Nutrition during breastfeeding: what to eat and what to avoid

The diet during breastfeeding is a very common topic. The truth is that there is always widespread doubt about what I can or cannot eat during breastfeeding. After avoiding certain foods during pregnancy, it is natural to wonder what you can eat while breastfeeding, on top of all the myths we may have heard. That is why our midwives have created the following post for you, to offer you the latest scientific evidence on the subject.

What diet should you follow while breastfeeding?

Your ability as a mother to produce breast milk in sufficient quantity and quality to support your baby's growth is resilient and is usually independent of the diet you follow. However, your breast milk production normally affects your nutritional status, as the demand for nutrients is higher during the breastfeeding stage.

Below we will review the changes in your nutritional status during breastfeeding, the effect your diet will have on the volume and composition of your breast milk, and the needs you will have as a breastfeeding mother.

Nutritional needs during breastfeeding

It is well known that the mother's nutritional needs during breastfeeding are high, even higher than during pregnancy, both in terms of energy needs and at a nutritional level.

But if you follow a balanced diet, the higher nutrient needs can probably be met by a general increase in food intake. If, on the other hand, you follow a restrictive diet, dietary supplements may be necessary.

Broadly speaking, during breastfeeding mums should eat a healthy, balanced diet that includes dairy products, meat and fish, and other foods rich in vitamins and minerals, and a daily multivitamin and mineral supplement should also be suggested, as you may have been told when you were discharged from hospital.

Energy needs (calories) during breastfeeding

During breastfeeding, the estimated energy needs or calories required during breastfeeding are based on the mother's age, weight, height and level of physical activity.

Here is a table with the energy needs for non-breastfeeding women, to which we will need to add the following additional needs for breast milk production.

• Breastfeeding from 0 to 6 months

During the 0 to 6 month breastfeeding stage you will need 330 kcal more per day than a woman who is not breastfeeding. The reason lies in the energy cost of exclusive breastfeeding of 500 kcal/day (based on an average breast milk production of 780 ml per day, with an average energy content of 67 kcal/100 ml).

And if my body uses 500 kcal, why do I need 330 kcal? The answer is based on the fact that this calculation takes into account that during this stage, and in a mum with an adequate diet, there is an additional energy cost required by breastfeeding of 170 kcal per day, which is "subsidised" by the mobilisation of the mother's own fat stores and which will lead to the gradual loss of the weight gained during pregnancy in the first 6 months postpartum.

For mums with a healthy body mass index and average height, this means total energy needs ranging from 2130 to 2730 kcal/day during the first six months of breastfeeding, depending on maternal age, weight, height and activity level.

• Breastfeeding from 7 to 12 months

When your baby is between 7 and 12 months old, production needs change, and your body now needs about 400 kcal more per day. This energy cost of breastfeeding is based on an average breast milk production of 600 ml per day, with the same energy content.

In this case, unlike the previous one, the calculation for this period does not include the subsidy from the mobilisation of tissue stores, because it assumes that the mother's weight is stable.

For women with a healthy body mass index and average height, this means total energy needs ranging from 2200 to 2800 kcal/day, also depending on maternal age, weight, height and level of activity.

Protein during breastfeeding

The dietary recommendation regarding protein for a breastfeeding mother is 71 grams per day, for the first six months of breastfeeding. This is equivalent to 25 grams more than the normal needs of women who are not breastfeeding.

A recommendation based on a breast milk volume of 780 ml per day, with a protein content of 1g / 100 ml and a utilisation efficiency of dietary protein for milk synthesis of 47%.

Vitamins and minerals during breastfeeding

You can find the needs for vitamin and mineral intake during breastfeeding in the earlier table, and in it you will see that a healthy woman with a balanced diet usually takes in sufficient amounts of most nutrients. To ensure that all vitamin and mineral needs are covered, the recommendation of clinical guidelines is to take a daily multivitamin and mineral supplement.

And if in your case you follow an unbalanced or restricted diet (vegetarian or vegan), this supplement would be especially important, as it would also be for those who had an iron deficiency or another condition affecting their nutritional status.

Can I take the same supplement as during pregnancy?

It is a perfectly valid option; however, some mums report that they do not tolerate these prenatal vitamins well because of their high iron content. That is why opting for a multivitamin with less than 30 mg of iron can have fewer gastrointestinal side effects and be better tolerated. Do check, though, that your daily multivitamin and mineral supplement provides you with at least 150 micrograms of iodine, because in countries where table salt is iodised, this requirement is partly covered by the diet.

HOW DOES BREASTFEEDING AFFECT THE MOTHER?

To produce breast milk, your body draws on all its available resources, so it can affect your weight and your nutritional status, partly through the mobilisation of tissue stores.

