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Foods to avoid while breastfeeding

While traces of what you eat and drink can pass into your breastmilk, in most cases, the amount is so minimal that it has no effect on your baby except to possibly introduce her to a new taste.

Breastfeeding can be tiring and challenging at times without having to worry about what you eat as well. Looking after yourself and eating a healthy diet will help to keep your energy levels up – but don’t deny yourself the things you love. What you eat won’t affect your ability to produce milk or the quality of it, but it is worth knowing what to look out for in case your baby reacts to something you’ve consumed.

By Mumsnet HQ | Last updated Sep 22, 2023

What foods might affect my breastmilk?

Not all of the following foods cause allergies but you might find that they have other effects:

  • Chocolate. If you’re a chocoholic you may want to consider that your favourite treat contains caffeine and in large quantities can have a laxative effect. Eating the whole chocolate fudge cake in one sitting might not be a good idea. (Although you might think differently if you’ve had a really bad day and long, sleepless night.)

  • Strong, potent tastes like garlic or hot spices. While neither of these will cause your baby any harm, eating a lot of something strong may affect the taste of your milk. You might find that your baby refuses to feed. On the other hand they might welcome the new taste. These tastes won't, however, be completely new for your baby. From week 16 of your pregnancy, she would have been able to taste traces of whatever you ate through the amniotic fluid.

  • Wheat, soy and eggs. There is no reason to exclude any of these foods from your diet while breastfeeding, but as common allergens you may need to consider them should your baby have a reaction. If you think they are causing a reaction you may need to give them up and reintroduce them slowly or wait until you’ve finished breastfeeding.

  • Dairy. Cow's milk products are perhaps the most common of food sensitivities in young babies. Some babies are intolerant to the protein found in cow’s milk. This is not the same as being lactose-intolerant so be careful to distinguish the two. Lactose intolerance occurs when your baby does not produce enough of the lactase enzyme required to break down the sugar in cow's milk. If you find your baby is reacting after a breastfeed, with a rash or tummy pains, speak to your GP or a dietitian. Again, you may need to cut dairy from your diet for a while although most children grow out of their cow's milk allergy by the time they are three.

  • Any food that another family member is allergic to. Allergies and food sensitivities can be inherited so keep an eye on those.

Food sensitivities are rare in babies that are still exclusively breastfeeding. If a sensitivity does appear, you will normally notice this when weaning and introducing your baby to solid foods. If you suspect that your baby may be intolerant to something in your diet then you should contact your GP or speak to your health visitor.

My baby is windy. Is it something I've eaten?

A bit of wind in babies is normal but can be a cause for concern if your baby is in discomfort. Some mums find that if they've eaten certain vegetables or pulses, their breastfed baby is extra gassy. The culprits are often cabbage, broccoli, cauliflower, garlic, onions, asparagus, artichokes, lentils and chickpeas. Excessive amounts of fruit, particularly prunes and apricots, can also have the same effect.

Any gas created in you is usually localised in your gastrointestinal tract and biology says it's not possible for it to enter your milk. However, anecdotally, many mums find reducing their intake of said veggies does reduce the problem.

If your baby's wind is chronic and persistent you may want to explore whether they have a sensitivity to cow's milk as this is often a common problem.

Can I eat fish while breastfeeding?

Fish is an important part of a balanced diet, allowing you to stock up on your omega-3 fatty acids that are essential for your baby’s eye and neural development. The good news is that, unlike during pregnancy, you do not have to be as strict with your fish intake while breastfeeding.

You can eat tinned tuna, shellfish and salmon while breastfeeding but you should still limit your intake of oily fish to two portions a week. Oily fish can contain high levels of mercury and pollutants and eating too much can produce unsafe levels of these contaminants in your milk.

You should completely avoid fish such as shark, marlin, swordfish and king mackerel. These bigger fish contain the highest levels of mercury. White fish such as cod, haddock, hake and plaice are all fine to eat.

If you’re a fan of sushi, you’ll need to use your judgement. Eat at a reputable restaurant and avoid street stalls and train station bento boxes that have been sat on display all day. If you are eating raw fish, avoid ones known to contain high amounts of mercury like mahi-mahi, fresh tuna and mackerel.

Can I eat peanuts while breastfeeding?

There’s no evidence that eating peanuts or peanut butter increases the chance of allergy in your child. Like anything, eating peanuts as part of a balanced diet is absolutely fine, unless of course you have an allergy yourself.

How do I know if my baby has been affected by the food I’ve eaten?

If you suspect that something you’ve eaten has upset your baby then you’ll probably notice one or more of the following changes in your little one:

  • Diarrhoea or constipation. Excessive caffeine may act as a laxative.

  • Windiness or bloating

  • Colic symptoms, especially a lot of crying. This is a common symptom of cow’s milk allergies.

  • Discomfort

  • Being extra fussy or out of sorts

  • Runny nose

  • Eczema or rashes

  • Milk rejection

Remember that babies can be unsettled for a number of reasons so don’t automatically assume it’s a reaction to food. It could be colic, a growth spurt or even just simple tiredness.

Can I drink caffeine while breastfeeding?

Yes you can – how else are you going to get through those early morning wake-up calls? But before you run out and celebrate this good news with a triple-shot flat white, bear in mind that high levels of caffeine in your breastmilk can have an effect on your baby.

