Since the composition of formula milk and breast milk is different, is it safe to feed with formula milk for a long time?

Yesterday we talked about the composition of breast milk and formula milk. Some netizens asked, since there are differences between the two, will long-term use of formula milk to replace breast milk have a negative impact on the baby? How to choose a good can of formula milk? Today we will analyze this issue from a scientific perspective.

01. Can milk powder replace breast milk?

Although there are differences between cow's milk and human breast milk, the two are not so different that they are completely irreplaceable. In fact, milk is rich in protein and is what many people call "complete protein", which means it contains all the amino acid components.

Therefore, it is feasible to use cow's milk to replace breast milk. Moreover, in many cases, it is very necessary to use cow's milk to replace breast milk: for example, the most common case is when the maternity leave is over and you have to go back to work. In this case, it is very necessary to let the baby drink cow's milk. Moreover, cow's milk feeding is very convenient to a large extent, for example, it is very convenient to use a bottle in public places. In addition, for babies who lack breast milk, cow's milk is an indispensable nutrition.

02. How to turn milk into milk powder?

Of course, you can't let your baby drink milk directly. First, it's inconvenient, and there are also problems with quality and freshness. Therefore, milk powder has become the main way to replace breast milk.

This is a schematic diagram of milk powder production, which looks like a relatively complicated process. Of course, to put it simply, the core process of milk powder processing is concentration and drying!

As for how to concentrate and dry, the simplest way is heating. The common method currently used in the market is high-temperature heating, which can quickly dehydrate the milk, thereby concentrating and drying it.

In addition to this, milk also has to undergo a sterilization process, which generally uses a similar method, namely high-temperature sterilization.

03. Does the high temperature process affect the key ingredients in milk?

So, does the high temperature process have an effect on the key components of milk? The answer is obvious. High temperature often triggers two processes: 1. Maillard reaction 2. Polymerization reaction

1. Maillard reaction. In the process of high temperature, a chemical process called Maillard reaction is often induced. What is Maillard reaction? In layman's terms, it is a non-enzymatic reaction between sugar and protein at high temperature. It was discovered by French chemist Louis-Camille Maillard when he tried to restore the human body's protein synthesis process and was named after it. (ref4)

2. Polymerization reaction. I believe everyone is familiar with this. Proteins are high molecular weight compounds composed of amino acids through peptide bonds. The peptide chains formed by a certain order of peptide bonds and disulfide bonds are called primary structures, and the regular conformations formed by the combination of primary structures form secondary structures, such as α helix, β fold, etc. The peptide chains are further folded on the basis of the secondary structure to form a complete spatial conformation, which is the tertiary structure. For proteins to play a role, they must have a specific structure to be completed, so famous biological giants are committed to interpreting protein structures.

High temperature is the most common factor that causes changes in the secondary and tertiary structures of proteins, causing them to unfold and aggregate into larger molecules.

04. What are the consequences of Maillard reaction and polymerization reaction?

So what are the consequences of Maillard reaction and polymerization reaction?

1. Natural small molecules are polymerized . Milk is rich in natural small molecules, which mainly include amino acids, sugars and lipids. We know that the intestinal absorption of organic matter is mainly carried out in the form of active transport. Small molecules are absorbed by cells under the action of transport carriers. Large molecules need to be degraded before they can be absorbed. For example, the protein we mentioned is difficult to be absorbed directly, but needs to be broken down into components such as amino acids and small peptides for absorption.

Due to the Maillard reaction in the milk powder processing process, many small molecules are polymerized to form large molecules that are difficult to absorb, thus reducing the absorption of natural small molecules, which often play an important role in the body. Let's take amino acids and sugars as examples.

I, lysine. Studies have found that the Maillard reaction will polymerize a large number of amino acids, especially lysine. You should know that lysine is one of the essential amino acids and needs to be supplemented through food. And because lysine itself is easily destroyed during processing, it is also called the "first limiting amino acid." The Maillard reaction will reduce the utilization of lysine, thus affecting nutrition.

Lysine itself plays an important role in the human body. For example, it is indispensable for human development and immunity. In addition, it also has a great impact on our central nervous system.

II. Reduce galacto-oligosaccharides. Galactooligosaccharides (GOS) are functional oligosaccharides with natural properties. Their molecular structure is generally 1-7 galactose groups linked to galactose or glucose molecules. In recent years, more and more studies have revealed the role of GOS. GOS is contained in animal milk, especially breast milk, and its important role is to help the human body establish intestinal microorganisms.

