What if choosing the right foods to eat was as simple as eating those that create a nonacidic or alkaline environment over those that create an acidic environment? Wouldn’t that make life simple? While you may not have thought of acids and alkalines since high school chemistry, this dichotomy is the basis of the alkaline diet.
The principles of eating so-called alkaline-producing foods were first made clear by French biologist Claude Bernard, a giant of science who made many important discoveries, including that the liver stores and releases glycogen and the pancreas releases digestive juices.
It was Bernard’s word on what was later called “homeostasis” that led to the evolution of the alkaline diet. Bernard believed that among the factors that promoted or disturbed a healthy internal environment was the pH of the body and blood. He theorized that an acidic environment, in particular, is a breeding ground for chronic disease — and that what you eat can impact your bodily pH.
Variations of this acid-alkaline dietary pattern have existed since the beginning of the 20th century. But its popularity skyrocketed again in the last few decades via early health influencers like Robert Young, author of The pH Miracle, and the Honduran herbalist Dr. Sebi (who inspired many people to adopt a vegan alkaline diet).
But is there any truth to these theories that the pH of food impacts blood pH, and, therefore, susceptibility to disease? And is the alkaline diet inherently a healthy dietary pattern?
In this article, we’ll take a look at the alkaline diet, comparing its claims to the available scientific evidence.
In order to understand the alkaline diet and its claims, we need to at least have a basic understanding of pH. Potential of hydrogen or pH is a measurement of the acidity or alkalinity of a liquid. The pH scale goes from 0.0 (highly acidic) to 14.0 (highly alkaline or “basic”) with a neutral point of 7.0.
Our stomachs are very acidic environments with a normal pH of 1.5–3.5. We secrete hydrochloric acid to help us digest our food, activate enzymes, and break down proteins into amino acids. Maintaining those stomach acids also helps protect us from pathogens in the digestive system.
On the other hand, blood is slightly basic or alkaline, with a pH of 7.35–7.45. The body’s acid-base balance is mainly controlled by the respiratory system and the renal system (kidneys). Maintaining this equilibrium is important for the functioning of basic bodily systems, and any disturbance in this pH can be a serious (and even life-threatening) problem.
So What Does the Alkaline Diet Claim?
The central claim of the alkaline diet is that what you eat can alter the pH level of your blood and cells. And that a more alkaline body pH (achieved from the food you eat) can prevent many diseases, including cancer and osteoporosis, while also providing increased energy and well-being.
When it comes to cancer, the theory is that cancer cells thrive in an acidic environment, so ingesting more alkalizing foods will create a more alkaline and anticancer environment. In this view, eating too many acid-forming foods can put your body into a state of acidosis and result in a decrease in blood pH, with serious metabolic and respiratory consequences in the body.
The bone health theory goes like this: Your body works diligently to keep your blood pH at a healthy level in your arteries and slightly lower in your veins. If you acidify your blood (by eating acid-forming foods, among other things), your body will do whatever it can to achieve equilibrium, including pulling calcium, an alkalizing mineral, from your bones.
To sum it up, the standard Western diet, according to this theory, degrades health and increases the risk of chronic diseases because it promotes an acidic body environment. And an alkaline diet alkalizes the body and blood, staving off chronic disease.
The Alkaline Diet: Foods to Eat vs Avoid
So what foods are supposed to contribute to this alkalizing effect in the body, and which foods don’t?
Most alkaline diet protocols encourage you to eat more alkaline foods that, when metabolized, also leave an alkaline “residue” in your body. Eating this way doesn’t necessarily mean removing all acidic foods from your diet, but instead prioritizing alkaline foods (75–80% of your diet) over acidic ones (20–25% of your diet).
Alkaline foods include many, but not all, vegetables, as well as some fruits, legumes, whole grains, nuts, seeds, herbs and spices, and cold-pressed oils. Neutral and low-acidic foods are also okay in moderation, the majority of which are fruit. Most of the high-alkaline foods are green in color, with leafy greens, green vegetables, and sprouts topping the list.
On the other hand, the foods to avoid on an alkaline diet are those believed to produce an acidic effect. Meat and poultry, dairy, eggs, bread, sweets, and condiments; processed, canned, and fast foods; and beverages like coffee, alcohol, and tea are all off-limits on an alkaline diet.
