Dr. Megan Sandel, a pediatrician, experiences a troubling revelation whenever she sees a patient in the Boston Medical Center’s Grow Clinic. The clinic seems like a normal health-care facility in an advanced country, she notes: a waiting room, a medical assistant taking a child to be weighed and measured and then into an examining room.
“But that’s where, in some ways, the picture changes,” said Dr. Sandel, the clinic’s co-director, “because when you walk into the room you see this really cute, what you think is a twelve-month old, but it turns out it’s a two-year old. It’s a two-year old who hasn’t outgrown their twelve-month-old clothes yet.”
Even more serious than what you see is what you do not see: the brain of the child during a critical window of cognitive development. And in that largely invisible universe of neurons and synapses, of myelin sheaths and the neurological connections that are supposed to be generating the abundant future of every small person, lifelong damage is being done. The medical diagnoses are “stunting” and “failure to thrive.”
That is malnutrition in America, which is chronic among the poor and has soared during the pandemic. Its long-term harm will be one of the most severe legacies of Covid-19.
The usual incidence of what the government calls “food insecurity” ranges from 13 to 21 percent of American households with children, varying with the state of the economy. Most of them are white, although Black and Hispanic families suffer at higher rates. As school meals ended and vulnerable parents lost jobs during the Covid-19 outbreak, the Grow Clinic’s caseload jumped 40 percent. Nationwide, the rate of food insecurity in families with children rose to 29.3 percent last spring and summer from 13.6 percent in 2019, before the pandemic. With the return of some jobs and bursts of government assistance, the level has gradually declined to 17.8 percent, according to a large sample of adults with children in their households, surveyed by the Census Bureau in April. Seven out of ten who reported that they “sometimes” or “often” did not have enough to eat said they simply couldn’t afford to buy more food.
The recent $1.9-trillion American Rescue Plan will help, but not sufficiently or indefinitely. It raises grants by what used to be called food stamps—the Supplemental Nutrition Assistance Program (SNAP)—by up to $100 a month per family. More significantly, the plan’s $3000 to $3600-per-child stipend for one year would re-conceptualize governmental aid if made permanent, evading bureaucratic red tape by providing direct cash payments. Medical professionals say that getting money into parents’ pockets is the best way to treat children’s malnutrition.
Without broader policy overhauls, though, food insecurity seems likely to remain both a result and a cause of hardship, a key link in the middle of a complex chain reaction. For poor families without government housing subsidies, for example, rent on the private market can soak up 40 to 60 percent of income. Paying rent is not optional. The bills for electricity, water, heat, phone, and car loans cannot be ignored. The part of the budget that can be squeezed is the part for food. And that’s what happens.
Furthermore, nutritious food is scarce in many poor neighborhoods, one reason that obesity and malnutrition can coexist. When you don’t have the resources to make rational choices, Dr. Sandel observes, you go for the less expensive soda, chips, and other junk food whose prices are lowered by government subsidies of the sugar and corn industries. And when her patients know that their SNAP and other funds are going to run out before the end of the month, they overeat when they can, stuffing their kids and using heavy cream to stretch dishes.
“Hunger” is an unscientific term that can embrace everything from starvation to passing discomfort. In deeply impoverished countries, it can kill by compromising the immune system to expose children to serious disease. In the United States, too, poorly fed kids get sick and miss school more often than their wealthier peers. When they are hungry in class—or online during the pandemic—their attention flags, they do not do well. “Learning is a discretionary activity, after you’re well-fed, warm, secure,” said Dr. Deborah A. Frank, who founded the Grow Clinic nearly forty years ago.
But something even more pernicious is happening to younger children who aren’t getting enough micronutrients during their first thousand days—the second and third trimesters in utero and the first two years after birth. For at least half a century, scientists have been documenting how the developing brain suffers from insufficient iron, iodine, folate, zinc, calcium, magnesium, selenium, and various vitamins, all found in balanced diets of fresh fruits and vegetables, meat, fish, eggs, and dairy products. The alarm is sounded in study after study, including the succinct warning in the Journal of Developmental & Behavioral Pediatrics that, after age two, “the effects of malnutrition on stunting may be irreversible, and some of the functional deficits may become permanent.”
Brain growth comes early. A newborn’s brain is about 10 percent of total body weight compared with an adult’s 2 percent. By her first birthday, her brain reaches about 70 percent of what it will be in young adulthood, and by age two, about 77 percent.
At the microscopic level, the target of malnutrition’s assault depends on the timing. Neurons, generated during the second trimester of pregnancy, are reduced in number; their maturation is impeded if inadequate nutrition occurs in the third trimester. Nutritional deficiency in that period can also lower the production of glial cells, which support and protect neurons. Midway into the first year, synapses develop in the part of the brain governing vision, a little later in the auditory and receptive language areas, and between one year and mid- to late adolescence in the prefrontal cortex, responsible for high-level cognition. The networks of synapses are generated and pruned by an interplay of genes, behavioral experience, learning, and nutrition.
