Thick breast milk

Breast milk composition | What’s in your breast milk?

It’s full of nutrients that feed and protect your baby, but did you know breast milk composition varies over time? Find out what’s in breast milk and how it changes to meet your baby’s needs

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As your baby’s first food, you might expect your breast milk ingredients to include basic essential nutrients, such as carbohydrates, proteins and fats, as well as water to keep her hydrated, which it does.¹ But breast milk is no ordinary food – it has more value than nutrition alone.

What’s breast milk made of?

Here are some of the other constituents of human milk present at every feed, many of which can’t be replicated:

• Millions of live cells. These include immune-boosting white blood cells, as well as stem cells, which may help organs develop and heal. ²
• More than 1,000 proteins³ that help your baby grow and develop, activate her immune system, and develop and protect neurons in her brain.
• All that breast milk protein is made up of amino acids. There are more than 20 of these compounds in your milk. Some of them, called nucleotides, increase at night and scientists think they may induce sleep.^4,5
• Over 200 complex sugars called oligosaccharides⁶ that act as prebiotics, feeding ‘good bacteria’ in your baby’s gut. They also prevent infections entering her bloodstream and lower her risk of brain inflammation.
• More than 40 enzymes.⁷ Enzymes are catalysts that speed up chemical reactions in the body. The ones in your milk have jobs such as aiding your baby’s digestion and immune system, as well as helping her absorb iron.
• Growth factors that support healthy development. ¹ These affect many parts of your baby’s body, including her intestines, blood vessels, nervous system, and her glands, which secrete hormones.
• On the subject of hormones, your breast milk contains lots of them!⁷ These clever chemicals send messages between tissues and organs to ensure they work properly. Some help regulate your baby’s appetite and sleep patterns, and even aid the bond between you.
• Vitamins and minerals – nutrients that support healthy growth and organ function, as well as help build your baby’s teeth and bones.¹
• Antibodies, also known as immunoglobulins. There are five basic forms of antibodies and all of them can be found in your milk.⁸ They protect your baby against illnesses and infections by neutralising bacteria and viruses.
• You may have heard of long-chain fatty acids because they play a pivotal part in building your baby’s nervous system, as well as aid healthy brain and eye development. ⁹ And, you’ve guessed it, there are several of these in your milk too!
• 1,400 microRNAs, which are thought to regulate gene expression, as well as help prevent or halt disease development, support your baby’s immune system, and play a role in remodelling the breast.¹⁰

While this is a long list, it’s only some of the ingredients in your breast milk – and scientists are still discovering more. Remarkably, the levels of these ingredients can fluctuate over time, depending on your baby’s age and needs.

Let’s start at the beginning…

The first few days: Colostrum

The early milk your breasts produce after your baby’s birth is called colostrum. This thick, sticky breast milk is often called ‘liquid gold’, not just because of its yellow or orangey colour, but because it’s so important for nourishing and protecting your vulnerable newborn.

At first you’ll produce very small amounts – just 40 to 50 ml (1.4 to 1. 8 fl oz) over 24 hours¹¹ – but as your baby’s stomach is only the size of a marble, that’s all she needs. Colostrum is also very easy to digest. And what it lacks in quantity it makes up for in quality.

The composition of colostrum

Colostrum has the same ingredients that your later milk will have – it’s just that the amounts of these ingredients are different, as it’s tailored to your newborn’s needs.

For example, colostrum is sometimes referred to as a natural vaccination because its levels of antibodies and white blood cells are so high. Your first milk needs to contain these so it can protect your baby from infections and diseases after she leaves the safety of your womb.

Colostrum’s protective qualities are also important for your baby’s digestive system. Babies are born with a permeable gut lining, which colostrum coats and seals.^12,13 This is particularly important if your baby is premature, as she’ll be more at risk from the dangerous gut condition necrotising enterocolitis (NEC). ¹³

It’s also rich in minerals and vitamins, with higher concentrations of vitamins A, E and K than mature breast milk. The percentage of protein in colostrum is higher too.¹ Colostrum also acts like a laxative that helps your baby pass her first poo, meconium.¹⁴

The next couple of weeks: Transitional milk

During the first week of your baby’s life, around two to four days after delivery, your breast milk changes in quantity. You may feel your breasts become fuller and firmer – a change known as your milk ‘coming in’. On the third day, your baby will consume 300 to 400 ml (10.5 to 14 fl oz) of breast milk per 24 hours, and by the fifth day this increases to 500 to 800 ml (18 to 28 fl oz), so it’s not surprising your breasts may feel bigger!¹¹

From day five to 14, your milk is called transitional milk.¹⁵ As the name suggests, it’s changing from colostrum to mature milk. It becomes creamier in colour and texture, and also higher in fat, calories and lactose (a natural sugar), making it the ideal food for your rapidly growing newborn.

