What's Not Good to Eat While Breastfeeding
Posted on June 07, 2026
Table of Contents
- Introduction
- Understanding How Your Diet Affects Your Milk
- Fish High in Mercury
- Herbs That Can Lower Milk Supply
- Caffeine and Your Baby’s Sleep
- Alcohol and Breastfeeding
- Understanding Food Sensitivities and Allergies
- Strong Flavors and Nursing Strikes
- Substances to Avoid Entirely
- How to Support Your Body While Breastfeeding
- When to Seek Help
- Conclusion
- FAQ
Introduction
If you have ever stared at a plate of spicy tacos or a second cup of coffee and wondered if it might affect your little one, you are not alone. It is common to feel a sense of hyper-awareness about everything you consume once you start nursing. At Milky Mama, we know that you want to provide the best for your baby while also taking care of your own needs.
The good news is that for most parents, a standard, varied diet is perfectly fine for breastfeeding. Your body is incredibly efficient at filtering what goes into your milk to ensure your baby gets exactly what they need. However, there are a few specific items that can impact your milk supply or your baby’s comfort.
In this guide, we will break down the categories of food and drink that require a bit more caution. We will cover which items might lower your supply, which ones could make your baby fussy, and how to spot signs of a true food sensitivity. Our goal is to help you feel confident and empowered as you nourish your baby.
Understanding How Your Diet Affects Your Milk
Before we dive into the "avoid" list, it helps to understand how your milk is made. Breast milk is created from your bloodstream, not directly from your stomach contents. This means that if you eat a gassy food like broccoli, the fiber and gas stay in your gut; they do not travel through your blood into your milk.
However, certain molecules—like caffeine, alcohol, and certain proteins—are small enough to pass into the milk. Some herbs can also affect the hormonal signals that tell your body to produce milk. Knowing the difference between what stays with you and what reaches your baby makes it much easier to navigate your meals. If you want a broader overview of foods that fit into a breastfeeding diet, our guide on what to eat when breastfeeding is a helpful next step.
Fish High in Mercury
Fish is generally a fantastic part of a breastfeeding diet because it contains DHA and omega-3 fatty acids, which support your baby’s brain development. However, certain types of fish carry a high risk of mercury contamination. Mercury is a heavy metal that can negatively affect a baby's developing nervous system.
When you consume high-mercury fish, the metal can accumulate in your body and pass into your milk. Because your baby’s brain is growing so rapidly, it is best to be cautious with your seafood choices.
Which Fish to Avoid
You should try to avoid or strictly limit fish that are large, long-lived predators, as they accumulate the most mercury. These include:
- Shark
- Swordfish
- King Mackerel
- Tilefish
- Marlin
- Bigeye Tuna
Safer Seafood Alternatives
You do not have to give up seafood entirely. In fact, we encourage most parents to eat two to three servings of low-mercury fish per week. Excellent choices include:
- Salmon
- Pollock
- Catfish
- Shrimp
- Canned light tuna (limit albacore or "white" tuna to once a week)
- Tilapia
Key Takeaway: Stick to "low and slow" fish choices—those lower on the food chain and lower in mercury—to get the brain-boosting benefits without the risks.
Herbs That Can Lower Milk Supply
While many herbs are used as galactagogues (substances that help increase milk supply), others have the opposite effect. These are often referred to as "anti-galactagogues." If you are struggling with an oversupply, these might be helpful, but for most parents trying to maintain or increase your milk, these herbs should be used sparingly.
Peppermint and Menthol
Small amounts of peppermint, like a single candy or a cup of tea, usually won't cause a problem. However, large amounts of peppermint or highly concentrated menthol can lead to a noticeable dip in milk production. This includes peppermint oil and strong peppermint infusions. If you notice your supply dropping, check if you have been using strong mint lozenges or drinking a lot of mint tea.
Sage and Rosemary
Sage is a well-known herb used by those who are ready to wean because of its ability to dry up milk. It contains compounds that can interfere with the hormonal process of lactation. While a little bit of dried sage in a stuffing recipe is likely fine, you should avoid medicinal amounts or sage-heavy essential oils.
Parsley
Similar to sage, eating massive quantities of fresh parsley can impact your supply. You would likely need to eat a large bowl of tabbouleh or drink concentrated parsley juice to see an effect, but it is worth keeping in mind if you are already worried about your ounces.
What to Do Instead
If you accidentally consume these herbs and notice a dip, don't panic. For many parents, supply will bounce back once the herb is out of your system. You can support your body’s natural production by focusing on hydration and nursing frequently. Our Lady Leche™ herbal supplement is designed to support your supply using ingredients rooted in clinical lactation expertise.
