Many people, especially parents, wonder if they can do anything to help their children grow taller. Height is an important aspect of health and has psychological and social implications as well. While genetic factors play a large role in determining height, environmental factors can also influence growth, particularly during childhood and puberty. Proper nutrition, exercise, sleep, and medical care may optimize growth potential. However, severe malnutrition or medical disorders are typically required to substantially reduce height from genetic potential. For the majority of healthy children, techniques marketed by some to enhance height usually have little effect compared to natural growth.
What determines height?
Human height is a highly heritable trait, meaning that genetic factors play a large role in determining growth and final adult stature. However, environmental factors, especially nutrition, also significantly influence height development.
Genetic factors
Research suggests that genetic factors account for approximately 80% of variation in height within a healthy population. The specific genes that control height are not fully understood, but studies have identified certain chromosomes and genetic markers associated with height variation.
Having two short parents greatly increases the likelihood that a child will also be relatively short. However, the effects of single gene disorders that severely stunt or limit growth are rare. Most differences in height between healthy individuals are subtle and involve multiple genes.
Environmental factors
While genes set the potential for growth, environmental factors influence how much of that potential is reached. Nutrition, illness, and trauma during infancy, childhood, and adolescence can affect the epiphyseal plates responsible for bone growth.
Poor nutrition from lack of adequate calories or micronutrients often limits growth. Height is very sensitive to nutritional deficiencies during childhood when growth velocity is highest. Improving diet can help children reach their height potential.
Chronic diseases and trauma can also reduce height by impairing growth. For example, growth hormone deficiency, hypothyroidism, and childhood cancers like leukemia have been associated with stunted height. Treatment of medical disorders can allow children to catch up on growth.
Socioeconomic status also impacts height. Poverty and food insecurity contribute to malnutrition which can impair growth. Access to healthcare also influences treatment of medical conditions affecting height. These environmental factors contribute to substantial average height differences between populations.
What is the normal height range?
Heights follow a normal bell-shaped distribution with most people clustered around the average. However, what is considered a “normal” height range depends on gender, ethnicity, and countries of origin.
By gender
Average adult heights in the United States are:
– Males: 176 cm (5 ft 9 in)
– Females: 163 cm (5 ft 4 in)
So males tend to be taller on average than females. The following table summarizes typical height ranges by gender:
| Height | Males | Females |
|---|---|---|
| Tall | > 180 cm (5’11”) | > 165 cm (5’5″) |
| Average | 170 – 180 cm (5’7″ – 5’11”) | 160 – 165 cm (5’3″ – 5’5″) |
| Short | < 170 cm (5'7") | < 160 cm (5'3") |
However, doctors evaluate height relative to population norms for the child’s gender and age. Children are considered short if their height falls below the 2.5th percentile.
By ethnicities
Average heights also differ slightly between ethnicities. For example, adult American men of European descent average 176 cm (5’9″) compared to 173 cm (5’8″) for those of African descent. Among women, European Americans average 163 cm (5’4″) vs 160 cm (5’3″) for African Americans. However, height variation between health individuals of the same ethnicity is much larger than these population averages.
Across countries
Due to nutrition and socioeconomic differences, average heights vary widely across countries. For instance, Bolivian adults average 157 cm (5’2″) while Bosnians average 176 cm (5’9″). Across 200 countries, the tallest men live in the Netherlands with an average height of 183 cm (6’0″) while the shortest live in Timor-Leste at 160 cm (5’3″). For women, Latvia has the tallest average at 170 cm (5’7″) compared to 150 cm (4’11”) in Guatemala.
Therefore, normal height ranges must factor in gender, ethnicity, and country of origin when evaluating an individual’s growth. Doctors typically use growth charts specific to a child’s demographics to assess their height percentile and growth trajectory over time.
How is height measured?
Height is usually measured during medical visits using a stadiometer. A stadiometer is a upright height rod with a movable headboard that slides up and down to rest on the head when measuring. The child stands straight with feet flat and shoulders relaxed while the headboard is lowered until it firmly touches the crown of the head. Height is then read to the nearest 0.5 cm or 1/8 inch.
Measuring infants under two years old requires laying them flat on their back on a hard surface. One person holds the head against the headboard while another straightens and holds the legs with knees extended. Length is then read from the stadiometer.
For accuracy, heights should be measured at the same time of day since people can be slightly taller in the morning after lying down. Height is also prone to measurement errors if not done carefully. However, well-trained medical staff usually follow proper technique to get reliable growth measurements.