“The stages of development are numerous and complex,” the biologist Mohamed El Hioui wrote in a 2019 summary of research studies. “Neural cells must proliferate, migrate to the right place, establish the right connections, form the right receptors for neurotransmitters and be well covered with myelin, a protective substance essential to the proper transfer of nerve messages. This meticulous assembly of neural cells is vulnerable to environmental stressors, including of course, malnutrition.”
The process is rapid at times, always delicate, and easily disrupted. Although the brain gets first priority in harvesting scarce nutritional resources, at the expense of the rest of the body, even slight food insecurity has been shown to affect young children, and “any sustained interruption to their nutrition or to their care, if not treated early, can result in irreversible damage to their development,” warned a 2007 paper from the Drexel University School of Public Health.
For example, protein deficiency diminishes the thickness of the cerebellum and the visual cortex, among other areas of the brain. During pregnancy, inadequate choline protein may be associated with a reduced transfer of nutrients by the placenta and adverse brain structure in the child. Since chicken eggs contain high amounts of choline, undernourished children in Ecuador who were fed eggs in a study reported in 2017, the youngsters “had significantly higher concentrations of biomarkers associated with improved child development and important physiological processes in the brain.”
Some early injuries never heal. Seventy-seven infants who had been hospitalized with protein deficiency in Barbados carried the effects into adulthood, despite getting nutritious food between ages one and twelve. In their thirties, they had compromised “verbal fluency, working memory, processing speed, and visuospatial integration” compared to a healthy group from the same classrooms.
Among poor pregnant women and young children who don’t eat enough meat, poultry, fish, spinach, or beans, ruinous iron deficiency is widespread. Anemia decreases the formation of the myelin sheath, whose fatty matter insulates nerve cells and helps accelerate nerve conduction. Inadequate iron also affects the metabolism in the hippocampus, critical for memory. And it can lead to low birth weight, which is associated with cerebral palsy and other neurological problems.
Even children who get adequate iron later do not recover fully. Decades of studies following anemic infants into their school years have found them scoring lower in “arithmetic achievement and written expression, motor functioning, and . . . spatial memory and selective recall,” according to a collection of research, From Neurons to Neighborhoods, assembled by the National Research Council and the Institute of Medicine.
Low iron also makes the body more susceptible to lead from the old water pipes often found in slum housing. “Iron and lead are absorbed in the same pathway,” Dr. Sandel explained. “If you’re iron deficient, you create more receptors, you’re iron hungry, you’re looking for iron wherever you can find it,” and you absorb lead more readily as well. “So part of the treatment for kids who are lead-exposed is iron therapy.”
Research on the brain has gone far beyond the most demonstrable biological effects of malnutrition into areas of behavior and mental illness, where food deprivation is hard to isolate from such other factors as parenting, family stress, poor housing, and the myriad hardships of poverty.
It’s been established that the brain generates and whittles away synapses as the environment demands, so that emotional support during infancy can shape a person’s later ability to form attachments. And kids who don’t get enough iron and protein often lack the energy needed for curiosity and communication with others, reducing interactions essential to cognitive development. Proven remedies have included both nutrition and increased psychosocial stimulation.
The Barbados study and other research have reported correlations between early malnutrition and later attention deficit disorders. Causal relationships have been hard to establish, but children who once suffered from malnutrition have displayed hyperactivity, poor socialization, and difficulties in emotional regulation. A study that followed children in twenty American cities from 1998 to 2000 found lower self-control and higher rates of delinquency among those who had experienced food insecurity. Increased schizophrenia afflicted adults whose mothers during pregnancy had suffered in the “Dutch famine” during World War II.
A family’s anxiety over insufficient food can spread to children, with a particular neurological impact. “There is growing evidence from both animal and human studies,” a group of scientists reported in 2016, “that persistently elevated levels of stress hormones can alter the size and architecture of the developing brain, specifically the amygdala, hippocampus, and prefrontal cortex.”
Then, writing last year in The American Journal of Clinical Nutrition, a team at the Department of Medicine at the University of California, San Francisco, added together the findings of numerous studies into a devastating litany of mental health implications that are expected to outlast the pandemic: “Individuals experiencing food insecurity,” their paper concludes, are “more likely to experience symptoms of depression, anxiety, and post-traumatic stress disorder (PTSD), as well as suicidality. Qualitative research suggests that financial and food insecurity can fuel feelings of sadness, shame, guilt, anxiety, and hopelessness.”
The Grow Clinic’s caseload might decline, and the virus might diminish quite soon. Its effects on children will not.