Breastfeeding parents often question how diet affects milk supply, leading to many myths about which foods are safe to eat. A frequent concern involves whether consuming salad lettuce can cause breast milk to dry up. The common varieties of lettuce found in grocery stores do not negatively impact milk production and are completely safe. This concern likely stems from confusion between different types of plants within the Lactuca genus.
The Myth of Salad Lettuce and Lactation
The myth that lettuce reduces milk supply is rooted in the medicinal properties of an unrelated species known as Wild Lettuce (Lactuca virosa). Wild Lettuce is a different plant from standard salad varieties, such as romaine, iceberg, or butterhead, which are all cultivars of Lactuca sativa. L. virosa has historically been used for its sedative and pain-relieving qualities.
The milky white fluid Wild Lettuce secretes from its stem, called lactucarium, contains compounds like lactucin and lactucopicrin. This substance, sometimes referred to as “opium lettuce,” has a mild sedative effect and was used as a natural analgesic and sleeping aid. These compounds are considered to have anti-galactagogue properties in high concentrations, meaning they could reduce milk production.
However, the common lettuce varieties consumed in salads contain only trace amounts of these compounds and are primarily composed of water and nutrients. Eating a salad made with Lactuca sativa will not decrease your milk volume. Some research suggests that lettuce extract may even have milk-enhancing properties due to its phytoestrogen content.
Identifying Foods That May Reduce Milk Supply
While salad lettuce is safe, certain culinary herbs and food components are known as anti-galactagogues because they may decrease milk supply when consumed in large quantities. These substances signal the body to reduce milk production by affecting prolactin, the hormone responsible for milk synthesis. The most commonly cited herbs are sage, peppermint, and parsley.
Consuming large amounts of sage, peppermint, or parsley, such as in concentrated teas or extracts, may effectively reduce milk supply and are sometimes used by parents who are weaning. The menthol content in peppermint is thought to be responsible for its potential anti-lactogenic effect. Small amounts of these herbs used for seasoning are generally not enough to cause a noticeable drop in supply.
Beyond diet, the most significant factors affecting milk supply relate to the principle of supply and demand. Infrequent nursing or pumping, poor latching, and formula supplements can all signal the body to decrease production. Certain medications, such as decongestants containing pseudoephedrine and hormonal birth control pills, can also interfere with hormonal signals. High levels of stress are another element that can affect robust production.