The alkaline diet (aka the alkaline ash or the acid-alkaline diet) has been promoted by celebrities and health influencers in recent years and has had ups and downs in popularity since the 1990s. Each time the fad diet emerges, there tends to be a wave of health professionals that debunk the main premise behind it, which causes the popularity to fade…until a new influencer uses it to boost their agenda.
What is Alkaline Diet
The Alkaline diet peddles the idea that certain foods promote higher acidity, or higher pH levels in the body, which proponents claim leads to negative health consequences such as cancer, arthritis, inflammation, weight gain, and more. Therefore, according to the “science” behind this diet, eating specific foods that make your body more alkaline can protect against those conditions as well as aid in weight loss efforts.
You may remember from chemistry class that pH is a measure of how acidic or alkaline something is. It ranges from 0 to 14.
- 0 is extremely acidic
- 7 is neutral
- 14 is very alkaline
How Does The Alkaline Diet Work?
The basis of the alkaline diet is that your diet can alter the pH value, which ultimately means the measurement of the acidity or alkalinity of your body. Proponents claim that when your body processes and digests food, certain foods produce waste that can lead the body to become more acidic, which can have negative effects such as inflammation and lead to chronic illness or disease. Therefore it is recommended to consume foods that produce alkaline residue/waste/ash so that your blood levels would be more alkaline. In selecting a mostly alkaline-food-based diet, you should be able to “alkalize” your body and improve your health.
What Makes Food Alkaline?
Some of the food sources that leave acidic ash include protein, phosphate, and sulfur, while alkaline components include calcium, magnesium, and potassium-rich foods.
Food groups are considered acidic, alkaline, or neutral:
Acidic: Meat, poultry, fish, dairy, eggs, and alcohol
Neutral: Natural fats, starches, and sugars
Alkaline: Fruits, nuts, legumes (beans, peas, and lentils), and vegetables
How Does A Food’s pH Value Affect Your Body?
There is solid evidence to support the claim that the pH of food impacts the acidity of the body, and in fact, one review found that “the human body has an amazing ability to maintain a steady pH in the blood,” regardless of diet. PH levels vary based on the regions of the body; for example, the stomach is highly acidic, which it needs to be to perform its job. The kidneys and lungs are largely in charge of maintaining a balanced pH within the body, and the various levels are very tightly controlled. Blood pH ranges from 7.2 to 7.45.
An eating pattern or ‘diet’ simply cannot alter your body’s pH. You may notice a difference in your urine pH, which can be measured with a simple urine test strip, but that won’t tell you your overall levels because urine pH doesn’t reflect your body’s pH. Your body has tightly regulated physiological mechanisms such as excreting excess acid through the urine in order to balance the body’s pH levels.
If your body’s pH changes, it’s because of a serious health issue and you would require medical attention. Urine with a high pH could indicate a urinary tract infection or kidney stones, while a low pH could be caused by diarrhea, starvation, or diabetic ketoacidosis.
What Happens to Food When It is Ingested and Broken Down in The Stomach?
In the largest part of the stomach (the body), food is churned and broken into smaller pieces, mixed with acidic gastric juice and enzymes, and pre-digested. At the exit of the stomach, the body of the stomach narrows to form the pyloric canal, where the partially digested food is passed on to the small intestine in portions.
Gastric juice is made up of digestive enzymes, hydrochloric acid and other substances that are important for absorbing nutrients. The hydrochloric acid in the gastric juice breaks down the food and the digestive enzymes split up the proteins. The acidic gastric juice also kills bacteria.
— Does the pH value of a food matter when digested? (Maybe you can ask the question better – this is answered in the above question ‘How a foods pH value affects your body, so I just made that answer longer)
What are alkaline foods?
Foods that are more alkaline include vegetables, fruits, nuts, seeds, beans, peas, and lentils.
Green Leafy Vegetables such as spinach, kale, celery, cabbage, and collard greens. These veggies have immense reserves of vitamins A, C, E, K, and B vitamins, they also contain high levels of carotenoids-antioxidants, along with high levels of iron, magnesium, potassium, and calcium. These nutrients are vital for our systems to perform normal bodily functions, build immunity, and also have anti-inflammatory/anti-cancer properties.
Studies also show leafy greens are essential for maintaining a healthy gut microbiome. Healthy bacteria love to feed on a unique sugar molecule found in leafy greens, which means they can multiply and prevent unhealthy bacteria from overgrowing and leading to gut dysbiosis.
Cruciferous vegetables such as cauliflower and broccoli contain immense amounts of vitamins A, C, k, and folate and phytochemicals, plant compounds that are valuable in lowering inflammation and reducing the risk of cancer.
Root Vegetables such as sweet potato, beets, and carrots are a great source of soluble and insoluble dietary fiber that helps to support healthy gut bacteria, improve cholesterol levels and lower the risk of heart disease and bowel cancer.
Virtually all fruits would be considered ‘safe’ foods for the alkaline diet and we know fruits contain many essential vitamins and minerals, fiber, and antioxidants. There is a plethora of research out there which indicates a high consumption of fruits can lower blood pressure, reduce the risk of heart disease and stroke, prevent some types of cancer, lower the risk of eye and digestive problems, and have a positive effect on blood sugar, which can help keep appetite in check.
