causal link, and have been unable to do so.
A 2018 review in Nutrients found no link to dietary composition and bone density/osteoporosis.
Many people also tout alkaline diet/water for cancer prevention (and a myriad of other illnesses). This gained momentum because of in vitro studies (cancer cells in Petri dishes) that show that these cells behaved “better” in more acidic environments, and could be killed in extremely alkaline environments. First, any cells (including our healthy normal cells) can be killed in extreme environments in a Petri dish: alkaline or acidic, nutrient deprived or oxygen deprived, or dosed with excessively high levels of pretty much any chemical.
This does not translate to what happens in a human, because it does not represent the complexity of our physiology, buffer systems, and our organ systems. Remember: you can do literally anything to cells grown on a piece of plastic.
A 2015 Review in BMJ found NO evidence or actual research regarding the efficacy of an alkaline diet to reduce cancer incidence, disease severity, or treatment outcomes. This systematic review of available evidence showed there is no data to support alkaline diets or alkaline water for cancer prevention or treatment.
There are also potential risks in adhering to any strict elimination diet (similar to the autoimmune protocol diet). These can include nutritional deficiencies and psychological factors such as health anxiety and the inability to participate in social gatherings like going to restaurants with friends and family.
Alkaline water is just water with additional minerals added to it. It also doesn’t affect the pH of your body.
Some folks who are curious about other potential benefits of drinking alkaline water often ask about things like alleviating symptoms of GERD or acid reflux, or alleviating symptoms of bladder issues. Unfortunately, the data aren’t convincing there, either.
Acid Reflux (GERD) occurs when stomach acid flows into the esophagus, causing symptoms like heartburn. Proponents of the alkaline diet suggest that consuming alkaline foods can help neutralize stomach acid and alleviate symptoms. There is some in vitro data suggesting that pH 8.8 water may aid in the inactivation of pepsin, an enzyme that can contribute to symptoms of GERD, but human evidence is weak. A recent small clinical study shows a small improvement in self-assessed symptoms per the reflux disease questionnaire (RDQ), but these would need to be validated using a more robust study design and sample size.
There are also some potential risks, especially among people who are purchasing concentrated alkaline drops to add to water. These concentrated drops are extremely alkaline and can cause damage to our tissues. Alkaline burns are a chemical burn that cause deeper burns than acid burns and lead to saponification, a process where fats are liquified and turns into soaps (anyone watch Fight Club?). As this happens on your skin, the alkali can penetrate deeper and deeper. There have been case reports of skin burns and ocular burns as a result of self-administration of concentrated alkali drops.
Some proponents claim that alkaline water can help alleviate symptoms of urinary tract infections (UTIs) or bladder issues by creating an environment in the urinary tract less conducive to bacterial growth or alleviating inflammation of interstitial cystitis. However, there is limited evidence to support this claim.
Drinking plenty of water, in general, is recommended for maintaining urinary tract health, but the specific benefits of alkaline water are not well-established. In addition, there could be digestive issues associated with high consumption of alkaline water.
Alkaline water can potentially interfere with medication absorption.While alkaline food and water aren’t going to change your blood pH, they can alter the stomach pH. If it becomes too alkaline compared to what it should be, it can alter the absorption rate of medications, either leading to too rapid or too slow absorption depending on whether the medication itself is acidic or basic.
(This is a similar phenomenon as you would see with medications like proton-pump inhibitors that are used to treat things like esophagitis, peptic ulcer disease, Non-erosive reflux disease, Zollinger-Ellison Syndrome, and GERD)
If the alkaline diet has anything going for it, it’s that it promotes eating fruits and vegetables, increasing fiber intake, and reducing processed foods. That has nothing to do with the pH of the foods, just more conscious attention on a balanced diet. While some people may experience weight loss, it is because of the restrictive nature of the diet, which eliminates entire food groups. This, coupled with risks of nutritional deficiencies is not a recommend practice for long-term weight management or disease prevention.
You always want to consult trained healthcare professionals when making significant dietary changes, especially when you have health concerns. Please don’t get your information from unqualified influencers on social media, especially if they are selling you a product that seems to be making claims that don’t hold up to scrutiny.