What the Alkaline Diet Gets Right
Ultimately, there’s a lot of focus on the consumption of whole, plant-based foods and the elimination of most animal products and processed foods on the alkaline diet. So whether or not the underlying theory of the alkaline diet is accurate, there’s no question that eating the preferred foods — whole plants — confers many nutritional benefits.
Conventional Western-style diets are notoriously low in fiber, which is one of the most severely lacking nutrients in industrialized societies. But because the alkaline diet prioritizes whole, plant-based foods, it can make it much more likely you’ll achieve the 25–35 grams of recommended fiber per day.
Eating more fruits and vegetables also means that you’ll be ingesting lots of vitamins, minerals, and antioxidants. And choosing whole foods over processed or fast foods improves your sodium-to-potassium ratio, which can benefit bone health, reduce muscle wasting, and mitigate other chronic diseases such as hypertension and strokes.
The diet may also be helpful for people with chronic kidney disease because it tends to be relatively low in protein. One systematic review showed evidence that the inclusion of alkaline-producing fruits and vegetables or a vegetarian diet low in acid-producing protein (animal products) can slow kidney disease by reducing metabolic acidosis.
In effect, the alkaline diet can be a perfectly healthy eating pattern for many people because it’s predominantly a plant-based one.
What the Alkaline Diet Gets Wrong
Food Affecting Blood pH
The big problem with the claims made by alkaline diet proponents is that they’re based on a misunderstanding of pH and how the body regulates blood pH. The relative alkalinity of the foods you eat doesn’t generally affect the alkalinity or acidity of your blood.
Acids are continuously being produced in the body during normal metabolic processes, but they don’t influence overall bodily pH in healthy individuals. Your body works hard to keep that 7.35–7.45 blood pH range, which is slightly on the alkaline side. If there’s too much acid or base in your system, built-in physiological buffers get rid of it through your urine.
Changing your diet might change the pH of your saliva or urine, but it’s practically impossible to affect the pH of your blood by what you eat. The only times that blood pH is affected is in the case of an acid-base disorder such as advanced stages of shock, diabetic ketoacidosis, or kidney failure — all of which are medical emergencies and not the result of not eating enough alkaline foods.
Focusing on the Wrong Benefits
Not only does the alkaline diet theory misunderstand the mechanisms through which your body regulates its pH, but the narrow focus on this one attribute of plant-based foods ignores the many benefits of plant-based eating that are actually backed up by science. A whole food, plant-based diet supplies an abundance of powerful antioxidants, fiber, and a rainbow of health-promoting phytochemicals. In short, the alkaline diet’s health benefits are real, but they likely have little to do with pH.
Confusing and Restrictive
With a focus mostly on pH and choosing the most alkaline foods, there’s a risk of dietary restriction to the point of nutrient deficiency. It’s easy to get confused about what you are and aren’t supposed to eat, as there’s a lack of consistency in the recommendations, which vary widely. Some lists, for example, say that mushrooms are highly acidic, while others tell us that they are alkalizing.
Little to No Scientific Backing
And most problematic of all, there’s minimal scientific evidence to support the alkaline diet’s biggest claims around diet alkalinity protecting against chronic disease or affecting blood pH.
One 2010 study found that low urine pH predicted neither low bone density nor bone fractures, while another from the same year discovered no correlation between dietary acid load and bone mineral density in older women. A 2011 study found no correlation between dietary acid load and lower bone density, except possibly in older men.
And a 2016 review of over 8,000 published articles relating to dietary pH and cancer found a single clinical trial on the topic. This trial found no relationship between the acid load of the diet and bladder cancer. The researchers concluded, “Despite the promotion of the alkaline diet and alkaline water by the media and salespeople, there is almost no actual research to either support or disprove these ideas.”
The Bottom Line
The alkaline diet, which focuses on pH balance, is a popular diet with many adherents and proponents. It is inherently whole food, plant-based, which can be great, and it’s been shown to be helpful for chronic kidney disease. But beyond that, there’s little to no scientific evidence to support its other health claims. In fact, it’s likely that its benefits have more to do with all of the known advantages that come with a whole food, plant-based diet that steers clear of added sugars, highly processed foods, and animal products.
Tell us in the comments:
- Were you already familiar with the alkaline diet? Have you ever tried it?
- What do you think of the alkaline diet approach?
- What other dietary patterns do you have questions about?
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