In the previous post we discussed about what puberty is and what are the different physical and emotional changes the body undergoes during that phase of life. In the current post we will discuss when the body transitions into the pubertal phase, the process involved and the factors that affect the puberty onset.
If you haven’t read the post yet, here is a quick link to get a gist of the subject under discussion. https://biodrivers.in/demystifying-puberty-bodys-transformative-journey-its-changes-challenges/.
Introduction
Puberty is a crucial developmental stage wherein the body gradually moves from childhood to adulthood. This developmental event is marked by growth spurts with the appearance of external sexual features and the ability to procreate. The timing of puberty generally ranges from ages 8 to 14 in girls and from ages 9 to 16 in boys. But at times, puberty may hit early in some kids, known as precocious puberty, while in some other it may commence late referred to as delayed puberty.
Having discussed the basics, let us now dive into the process that marks the onset of puberty.
The Hypothalamic-pituitary-gonadal axis.
The hypothalamic-pituitary-gonadal axis (HPG axis) is a hormone-regulating mechanism. It primarily consists of the hypothalamus, the pituitary gland and the gonads (ovaries in females and testes in male). These body parts work in a synchronized fashion to regulate the reproductive and the sexual development in both males and females. The axis also plays an important role in the immune system of our body. The HPG axis is active during three main stages of life-
The axis begins its development in fetal life at around 10 weeks of gestation.
It is peak of its activity during infancy, i.e. up to 2 years of age.
From 2 years till 8-9 years it remains quiescent (inactive). A period known as pre-pubertal. And, finally resumes its activity at puberty.
The HPG axis and onset of puberty.
The HPG axis is responsible for the beginning and regulation of puberty. When the body reaches at pubertal age, the gonadotrophin-releasing hormone (GnRH) neurons secrete GnRH. This hormone then travels to the pituitary gland, stimulating it to release Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH). After synthesis and release, they enter the bloodstream and reach the gonads i.e. ovaries and testes. They then induce the secretion of sex hormones (testosterone, estrogen and progesterone) and initiate the production of sperms (males) and release of egg cells (females). The secretion of sex hormones then lead to the various physical and physiological changes associated with puberty.
Factors affecting Puberty.
The HPG axis plays a vital part in pubertal onset puberty but what exact is the mechanism that triggers the HPG axis to secrete the GnRH is still a matter of active research. But studies have emphasized the interconnections between genetic, nutritional status, lifestyle-factors and environmental parameters to play an important role in puberty.
Genetic Control of Puberty: The timing of the pubertal onset is a highly polygenic process, i.e. it is under the control of many different genes. Three major groups of genes are categorized: puberty-inhibitor genes, puberty-activator genes and genes with dual-effect. Also, researches have shown that both paternal and maternal timings of puberty have a strong influence on the pubertal timings of their children irrespective of their sex. Different studies have estimated that 50-80% of the variation in pubertal onset in genetically controlled.
Nutritional Status and Puberty: In both boys and girls the nutritional status plays a significant role in pubertal onset. In fact, the nutritional quality of mothers during pregnancy also has a hand in pubertal timing. Also, nutrition status during fetal life (i.e. intrauterine, still inside the womb) and early infancy (0-2 years) also have a marked influence on puberty.
The years through infancy, childhood and puberty clubbed with a wholesome and balanced diet boosts a proper and normal development while transitioning from childhood to adolescence. During pubertal development there is a surge in growth, thus, the nutritional requirements also increases exponentially. This prerequisite demands for a complete package of all essential nutrients- both micronutrients and macronutrients (calcium, iron, folate, zinc, protein etc.) to fuel a power-packed and holistic pubertal development.
Lifestyle factors affect puberty: As per reports and research it has been observed that the mean age to enter puberty has deviated from past few years owing to changing lifestyle habits. Precocious puberty (early onset of puberty) in girls and delayed puberty in boys is common phenomenon now-a-days. High and ultra processed foods, added sugars, inactive and sedentary routine have caused a havoc in the pubertal development.
In accordance to the report titled “The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know,” ecologist Sandra Steingraber explains that kids who are more active produce a hormone melatonin (it is a hormone that serves as body’s internal clock and is a inhibitory signal for puberty). Therefore, kids who follow a sedentary lifestyle produce less quantity of melatonin which serves as a trigger to enter the puberty earlier than normal.
Also, inactive lifestyle serve as an important factor in promoting obesity. Thus, obese or overweight girls are prone to enter puberty early while obese boys may suffer from delayed pubertal onset.
Environmental Factors: In recent years we human beings and kids especially have been greatly exposed to the diverse world of plastics, various synthetic chemicals and substances that mimic the hormones and tricks the body to enter puberty early. These chemicals are collectively referred to as endocrine disruptors (EDs) . They adversely impact the body’s endocrinology and impairs the normal pubertal development. Some examples are phthalates (plasticizers), polybrominated biphenyls, bisphenol A, herbicides, etc.
Click here for some interesting reads Xenobiotics: https://biodrivers.in/the-uncalled-guests/ and All about Plastics we use https://biodrivers.in/do-we-know-all-about-the-plastic-bottles-in-use/
Concluding Note
Puberty is an important phase of life that forms the basis of sexual development and maturity enabling the mankind to procreate and continue the cycle of life. Thus, it is very crucial to be prepared for this transition both-physically and mentally. The above mentioned factors serve as critical points that need to be focused upon during developmental years. No single factor holds the situation, but a combination of all factors play a significant part for a normal and proper pubertal development.
Disclaimer: Articles by BioDrivers/Megha Machhar are based on internet sources and should be used for widening knowledge. The reader should seek professional help when diagnosed with any medical condition.
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