Coffee, chocolate and soft drinks, particularly energy drinks, all contain large amounts of caffeine, as do most cold and flu medicines. Some babies will be more sensitive than others to caffeine, particularly younger babies. Newborns often struggle to metabolise coffee but this improves as they get older.
When my daughter was 3 weeks old, I had two strong coffees and a big coke in the same day. She stayed awake for eight hours that night. I'm not sure if the two were connected but I've not done it since!
NHS advice is to limit your caffeine intake to 200mg or less per day, which amounts roughly to two cups of instant coffee. You may be feeling tired as sin, but it's thought that the caffeine you consume could keep your baby awake – which isn't what anyone with a newborn is aiming for.

However, a recent review by the University of Warwick has highlighted the need for more extensive research on this subject. The study, by a research team from the university's medical school, has found no real evidence of positive or negative effects of maternal caffeine consumption on a breastfed baby. But before you stick the kettle on, the team isn't suggesting that caffeine has no effect at all – it just doesn't think there are sufficient studies of good quality to inform new mothers about how much caffeine they can actually have.

Lead researcher on the team, Aimee McCreedy said: “It's understandable that the NHS suggests that breastfeeding mothers restrict their caffeine intake to half of the usual recommended allowance for adults. This cautious approach likely reflects the paucity of good evidence. However, the lack of evidence is surprising given the promotion of exclusive for the first six months from birth and the importance of infant nutrition for health.”

Dr Yen-Fu Chen, the principal research fellow at Warwick Medical School said: “There is ample opportunity for well-designed studies to examine the effects of caffeine intake by mothers on their infants, and such research is overdue given the importance of maternal and child well-being at this crucial stage of life.”

So, the upshot is, there's no real evidence to suggest 200mg is the correct limit for caffeine intake, but not enough research has been done to provide a more accurate one. Which means it's probably best to stick to decaf for the most part… Sorry.

“My babies were exclusively breastfed until six months. Most days I limited it to a cup in the morning and then only when I felt I need a boost. The rest of the time I drank decaf. Once they were older I was more relaxed and just monitored it.”

Can I drink alcohol while breastfeeding?

After nine months off the booze during pregnancy, you might feel like treating yourself to a well-deserved glass of something nice after your baby is born. However, just like caffeine, alcohol can enter your baby’s system through your breastmilk – although in small amounts this isn’t harmful.

The most I've drunk is two or three units with no effect on my son. If I have ever got drunk, I make sure there is stored milk for him – but that's mostly because being drunk and taking care of a eight-week-old isn't advisable! As a guideline, it is fine to drink one or two units of alcohol in a single sitting once or twice a week. A unit of alcohol equates to half a pint of 4% beer, a single 25ml measure of spirits or a half of a 125ml glass of 11% wine. It can take 2-3 hours to metabolise a glass of wine depending on your weight and height. So, if you are going to enjoy a drink it’s a good idea to time it around your baby’s feeds.

When drinking, the level of alcohol in your breastmilk is the same as the level of alcohol in your blood, so drinking excessively and breastfeeding is going to have obvious effects on your little one. Newborns in particular may struggle to metabolise the alcohol in your milk but this improves as your baby gets older. Too much alcohol in your system could make your baby sleepier or even agitated.

Here are some things worth knowing if you are going to drink and breastfeed:

  • If you are off to a special occasion and want to have a drink, try expressing milk in advance that can be fed to your baby later on without concern.

  • Drinking with a meal will slow down the rate at which the alcohol enters your blood.

  • If you have more than one drink, wait two hours per drink before breastfeeding.

  • If you do feel you have drunk too much (enough to become ill), it is best to wait 12 hours before breastfeeding.

  • Don’t co-sleep with your baby if you've been drinking. How you sleep will be affected by how drunk you are and you could cause harm to your little one without knowing it. Sleeping with your baby whilst drunk can increase the chances of a cot death occurring. Alcohol can also impair your judgement about your baby’s needs.

  • There is no need to ‘pump and dump’ as the alcohol in your breastmilk will decrease at the same rate as your blood levels. The only reason you might need to express and discard milk is if your breasts have become engorged and uncomfortable.

“I was not against having a glass of wine (or even two sometimes) and would still feed my son. I would never get plastered but I didn't mind having a drink with dinner knowing I may need to feed afterwards. I was much more cautious when he was a newborn but the older he got the more I relaxed.”

Should I take vitamins when breastfeeding?

Vitamin D is recommended for pregnant and breastfeeding women. The recommended amount is 10mcg a day. A good postnatal multi-vitamin will contain this. You should be able to get all your other vitamins from a well-balanced diet.

Are there any foods that will improve my milk supply?

You may find yourself hungrier than usual when breastfeeding, especially if your little one is experiencing a growth spurt and many breastfeeding mums get particularly thirsty. Eating well, staying hydrated and feeding your baby on demand is the best recipe for improving your milk supply.

Although there is no scientific basis for it, some foods and herbs are often said to promote lactation. According to Mumsnetters, the following foods have helped boost their milk supply:

  • Oats. If you don’t like porridge, then Porridge. I swear by it. My milk supply was low and I just ate porridge and drank lots of water and it really increased my milk. I got my last child to six months on my milk. I really think porridge helped. flapjacks are a good alternative.

  • Fenugreek. This can be eaten in either seed or tablet form and is found at most health foods shops.

  • Brewer’s Yeast. This is also available in tablet form.

  • Non-alcoholic beer also has the same properties.

  • Fennel. If you don’t like the strong taste of the vegetable, try drinking it as a tea.

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