But rest assured it’s still full of protective antibodies, live cells, ‘good’ bacteria and other bioactive ingredients to help keep her healthy.¹⁵

Four weeks onwards: Mature milk

By the time your baby is four weeks old, your breast milk will be fully mature. It’s rich in protein, sugar, vitamins and minerals, plus numerous bioactive components – such as hormones, growth factors, enzymes and live cells – to support your baby’s healthy growth and development.⁷

From four weeks, the nutritional content and levels of ingredients in mature milk generally remain fairly consistent. But the composition of your breast milk can still change from day to day and feed to feed.

For example, if you or your baby are ill, your body will make antibodies to fight that particular illness, which become part of your milk. And, remarkably, as your baby begins exploring the world and putting toys in her mouth, the level of protective bacteria-fighting enzymes in your milk rises. ¹⁶ This variation in breast milk composition shows how it adapts to your baby’s changing needs.

What are foremilk and hindmilk?

You may notice your milk seems thicker and creamier towards the end of a feed. This is because, as the feed progresses, the fat composition gradually increases due to the mechanics of milk moving through the breast. It’s often referred to as hindmilk, while the first more ‘watery’ milk is known as foremilk. These two names might lead you to think there’s a switch where foremilk becomes hindmilk, but there isn’t. The change is a gradual process.¹⁵ Both are essential parts of a completed feed, and rich in vitamins, minerals, protein and sugars.

Your milk’s fat content relates to how drained your breast is. Your breasts will be fuller at the start of some feeds (milk lower in fat) and more drained at the start of other feeds (milk higher in fat). So don’t worry too much about foremilk and hindmilk – over 24 hours your baby will end up consuming a similar amount of fat in total each day. ¹⁷

Breast milk composition after six months

You may be wondering what happens to your milk if you continue breastfeeding long-term. Can your body really keep producing such high-quality mature milk for months and months, or even years? The answer is, don’t underestimate your breasts!

While it’s true you’ll need to start introducing solids at six months to bolster your baby’s stores of certain nutrients, such as iron,¹⁸ your milk will still make up a large part of her diet.

For example, when your baby is seven months old she will still be getting 93% of her calories from breast milk. Even between 11 and 16 months, around half of her daily calorie intake will be from milk.¹⁹

So relax in the knowledge that you can both continue to enjoy the benefits of breastfeeding for many months to come.

References

1 Ballard O, Morrow AL. Human milk composition: nutrients and bioactive factors. Pediatr Clin North Am. 2013;60(1):49-74.

2 Hassiotou F et al. Cells in human milk: state of the science. J Human Lact. 2013;29(2):171-182.

3 Beck KL, et al. Comparative proteomics of human and macaque milk reveals species-specific nutrition during postnatal development. J Proteome Res. 2015;14(5):2143-2157.

4 Zhang Z et al. Amino acid profiles in term and preterm human milk through lactation: a systematic review. Nutrients. 2013;5(12):4800-4821.

5 Sánchez CL et al. The possible role of human milk nucleotides as sleep inducers. Nutr Neurosci. 2009;12(1):2-8.

6 Moukarzel S, Bode L. Human milk oligosaccharides and the preterm infant: a journey in sickness and in health. Clin perinatol. 2017;44(1):193-207.

7 Hamosh M. Bioactive factors in human milk. Pediatric Clinics. 2001;48(1):69-86.

8 Brandtzaeg P. The mucosal immune system and its integration with the mammary glands. The J Pediatr. 2010;156(2):S8-15.

9 Uauy R et al. Essential fatty acids in early life: structural and functional role. Proc Nutr Soc. 2000;59(1):3-15.

10 Alsaweed M et al. Human milk cells and lipids conserve numerous known and novel miRNAs, some of which are differentially expressed during lactation. PLoS One. 2016;11(4):e0152610.

11 Neville MC et al. Studies in human lactation: milk volumes in lactating women during the onset of lactation and full lactation. Am J Clin Nutr. 1988;48(6):1375-1386.

