Why Are Young Girls Starting Puberty So Early?

Puberty is a transformational time of mental, emotional, and physical changes, but more young girls are showing signs of puberty at earlier ages than ever before. Why is this happening, and what can we do about it? What are the potential causes of early puberty, and how can you, as a parent, help prevent these changes from happening too early for your child? And if they do happen, how do you navigate those waters?

What does puberty usually look like?

Puberty is the body’s process of physical and sexual maturation. Changes in body composition, overall growth, and psycho-social maturity occur as well. Normally, puberty occurs between the ages of 8 and 14 in girls. As adolescents mature, they go through different stages, and doctors have objective ways of assessing which stage of puberty they may be in.

There are five stages of puberty, with the first stage being marked by the development of breast buds. In girls, this process can start as early as eight years old, and will slowly develop over years, with the average age of menarche (a girl's first period) at 13 years old.

Signs of puberty in girls will include:

• Breast development

• Pubic and/or underarm hair growth

• Rapid height increase

• Acne

• Start of menstruation

• Body odor

Signs of puberty before the age of 8?

If your child is exhibiting signs of precocious puberty (before she's eight years old), a visit with your MD or naturopathic doctor will help determine the cause of these changes. Your doctor will start with a thorough intake and physical examination, noting any pubertal milestones and onset of secondary sexual characteristics. A wrist x-ray may also be conducted to see if bones are maturing too rapidly. The next step would be to determine if there is an elevated level of sex hormones in the blood, followed by additional testing to see if the increase in hormones is due to any other underlying cause.

Factors in early menstruation

Although earlier onset of puberty is not fully understood, we do know that it is likely a result of a combination of modifiable (like lifestyle and toxic exposure) and non-modifiable (like genetic and ethnic) factors. For instance, girls of Latin American and Afro-Caribbean descent tend to have breast development, pubic hair growth, and begin menstruation at an earlier age than Caucasian girls. In terms of the modifiable factors, the neurological and hormonal systems that regulate pubertal timing are complex; we know that a variety of environmental factors may be contributing to this concerning trend.

Puberty onset is earlier in developed nations

Studies have shown that girls in developed nations have been demonstrating signs of puberty and menarche at earlier ages over the past few decades. In 1950, the average onset of puberty in girls was around 13 years of age, and in 2010 it was 10.5 years of age. If we look at the trends of menarche from the years 1840-2000, we see the average go from 16 years old to 12 years old. That number is continuing to trend even lower today.

Toxic exposure

Endocrine Disrupting Chemicals, or EDCs, mimic naturally occurring hormones in the body such as estrogen. Estrogen is a key hormone involved in the progression of puberty in young girls. Nearly 800 chemicals are suspected endocrine disruptors, including BPA and phthalates, and a number of them have been identified as possible agents leading to the early onset of puberty in young girls. Heavy metals, such as mercury, can also interfere with hormone function.

We are all exposed to these toxins, despite our best efforts to reduce contact. In addition to avoiding them (learn to read cosmetic labels!), ways to reduce toxin levels in the body include: 

• Drinking plenty of water.

• Increasing physical activity—sweat it out!
• Including a variety of sources of fibre in the diet, such as leafy greens, legumes, and seed.

• Supporting liver detoxification by incorporating sources of vitamin C (kiwis or citrus fruits), cilantro or parsley, and lemon juice into the diet.

Diet & lifestyle

With the increasing prevalence of childhood obesity over the past few decades, research has shown that this trend also contributes to the earlier onset of puberty in young girls. It has been shown that girls with a higher body fat content (which correlates to a higher body mass index, or BMI, for age) begin to develop breasts between the ages of 8.0 and 9.6, compared to a later age in girls with normal BMIs. Certain foods have also been implicated in early puberty in girls. Milk (even organic milk) contains a hormone called insulin-like growth factor 1 (IGF-1). This hormone has been specifically connected to earlier onset of puberty. However, associations between dairy consumption and early puberty are still unclear8: it is possible that the protein in milk may contribute to increasing the body’s own production of IGF-1 which triggers growth of cells. Many other studies have shown a relationship between animal protein consumption (including red meat and dairy) and earlier puberty. One possible explanation is that animal products are more likely to contain the endocrine-disrupting chemicals discussed above due to large scale conventional farming practices that are more common today than, say, 20 years ago.

A mineral-rich, plant-based diet is a good strategy for health in general and may contribute to a healthier age for the onset of puberty. Interestingly, consumption of soy-based foods in childhood may protect girls from early menarche through a number of possible mechanisms related to hormonal regulation and detoxification. This refers to whole soy foods such as GMO-free tofu and edamame. Soy is currently one of the most prevalent GMO crops and infants who are fed soy-formula may actually be at an increased risk of early puberty.

Help your child maintain a healthy body composition

• Ensure at least 60 minutes of moderate to vigorous physical activity per day.
• Eat a plant-based, whole foods diet.
• Limit processed foods that are high in refined sugars, such as soft drinks or packaged foods.
• Involve your children in meal prep and cooking: they’ll be more inclined to eat healthy food that they had fun preparing themselves!
• Keep screen time to a minimum and avoid it altogether for at least 60 minutes before bed to ensure a good sleep.
• Encourage mindfulness practices such as deep breathing exercises, quiet time, or daily stretching.

Psychosocial impact of early puberty

Aside from the obvious physical changes that occur during puberty as secondary sexual characteristics develop, let’s talk about the not-as-obvious psychosocial impacts that these changes may have on girls developing at a younger age. Girls are sensitive to societal responses to their development and may experience feelings of being isolated or misunderstood by others if they mature earlier than their peers. Changing levels of hormones may also trigger erratic behaviour that may be perceived negatively by others, potentially resulting in conflict, social challenges, or trouble with friendships. For these reasons, it is important to maintain open and honest lines of communication. The development of secondary sexual characteristics may prompt unwanted attention for which a young girl may be unprepared, so keep your child informed about the changes happening in their body, what they can expect to happen next, and the different emotions they may experience can help keep them from feeling misunderstood. Instilling confidence and body positivity is especially important, such as encouraging exposure to empowering role models of healthy femininity. Ultimately, how you respond to these changes will have an impact on how your child responds, so creating positive dialogue and a safe environment for communication is key.

Many causes of early puberty are something we can help to stop. The solution starts with a focus on solid foundations of health: clean diet, regular movement, and low toxic exposures--don't forget to avoid toxins in menstrual products! Be sure to visit your family health care provider if you have any concerns about early puberty to ensure the healthy growth and development of your child.