Maternal weight and breastfeeding

In a breastfeeding mum, weight after birth is highly variable. During the first six months after birth, a mild and gradual weight loss usually occurs. This loss depends directly on the weight gained during pregnancy, age, parity, race, smoking, exercise and returning to work outside the home.

But it is true that the data on the effect of breastfeeding on weight changes after childbirth are contradictory. On the one hand, most studies indicate that breastfeeding has little effect on maternal weight. We therefore find cases in which breastfeeding women had less weight loss than women who were not breastfeeding, and other studies in which this weight loss was greater in breastfeeding mothers than in non-breastfeeding mothers, with five studies of high methodological quality standing out among them.

Vitamins, minerals and breastfeeding

During breastfeeding, there is an increase in dietary needs on the part of the mother for vitamins, because fat-soluble and water-soluble vitamins are secreted into breast milk. If in your case you follow a balanced diet, as we have seen, this increased nutrient requirement can be met by a general increase in food intake. Or if, on the contrary, you follow a restrictive diet, supplementation may be necessary.

Bone mass and breastfeeding

If we take bone mass into account, science warns us that it decreases during breastfeeding, and that our bones can be remineralised after weaning and the resumption of menstruation. This is because breastfeeding is associated with bone resorption, due to a decrease in estradiol (female sex hormone). Although it is proven that this loss is temporary, and that your recovery will occur with the return of your period and weaning. And to conclude with a myth, breastfeeding is not associated with a higher risk of hip, vertebral or forearm fracture.

That is why during breastfeeding the recommended dietary allowance of calcium is the same as for women who are not breastfeeding, although approximately 200 mg per day are secreted into breast milk during breastfeeding.

Calcium needs during breastfeeding do not increase, because the bone loss induced by breastfeeding is not prevented by increasing calcium intake, and also because this bone loss recovers after weaning.

DIETARY RECOMMENDATIONS DURING BREASTFEEDING

After all this information, we will now set out the recommendations on the products most commonly consumed and asked about during breastfeeding.

Fish and breastfeeding

Fish and seafood provide high-quality protein and other essential nutrients for the diet. In particular, it has been suggested that the consumption of fish by breastfeeding mothers is beneficial for the baby because fish contains large amounts of long-chain omega-3 polyunsaturated fatty acids (n-3 LCPUFA), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are important for the baby's brain development. However, the available data are insufficient to demonstrate an association between maternal intake of n-3 fatty acids during breastfeeding and the later cognitive function of the offspring.

A possible disadvantage of fish intake is exposure to mercury. Almost all fish and seafood contain traces of mercury. For most people, the risk from mercury through the consumption of fish and seafood is not a health problem.

The consumption of certain fish and seafood by women who are breastfeeding may pose a greater risk to the developing nervous system of the breastfed baby, since both inorganic and organic mercury are transferred from maternal serum to human milk. Concentrations of mercury in human milk are highly variable and tend to decrease between colostrum and mature milk. Mercury intake can be minimised by avoiding the consumption of predatory fish (for example, pike, garfish, mackerel, tilefish, swordfish).

It is recommended to eat between two and three portions a week of fish and seafood with a high omega-3 content and a low mercury content; below we give you a list of options. It is recommended to avoid fish such as shark, swordfish, king mackerel, garfish, orange roughy, bigeye tuna or tilefish, because they contain high concentrations of mercury.

Caffeine and breastfeeding

Most women who breastfeed can have a moderate amount of caffeine without any significant effect on their babies. Scientific evidence defines moderate caffeine consumption as two or three cups of a caffeine-containing drink a day.

However, there are times when breastfed babies are sensitive to caffeine and become irritable or have difficulty sleeping, even with small amounts of caffeine. This sensitivity usually decreases with time, as babies reach reach adult levels of caffeine clearance between three and five months of life.

Non-nutritive sweeteners and breastfeeding

Saccharin, sucralose and acesulfame potassium have been found in breast milk at low levels. What this tells us is that a maternal intake of typical amounts of sugar probably does not cause adverse effects in the baby, although there are experts who advise against maternal intake of large amounts of sugar. It must be said that aspartame is not secreted into breast milk, even when consumed in amounts far higher than typical.

Foods you should not eat during breastfeeding

If you are breastfeeding your baby, there are foods you should avoid, such as fish with a high concentration of mercury, as we mentioned earlier. Otherwise, there is no scientific evidence recommending a dietary restriction for the breastfeeding mother. To mention a particular case, unpasteurised dairy products or undercooked meat do not present special risks to the health of the breastfeeding woman or her babies.

