PRAL Score of Plant-Based Foods

PRAL (Potential Renal Acid Load) is a measure of the acidifying or alkalizing potential of foods on the kidneys, calculated using the Remer-Manz formula. The formula incorporates protein, phosphorus, potassium, magnesium, and calcium content per 100g: PRAL = (0.49 × protein) + (0.037 × phosphorus) − (0.021 × potassium) − (0.026 × magnesium) − (0.013 × calcium). Negative PRAL values indicate alkaline-forming foods that reduce acid load, while positive values indicate acid-forming foods that increase acid load. The unit is mEq/100g (milliequivalents per 100 grams).

The most alkaline-forming plant foods include raisins (−21.0 mEq/100g), spinach (−14.0 mEq/100g), dried figs (−13.7 mEq/100g), beet greens (−13.1 mEq/100g), and kale (−12.8 mEq/100g). Other alkaline-forming foods include bananas (−5.5 mEq/100g), carrots (−4.9 mEq/100g), tomatoes (−3.1 mEq/100g), oranges (−2.7 mEq/100g), and broccoli (−1.2 mEq/100g). These foods are rich in potassium, magnesium, and calcium, which contribute to their alkaline-forming properties.

Among plant foods, grains and higher-protein legumes tend to have positive PRAL scores. Wheat and oats are more acid-forming than most vegetables and fruits, due to their protein and phosphorus content relative to their mineral base. However, plant-based foods generally produce far less acid load than animal products like meat, poultry, and dairy. Even acid-forming plant foods contribute significantly less to systemic acid burden than their animal-based counterparts.

No — eating alkaline-forming foods does not directly change your blood pH, which is tightly regulated between 7.35 and 7.45 by respiratory and renal buffering mechanisms. The blood pH remains constant regardless of food intake. However, chronically high acid-forming diets can increase the kidney's acid excretion burden, which may affect bone health and kidney function over time. Consuming more alkaline-forming plant foods reduces the acid load your kidneys must handle, supporting kidney health and potentially preserving bone mineral density.

Fruits and vegetables have negative (alkaline-forming) PRAL scores because they are rich in potassium, magnesium, and calcium while relatively low in protein and phosphorus. The Remer-Manz formula weights the basic minerals (K, Mg, Ca) heavily in the negative direction, while protein and phosphorus (acid precursors) are weighted positively. Since fruits and vegetables contain abundant basic minerals and minimal protein, their overall PRAL score is negative, classifying them as alkaline-forming. This mineral composition makes them valuable for counteracting acid load in the diet.

Yes — diets higher in alkaline-forming foods have been associated with better kidney function and reduced progression of chronic kidney disease in some studies. A high acid load from protein-heavy, mineral-poor diets requires the kidneys to excrete more acid, which over time may stress kidney function. Consuming more plant-based, alkaline-forming foods reduces this burden. A whole-food plant-based diet naturally provides abundant alkaline-forming foods (vegetables, fruits, legumes) while minimizing acid-forming foods, supporting long-term kidney health and overall metabolic balance.

A whole-food plant-based diet typically has a far more alkaline (negative) net PRAL score than omnivorous or carnivorous diets. Plant-based diets emphasize vegetables, fruits, and legumes — the most alkaline-forming foods — while naturally limiting high-acid-forming animal products like meat, fish, and dairy. Even when plant-based diets include grains (which are more acid-forming than vegetables), the overall PRAL typically remains lower than diets with significant animal product consumption. Studies show plant-based eaters have substantially lower dietary acid loads and better renal function indicators than omnivores.

The Remer-Manz formula is a validated method for calculating Potential Renal Acid Load (PRAL) based on nutrient composition: PRAL (mEq/100g) = (0.49 × protein[g]) + (0.037 × phosphorus[mg]) − (0.021 × potassium[mg]) − (0.026 × magnesium[mg]) − (0.013 × calcium[mg]). The coefficients reflect the relative contribution of each nutrient to systemic acid production. Protein and phosphorus increase acid load, while potassium, magnesium, and calcium decrease it. This formula was developed by Remer and Manz in the 1990s and has become the standard method for estimating food-induced renal acid load.

Plant proteins can produce less acid load than animal proteins because plant-based foods typically contain more potassium, magnesium, and calcium relative to their protein content, offsetting some of the acid-forming effect. For example, legumes (beans, lentils) and whole grains contain protein but also significant mineral content that buffers acidity. Additionally, plant foods lack the sulfur-containing amino acids (methionine, cysteine) found abundantly in animal proteins, which generate sulfuric acid when metabolized. A plant-based diet emphasizes this mineral-rich, lower-sulfur-amino-acid protein profile, resulting in substantially lower net dietary acid load than protein from meat, fish, and dairy.