What is growth?
Growth is what we know as the increase in the size of the body with age. We can see this by measuring either height or weight. In babies, this is also done by measuring the roundness of the head (circumference) and their length from head to toe.
The parts of the body that show the most growth are the arms, legs and torso, but virtually all parts of the body grow at different rates.
Some parts of the body are already almost fully grown at birth, including the head and eyes. For example, by age 2, a child’s skull is already about 90% of adult size.
What is development?
Development is more often referred to as “functional development”, but the word has different meanings in different areas of science. Sometimes, the whole of pregnancy is called “development”, from fertilization to birth.
For example, although the brain does grow in size, especially in the first year , its functional development continues, as kids learn cognitive, language and communication skills.
Development also refers to maturation. For example the immune system “matures” as it gets better at recognizing and dealing with different types of viruses, so kids get infected less often with age.
What controls growth and development?
Growth happens when a child’s tissues make more cells, the smallest working part of the body. Cells make copies of themselves using nutrients and products that they make. This is controlled by a combination of genes, the infant’s hormones and nutrients, but in fact it is much more complicated.
In bones, for example, it is slightly different. The cells inside bones don’t just multiply, but they produce a hard material called bone mineral from a softer material called cartilage. Bone get longer by add layers and layers of mineral over time.
Which nutrients are important for growth and development?
All the nutrients that children consume are absorbed during digestion into a from that cells can use to make energy, and to make more products they used to make copies of themselves, and increase the size of tissues. Nutrients also contribute to other parts of the body that support growth and development, like the immune system and the brain. For example, the immune system prevents illnesses and promotes healing, so kids get back to growing again. While the brain controls physical movement, which help with height growth.
Specific macro-nutrients for height and physical growth include:
- Protein: the bulk nutrient that breaks down into amino acids, which are used to build new parts of cells, especially in muscle. Muscles grow in length and strength naturally as bones get longer. Bones also grow better in response to physical activity.
- Carbohydrates: these are found in grain (rice, wheat, etc) in complex form, and in simpler forms in milk and fruit. The body converts them to glucose that all tissues need to produce energy for growth.
Specific micronutrients include:
- Calcium & phosphorus – these minerals are used to make bone mineral, which gives it its strength and structure. Calcium also controls how cells divide and how they move, such as how muscle twitch. Calcium intake through milk has been reported to have a positive effect on bone growth in toddlers 
- Vitamin K – a special vitamin that takes calcium from the bloodstream and deposits it into the areas where new bone mineral is being made (growth plates), like the arms and legs.
- Vitamin C – helps the body to make collagen, but not just in skin. This elastic substance is also made inside bones and helps to make them flexible, not just hard. Vitamin C also helps with the immune system and helps with healing during illnesses, so kids can get back on the road to growing sooner.
- Vitamin D – has a special role in the intestine to help it absorb calcium better. Children lacking enough of this vitamin may cause a condition called “rickets”, where children’s bones become bent and crooked 
- Zinc: has many roles in growth, including supports hormones that control growth, supports new collagen formation in bones, and controlling cells to divide. Lack of zinc is a major cause of stunting (shortness) in children around the world and is 4-times more common in malnourished kids  .
- Magnesium, manganese and molybdenum: these makes up a small part of bone minerals, and help with energy production
- B-vitamins, iron: used to make more energy inside the cells of bones and muscles, and to produce enough red blood cells to keep tissues oxygenated and growing properly.
Why do you need a complete source of nutrients for growth?
Growth involves the whole body, and it takes all nutrients to work together to help with growth and development. Missing just one, however, is enough to have an impact, especially if it is used in different parts of the body.