Alcohol and breastfeeding

With regard to alcohol, it is known that a small percentage of alcohol passes into breast milk, which is why there is no amount of alcohol that is considered "safe" during breastfeeding. The recommendation of the scientific evidence is to avoid exposing the baby to alcohol, by avoiding its consumption, or, if you do drink, to avoid breastfeeding for two hours after a single portion of alcohol (360 ml of beer, 150 ml of wine, 45 ml of spirits at 80 degrees. If you also consume more alcohol than the amounts above, you should abstain from breastfeeding your baby for two hours more for each portion of alcohol consumed.

Should I express milk and throw it away if I drink alcohol?

It is not necessary to express and discard breast milk after drinking alcohol, unless your breasts are uncomfortably full of breast milk, very engorged before enough time has passed for the alcohol to leave your body.

Specific diets and breastfeeding

Every mum and her baby are unique, and there will be a situation for every mum, which is why below you will find possible common diets that we come across as health professionals in our day-to-day work.

Before we begin, we will bear in mind that mild or moderate variations in the maternal diet, energy balance and aerobic exercise do not usually affect breast milk production.

The normal amount of breast milk produced by a healthy woman is approximately 750 to 800 ml of breast milk per day, with exclusive breastfeeding and when breastfeeding is fully established.

But this volume varies from one mum to another and can even exceed 2,000 ml per day, for women who breastfeed twins or triplets.

Also, bear in mind that in the first days of breastfeeding, your production volume will be low, and this is normal. After 3 or 4 days, it increases noticeably, and then it gradually increases, meeting your baby's needs.

Weight-loss diet and breastfeeding

Can you follow a calorie-restricted diet during breastfeeding? If you are thinking of going on a diet after giving birth, or while you are offering your baby breast milk, you can. The evidence tells us that mild or moderate reductions in the mother's energy intake appear to have a limited effect on breast milk volume. In addition, it is known that moderate weight loss with or without exercise does not negatively affect breastfeeding.

Once breastfeeding is established, if you are overweight/obese you can restrict your energy intake by 500 kcal/day and do aerobic exercise four days a week. This will promote a weight loss of 0.5 kg/week without compromising your breast milk production.

Bear in mind that exercise on its own, without a diet, does not appear to achieve postpartum weight loss. Diet plus exercise is the most effective weight-loss strategy for breastfeeding and non-breastfeeding postpartum women.

In addition, you can follow this diet with peace of mind, since it rarely causes "lactation ketoacidosis" syndrome in breastfeeding women, very commonly associated with restrictive diets and especially with a low intake of carbohydrates.

Severe diet and breastfeeding

If you are thinking of following a more severe diet, be careful. In this case, a nutritional deprivation that is more extreme can have substantial effects on breast milk volume. A study reports that mums who reduced their daily intake to less than 1,500 kcal produced 15% less breast milk than when they followed a normal diet.

Vegetarian diet and breastfeeding

If this is your case, and you are a breastfeeding mother following a vegetarian diet, the evidence highlights the need for us to be aware of the potential risk of deficiencies in minerals, protein and vitamins. It will all depend on the degree of dietary restriction (ovo or lacto-vegetarian, for example), and supplementation with calcium, vitamin D and vitamin B12 may be necessary to meet the recommended intake of these nutrients.

Vegan diet and breastfeeding

If this is your case, and you are a breastfeeding mother in good health who does not eat meat, chicken, fish or dairy products, you will need to take a vitamin supplement containing vitamin B12. Most multivitamin preparations available on the market contain an adequate dose of B12.

Fasting and breastfeeding

Fasting is very much in fashion nowadays; it is worth knowing that short-term fasting does not reduce the breast milk supply, but it can have a minor effect on the composition of breast milk. This is possible because the body makes metabolic adaptations during short-term fasting that safeguard breast milk production.

On the contrary, long-term fasting can negatively affect the nutritional status of breastfeeding women. A possible recommendation, for example, is that breastfeeding women may be exempt from fasting during Ramadan for health reasons.

Avoiding foods to prevent atopic disease in the offspring.

It is not recommended that, as a breastfeeding mother, you avoid foods with the aim of preventing allergy, not even in high-risk babies. It is true that there are schools of thought that recommend avoiding the intake of peanuts, milk and/or eggs during breastfeeding to reduce the frequency of atopic disease in babies, but most of the evidence does not support this theory.

So it does not seem acceptable for us to recommend that the breastfeeding mum avoid certain foods so that her baby does not develop a defined food allergy.

Conclusion on diet during breastfeeding

As we have always seen, every case is different, and in this post you can get an idea of the best possible diet during your breastfeeding. But in the end we all know what should and should not be eaten, and a Mediterranean diet is optimal for our breastfeeding. Lots of encouragement with this stage!

Bibliography

The Happymami Project is based on scientific evidence; we are aware that science evolves every day, so if you have more up-to-date scientific evidence than ours, we would be delighted to receive it. We work every day to offer the best and most up-to-date information to our mums.

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