This is the second in a series of First Focus blog posts commemorating the 50th anniversary of the War on Poverty and offering modern ways to continue fighting child poverty. The first blog in the series can be found here.

Last week was the 50th anniversary of President Johnson declaring a War on Poverty. While we have made great strides in reducing poverty, today we are faced with 1 in 4 children – 25.5 percent – under age 5 live in poverty. That the youngest members of our country are also the most likely to live in poverty shows a profound failure to prioritize the well-being of this most vulnerable age group and a significant missed opportunity to invest in the future of this country.

Brain development research has found that a child’s first few years are essential for healthy development. During these years, a child is developing the brain circuitry they will have for the rest of their life. Adverse experiences before birth and in the early years negatively impactphysiological responses, such as the immune system, overall health, and brain architecture throughout childhood and into adulthood.

One of the reasons for these negative impacts is stress. Our response to stress typically includes increased heart rate, higher blood pressure, and the release of stress hormones such as cortisol, all a major shift from our body’s relaxed state. There are no negative effects when we experience stress for short amounts of time and return to our relaxed state. In fact, our body’s response to stress helps us deal with the situation that is causing stress. The same is true for young children, whose bodies have the same reaction to stress as adults. Short exposure to stressful situations followed by a return to the body’s relaxed state are important for children to learn how to adjust to and deal with stress, which is important throughout life. The key is that these stressful situations, such as meeting new people or overcoming a fear, must be short lived and happen with the support of caring adults who have safe, warm, and engaging relationships with the child. The circuits in the brain that deal with stress are highly susceptible to change during a child’s early development, so it is important that young children are not overexposed to stress and have the support systems to overcome it when they experience stress. Overexposure or prolonged exposure to stressful situations affects developing brain circuits, leading to poorly controlled stress response. This means that the child’s stress reaction will be overly reactive or slow to turn off when faced with stressful situations throughout their life. A prolonged stress response also wears out the systems that control the stress response and increases the risk of stress-related physical and mental illness later in life.

This overexposure to stress is called toxic stress. Toxic stress affects children who are abused or neglected, but also children who are raised in poverty. Environmental factors normally associated with low income families, such as lack of adequate heating and nutrition and lack of stable and responsive relationships lead to toxic stress and are associated with a higher incidence of cardiovascular, respiratory and psychiatric diseases in adulthood.

Even living in poverty for a short time increases toxic stress and has negative implications for brain development and throughout life. Self-reported health status of adults who fell into poverty as children is the same as or worse than that of adults who lived in chronic poverty as children, and both are considerably worse than for adults who never experienced poverty as a child. Many working families live on the brink of poverty or dip below the poverty line for short periods, especially during and after economic recessions. Major events such as the birth of a child can also send many families into poverty.

President Johnson realized the pernicious effect of early childhood poverty and worked to mitigate these effects by making Head Start an essential part of the War on Poverty. Head Start still exists today and offers low-income 4-year-olds high-quality preschool, including wraparound and parent engagement services to help fight the negative effects of early childhood poverty and prepare children from low-income families for school and life. But Head Start cannot reach all the children it is intended to. In fact, Early Head Start, which was authorized in 1994 for children under age 4, serves only about 4 percent of eligible children, while Head Start only serves 42 percent of eligible children. Other sources of affordable early childhood education and care are also limited, meaning many children from low-income families are left out entirely or must settle for lower quality preschool that does not have the same positive impact as high-quality preschool. The result is an opportunity gap between children from higher income families who attended high-quality preschool and enter kindergarten ready to learn and children from low-income families who could not attend preschool and are not ready to learn when they enter kindergarten. This is exemplified by the word gap: children who live in low-income families hear about 30 million fewer words than their higher-income peers by the time they enter kindergarten.

Fifty years since it was first declared we should renew the War on Poverty and focus on child poverty. We should expand on Johnson’s effort and invest in high-quality early education and invest more in evidence-based home visiting to combat the effects of early childhood poverty. We also know what works to reduce poverty, such as the Supplemental Nutrition Assistance Program, the Earned Income Tax Credit, and the Child Tax Credit, all of which help reduce child poverty and therefore reduce the number of children exposed to toxic stress during their developing years. We’ve used these methods to reduce poverty in the past 50 years; we should now expand our efforts to reduce early childhood poverty and invest in the future of our country.