Caffeine and Your Baby’s Sleep
Most breastfeeding parents live on caffeine, and for good reason—newborns don't exactly respect a 9-to-5 sleep schedule! The good news is that most babies handle moderate amounts of caffeine just fine. However, some babies are more sensitive than others.
How Much Is Too Much?
Current guidelines suggest that up to 300 milligrams of caffeine per day is safe for most breastfeeding parents. That is roughly the amount in two to three small cups of brewed coffee.
Keep in mind that caffeine is also found in:
- Black and green tea
- Energy drinks
- Certain sodas
- Chocolate
- Some over-the-counter headache medications
Signs Your Baby Is Caffeine-Sensitive
Newborns, especially those born prematurely, process caffeine much more slowly than adults. If your baby is unusually fussy, jittery, or having a hard time staying asleep even when they are clearly tired, your caffeine intake might be the culprit.
If you suspect caffeine is the problem, try cutting back for a week to see if their behavior improves. You can also try timing your coffee so you drink it right after a nursing session, which gives your body more time to process it before the next feed. For more ideas on drinks that fit into a breastfeeding routine, see our guide to what drinks help boost milk supply.
Alcohol and Breastfeeding
There is a lot of conflicting information about alcohol and nursing. At Milky Mama, we follow the guidance that while the safest option is to avoid alcohol entirely, an occasional drink is generally considered compatible with breastfeeding if managed carefully.
The "Pump and Dump" Myth
One of the biggest misconceptions is that you need to "pump and dump" (express milk and throw it away) after having a drink to clear the alcohol. Alcohol leaves your milk at the same rate it leaves your bloodstream. Pumping does not speed up this process.
Safety Guidelines for a Drink
If you choose to have an occasional alcoholic beverage, here are a few tips to keep things safe:
- Wait it out: It typically takes about 2 to 3 hours for one standard drink (12 oz beer, 5 oz wine, or 1.5 oz liquor) to clear your system.
- Time it right: If possible, have your drink right after a nursing session so your body has time to process it before the baby is hungry again.
- Stay hydrated: Drink plenty of water alongside your beverage.
- Never bed-share: If you have consumed alcohol, you should never sleep in the same bed as your baby, as this significantly increases the risk of SIDS.
Understanding Food Sensitivities and Allergies
Sometimes, it isn't a specific "bad" food that causes trouble, but rather a sensitivity your baby has to a specific protein in your diet. The most common culprit is cow's milk protein.
Cow's Milk Protein Allergy (CMPA)
If your baby has an allergy to the protein found in dairy, they might experience significant discomfort. This is not the same as lactose intolerance; it is an immune response to the protein. Because these proteins pass into your milk, your baby reacts when they nurse.
Signs of a dairy sensitivity include:
- Extreme fussiness or colic-like symptoms
- Skin rashes or eczema
- Congestion or wheezing
- Green, mucousy, or bloody stools
- Frequent, forceful spitting up
Other Common Allergens
While dairy is the most frequent issue, some babies may also react to:
- Soy
- Eggs
- Peanuts or tree nuts
- Wheat (Gluten)
How to Identify a Sensitivity
If you suspect your baby is reacting to something you are eating, start a food diary. Record what you eat and your baby’s symptoms for about two weeks. Look for patterns. If you suspect dairy, you may need to eliminate all dairy products for 2–3 weeks to see if symptoms resolve, as the protein can stay in your system for some time.
Before starting a restrictive elimination diet, it is always a good idea to consult with a certified lactation consultant or your pediatrician to ensure you are still getting the nutrients you need. You can also read more in our post on breastfeeding and food sensitivities.
Strong Flavors and Nursing Strikes
Did you know that your breast milk actually changes flavor based on what you eat? This is actually a "fun fact" of breastfeeding—it introduces your baby to the flavors of your family's culture long before they start solids. However, some babies are more "picky" than others.
Garlic and Onions
Some studies show that babies actually stay on the breast longer and suck more actively when the milk tastes like garlic. However, other babies might find the strong scent or taste off-putting and may briefly go on a "nursing strike" (refusing to latch).
Spicy Foods
The "heat" of spicy food generally does not pass into the milk in a way that burns the baby. However, it can change the smell or flavor of the milk. If your baby seems to pull away or act fussy after you have a particularly spicy meal, they might just be sensitive to the change in taste. For more support around feeding changes and latch concerns, our Certified Lactation Consultant Breastfeeding Help page is a great place to start.
Substances to Avoid Entirely
While most things are fine in moderation, there are some substances that are not recommended while breastfeeding due to known safety risks.
