Is Green Tea safe while breastfeeding?

Summary of use during breastfeeding

Green tea (Camellia sinensis) leaves and stems contain caffeine, l-theanine, polyphenols (e.g., quercetin), and tannins. Fussiness, jitteriness and poor sleep patterns have been reported in the infants of mothers with extremely high caffeine intakes (see the LactMed record on caffeine for details). The excretion of l-theanine into breastmilk has not been studied. Giving tea directly to infants can interfere with iron absorption and cause anemia,[1] but anemia in breastfed infants has not been reported with maternal tea ingestion. Application of wet tea bags to the nipples has been studied as a method of reducing nipple pain during the first few days of nursing. Two small, moderately well-controlled studies found a positive effect of the tea bags, but warm water compresses were as at least as effective as tea bags.[2,3] No studies were found that examined the use of oral green tea extract, topical application of green tea extract to the nipples, or to the topical product Veregren applied to genital warts during breastfeeding. Topical products applied away from the breast should pose negligible risk for the breastfed infant. Green tea is reportedly used to increase milk supply by some mothers in Türkiye.[4]

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Effects on the breastfed infant

Relevant published information was not found as of the revision date.

Effects on milk supply

Relevant published information was not found as of the revision date.

Levels in milk

Caffeine is excreted into breastmilk. Refer to the LactMed record on caffeine for details. No components of green tea besides caffeine have been measured in milk after the ingestion of tea, but some have been measured after the ingestion of other foods.

Maternal Levels. Quercetin can be found in breastmilk of mothers with normal diets.[5] Milk samples from 17 nursing mothers on uncontrolled diets were taken at 1, 4 and 13 weeks postpartum at times between 10 am and 1 pm. Average quercetin levels in breastmilk were 48 nmol/L at week 1, 60 nmol/L at week 4 and 51 nmol/L at week 13. Because of the uncontrolled diet and varying sampling times, the range of values among individuals was large.[6]

Quercetin was measured in the milk of 11 mothers after they received an onion soup that contained either 0.8 or 1 mg/kg of quercetin glucosides. A baseline milk sample was obtained after a 5-day low-quercetin diet, and 7 milk samples were obtained over the 48 hours following soup ingestion. Baseline total (from conjugated and unconjugated) quercetin in breastmilk averaged 45 nmol/L. An average peak milk quercetin level of 68 nmol/L was attained at an average of 11.9 hours after the soup meal. The average half-life of quercetin in breastmilk was 50.3 hours.[7]

Infant Levels. Relevant published information was not found as of the revision date.