Contrary to popular belief that citrus fruits such as lemons, limes, and oranges are highly acidic and thus would have an acidic effect on the system, they are actually still promoted as part of the alkaline diet. If you have reflux or GERD, citrus fruits can exacerbate these conditions so if you find that they cause your symptoms to be worse you should limit them.
Other alkaline fruits include bananas, avocados, tomatoes, pineapples, grapes, kiwi, and mango.
What are Acidic Foods to Avoid?
Acidic foods fall into the acidic range of the pH scale and are different from acid-forming foods. Acidic foods have an acidic pH that doesn’t always leave acidity behind. Whereas acid-forming foods are thought to promote acidity in the body.
Foods that are claimed to be acidic advocates claim should be avoided on an alkaline diet include:
- meat (including chicken, turkey, and beef)
- processed foods/drinks that contain refined sugar (such as soda, pastries, candy, and white bread)
Does The Alkaline Diet Work?
The alkaline diet does encourage fairly healthy eating patterns, including emphasizing unprocessed and plant-based foods and limiting red meat and refined grains. One study found that following an alkaline diet would increase several micronutrients, such as potassium and magnesium, which could help lower the risk of hypertension and stroke and improve cardiovascular health, bone health, and cognition.
However, there is a difference between if a diet works because it is just promoting healthier food choices, or if it is actually backed by science for what it claims to do. As mentioned previously, the food that we consume does not have enough power to sway one way or another what our bodies were created to do.
There is no research to indicate that the pH of food has any impact on overall health, whereas there is plenty of evidence that shows it simply is not possible to change the body’s pH through diet.
Diet claiming certain foods cause inflammation and cancer also creates unnecessary fear around foods that are dangerous and can contribute to disordered eating behaviors – which is a major cause for concern.
Does Alkaline Diet Help Weight Loss?
If a person is consuming more fruits, veggies, nuts, seeds, beans, peas, and lentils, and reducing processed foods, soda, alcohol, and other categories such as dairy, meat, and fish, then naturally, they will likely lose weight due to restricting overall calories.
For the average person, there may be some benefits to following the Alkaline Diet, but not for the reasons that made it famous. The Alkaline Diet is a plant-based diet that cuts out things like high-fat protein, alcohol, and processed foods. Eating a plant-based diet and avoiding the above-mentioned foods will definitely aid in weight loss and will certainly have some health benefits. These benefits, however, are not created or taken away by their alkaline or acidic nature.
Does it Prevent Cancer?
Some studies have shown that cancer cells thrive in highly acidic environments – in other words, environments with a low pH. Proponents of the alkaline diet believe that if you eat a diet high in alkaline foods (high pH) and limit acidic foods, you can raise the body’s pH levels (make the body more alkaline) and make your body a poor environment for cancer.
However, the studies suggesting that an acidic environment helps cancer cells grow studied cells in a dish. They do not represent the complex nature of how tumors behave in the human body. Comprehensive reviews on the relationship between diet-induced acidosis — or increased blood acidity caused by diet — and cancer concluded that there is no direct link.
More importantly, there’s no way the foods you consume can alter the pH levels of your blood. The pH of the body is tightly regulated. 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 alkaline food that it impacts your blood.
Controversies and Ancestral Alkaline Diet
The alkaline diet tends to be touted by celebrities and wellness influences that have little to no understanding of the intricacies of complex topics such as health, weight loss, cancer, human biology, and how to understand and interpret research. Unfortunately, misinformation spreads more quickly than the truth because it usually sounds compelling and alarming.
It promotes the false idea that it is possible to change blood pH with diet. This is untrue and considered misinformation because major changes in blood pH could be life-threatening and food does not have an impact on the pH levels in your body.
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.
Should you Start an Alkaline Diet? (A Dietitian’s Perspective)
Fad diets such as the Alkaline diet promote misinformation and fear around foods. When you look at the largest body of highest quality evidence out there, there are no negative impacts of consuming dairy, fish, and meats in moderation – especially when fruits, vegetables, nuts, seeds, and legumes are abundant. People do not have to eat these foods if they don’t want to, but they do contain great sources of nutrients such as protein, B vitamins, Omega 3s (fish), calcium (dairy), zinc (dairy), and more, so promoting fear around perfectly healthy foods is something that is unnecessary.
We also know consuming a more plant-based diet has positive impacts on health, but sometimes our bodies do not absorb nutrients from plants as well as they do from animal sources – for example, Omega 3s, Iron, and protein. So if someone is avoiding meat, fish, and dairy, they should ensure they are getting enough of these nutrients from plant-based sources.
We tend to over-complicate healthy eating. There are amazing benefits to increasing the consumption of fruits, veggies, nuts, seeds, and legumes and reducing the consumption of processed foods. However, labeling it as a diet and promoting misinformation and unnecessary fears around food is not a good look.
The Alkaline Diet promises to combat disease and cancer, but its claims aren’t backed by solid evidence. Although it may naturally yield health-promoting benefits by restricting junk foods and promoting more plant foods, fiber, vitamins, minerals, and antioxidants, this has nothing to do with your body’s pH levels and there are many eating patterns that promote the consumption of the same nutrients and thus reaping their inherent benefits.
About the Author
Felicia is a Registered Dietitian and nutritionist with a Master’s in Applied Human Nutrition. She has a strong wellness background and experience of working at research centers and healthcare/private practice for 12+ years.
Felicia is passionate about helping others fight through the massive amounts of nutrition misinformation in the online world, and to navigate life and health, but most importantly, enjoying it while doing it.