12 Marchbank T et al. Pancreatic secretory trypsin inhibitor is a major motogenic and protective factor in human breast milk. Am J Physiol Gastrointest Liver Physiol. 2009;296(4):G697-703.

13 Herrmann K, Carroll K. An exclusively human milk diet reduces necrotizing enterocolitis. Breast Med. 2014;9(4):184-190.

14 Lawrence RA, Lawrence RM. Breastfeeding: A guide for the medical profession; 2011. 1114 p.

15 Martin CR et al. Review of infant feeding: key features of breast milk and infant formula. Nutrients. 2016;8(5):279.

16 Montagne P et al. Changes in lactoferrin and lysozyme levels in human milk during the first twelve weeks of lactation. InBioactive components of human milk 2001 (pp. 241-247). Springer, Boston, MA.

17 Kent JC, et al. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Pediatrics. 2006;117(3):e387-395.

18 Kuo AA et al. Introduction of solid food to young infants. Matern child health J. 2011;15(8):1185-1194.

19 Dewey KG et al. Breast milk volume and composition during late lactation (7-20 months). J Pediatr Gastroenterol Nutr. 1984;3(5):713-720.

Why is my breast milk clumpy?- Ask an LC — Mattos Lactation

" Dear Shondra,

A couple of days ago, I noticed a slimy substance (pic below, left) hanging in my pump. Upon further inspection, I noticed a huge piece in my milk, which shrunk as I moved it around. Since then, every time I pump my right breast, the milk from that breast gets clumpy while sitting in the bottle (pic below, right). Why is my breast milk clumpy? Is this fat or something else?" 

First day

Couple days later

Clumpy breast milk is often very perplexing to parents, especially when the clumps develop soon after pumping. From the pictures that you've provided, and based on the information you've shared, it sounds like the clumpy milk may be due to a case of subclinical mastitis. 

Other descriptors for clumpy milk may include Slimy, thick and gooey, stringy, globs, mucusy. lumpy,

Though mastitis is a term that, by definition, means breast inflammation, in some cases, mastitis can be caused by an infection. If your clumpy breastmilk is, in fact, due to subclinical mastitis, it means that you have mastitis from a breast infection without having any symptoms of it.

It is possible the "milk plugs" -the milk that was hanging in your pump on the first day- developed as a result of the infection. It's also possible, though less likely, the infection in your right breast started due to a lack of milk flow from the plugs.

Though finding the cause of the infection is less important than finding the right treatment, it may be helpful to know the risk factors of developing a breast infection:

• Infrequent or incomplete milk removal

• Your baby was recently ill with a staph infection

• You have damage to your nipple skin or breast tissue

• A topical bacterial infection improperly treated as thrush

If you've maintained regular, frequent, and complete milk expression, it's unlikely that the clumpy milk is due to anything else other than a bacterial infection.

 A coagulase positive staph strain like Staphylococcus aureus is the most common culprit. 

Here's a video showing the tale-tell sign of a subclinical infection- milk that is chunky or turns gelatinous soon after expression. If you feel that you need to strain your milk, it's worth going in to get a culture and sensitivity test done. 

Sometimes blood may also be present, which can be even more confusing to parents and providers alike. Even though this picture (left) looks a bit different than the other examples in this post (more like a blood clot than a lump of coagulated milk), this too is clumpy breast milk due to a subclinical staph infection. The appearance is due to blood in the milk, potentially from ruptured capalaries from expression or breast bleeding as a result of the infection .

Because some parents aren't aware that clumpy milk is a sign of a breast infection, subclinical mastitis may go untreated, resolving in due time. In other cases, subclinical mastitis develops into full-blown mastitis, which prompts parents to seek medical care. Rarely it just continues till weaning.

Breast milk fat plug vs. Clumpy breast milk

I've seen posts on the coveted fat plugs- where stored milk develops a fat cap and though not frozen, doesn't pour due to the amount of sticky fat "plugging" the top of the bottle.

If you're one to have experienced it already, you may now be curious about if the plugging phenomenon was due to a not so obvious case of mastitis.

You can rest assured that the odds are low that the plugging effect was due to anything other than a super thick lipid (fatty) layer in your breastmilk.

Generally speaking, clumpy milk due to mastitis will have one or two large masses but will not form a unified layer. Additionally, if left to sit, the lumpy milk may return to a liquid state, whereas the fat plug seen in expressed human milk tends to develop after a few hours left in the fridge.

