What are the benefits and risks of following an alkaline diet?

From the Guidelines

The alkaline diet has limited proven health benefits, and its effects on health are likely due to the emphasis on whole, plant-based foods rather than any impact on body pH. This eating pattern emphasizes fruits, vegetables, nuts, and legumes while reducing meat, dairy, eggs, grains, and processed foods. Potential benefits include increased fruit and vegetable consumption, which provides essential vitamins, minerals, and antioxidants that support overall health 1. The diet may help reduce acid reflux symptoms in some people and could support bone health by reducing acid load, though evidence for this is mixed. Weight loss might occur due to the focus on whole foods and reduced calorie intake. However, the diet's fundamental premise—that it significantly alters blood pH—is not supported by science, as the body tightly regulates blood pH regardless of diet.

Some studies suggest that a diet high in fruits and vegetables can help reduce the risk of kidney disease and kidney disease progression by reducing net endogenous acid production 1. A study published in the American Journal of Kidney Diseases found that increasing fruit and vegetable intake can help reduce net endogenous acid production and slow the loss of kidney function with aging. However, it is essential to note that the alkaline diet's health effects are likely due to the overall dietary pattern rather than any specific effect on body pH.

Risks associated with the alkaline diet include potential nutritional deficiencies, particularly in protein, calcium, and vitamin B12, if animal products are severely restricted. The diet can be expensive and socially limiting, and some followers might avoid necessary medical treatments in favor of the diet's purported benefits. A well-planned and balanced diet that includes a variety of whole foods, rather than a specific "alkaline" diet, is likely to provide the most significant health benefits. A study published in Circulation found that dietary patterns that emphasize whole, minimally processed foods, such as the Mediterranean and DASH diets, can help reduce the risk of cardiovascular disease, diabetes, and obesity 1.

Key points to consider when evaluating the alkaline diet include:

• The diet's emphasis on whole, plant-based foods
• The potential for nutritional deficiencies if animal products are severely restricted
• The lack of evidence supporting the diet's fundamental premise—that it significantly alters blood pH
• The potential benefits of a diet high in fruits and vegetables for reducing the risk of kidney disease and kidney disease progression
• The importance of a well-planned and balanced diet that includes a variety of whole foods.

From the Research

Benefits of an Alkaline Diet

• Consumption of abundant alkaline-forming foods can result in improvement in bone mineral density (BMD) and muscle mass, protection from chronic illnesses, reduced tumor-cell invasion and metastasis, and effective excretion of toxins from the body 2
• An alkaline diet may prevent osteoporosis and protect pancreatic beta cells with its antioxidant effects 2
• Reducing the dietary acid load through a low-protein diet with greater use of vegetable proteins and increased fruits and vegetables (F&V) intake can slow progression or occasionally improve renal function while maintaining the nutritional status of the individual 3
• An alkaline diet may reduce the risk of chronic diseases, such as coronary heart disease (CHD), cardiovascular disease (CVD), and cancer, and lower total mortality rates 2

Risks of an Alkaline Diet

• There is a lack of comprehensive tools to research the acid-base hypothesis and recommend managed diets, which can make it difficult for individuals to follow an alkaline diet effectively 4
• The Western diet is often viewed as being overly acid due to its high-level of animal-based protein and low-level of vegetable intake, which can lead to low-grade metabolic acidosis and interstitial acidosis 4, 5
• The continuous consumption of acid-producing diets can lead to bone loss and muscle loss in older adults with mildly and moderately impaired renal function 5

Considerations for Following an Alkaline Diet

• Food selection is important, particularly in the ageing population, as the ability to excrete acid compounds is reduced with declining kidney function 4
• The potential acid load of foods (PRAL) and the net endogenous acid production (NEAP) are two systems used for calculating the Dietary Acid Load (DAL), but they have weaknesses and do not provide complete assessments of the impact of foods on DAL 4
• Further studies are warranted to fully understand the benefits and risks of an alkaline diet and its potential role in reducing morbidity and mortality from chronic diseases 6