Herbs and spices while breastfeeding? What is up with people saying “avoid sage (for example) and other spices this Thanksgiving”?—Data-seeking BFing mom
The reason people say this is that there are a set of, basically, old wives’ tales about sage and other herbs (peppermint, oregano, lemon balm) being used to decrease milk supply. By extension, if you did not want to decrease milk supply, you would want to avoid these.
However, and I cannot emphasize this enough, there is no evidence that herbs actually have this effect. One source I found noted that sage is used in some cultures to increase milk supply.
In addition, even when people suggest that sage could decrease milk supply, they are talking about a lot of it — like, drinking sage tea or adding sage oil to your food in a systematic way. Eating some sage-and-chestnut stuffing would not do it. And, again, there is no evidence to suggest that any of these approaches would have any impact.
In conclusion: enjoy your (fully herbed and spiced) meal.