I remember the day the mother of triplets handed me a couple of bottles of Guinness beer and said, “This is the secret to making milk.” I thanked her politely and didn’t tell her that I just don’t like beer. Much less dark beer. I also doubt that beer — Guinness or any other brand — has magical powers for making more milk. So, I looked at the science about whether beer makes more milk.
How does beer affect prolactin levels?
De Rosa and colleagues conducted a comparative study to determine the effects of three different fluids on serum prolactin levels:
- beer (6% ethanol)
- sparkling water only
- sparkling water with 6% alcohol
Researchers studied 11 non-lactating women (18-36 years old), during the early follicular phase of their menstrual cycles. Before consuming the fluid, the women consumed nothing by mouth, not even water, for a period of 12 hours, and had at least 1 hour of bedrest. They were instructed to drink a pre-assigned fluid within 15 minutes. Then…
- They drank the first pre-assigned fluid. After drinking it, they had their blood tested at 30, 60, 90, and 120 minutes.
- After 48 hours, the women consumed a second pre-assigned fluid. Investigators again measured prolactin levels again.
- After another 48-hours, they drank the third pre-assigned fluid within 15 minutes. Investigators again measured prolactin levels.
(Researchers gave the women the fluids in a different order.)
Prolactin levels peaked at 30 minutes in all of the women, regardless of the fluid they consumed. However, the rise in prolactin level was significantly larger (p < 0.005) after the women consumed beer (27.1 +/- 13.7 ng/mL) compared to water (12.6 ng/mL +/- 4.1) or water with 6% ethanol (12 ng/mL +/- 2.2).
Remember, though, that these women were not lactating, and this study doesn’t prove anything about whether or not beer makes more milk.
Is the alcohol responsible for the increased prolactin levels?
Carlson and colleagues studied the effects of beer on prolactin levels in 12 adults: 5 healthy men aged 31-47 years, and 7 healthy, non-lactating women aged 22-46 years. Researchers drew baseline samples of blood. Then, 11 subjects consumed 800 mL of beer with 4.5% alcohol during a 30-45 minute period; one woman consumed 800 mL of non-alchoholic beer.
Then, researchers wanted to determine serum prolactin levels. So, they took blood samples every 15 minutes for 2.5 hours and here’s what they found:
- In the men, mean baseline levels of 7 ng/mL rose to a mean (peak) of 12.0 ng/mL
- In women, mean baseline levels of 9.6 ng/mL increased to 22.6 ng/mL
Interestingly, the woman who consumed the non-alcoholic beer had a similar response. But again, none of these women were lactating, so we don’t know if beer makes more milk.
These studies are old. Do we know any more?
These studies were carefully done; that’s why I included the details. As far as I can tell, these are the only studies that look at prolactin levels after women consume beer.
What does all of this prove? Does beer make more milk?
- Two studies clearly showed that consumption of beer is associated with increased prolactin levels among nonlactating subjects. According to Carlson, et al., even non-alcoholic beer created a peak prolactin level similar to those who consumed the alcoholic beer.
- Something in the beer affects prolactin levels, but it’s not the ethanol. Note that in De Rosa’s study, prolactin levels increased when the women drank the beer containing 6% ethanol, but not when they drank water that contained 6% ethanol.
- We don’t know what causes the increase in prolactin levels. Perhaps the B vitamins or a polysaccharide from barley is the agent that elevates the prolactin levels.
- It’s tempting to assume that if prolactin levels rise, milk volume will increase. But we have no solid proof of that. And we are a long way from proving that beer makes more milk.
- Even if the prolactin levels resulted in an increased milk supply, it cannot be assumed that the nursling will consume more milk. Infants have a greater number of sucks but a lower overall milk intake when their mothers consume alcoholic beer as compared to when they consumed non-alcoholic beer or orange juice.
- It’s unclear whether beer is a true galactagogue — a substance that makes more milk.
So how does that affect what we say or do about drinking beer?
Hold on. Just like with other things we’ve heard about increasing milk supply, like drinking Gatorade or using fennel, there’s much more you need to know before you decide to drink beer or any other alcoholic beverage. Stay tuned, I have others post coming up to address alcohol consumption and minimizing effects of alcohol while breastfeeding!
Meanwhile, without clear proof one way or the other, what do you think? Do you think beer makes more milk? Tell me in the comments below!