For years, alkaline diets have garnered interest from health professionals, lifestyle bloggers and nutrition researchers. Because it is based on more thorough theories than we typically hear in the diet world, we have great research to confirm why this diet should take a back seat when it comes to trustworthy nutrition advice.

The foundation

Think of a diet like a building; it needs a firm foundation for the structure to stand on. An alkaline diet is based on the following, rather weak, building blocks:

·      Foods are classified as acidic, neutral or basic depending on the minerals such as calcium and phosphorus that are found in food.

·      “Acidic” foods, including grain products, animal proteins, dairy, many beans and legumes, sugar, alcohol and coffee, are limited based on the erroneous theory that acidic foods are damaging to the pH balance of the body.

·      “Alkaline” foods, usually defined in these diets as vegetables and fruit, in large amounts are thought to protect against osteoporosis, cancer, obesity, Type 2 Diabetes and mental illness, among other health conditions. Note that these claims are largely unsupported.

·      Individuals may be encouraged to take alkaline supplements or drink alkaline water to further promote alkalinity. This is despite the fact that alkaline supplements may be unregulated and harmful and the lack of evidence for alkaline water.

·      Urine pH is wrongly used to interpret body pH (this link will answer all your questions regarding monitoring urine pH).

This is a very brief overview of an alkaline diet. There are  many different theories on how acidic and alkaline foods affect the body. As well, the diet will differ depending on the reference book or website, and which foods are classified as acidic or alkaline. You can count on two things though: there will be a focus on fruits and vegetables (of which most of us need more), and a limit on protein (many are considered acidic).

Is the foundation firm?

While the ideas behind this diet may sound convincing, as we’ve implied, there are some large cracks in the foundation. Here are a few points to consider:

·      The equations used to classify foods as acidic or alkaline are questionable and don’t consider how different body systems influence the pH of foods. This means it is very difficult to determine the acidic or alkaline influence of a food.

·      The diet largely ignores the roles that the kidney and lungs play in pH balance. These body systems are involved in tightly controlling blood pH, without taking minerals from the bones to neutralize acid.

·      Researchers have done high-quality studies on the impact of acidic foods on the body. At this point there is no good evidence to support the hypotheses and claims about the alkaline diet. Let’s look at an example.

Will acid from food harm your bones?

Supporters of alkaline diets claim that acidic foods are harmful to bone health as minerals are taken from the bones to neutralize the acid from food. A credible study led by Alberta researcher Tanis Fenton explored all the high-quality research done on this topic prior to 2011 to test if the claim is true. When the research team combined all the results from the studies, they found no support for the claim that acid from our modern diet causes osteoporosis or that an alkaline diet or alkaline supplements prevent osteoporosis. Research since 2011 has not indicated otherwise. In addition, some research would suggest that protein (considered acidic) has a positive impact on bone healthin addition to other benefits such as feeling satisfied after a meal and maintaining muscle.

What about some of the other claims of the alkaline diet, such as weight loss or cancer prevention? By restricting many of the foods you might typically eat, you will likely lose weightAccording to the American Institute for Cancer Researchan alkaline diet isn’t the cure we hope for.

One question remains

To recap, the science behind the alkaline diet is not sound, and there is no high-quality evidence to back up the claims. However, regardless of the diet and how you interpret the research, one important question must be considered when approaching all diets: Will following this diet be harmful to my health?

The fact that an alkaline diet focuses on vegetables and fruits, incorporates plant proteins and limits processed foods is encouraging. However, following this diet could also have negative consequences:

·      Eliminating nutritious foods, such as dairy products and many whole grains and protein sources, without careful planning for how to replace lost nutrients can contribute to nutrient deficiencies.

·      Low protein intake is especially concerning for the elderly, individuals with cancer or a chronic health condition and athletes. Protein is crucial for immune function, muscle maintenance, bone strength and blood supply, among many other functions.

·      Unregulated supplements that promote “alkalinization” may be harmful.

·      Following a strict eating plan can contribute to eating disorders such as orthorexia. In addition, if a diet is difficult to follow or causes stress, are the perceived benefits worth it or even offset?

The best blueprint for a sturdy structure

When you hear talk about the dangers of our acidic Western diet, people are often referring to a diet based on highly-processed foods, fast food, added sugar and large amounts of animal products. I will be the first to agree that a diet based on these foods will not make you feel your best. However, when we swing all the way to an eating plan that discourages many nutritious foods, such as lean meats, legumes, dairy and whole grains, we make nutritious eating much more complicated than it needs to be. This is the last thing people struggling with poor eating habits need. Let’s leave complicated eating plans behind and simply try to include more minimally-processed and whole foods, find fun ways to cook and eat meals at home and move our bodies in ways we enjoy.



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Kristina Isaac, RD.

Registered Dietitian

Kristina (BSc, RD) is a registered dietitian and blogger for Nourish Move Thrive. She enjoys finding creative, fun and simple ways to communicate the science of nutrition.

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