Marketing for the alkaline diet makes it sound like it will cure everything from cancer to arthritis as well as promote weight loss. The alkaline diet enthusiasts claim that eating foods that make your body more alkaline, as opposed to acidic, changes the body’s pH balance to improve health. While it’s true that some foods are more alkaline than others, what we eat has no lasting effect on our body’s pH. Many body systems work together to keep body pH within a narrow range, and our food choices do not change them.

Just what is pH?

A pH level measures how acidic or alkaline a solution is. pH ranges from 0 to 14, with a pH of 0 totally acidic and a pH of 14 completely alkaline. A pH of 7 is neutral. pH levels vary throughout your body; blood is slightly alkaline with a pH between 7.35 and 7.45 while the stomach is acidic at 3.5 or below.

What we eat can affect the acidity of our urine, because one of the kidneys’ jobs is to excrete acid to help keep the body’s pH at a steady level. While urine acidity can contribute to kidney stones, it doesn’t cause weight gain.

What foods are on the alkaline diet?

The alkaline diet is primarily based on plant foods: fruit, vegetables, soy foods, nuts, seeds, gluten-free grains like quinoa and amaranth, and legumes. The 2015-2020 Dietary Guidelines recommend a plant-based diet to promote good health, and the alkaline diet fits these guidelines.

The alkaline diet eliminates dairy, eggs, meat, and grains that contain gluten such as wheat. It’s certainly possible to choose a healthy diet without including these foods, but the current science does not demonstrate health benefits of avoiding these foods when they are included in moderate amounts in a meal plan that is based on vegetables, fruit, and plant sources of protein. One benefit of the alkaline diet is that it does not include processed foods like canned and packaged snacks and convenience foods that are high in calories, added sugar, sodium, and fat and provide few essential nutrients.

Our recommendation:

While there is no solid science that backs up the health and weight loss claims of the alkaline diet, eating more vegetables, fruit, and plant sources of protein while limiting convenience foods, packaged foods, and foods high in added sugar follows the recommendations of the 2015-2020 Dietary Guidelines. You may lose weight because you’re changing your food choices and consuming less calories, not because of the pH of the foods you eat.

By Lynn Geiger, RDN, CDE, CPT, CHWC

References:

Schwalfenberg GK. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health? Journal of Environmental and Public Health. 2012;2012:727630. doi:10.1155/2012/727630.

Stroehle A, Hahn A, Sebastian A. Estimation of the diet-dependent net acid load in 229 worldwide historically studied hunter-gatherer societies. Am J Clin Nutr February 2010 vol. 91 no. 2 406-412

Fenton TR, Huang T. Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ Open. 2016 Jun 13;6(6):e010438. doi: 10.1136/bmjopen-2015-010438.

Williams RS, Heilbronn LK, Chen DL, Coster AC, Greenfield JR, SAmocha-Bonet D. Dietary acid load, metabolic acidosis and insulin resistance - Lessons from cross-sectional and overfeeding studies in humans. Clin Nutr. 2016 Oct;35(5):1084-90. doi: 10.1016/j.clnu.2015.08.002. Epub 2015 Aug 12.

http://www.eatrightpro.org/resource/media/trends-and-reviews/book-reviews/the-alkaline-cure

The Alkaline Cure book review by Kelly Pritchett, PhD, RD, CSSD. Accessed 4-12-17.

2015-2020 Dietary Guidelines for Americans. https://health.gov/dietaryguidelines/2015/ Accessed 4-12-17.

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