Are Dairy Products Acidic? Understanding the Impact on Your Nutrition Diet

October 11, 2025 •

4 min read

While often perceived as a neutral food, fresh cow's milk actually possesses a slightly acidic pH, typically ranging from 6.5 to 6.7. However, determining whether dairy products are acidic is more complex than just a simple pH reading, as processing and fermentation significantly alter their properties and impact on your body.

Quick Summary

An examination of dairy acidity reveals that while most products, including milk and cheese, are acid-forming after digestion, fermented options like yogurt can be alkaline-forming. The body's blood pH is regulated regardless of diet, but dietary acid load can be a consideration for specific health conditions. The pH varies greatly between products based on processing and fermentation.

Key Points

Fresh milk is slightly acidic: Untreated cow's milk has a pH of 6.5–6.7, while pasteurized milk is considered acid-forming after digestion.
Fermented dairy products are more acidic: The fermentation process in products like yogurt and cheese lowers their pH considerably.
Post-digestion effect varies: While most milk and hard cheeses are acid-forming, some fermented products like yogurt and buttermilk can be alkaline-forming after being metabolized.
The body regulates its own pH: The acid-ash hypothesis, which claims that dietary acidity leaches calcium from bones, is not supported by scientific evidence.
Dietary acidity impacts certain conditions: Individuals with GERD or kidney issues might need to monitor their intake of dairy and other acidic foods, but most healthy people are not affected.
A balanced diet is key: Focusing on a varied diet rich in fruits and vegetables, alongside dairy, is more important than worrying about the specific acidity of one food group.

Unpacking the Acidity of Dairy

The question of dairy's acidity is often oversimplified. It's crucial to distinguish between a food's measurable pH level and its effect on the body's internal acid-base balance, particularly regarding the popular 'alkaline diet' concept. Understanding both aspects provides a clearer picture of how dairy fits into a balanced nutrition plan.

The pH of Milk: A Starting Point

Fresh, untreated cow's milk starts with a pH of about 6.5 to 6.7, putting it on the slightly acidic side of the scale. This mild acidity is due to its composition, which includes lactic acid. Over time, as milk sours, bacteria ferment lactose into more lactic acid, causing the pH to drop and the milk to become more acidic. The type of animal, its health, and feed can also influence the initial pH. Pasteurized and canned milk are generally considered acid-forming.

Fermentation and Processing: Acidity Drivers

Fermented dairy products, such as yogurt and cheese, showcase how processing can drastically change a food's acidity. The fermentation process relies on lactic acid bacteria, which actively lower the pH to create the product's characteristic texture and flavor. For example, yogurt typically has a pH between 4.0 and 4.4, while Cheddar cheese's pH is around 5.1. The longer a food is fermented, the lower its pH will typically be.

The Complexities of Acid-Forming vs. Alkaline-Forming

Here lies one of the biggest points of confusion. While many dairy products have a physically acidic pH, some are considered alkaline-forming once digested by the body. The acid-ash hypothesis suggests that some foods leave an acidic 'ash' in the body, while others leave an alkaline 'ash'. Under this theory, while hard cheeses and pasteurized milk are typically acid-forming, yogurt and buttermilk can be alkaline-forming. However, the scientific community widely refutes the notion that diet significantly alters the body's blood pH, which is tightly regulated by internal mechanisms. The primary health considerations for dietary acidity relate more to kidney burden and dental enamel erosion.

What About Dairy and the Acid-Ash Theory?

Proponents of the alkaline diet claim that dairy products, due to their high protein and phosphorus content, cause calcium to be leached from bones to neutralize acidity, thereby harming bone health. Extensive scientific research, however, does not support this theory. In fact, studies show that dairy consumption is associated with positive calcium balance and stronger bones. The body naturally regulates its pH, and a balanced diet with plenty of fruits and vegetables—which are generally alkaline-forming—is what's key for overall health, not avoiding entire food groups like dairy.

A Product-by-Product Acidity Guide

Let's break down the acidity of common dairy products based on both their physical pH and their effect on the body.

