They say you are what you eat, but where you were raised may have a powerful impact on food choice, too. Researchers from the University of Southampton in the UK discovered that the more fast food restaurants in a neighborhood, the more likely it was for children to grow up with weak bones. The study, published in the journal Osteoporosis International, reveals how much influence a neighborhood can have on a child’s development at a very early age.

According to the NIH's Osteoporosis and Related Bone Diseases National Resource Center, early childhood bone development is necessary to prevent osteoporosis and fractures later in life. So for the study, researchers examined the bone mineral density (BMD) and bone mineral content (BMC) of 1,107 children at birth, and followed up with them again when they were four-and six-years-old. Both BMD and BMC are measurements used to evaluate and project a child’s bone health and growth.

Children who were born in neighborhoods with an abundance of fast food chains had poorer bone health than those who were born in neighborhoods with fewer chains and more healthy food stores and greengrocers. Kids born in areas where there was greater access to healthy foods actually had higher BMD at ages four and six.

"These findings suggest that the exposure of mothers and children to more healthy food environments might optimize childhood bone development through its influence on the quality of the maternal diet and dietary choices during childhood," said the study's co-author Cyprus Cooper, the chair of the International Osteoporosis Foundation, in a press release.

Put it another way: Pregnant women's fast food intake may have a ripple effect on how their children develop. The National Institute of Arthritis and Musculoskeletal Skin Diseases (NIAMS) reported that by the time girls turn 18 and boys 20, they should have developed up to 90 percent of their bone mass. In their late twenties it’s already too late, NIAMS said, because their bone mass would have peaked by then. This is why it's recommended parents invest in their children's bone health during early childhood.

Protein, calcium, vitamin D, fruits, and vegetables all positively influence bone health, especially during those early years. Researchers believe that their study results could influence zoning policies to replace some fast food restaurants with healthier food stores. Already because of the findings UK lawmakers have begun to form local planning laws that would ban fast-food outlets within 400 meters of schools.

However, in a recent study published in 2014, healthy food access didn't exactly lead to a healthier childhood. NYU researchers found when healthy grocery stores were full of government-subsidized fruits, vegetables, and whole grains in low-income and ethnic minority neighborhoods it barely made a dent at improving children’s diets.

Food choice is complex. Just because healthful foods are available at affordable prices doesn’t mean the community members' behavior will change along with it. New healthful supermarkets may play an important role, but it'll take more research to figure out how policies should be structured to support long-term and positive changes.

"More extensive research is needed, but if confirmed in further studies, this would imply that action to improve the food environment could have benefits for childhood bone development."

Source: C Cooper, Vogel C, Parsons K, Godfrey S, Robinson NC, Harvey H, and Inskip C. Greater access to fast-food outlets is associated with poorer bone health in young children. Osteoporosis International. 2015.