The expression “First 1000 Days” has great significance for the relationship between the human microbiome and the microbiome.
One thousand days is about three years after birth, and the microbiome ecosystem formed during this period is the basis for the face of the partners with whom they will share the rest of their long lives.
Where did these numbers come from?
*This article is part of the series “By What Age Are Intestinal Bacteria Determined? The Bacteria That Walk with You as You Grow from Baby to Child” (to be published at a later date) is part of a series.
It is recommended to read this article in conjunction with another series, “Pregnancy, Childbirth, and the Microbiome in a Nutshell for All Pre-Moms & Dads (focusing on gut and vaginal bacteria)” (to be released at a later date).
Table of Contents
- Are intestinal bacteria determined by the age of fat?
- Intestinal bacteria up to 1 year old
- The face of intestinal bacteria
- diversity
Are intestinal bacteria determined by the age of fat?
Maria Gloria Dominguez-Bello and Rob Knight, along with Jeffrey I. Gordon, a leading authority on modern microbiology, and colleagues, published a paper in 2012 that was the first to comprehensively show the relationship between the microbiome (here, gut bacteria) and age and region. Their findings.
They conducted a cohort study of people from three countries – the United States, indigenous peoples of Venezuela, and Malawi – and made some interesting findings.
そのなかのひとつが、腸内細菌の構成は3歳までに決まるというものだ。
もっともこの傾向はベネズエラとマラウイの人々により強く見られ、アメリカの子どもたちは1歳の時点ですでに大人と同じような腸内細菌の構成を持っていた。
もしかしたら、腸内細菌の成熟スピードには地域差があるのかもしれない。
Three years later, researchers beginning a Swedish cohort study (2,3) concluded that even at age 5 years, Swedish children still do not have the same level of intestinal bacterial maturation as adults.
Other controversial theories, such as the Danish four-year-old theory (4) and the American five-year-old and older theory (5), share a similar focus on the establishment of the symbiotic microbiome ecosystem during childhood and the impact of the microbiome during this period of rapid physical and mental development.
And needless to say, from the moment life enters the belly, the mother’s microbiome begins to change, transforming into a configuration suitable for nurturing the fetus in the belly, and even into a configuration that should be handed to the fetus at the moment of birth.
From the moment of conception through childhood, the microbiome seems to assist human development by flexibly building the best ecosystem for each moment.
Intestinal bacteria up to 1 year old
Humans are born in a more immature state than other animals.
In other words, they are in a very unstable state for some time after birth, while at the same time they are growing at a remarkable rate.
Babies who are born weighing approximately 3 kg generally gain an additional 1 kg at the one-month checkup, and by the time they reach three months, their weight doubles.
The child’s head begins to settle and, in the earliest stages, the child begins to turn over in bed.
If you have ever raised a child, you know how much a baby can learn to do in a year.
So, what kind of transition does the intestinal bacteria undergo until the age of 1 year?
There are still few large cohort studies of babies up to one year of age.
Nevertheless, the symbiotic pattern between babies and intestinal bacteria is gradually becoming clearer, especially in the Swedish research results mentioned above and the Chinese study (6).
The face of intestinal bacteria
The bacteria that live in the intestines of newborn babies are the main members of a group of bacteria known as the facultative anaerobes.
These bacteria, represented by Escherichia coli, Staphylococcus, and Streptococcus, can live with or without oxygen.
Soon thereafter, bacteria known as biophilic anaerobes, such as Bifidobacterium, Bacteroides, and Clostridium, will increase in number. They cannot survive in the presence of oxygen, but they are the majority in our human colon.
So, perhaps we can say this.
Newborn babies do not have a strong anaerobic environment in their colon like adults.
There, the bacteria that can live in the presence of oxygen consume it, turning the large intestine toward an anaerobic environment and making room for the biophilic anaerobic bacteria that should subsequently increase.
The intestinal bacteria are helping the immature baby’s colon to become what it should be.
diversity
The diversity of bacteria in the gut of individual babies (called alpha diversity) is lowest immediately after birth and continues to increase toward the age of one year.
Only selected bacteria are active at first to promote the baby’s growth and protect it from pathogens, and then they gradually welcome other bacteria into their lives.
菌たちが多様性を高めながら生態系をつくりあげていくさまは、柔軟で巧妙だ。初期に活躍する菌たちが次に棲みつく菌たちの環境を整え、ときには棲み着く菌を取捨選択していく。
そして、無事に生態系に含まれることになった菌たちは、別の菌の代謝物質などを利用しながら、相互に関連したネットワークを編み上げていくのだ。
On the other hand, the degree of difference (called beta diversity) when one baby is compared to another baby is greater when the baby is younger, and the individual differences become progressively smaller as the baby ages.
What can be said from this is that there is a great deal of individual variation in the early process by which babies acquire symbiotic bacteria.
Factors influencing this process may include delivery methods and regional differences, as we have already seen, as well as differences in nutritional sources, as we will see later in the article.
どんな菌たちがどのようなスピードで増えるのが理想的なのかはまだわかっていない。しかし、この初期の「個人差」が赤ちゃんの病気のかかりやすさや、その後の人生での疾患リスクにかかわっていそうだということが、少しずつ明らかになってきている。
What exactly do the germs do in the development of the baby?
In the next article, we will look at the function of bacteria from the perspective of function.
