Spearmint (Mentha spicata) is a common herb used in teas, chewing gums, and flavorings. Its use sparks inquiry among breastfeeding individuals who are cautious about how herbal consumption might affect milk production. Concerns arise because some herbs in the mint family are traditionally linked to reduced milk volume. This article examines the biological theories and current evidence to determine spearmint’s actual impact on milk supply.
The Mechanism Behind Spearmint’s Potential Effects
Spearmint is studied in a hormonal context due to its anti-androgenic properties. It contains compounds, such as carvone and limonene, which reduce the levels of androgens, like testosterone. This effect is supported by studies showing that regular consumption can significantly lower free testosterone in women with certain hormonal conditions.
The hormonal theory connecting this to lactation is based on the inhibitory relationship between androgens and prolactin. Prolactin stimulates milk production in the mammary glands. Androgens can suppress prolactin activity, thereby inhibiting milk synthesis. Therefore, spearmint, by lowering androgen levels, is theoretically considered a potential galactagogue that could indirectly promote milk supply by removing a hormonal brake.
What Research Shows About Spearmint and Milk Supply
Despite the theoretical pathway suggesting a potential increase in milk supply, high-quality human clinical trials on spearmint’s effect on lactation are currently absent. The consensus among lactation experts is that typical consumption of spearmint, such as in tea, does not reliably decrease milk production. This contrasts with traditional uses where spearmint is occasionally considered a mild herbal aid to support milk flow.
Moderate intake of spearmint tea is unlikely to pose a risk to an established milk supply for most individuals. Strong claims of spearmint acting as a powerful supply booster or reducer lack robust scientific backing. The focus on spearmint often stems from the known effects of its close botanical relative, which has a different chemical profile and a stronger association with supply reduction.
Distinguishing Spearmint From Peppermint
Confusion about spearmint’s safety is often due to its close relationship with peppermint, which is known to have a stronger potential to decrease milk supply. The primary chemical difference lies in the concentration of menthol, the compound that gives mint its cooling sensation. Peppermint (Mentha piperita) essential oil is rich in menthol, containing 30% to 50% of the compound.
Menthol is strongly associated with suppressing milk production, likely by inactivating the STAT5 and mTOR signaling pathways within the mammary epithelial cells that are crucial for milk synthesis. In contrast, spearmint (Mentha spicata) contains negligible amounts of menthol, often less than 1% in its essential oil or “no measurable amount” in the tea form. This significantly lower menthol content makes spearmint the safer alternative for breastfeeding individuals consuming mint flavorings.
Practical Advice and Safety for Consumption
Individuals consuming spearmint while nursing should prioritize moderation and form of intake. Drinking one to two cups of spearmint tea daily is generally considered safe and poses minimal risk to milk production. It is recommended to use the tea form rather than highly concentrated essential oils or supplements, as these deliver a much higher dose of active compounds.
Monitoring the infant’s feeding behavior and output, such as wet and dirty diapers, is the most practical way to assess any potential effect on milk supply. If concerns about production exist, consult with a certified lactation consultant or healthcare provider before incorporating any new herb. Spearmint should be used as a supplemental beverage, as proper hydration remains necessary for maintaining a steady milk supply.