A1 vs A2 milk? Experts tell which type of milk can benefit gut and skin health more

Milk is widely known for its nutritional benefits, which range from helping build strong bones with calcium to repairing muscles with protein and providing essential vitamins like B12 and D for energy. In recent years, there has been greater awareness of the differences between the two types of milk, A1 and A2. While both are consumed in the same way as regular milk, they differ in their protein composition and animal source. A2 milk comes from Indian cow breeds like Gir and Sahiwal and is often considered easier to digest for some individuals. On the other hand, A1 milk usually comes from western cow breeds like Holstein and Jersey and is commonly available in the market.

To better understand these differences, Health Shots spoke to dietitian and founder of FISICO Diet & Aesthetic Clinic, Vidhi Chawla, who explains how each type of milk can have different effects on gut and skin health.

“Milk has long been considered a nutritious food, but in recent years, the debate between A1 and A2 milk has attracted attention, particularly for its effects on gut health and skin. Understanding the difference between the two can help individuals make an informed choice based on their body’s response,” says Chawla.

What is the difference between A1 milk and A2 milk?

A1 and A2 are types of milk whose method of consumption is similar, but the compounds and sources make them different from each other. The dietitian says their main difference lies in the type of beta-casein protein present in the milk. Regular milk is a mixture of both A1 and A2.

• When A1 β-casein is digested, it can release a small peptide called beta-casomorphin-7 (BCM-7). A2 β-casein is less likely to release BCM-7.
• PMC states that BCM-7 may act on opioid receptors and affect gut physiology and immune responses.
• This means that A2 milk is easily broken down and does not form a certain peptide. Whereas A1 milk produces a peptide called BCM-7.

What is the role of BCM-7 in gut health?

• This peptide may alter gut microbial fermentation patterns and short-chain fatty acid profiles, which may indirectly affect systemic inflammation and the skin. According to PubMed Central, evidence in this regard is emerging and not yet definitive.
• Whereas, according to the MDPI journal, it can trigger digestive symptoms like stomach discomfort. However, it has also been suggested that it is likely that these adverse effects are limited to only a portion of the population.

A study cited in Research Gate also suggests that A1 milk and the peptide BCM-7 may be linked to heart disease, diabetes, autism, sudden infant death syndrome, and inflammation in the digestive tract. The results are mixed, and further study is needed.

Effects on skin health

The dietitian says gut health and skin health are closely linked through the gut-skin axis.

• In sensitive individuals the digestive inflammation caused by A1 milk may indirectly show up on the skin as acne, dullness or eczema flare-ups.
• A2 milk, being easy to digest, can help reduce internal inflammation, which can support clearer skin, better hydration and an improved skin barrier over time.
• It is important to note that milk affects the skin of every person differently. Overall diet quality, hormonal health and overall gut balance also play a role.

What does the medical evidence show?

• According to PubMed, in a double-blind, randomized crossover trial of 41 adults, consumption of A1 β-casein milk (vs. A2) significantly increased stool consistency (stool softness), and abdominal pain was only related to stool softness during the A1 phase, not during the A2 phase.
• The MDPI says that a 2016 randomized crossover study (on individuals with self-reported dairy intolerance) found that switching to milk containing only A2 β-casein resulted in fewer gastrointestinal symptoms, fewer markers of inflammation, longer colonic SCFA (short-chain fatty acids) production, and shorter transit time compared to regular milk containing A1/A2 β-casein.
• PubMed says A2 may be better tolerated and more “microbiome-friendly” for some people.

What to try and what to expect?

For those experiencing digestive discomfort or frequent skin issues, Vidhi Chawla suggests:

• Try switching to A2 milk continuously for 2-3 weeks.
• Observe changes in digestion, bloating, bowel regularity and skin texture.
• Choose plain, unsweetened, minimally processed A2 milk with no additives.
• If symptoms persist, it may be appropriate to increase overall dairy intake or explore alternative calcium sources under professional guidance.

(Note to readers: This article is for informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your doctor with any questions you have about any medical condition.)