Intestinal microorganisms are important components of our human body. They play a critical role in human digestion and absorption, are an important source of human immunity, and have an important impact on regulating human physiology, such as promoting body repair and reducing food allergies. In recent years, it has been the hottest field in the field of life sciences. Basically, every issue of top journals such as Nature Science will have research content on intestinal microorganisms.

Galacto-oligosaccharide plays an important role in the establishment of intestinal microorganisms. It is an important nutrient for bifidobacteria and lactobacilli, which are common intestinal microorganisms. Therefore, it can promote the establishment of intestinal flora and maintain its health.

In a cohort study, the intestinal microorganisms of infants were identified by whether or not galacto-oligosaccharides were added. It was found that the addition of galacto-oligosaccharides significantly improved the intestinal microorganisms of infants and increased the beneficial lactobacilli and bifidobacteria.

Description: Lactobacillus and Bifidobacterium are important intestinal microorganisms and are beneficial to the human body. In terms of the common reaction of infant intestinal function, the detection of feces also reflects the effect of GOS itself. Compared with the group without GOS, the group with GOS (0.24 g/100 mL) performed better, which was manifested by improving the frequency of infant bowel movements and reducing the pH value of feces.

illustrate:

a. Scoring criteria for stool consistency: 1 watery, 2 mushy, 3 soft and formed, 4 hard and formed

b. The lower pH value of stool is beneficial to inhibit the reproduction of pathogens, but facilitates the reproduction of beneficial intestinal microorganisms.

Galacto-oligosaccharides play a significant role, but they are easily lost. During the processing of milk powder, they will polymerize with whey protein due to the Maillard reaction, making them difficult to absorb and affecting nutrition.

2. Increase the difficulty of absorbing large molecular proteins. Whey protein is the main protein component in milk powder and its main nutrition. However, heating can easily change the structure and functional properties of whey protein. For example, studies have found that during the processing of milk powder, heating causes the globular whey protein structure to unfold and form an irregular curled conformation. These structures will polymerize to form larger molecular polymers, which are not conducive to absorption (ref6).

In fact, due to the problems of milk powder processing, formula feeding often causes some problems compared to breastfeeding.

In a randomized, prospective study, the authors found that there was a significant difference in the incidence of constipation and flatulence between infants fed breast milk and those fed regular formula, with infants fed regular formula having a higher risk of developing symptoms of intestinal intolerance, especially constipation, by up to 35% (ref6)

05. How to choose a good can of milk powder?

Although breast milk has many benefits, there are still many cases where it is necessary to supplement with formula milk. Sometimes this replacement is even a necessary choice. For example, there is a lack of breast milk, breast milk allergy, and of course the most common type: maternity leave is over and breastfeeding cannot be done in time.

Therefore, milk powder has become the most common breast milk substitute. So how to judge a good can of milk powder?

1. Processing technology. In the second part, we spent a lot of space analyzing the impact of heating during the milk powder processing. Therefore, reducing the heating process as much as possible is the best choice for milk powder. By completing the processing once, the Maillard reaction caused by repeated processing can be reduced as much as possible, thereby reducing the loss of nutrition.

Minimize the damage to nutrients (one-time processing vs. repeated processing)

2. Choose a brand that retains natural small molecules. Of course, what if the product itself does not indicate whether it is completed in one go? Then choose a brand that retains natural small molecules.

If a brand's product retains natural small molecules, you can basically be sure that they have adopted more advanced methods in the processing process to minimize the adverse consequences of Maillard reaction and polymerization reaction, retain more nutrients, and naturally be more beneficial to the baby. Why not mention large molecules? (Because they are the main components of milk, they will not be lost)

References

1. Carlson S. A double-blind test of astrology[J]. Nature, 1985, 318(6045): 419-425.

2. Maillard L C. Action des acidesamines sur les sucres: formation des melanoidines par voie methodique[J].CR Acad. Sci.(Paris), 1912, 154: 66-68.

3. Ben XM, Li J, Feng ZT, et al. Low level of galacto-oligosaccharide in infant formula stimulates growth of intestinal Bifidobacteria and Lactobacilli[J]. World journal of gastroenterology: WJG, 2008, 14(42): 6564.

4. Yang Hehong, Liu Qian, Kong Baohua, et al. Changes in properties of whey protein isolate during Maillard reaction[J]. Food Science, 2012, 33(23): 98-102.

5. Xu Xiu, Guo Zhiping, Luo Xianqiong, et al. Effects of α-lactalbumin and AA/DHA-enriched formula milk on physical growth and tolerance of full-term infants [J]. Chinese Journal of Child Health Care, 2006, 14(3): 223-225.