A culture done by your provider will give valuable information as to what bacteria is causing the infection, and the sensitivity & resistance test will show which antibiotic will be most effective. With that information, you then can choose which route of treatment you feel most comfortable with- treating it with prescription antibiotics or attempting a more natural/homeopathic route.  

Despite being super scary, there's little concern about feeding your baby your milk, whether expressed or directly from the breast. As you noticed, moving the fluid around or letting it set on your counter for a bit will liquefy the clump. 

COMING SOON: SUBSCRIBE TO THE BLOG TO BE NOTIFIED WHEN IT’S POSTED!!

Or, as mentioned above, straining is also an option. :)

I hope it resolves soon!

Shondra MattosDecember 1, 20191 Comment

Composition of breast milk | What is breast milk made of?

Breast milk is rich in nutrients that nourish and protect your baby. But did you know that its composition changes over time? Find out what breast milk is made of and how it adapts to your baby's needs.

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Breast milk is a baby's very first food, so of course
contains essential nutrients - carbohydrates, proteins, fats, and water to maintain water balance in the body. ¹ All this is true. But mother's milk is not just a food product, and it performs not only nutritional functions.

What is breast milk made of?

Each serving of breast milk contains many other ingredients, many of which are unique.

• Millions living cells. These include white blood cells, which are responsible for strengthening the immune system, and stem cells, which promote the growth and repair of organs. nine0010 2
• More than 1000 ³ proteins that help your baby's body grow and develop, strengthen his immune system, form and protect brain neurons.
• All proteins in breast milk consist of amino acids . There are more than 20 types of them in milk, and they also include nucleotides, the content of which rises at night. Scientists suggest that they can have a hypnotic effect. ^4.5
nine0018 More than 200 complex sugars - oligosaccharides ⁶ that act as prebiotics necessary to maintain a healthy microflora in the intestines of the child. In addition, they prevent infections from entering the bloodstream and reduce the risk of brain inflammation.
• More than 40 enzymes ⁷ . Enzymes serve as catalysts for chemical reactions in the body. Breast milk enzymes stimulate digestion and immunity, and help the baby's body absorb iron. nine0023
• Growth factors contributing to the normal development of the body. ¹ They affect the state of many organs and systems, including internal organs, blood vessels, nervous system and glands responsible for the production of hormones.
• By the way, there are a lot of hormones in breast milk! ⁷ These smart chemicals are responsible for the exchange of information between tissues and organs, ensuring their normal functioning. Some hormones control appetite, others sleep, and some are even responsible for strengthening the bond between mom and baby. nine0023
• Vitamins & Minerals - Nutrients that support normal growth and function of organs and the formation of teeth and bones. ¹
• Antibodies or immunoglobulins. There are five main types of antibodies, and all of them are present in breast milk. ⁸ Antibodies neutralize bacteria and viruses, protecting the child's body from infections and diseases.
• You may have heard of long chain fatty acids , which play a key role in the formation of the child's nervous system and the development of the brain and eyes. ⁹ So, they are also present in breast milk!
• 1400 species miRNA . It is believed that they control gene expression, prevent and stop the development of diseases, support the immune system of the child, and also affect the change in the structure of the mother's breast. ¹⁰

This long list includes only a subset of the ingredients in breast milk—and scientists are discovering new substances in the meantime. Interestingly, the content of these ingredients varies depending on the age and needs of the child. nine0003

Let's start from the beginning...

In the early days: colostrum

The first milk that is produced immediately after the birth of a baby is called colostrum. This thick, sticky liquid is often referred to as "liquid gold," and not just for its yellow or orange color. Colostrum performs an important function of nourishing and protecting the fragile body of a newborn baby.

Very little milk is produced at first - only 40-50 ml per day ¹¹ . But the stomach of a newborn is very tiny, so this is quite enough. In addition, colostrum is very well digested. And the small volume is more than offset by its high-quality composition. nine0003

Composition of colostrum

Colostrum contains the same substances as breast milk in the following weeks, but in a different ratio, according to the needs of the newborn.

Colostrum, for example, is sometimes called nature's vaccine for its high levels of antibodies and white blood cells. After the child leaves safe mother's womb, the first milk helps to protect it from infections and diseases.