Cow's Milk: Slightly acidic (pH 6.5-6.7). Most pasteurized milk is considered acid-forming after digestion.
Yogurt and Buttermilk: Very acidic physically (pH 4.0-4.8), but often considered alkaline-forming due to the beneficial bacteria and fermentation process.
Hard Cheeses: Such as Cheddar, are acidic (approx. pH 5.1) and are considered acid-forming after digestion.
Cottage Cheese: Mildly acidic (pH ~4.5-5.0) and classed as an acidifying food.
Butter and Ice Cream: These products are also considered acid-forming.

Acidity Comparison: Dairy vs. Other Foods


Food Type	pH Level	Post-Digestion Effect	Dietary Context
Pasteurized Milk	6.7-6.9 (slightly acidic)	Acid-Forming	Protein and phosphorus content contribute to acid-forming properties.
Yogurt (Plain)	4.0-4.4 (acidic)	Alkaline-Forming	Lactic acid content is high, but the body's metabolic response is different.
Hard Cheese	~5.1 (acidic)	Acid-Forming	High in protein, contributes to dietary acid load.
Lemons	2.0-3.0 (very acidic)	Alkaline-Forming	Citrus fruits, despite their high acid content, are well-known to have an alkalizing effect.
Red Meat	N/A	Acid-Forming	High in protein and phosphorus, known to contribute to dietary acid load.
Leafy Greens	N/A	Alkaline-Forming	Abundant in alkaline minerals, promoting an alkaline-forming effect.

Who Should Be Mindful of Dairy Acidity?

For most healthy individuals, consuming dairy as part of a balanced diet is not a concern, as the body's regulatory systems manage pH levels effectively. However, certain individuals may need to consider the acidity of dairy products:

Those with GERD (Gastroesophageal Reflux Disease): Acidic foods can trigger or worsen symptoms of heartburn in some people. Dairy may temporarily soothe symptoms by coating the esophagus, but can also trigger more stomach acid production, causing issues.
Individuals Following an Alkaline Diet: People who choose to follow an alkaline-based diet for various health reasons will typically avoid or limit dairy products, especially acid-forming ones like milk and hard cheeses.
Those with Kidney Concerns: For individuals with kidney disease, managing dietary acid load may be beneficial to lessen the burden on the kidneys.

For more detailed information on the pH of various milk and dairy products, a reliable source like Healthline offers a comprehensive overview.

Conclusion: Finding the Right Balance

So, are dairy products acidic? The answer is nuanced. Physically, most dairy products are slightly to moderately acidic due to their composition and processing. When it comes to the body's internal acid-base balance, most dairy is acid-forming, though some fermented products can be alkaline-forming. The scientific consensus is clear that diet does not significantly affect blood pH, and the controversial acid-ash hypothesis regarding bone health has been debunked. For most people, the key is to focus on a balanced diet rich in fruits and vegetables, alongside nutrient-dense foods like dairy, without overly focusing on the fear of dietary acidity. Individuals with specific health conditions, like GERD, should consult a doctor or registered dietitian to understand their personal needs regarding dairy consumption.

Frequently Asked Questions

Fresh milk has a slightly acidic pH (6.5-6.7). Most pasteurized milk and processed dairy products are considered acid-forming after digestion, but this does not affect the body's blood pH.

Hard cheeses are acidic due to the cheesemaking process and are considered acid-forming after digestion. However, the body's blood pH is tightly regulated and not influenced by dietary cheese consumption.

Yes, yogurt is physically acidic, with a pH typically between 4.0 and 4.4, due to the lactic acid produced during fermentation. However, despite its physical acidity, yogurt is sometimes considered an alkaline-forming food once metabolized.

For some individuals with GERD or acid reflux, acidic foods like some dairy products can trigger or worsen heartburn symptoms. While milk may temporarily soothe, it can also stimulate stomach acid production, potentially causing more issues.

No, scientific evidence does not support the 'acid-ash' theory that dairy products leach calcium from bones to neutralize acidity. Studies show that dairy consumption has a positive effect on bone health.

A food's pH is its measurable acidity or alkalinity. Its effect on the body refers to the residue left after digestion. Some foods with a low pH (e.g., citrus fruits) can be alkaline-forming in the body, while some foods with a slightly acidic pH (e.g., milk) can be acid-forming.

Individuals following an alkaline diet typically avoid most dairy products, which are often classified as acid-forming. They instead focus on alkaline-forming foods like fruits, vegetables, and some nuts.