When does peak growth occur?
The two main periods of rapid growth are infancy and puberty.
Infancy growth
Infants grow the fastest in their first year of life. A newborn loses a bit of weight initially after birth but then gains about 25 cm (10 inches) in length on average from birth to one year old. Rapid infancy growth slows after the first year.
Pubertal growth
The peak growth spurt occurs around the time of puberty which typically starts between ages 10 to 14. Boys tend to hit puberty later than girls. During puberty, adolescents grow about 20-25 cm (8-10 inches) as sex hormones increase growth velocity. About 95% of adult height is reached by age 17 in girls and 18 in boys.
Growth chart
The following CDC growth chart approximates average height velocities during childhood:
Peak growth velocities occur around ages 1-2 years and 12-14 years for girls and 14-16 years for boys. Growth slows significantly after puberty but can continue at slower rates into the mid-twenties. When final adult height is reached depends on when puberty starts and ends.
Can you influence height?
Genetics largely determines height potential, but environmental factors can influence growth, especially for children. While miraculous height gains are unrealistic without medical disorders, certain healthy practices may help optimize growth.
Nutrition
Ensuring adequate nutrition and calories is key for reaching genetic height potential. Protein provides amino acids for muscle growth. Vitamin D and calcium build strong bones. Zinc supports growth hormone levels. Iron carries oxygen needed for energy production.
Healthy foods like milk, eggs, meat, seafood, nuts, beans, vegetables, and fruits help provide necessary micro- and macronutrients. If picky eating is limiting nutritious foods, supplements can fill dietary gaps.
Very restrictive diets or malnutrition substantially impair growth. However, most healthy children eating regular diets already receive sufficient nutrition to support their growth trajectory. Flooding children with extra protein or vitamins does not accelerate growth beyond their norms.
Exercise
Exercise stimulates growth hormones and helps build strong muscles and bones. Weight-bearing activities like sports, jumping, and running are especially beneficial during growth years. Low-impact exercises like swimming and cycling also improve fitness needed for growth.
However, competitive athletics at young ages can harm growth if nutrition and rest are insufficient to balance the demands. Growth potential might be better optimized focusing more on skill development than hours of intense training exceeding capacity.
Sleep
Deep sleep triggers human growth hormone release which peaks during early sleep. Growth hormones are essential for childhood development.
Chronic sleep deprivation can suppress growth hormones. Aim for 9+ hours of sleep nightly for children and 8+ hours for teenagers. Also try maintaining a consistent sleep schedule. Optimal sleep habits support reaching height potential.
Medical care
Regular doctor visits allow monitoring growth trajectory and screening for medical problems impairing height. Endocrine disorders, genetic syndromes, and childhood cancers are examples of conditions that can limit growth if untreated.
Early detection and management of illnesses enables the best chance of reaching normal stature. Providing adequate medical care helps children grow to their potential.
Other techniques
Stretching exercises, inversion boards, special shoes or diets, and supplements like growth hormone do not substantially increase height in healthy children. Most alternative height techniques lack credible scientific support and are unlikely to exceed gains from natural growth.
The FDA has approved synthetic growth hormone injections for children with true growth hormone deficiencies. However, height outcomes are typically modest, gaining about 2-3 inches on average. Potential side effects include joint pain, edema, and metabolic complications.
Excessive interventions trying to make children taller than their norms often prove disappointing compared to working within natural growth limitations. Genetic potential should be appreciated when considering height goals.
What if growth seems abnormal?
While most variation is normal, some children have growth patterns concerning for underlying health problems. Consult a pediatrician if growth concerns include:
– Falling below lower height percentiles
– Crossing two major percentile lines on growth charts
– Significantly shorter than parents or siblings were at same age
– Puberty and growth spurt not started by age 14 (boys) or 13 (girls)
– Unexplained decreased growth velocity
Medical evaluation involves plotting growth trends on a growth chart, assessing puberty status, testing for nutritional deficiencies, and checking hormones related to growth. Treatment depends on the cause but may include hormones, counseling for constitutional delay of growth and puberty, or specialist referral.
Conclusion
Genetics largely determines height potential, but environmental factors like nutrition, sleep, and exercise also impact growth. While extreme measures offer little benefit, focusing on healthy lifestyle practices can help children achieve their natural height possibilities. Monitoring growth patterns allows early intervention if abnormalities suggesting underlying conditions are found. However, most variations in healthy children’s growth are normal. Rather than undue concern over maximizing height, appreciating children’s natural variations is often best.