Are Beans Highly Acidic? Separating Fact from Diet Fiction

November 3, 2025 •

4 min read

Most people assume beans are acidic, but a nutritional analysis reveals that many beans are actually alkaline-forming, meaning they produce alkaline ash after digestion. This dispels the common myth that beans contribute to an overly acidic diet and cause issues like acid reflux.

Quick Summary

This comprehensive guide clarifies the truth about beans' pH levels and their effect on the body, differentiating between the food's natural acidity and its metabolic impact. It explores why some people experience discomfort after eating beans and provides practical tips for preparation to improve digestibility.

Key Points

Alkaline-Forming, Not Acidic: Most beans are metabolically alkaline-forming, not highly acidic, due to their mineral composition, which produces an alkaline residue after digestion.
Digestive Discomfort Explained: Any discomfort often comes from fermentable carbohydrates (oligosaccharides) in beans causing gas and bloating, not from a systemic acidic effect on the body.
PRAL Score is Key: The potential renal acid load (PRAL) is a more accurate measure of a food's acid-forming potential than its raw pH; most beans have a negative PRAL score, indicating an alkaline effect.
Neutralize Anti-Nutrients: Soaking, sprouting, and proper cooking are effective methods for reducing phytic acid and lectins, which can cause digestive irritation and hinder mineral absorption.
Not All Legumes Are Alike: While most beans are alkaline-forming, some legumes, like lentils, have a mildly acidic PRAL score, though they are still nutritious.
Preparation Matters: Techniques like soaking and rinsing can drastically improve the digestibility of both dry and canned beans, making them easier on the stomach.

Understanding the Truth About Beans and Acidity

When evaluating a food's acidity, it's essential to distinguish between its inherent pH and its potential renal acid load (PRAL), which measures how much acid it produces in the body after digestion. While some raw beans may have a slightly acidic pH, the metabolic effect of most beans is alkaline-forming due to their mineral content. This is often the source of confusion for those interested in balancing their body's pH.

The Science Behind PRAL and pH

The pH scale ranges from 0 to 14, where 7 is neutral, below 7 is acidic, and above 7 is alkaline. The PRAL score, however, is a more useful metric for dietary impact. A negative PRAL score indicates an alkaline-forming food, while a positive score signifies an acid-forming one. A balanced diet typically includes a mix of foods to maintain overall homeostasis, rather than obsessing over the pH of a single ingredient. For example, animal proteins like meat and dairy are generally acid-forming, whereas most fruits, vegetables, and legumes are alkaline-forming.

Are Some Beans More Acidic Than Others?

While most beans have an alkaline-forming effect, there can be slight variations. For instance, kidney beans and lima beans are considered alkaline-forming, while some canned beans might have a neutral or slightly acidic pH due to processing or added ingredients. It is important to note that even when they are mildly acidic in their raw state, their final impact on the body is overwhelmingly positive and not conducive to creating systemic acidity.

Kidney Beans: Often cited as an alkaline-promoting food.
Lima Beans: Tend to be more alkaline with a pH around 6.5.
Navy Beans: Research shows these have an alkaline PRAL value of -1.1.
Canned vs. Dry Beans: The processing of canned beans can sometimes alter their pH slightly, but the mineral profile still makes them beneficial.

Why Do Some People Experience Discomfort with Beans?

The perception of beans causing 'acidity' or heartburn often stems from digestive issues rather than their pH. Beans contain complex carbohydrates called oligosaccharides, which are fermented by gut bacteria in the large intestine. This fermentation process produces gases like hydrogen, carbon dioxide, and methane, which can lead to bloating, flatulence, and general discomfort. These are not symptoms of systemic acidity but rather a localized digestive reaction.

Moreover, beans contain phytic acid, an antinutrient that can bind to minerals like calcium and iron and hinder their absorption. However, proper preparation methods can significantly reduce phytate levels. Another component, lectins, are proteins that can cause irritation in the digestive tract for some individuals. Cooking methods like soaking and boiling are effective at neutralizing these anti-nutrients.

Tips for Improving Bean Digestibility

Here is a list of preparation techniques to reduce digestive discomfort from beans:

Soaking: Soaking dry beans for 8-12 hours before cooking and then discarding the soaking water can significantly reduce indigestible oligosaccharides.
Sprouting: This process can neutralize phytic acid and enzyme inhibitors, making the beans easier to digest and absorb nutrients from.
Rinsing: For canned beans, rinsing them thoroughly removes some of the excess sodium and potentially gas-producing compounds.
Long, Slow Cooking: Cooking beans thoroughly at a consistent temperature breaks down complex sugars and other compounds that cause digestive upset.
Add Kombu Seaweed: Adding a small piece of kombu to the pot while cooking beans can help tenderize them and improve digestibility.

Comparison of Common Bean Types by Acidity and PRAL Score


Bean Type	Raw pH	PRAL Score	Comments
Green Beans	5.7–6.2	Alkaline-forming	Requires pressure canning due to low acid content for preservation.
Kidney Beans	5.4–6.0	Alkaline-forming	Considered one of the healthier choices for managing acid reflux.
Navy Beans	Neutral pH	-1.1 (Alkaline)	Possesses an alkaline-promoting effect after digestion.
Lentils	Neutral pH	+2.1 (Acidic)	A notable exception among legumes, with a mildly acidic PRAL score.
Soybeans	6.0–6.6	Alkaline-forming	Like many legumes, it's an alkaline-promoter despite its potential for anti-nutrients.

Conclusion: The Alkaline Truth About Beans

In conclusion, the idea that beans are highly acidic is largely a misconception rooted in a misunderstanding of how the body processes food. While some people may experience digestive discomfort due to gas-producing carbohydrates, the metabolic effect of most beans is alkaline-forming. The discomfort is localized to the digestive tract and is not a sign of a systemic 'acidic' condition. By using proper preparation methods like soaking and cooking, you can enjoy the considerable health benefits of beans, which include being an excellent source of protein, fiber, and essential minerals. Including beans in your diet is a great way to improve digestive health and overall well-being, especially for those following a plant-based diet.

Frequently Asked Questions

Yes, many beans are generally considered good for acid reflux because they are alkaline-forming and can help balance stomach acid levels. Fiber in beans also helps improve overall digestive function.

Food pH measures the acidity or alkalinity of the food itself (0-14). The PRAL (Potential Renal Acid Load) score measures the acid load a food places on the kidneys after it's been metabolized by the body. Most beans have an alkaline (negative) PRAL score.

Soaking beans does not change their fundamental pH, but it does reduce oligosaccharides and phytic acid, which can cause digestive distress. This improves digestibility, which is often what people associate with 'acidity'.

Heartburn or discomfort from beans is typically caused by the fermentation of complex carbohydrates by gut bacteria, not by the beans' actual acid content. This fermentation process can create gas that causes bloating and other symptoms.

Cooking methods don't change the metabolic effect of beans from alkaline to acidic. However, certain techniques like long cooking times and discarding soaking water can reduce the compounds that cause gas and digestive issues.

While the brines in canned beans can sometimes be slightly acidic, rinsing them can remove any such effect. The beans themselves remain alkaline-forming after digestion, regardless of whether they are from a can or cooked from dry.

Split peas, black-eyed peas, and lentils that have been thoroughly cooked are often reported to be easier on the digestive system for some individuals. Using proper soaking and cooking techniques also helps reduce gas-producing compounds in all types of beans.