However, like many diets, it has its controversies with mixed scientific results, so we decided to dig into it to help you get a better understanding of exactly what it is and how it can work for you—or not. Here’s everything you need to know.
What is the alkaline diet?
“The alkaline diet is a popular diet that claims that replacing acid-forming foods with alkaline foods can improve your health,” says Jerlyn Jones, MS, MPA, RDN, LD, CLT, registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics. “The overall idea is that the foods you eat can alter the pH value—the measurement of acidity or alkalinity—of your body, and protect your body from chronic diseases, cancer, inflammation, and bone disease.”
Any food with a pH of 7.1 to 14.0 is considered alkaline. Although the alkaline diet purportedly promises this pH change, our bodies don’t quite work like that.
“Except for changes in the pH of our saliva and urine, the foods we eat can’t alter our body’s pH,” says Jones. “Rather, the effect food has on the kidneys, called the ‘potential renal acid load’ or PRAL, is used to determine where foods fit in the context of the alkaline diet.“
To put that in context, Jones explains that lemons are acidic, but are considered a “high alkaline food” because they have a low renal acid load.
To dig a bit deeper, you need to understand the process of digestion and metabolism. “When food enters the stomach, it enters into an extremely acidic environment due to the presence of hydrochloric acid (HCL),” says says Amber Pankonin, MS, RD, LMNT, registered dietitian and owner of the food blog Stirlist. “So, when food leaves the stomach and enters the small intestine, it will still be acidic as it enters the small intestine, but then is quickly neutralized by hormones from the pancreas and small intestine.”
Adds Keri Gans, MS, RDN, CDN, registered dietitian nutritionist and author of The Small Change Diet, “Unfortunately, the science for the theory behind this diet is lacking. Our bodies, thanks to our lungs and kidneys, are naturally designed to keep a neutral pH.”
What are the benefits of the alkaline diet?
As shaky as the science is, there may be benefits to trying an alkaline diet. “The one good thing about the diet is that it does encourage consuming most fruits and veggies, soybeans, tofu, some nuts, seeds and legumes—all of which are considered alkaline-friendly,” says Gans. “It also stresses the importance of limiting overly processed foods.”
A 2012 review article found the alkaline diet may result in some health benefits, such as:
- It may prevent fractures in seniors and women. “An alkaline diet has a positive effect on bone health, and reduces muscle wasting,” says Jones. “A diet rich in potassium and magnesium with a reduced acid load preserves muscle mass in seniors and women.”
- It could reduce the risk of additional chronic diseases, such as hypertension and strokes. “This is because fruits and vegetables are high in potassium, which also helps to ease tension in your blood vessel walls, which helps further lower blood pressure,” says Jones.
- It may benefit postmenopausal women. “It could increase the growth hormone in postmenopausal women due to potassium bicarbonate, rich in alkali, which may also improve brain function and reduce the risk of heart disease,” says Jones.
- It may make cancer treatments more effective. “In regard to cancer, specific chemotherapy drug treatments (epirubicin and adriamycin) may be more effective in an alkaline environment, while other drug treatments (such as cisplatin and mitomycin C) are more effective in an acidic environment,” says Jones. “Overall, though, current research doesn’t support an alkaline diet for cancer protection.”
Related: What Is the Anti-Inflammatory Diet?
What are the risks of the alkaline diet?
There may be some benefits to the alkaline diet, but it comes with risks, too.
“There can be an increased risk of certain vitamin or protein deficiencies because it eliminates whole food groups—dairy, protein foods, and grains,” says Jones. This also includes caffeine and alcohol.
It could also lead to excess potassium levels. “Excess potassium can be harmful in patients with kidney disease, any condition that affects how the body handles potassium, or those who take certain medications,” adds Jones. “The alkaline diet is also not supported by current scientific literature for cancer prevention or treatment.”
And, once again, the potential benefits surrounding cancer have not been conclusive.
“I have seen this diet being promoted to those with cancer, and this could potentially be harmful considering that cancer patients are encouraged to eat what they can during treatment and get adequate calories and protein,” says Pankonin. “There is also no credible scientific research that supports the theory that this diet cures cancer or is a replacement for cancer treatment.”
What foods can you eat on the alkaline diet?
“Most fruits and vegetables, soybeans and tofu, and some nuts, seeds, are alkaline-promoting foods,” notes Jones. “A list of alkaline foods to eat include fruit, unsweetened fruit juices, dates, vegetables, soy foods, mineral water, seeds, legumes, and some nuts. These foods have a lower potential renal acid load.”
Related: 40 Best Foods for Weight Loss
What foods should you avoid on the alkaline diet?
According to Jones, these include acidic forming foods such as meat, chicken, fish, dairy foods like cheese, eggs, grains (rice, oats), canned and packaged snacks, soda and alcohol.
The bottom line
“In general, the alkaline diet is based on whole and minimally processed foods,” says Jones. “However, no standardized alkaline diet exists, and this diet is highly restrictive and can be tough to maintain over time. It doesn’t provide adequate protein and essential vitamins and minerals such as calcium, vitamin D, B vitamins, and iron, meaning supplementation is needed.”
If you’re looking to try a personalized eating plan like an alkaline diet, it’s best to work with a registered dietitian nutritionist, who can help you make the healthiest possible decision for you.
Next up, here are the top foods you can eat on the keto diet.
- Jerlyn Jones, MS, MPA, RDN, LD, CLT, registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics.
- Amber Pankonin, MS, RD, LMNT, registered dietitian and owner of the food blog Stirlist
- Keri Gans, MS, RDN, CDN, registered dietitian nutritionist and author of The Small Change Diet