A new study found that former smokers with diets high in tomatoes and fresh fruit had a slower rate of decline in lung function, suggesting those foods may help restore lungs damaged by smoking. Researchers also found that among all adults, including people who’d never smoked or had stopped, those with the highest tomato consumption had the slowest decline in lung function—meaning the benefits may not just be for former smokers. The study offers important evidence for the effect of diet on lung function.
"This study shows that diet might help repair lung damage in people who have stopped smoking. It also suggests that a diet rich in fruits can slow down the lung's natural aging process even if you have never smoked," Vanessa Garcia-Larsen, assistant professor in the Bloomberg School's department of international health and the study's lead author, said in a statement.
Poor lung function is linked to mortality risks from a host of diseases, including chronic obstructive pulmonary disease (COPD), heart disease, and lung cancer. Diet, the study suggests, can help delay the natural decline in lung function, keeping people healthier longer. "The findings support the need for dietary recommendations,” Garcia-Larsen said, “especially for people at risk of developing respiratory diseases such as COPD."
To reach that conclusion, researchers at the Johns Hopkins Bloomberg School of Public Health looked at lung function in more than 650 people over a ten-year period, starting in 2002. The participants (from Germany, Norway, and the United Kingdom) completed questionnaires about their diets and overall nutritional intake, along with taking a pair of lung tests: One measured how much air they could expel in one second, while the other gauged how much they could inhale in six seconds. Researchers controlled for factors such as age, height, sex, body mass index (an indicator of obesity), socio-economic status, physical activity, and total energy intake. Then they repeated the tests ten years later.
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They found that adults who averaged more than two tomatoes or more than three portions of fresh fruit a day showed a slower decline in lung function than those who didn’t eat many tomatoes or fresh fruit (less than one tomato daily or less than one portion of fruit a day). That may sound like a lot, and the protective effect only correlated with fresh fruits and vegetables—processed foods like tomato sauce didn’t show the same link.
It’s important to note that this is an observational study, meaning there might be any number of hidden, complicating factors in the data. But the researchers suggest it offers evidence for another approach to maintaining lung health.
"Lung function starts to decline at around age 30 at variable speed depending on the general and specific health of individuals," Garcia-Larsen explained. "Our study suggests that eating more fruits on a regular basis can help attenuate the decline as people age, and might even help repair damage caused by smoking. Diet could become one way of combating rising diagnosis of COPD around the world."