Foods: What Foods Is Galactose Present In?

November 18, 2025 •

3 min read

While most people associate galactose with milk, it is actually found in a broader range of foods. This simple sugar, a component of lactose, is present in varying amounts across dairy, some fruits, vegetables, and other processed items.

Quick Summary

Galactose is a simple sugar found primarily in dairy as part of lactose, but also in many fruits, vegetables, and fermented foods. High concentrations appear in milk and yogurt, with lesser amounts in specific plant-based sources.

Key Points

Dairy is the Main Source: Galactose is primarily found in milk and dairy products like yogurt, cheese, and ice cream, as a component of lactose.
Fermentation Increases Free Galactose: Fermented dairy (yogurt, kefir) and fermented plant products (miso, soy sauce) can have higher levels of free galactose due to microbial activity.
Plant-Based Foods Also Contain It: Many fruits and vegetables, including legumes, avocados, cherries, and bell peppers, are also sources of galactose, though typically in smaller amounts than dairy.
Content Varies by Processing: The amount of galactose in a food can change based on processing, fermentation, ripening, and aging, such as with aged cheese or ripe tomatoes.
Galactosemia Requires Dietary Restriction: Individuals with galactosemia must follow a low-galactose diet and be aware of all potential food sources, including less obvious ones.

What Exactly Is Galactose?

Galactose is a monosaccharide, or simple sugar, that is a component of the disaccharide lactose, commonly known as milk sugar. In mammals, lactose is broken down into glucose and galactose during digestion. For most people, the body then converts the galactose into glucose for energy using a series of enzymes. However, individuals with a rare genetic condition called galactosemia cannot properly metabolize galactose and must adhere to a strict low-galactose diet.

The Major Source: Dairy and Fermented Products

The most significant dietary source of galactose is lactose from dairy products. As lactose is broken down, it releases galactose, making all dairy-based foods important to consider for those monitoring their intake.

Milk: A primary source of lactose, and therefore galactose. Both human and bovine milk contain lactose.
Yogurt and Kefir: These fermented dairy products can contain a significant amount of free galactose. As fermentation proceeds, the bacteria break down the lactose, increasing the concentration of free galactose. Greek yogurt, in particular, can contain measurable levels.
Cheeses: The galactose content in cheese can vary widely depending on the type and aging process. Younger cheeses, like low-fat mozzarella and cottage cheese, tend to have higher levels, while certain aged cheeses, such as some types of Swiss, Gruyere, and Parmesan, contain negligible amounts as the fermentation and aging process depletes the sugar.
Processed Dairy: Other items like ice cream, buttermilk, cream, and desserts made with milk are also sources of galactose.

Surprising Plant-Based Sources

While dairy is the most obvious source, various plant foods also contain galactose, either freely or as part of larger molecules like oligosaccharides. For individuals on a restrictive diet, these sources are also important to be aware of.

Legumes: Beans, lentils, chickpeas, and peas contain oligosaccharides such as raffinose and stachyose, which are composed of galactose units. When these are broken down in the gut, they release galactose. For instance, dry blackeyed peas and green peas have been shown to contain significant galactose content.
Certain Fruits: Some fruits contain detectable levels of free galactose. Examples include papayas, dates, kiwi, cherries, plums, and avocados. The galactose content can also increase as the fruit ripens or during storage, such as with tomatoes.
Vegetables: Vegetables such as bell peppers, beets, tomatoes, celery, and mushrooms can contain varying amounts of galactose. Research shows that levels can fluctuate depending on the season, variety, and storage.
Seaweed and Gums: Galactose is also a structural component in some plant gums and mucilages. Sugar beets and certain types of seaweed, used in some food thickeners and additives, contain galactose.

The Role of Fermented Plant Foods

Similar to fermented dairy, fermented products made from plant sources can also contain free galactose. For example, soy sauce, miso, and natto—all fermented soybean products—have higher concentrations of free galactose than nonfermented soy alternatives. This is because the fermentation process releases the galactose from the soybeans' natural oligosaccharides.

Comparison of Galactose Sources

To illustrate the variability, here is a comparison of common foods and their typical galactose content (per 100g serving). Note that specific values can differ based on processing, preparation, and variety.


Food Category	Example Food Item	Estimated Galactose Content (mg per 100g)	Notes
High Galactose Dairy	Dulce de Leche	~1030 mg	High sugar dairy product.
Fermented Dairy	Low-fat Greek Yogurt	~600-700 mg	Fermentation releases free galactose.
Fermented Soy	Miso	~200 mg	Fermentation breaks down soy oligosaccharides.
Fruit	Cherries, sweet, raw	~590 mg	Content can vary with ripeness.
Legume	Dry Blackeyed Peas	~521 mg	Contains oligosaccharides that release galactose.
Vegetable	Raw Celery	~480 mg	Also contains measurable levels.
Aged Cheese	Hard Parmesan (>10 months)	Negligible	Aging process depletes lactose/galactose.

Conclusion

Galactose is not limited to dairy products; it is present across a diverse range of foods, including many plants and fermented goods. For those managing a galactose-restricted diet, understanding these sources is crucial for effective dietary planning. While dairy remains the most concentrated source due to its lactose content, legumes, specific fruits, vegetables, and fermented foods also contribute to overall galactose intake. Awareness of these varied dietary sources is key for informed nutritional decisions.

Authoritative Source on Galactosemia

For further reading on managing galactose intake, especially for individuals with galactosemia, the Galactosemia Foundation offers valuable dietary resources and information.

Frequently Asked Questions

No, lactose is a disaccharide (a sugar composed of two simple sugars), while galactose is one of the two monosaccharides (simple sugars) that form lactose, along with glucose.

Yes, many individuals with lactose intolerance can tolerate some galactose. Lactose intolerance is caused by a lack of the enzyme lactase, which is needed to break down lactose. Galactose itself does not require this enzyme for absorption.

Some aged cheeses, particularly hard, well-aged varieties like Parmesan, Swiss (Emmentaler), and Gruyere, have negligible or low levels of galactose. The aging process causes fermentation that breaks down the lactose and, subsequently, the galactose.

Legumes such as beans, lentils, and peas contain oligosaccharides that release galactose when digested. Specific examples include blackeyed peas and split green peas.

Fruits are typically a minor source of free galactose compared to dairy, but some, like cherries, papaya, dates, and kiwi, do contain measurable amounts. The content can also increase with ripening.

Yes, galactose can be present in processed foods, especially those that contain dairy ingredients like milk powder, whey, or cheese. It can also be in some additives derived from plant gums and mucilages.

Honey can be a source of galactose, with some reports indicating it can have a notable concentration. Honey is a mix of simple sugars, and its exact composition can vary.