In addition, the protective properties of colostrum play an important role in strengthening the baby's digestive system. Colostrum protects and strengthens the mucosa of the gastrointestinal tract, which is highly permeable in newborns. nine0010 12.13 This is especially important if the baby is born prematurely, as this increases the risk of necrotizing enterocolitis. ¹³

In addition, colostrum is rich in minerals and vitamins, and contains more vitamins A, E and K than in mature breast milk. The protein content is also increased. ¹ Colostrum also has a laxative effect, helping to eliminate meconium (original feces). ¹⁴

In the next few weeks: transitional milk

During the first week of a baby's life, about two to four days after birth, breast milk production increases. The breast becomes larger and firmer - milk begins to "come". On the third day, the baby consumes 300-400 ml of breast milk per day, and by the fifth day - already 500-800 ml. No wonder breasts seem bigger!

Milk produced from days 5 to 14 is called transitional milk. ¹⁵ As the name suggests, this period is the transition from colostrum to mature breast milk. It becomes thicker and lighter, the content of fat and lactose (natural sugar) increases in it, and the calorie content increases. All this makes transitional milk an ideal food for the rapidly growing body of a newborn. nine0003

But despite the change in structure, transitional milk still contains a large amount of antibodies, living cells, beneficial bacteria and other biologically active substances necessary for the health of the child. ¹⁵

After four weeks: mature milk

By the time the baby is four weeks old, breast milk
has reached full maturity. It is rich in proteins, sugar, vitamins and minerals, as well as all kinds of biologically active components - hormones, growth factors, enzymes and living cells. All this ensures healthy growth and development of the child. nine0010 7

After four weeks, the nutritional content and ingredient ratios of mature milk are generally fairly stable. However, the composition of milk at different times and in different feedings can still vary.

For example, if a mother or child is sick, the mother's body produces antibodies to the causative agents of this disease, and these antibodies pass into breast milk. And when the baby begins to explore the world and taste toys, the content of protective antibacterial enzymes in breast milk increases. nine0010 16 In other words, the composition of breast milk is adapted to the needs of the baby.

What is foremilk and hindmilk?

You may have noticed that milk becomes thicker towards the end of a feed. The fact is that as you feed, the fat content of milk gradually increases. This is due to the mechanical features of the movement of milk in the breast. The thick milk coming at the end of a feed is often referred to as "hind" milk, while the thinner milk at the beginning of a feed is often referred to as "fore". You might think that the transition from "front" milk to "back" occurs at some specific moment, but this is not so - the change in consistency occurs gradually. nine0010 15 Both types of milk are essential for a full serving and both are rich in vitamins, minerals, protein and sugar.

The fat content of milk depends on how full the breast is. At the beginning of feeding, the breasts can be filled more (and then the milk will be less fat) or less (and then the milk will be more fat). But do not worry about the amount of "forward" and "hind" milk - in general, every day the baby receives approximately the same amount of fat. ¹⁷

Composition of breast milk after six months

You may be wondering what will happen to milk during
prolonged breastfeeding. Will the body be able to produce high quality mature milk for months or even years? Answer: do not underestimate the possibilities of the mother's breast!

Although it is indeed time to start solid foods at six months of age to replenish the baby's stores of certain nutrients, such as iron, ¹⁸ breast milk still plays a big role in his diet.

For example, at the age of seven months, a baby still receives 93% of its calories from breast milk. And even between 11 and 16 months, mother's milk provides the baby with about half of the daily calorie intake. ¹⁹

So rest easy, breastfeeding will benefit you and your baby for many months.

Literature

1 Ballard O, Morrow AL. Human milk composition: nutrients and bioactive factors. Pediatric Clin North Am. 2013;60(1):49-74. Ballard O., Morrow AL, "Composition of breast milk: nutrients and biologically active factors". Pediatrician Clean North Am. 2013;60(1):49-74.

2 Hassiotou F et al. Cells in human milk: state of the science. J Human Lact . 2013;29(2):171-182. — Hassiot F. et al., "Breast Milk Cells: What the Science Knows." J Human Lact (Journal of the International Association of Lactation Consultants) . 2013;29(2):171-182.

3 Beck KL Comparative proteomics of human and macaque milk reveals species-specific nutrition during postnatal development. J Proteome Res . 2015;14(5):2143-2157. - Beck K.L. et al., "Comparative proteomics of human and macaque milk demonstrates species-specific nutrition during postnatal development." nine0169 G Proteom Res. 2015;14(5):2143-2157.