Tobacco and Vaping
Nicotine is a stimulant that passes into breast milk and can cause a baby’s heart rate to increase and disrupt their sleep. More importantly, smoking or vaping decreases your levels of prolactin, the hormone responsible for milk production. This can lead to a significant drop in supply. Secondhand smoke also increases the risk of respiratory infections and SIDS.
Cannabis
Current medical advice from major health organizations recommends avoiding cannabis while breastfeeding. THC (the psychoactive component) is fat-soluble, meaning it stays in your fat cells and breast milk for a long time—potentially several weeks. While we are still learning about the long-term effects, some studies suggest it may impact a baby’s motor development and brain growth.
How to Support Your Body While Breastfeeding
Rather than focusing solely on what to cut out, we find it is much more empowering to focus on what to add in. Breastfeeding is hard work! Your body needs extra energy and nutrients to keep up with the demands of making milk.
Boost Your Calories
Most breastfeeding parents need an extra 450 to 500 calories a day. If you are feeling extra hungry, listen to your body. Focus on nutrient-dense snacks like nuts, seeds, yogurt, and fruit. Our Emergency Brownies are a fan-favorite for a reason—they are a delicious lactation snack that pairs well with a busy breastfeeding routine.
Hydrate, Hydrate, Hydrate
You don't need to force-feed yourself water, but you should drink to thirst. A good rule of thumb is to have a glass of water every time you sit down to nurse. If plain water gets boring, our Lactation LeMOOnade™ or Pumpin' Punch™ can provide hydration along with lactation-supporting ingredients. If you want to browse more options, the lactation drink mixes collection is another helpful place to look.
Action Steps for a Healthy Breastfeeding Diet
- Focus on variety: Eat a rainbow of fruits and vegetables to expose your baby to different flavors.
- Watch for patterns: If your baby is fussy, look at your food diary before assuming you need to cut out whole food groups.
- Prioritize protein: Aim for 2-3 servings of protein daily to support your own tissue repair and milk quality.
- Keep it simple: Don't stress over the occasional "unhealthy" meal. Your body is designed to make perfect milk even if your diet isn't perfect.
"Your well-being matters just as much as the milk you produce. If a strict diet is making you miserable, it isn't sustainable. Find a balance that keeps you and your baby happy."
When to Seek Help
If you are worried about your milk supply or your baby’s reactions to food, you do not have to figure it out alone. Milky Mama was founded by Krystal Duhaney, RN, BSN, IBCLC, because we believe every parent deserves accessible lactation support.
If you notice your baby is not gaining weight, is having fewer than six wet diapers a day, or seems to be in constant pain after eating, reach out to a professional. A certified lactation consultant can help you troubleshoot latch issues, supply concerns, or potential sensitivities. If you want a more structured next step, our Breastfeeding 101 course is built for parents who want extra education and confidence. You can also connect with other parents in the Official Milky Mama Lactation Support Group on Facebook.
Conclusion
Feeding your baby is a journey that changes every day. While there are a few things that are not good to eat while breastfeeding—like high-mercury fish or excessive amounts of certain herbs—the list of what you can eat is much longer. Most babies are resilient and will thrive on whatever healthy, varied diet you enjoy.
- Limit high-mercury fish like swordfish and king mackerel.
- Be mindful of supply-killers like large amounts of sage or peppermint.
- Watch for baby's cues regarding caffeine and dairy sensitivities.
- Prioritize your own nutrition and hydration to keep your energy up.
You are doing an amazing job providing for your little one. Remember, every drop counts, and your dedication to your baby’s health is what matters most. If you need a little extra boost, we are here to support you with snacks, supplements, and expert advice every step of the way.
FAQ
Does spicy food cause diaper rash?
Spicy food itself does not usually cause diaper rash, as the "heat" doesn't pass through the milk in that way. However, if a baby has a sensitivity to a specific ingredient in a spicy dish, it might cause more frequent or acidic stools, which can lead to skin irritation.
Can I eat peanuts while breastfeeding?
Yes, unless you have a peanut allergy yourself, there is no need to avoid them. In fact, some research suggests that exposing your baby to allergens through breast milk may actually help reduce their risk of developing a food allergy later in life.
How long does it take for food to enter breast milk?
Most substances show up in your breast milk about 2 to 6 hours after you consume them. If your baby has a reaction, it usually happens within this window, though some proteins like dairy can take longer to cause a noticeable change in symptoms.
Will drinking more milk increase my milk supply?
No, drinking cow's milk does not specifically increase human milk production. While the calcium and vitamin D are great for your health, your supply is primarily driven by the "supply and demand" of removing milk from the breast and staying well-hydrated with any fluids.
This product is not intended to diagnose, treat, cure, or prevent any disease. Consult with your healthcare provider for medical advice.
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