However, the protective effects stem only from fresh varieties - meaning canned or processed tomatoes and apples don't work.
The natural decline in lung function over 10 years was slower among former smokers with a diet high in tomatoes and fruits, especially apples.
Johns Hopkins Bloomberg School of Public Health scientists concluded the benefits are derived from two tomatoes or three fruits each day.
They suggested apples were the fruit that packed the strongest punch due to its abundance of chemicals that are good for the lungs.
The findings offer hope of a way for smokers to avoid developing the incurable chronic obstructive pulmonary disorder (COPD).
What is COPD?
COPD is the umbrella term for diseases from emphysema to acute bronchitis which can cause wheezing and breathlessness.
Figures suggest around 1.2 million Britons and more than 11 million Americans are living with the potentially fatal COPD.
Lead author Dr Vanessa Garcia-Larsen said: '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.
'The findings support the need for dietary recommendations, especially for people at risk of developing respiratory diseases such as COPD.'
How was the study carried out?
Researchers assessed the diet and lung function of more than 650 adults for the study, published in the European Respiratory Journal.
The same lung tests, which measures their capacity to take in oxygen and expel it, were then repeated on the volunteers a decade later.
The study showed the diet can slow natural ageing. Among former smokers, the diet-lung-function connection was even more striking.
What did they find?
Ex-smokers who ate a diet high in tomatoes and fruits had around 80ml slower decline over the ten-year period.
This suggests that nutrients in their diets are helping to repair the damage done by smoking, according to Dr Garcia-Larsen.
She added: 'Lung function starts to decline at around age 30 at the variable speed depending on the general and specific health of individuals.
'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.'
Poor lung function has also been linked to heart disease over the years.
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