Introduction

Chicken soup is often touted as a folk remedy for common ailments, but according to a recent study in the American Journal of Clinical Nutrition, vegetable soup may have some disease fighting properties as well.

Scientists suspect that carotenoids, antioxidant compounds found in produce, may be responsible for this effect. Initial research centered on one carotenoid, beta-carotene, but later research has expanded to include a range of carotenoids found in commonly consumed foods.

A possible link between diet and lung cancer

In this study, scientists analyzed the food records of 124,000 women and men participating in two long-range US studies, the Nurses' Health Study and the Health Professionals Follow-Up Study, to determine how much of five different carotenoids their diets contained. The scientists then looked at the relationship between carotenoid intake and lung cancer incidence. Overall, those individuals who consumed a diet high in a variety of carotenoids had a significantly lower risk of developing lung cancer.

When the researchers looked at individual carotenoids, they found that those who ingested the most alpha-carotene, found primarily in carrots, and lycopene, found predominately in tomatoes, had a significantly lower lung cancer risk. For those participants who never smoked, there was a 63 % lower risk of lung cancer among those who consumed the most alpha-carotene compared to those who consumed the least. The association between lung cancer risk and lycopene intake was somewhat different, but smokers who consumed the most lycopene also had a significantly lower risk of lung cancer. That led researchers to suggest that consuming a lycopene-rich diet might be particularly important for current smokers.

Choose food over supplements

The researchers note that fewer than 10% of lung cancers occur in nonsmokers. Thus, smoking cessation is by far the best way to lower the risk of lung cancer. Furthermore, the researchers in this study analyzed intakes of cartotenoids in foods, rather than in dietary supplements. This makes sense--while many studies have shown the cancer fighting potential of fruits and vegetables, there is less evidence that dietary supplements provide this same benefit. While the overall data indicate that carotenoids are the compounds in fruits and vegetables responsible for lowering lung cancer risk, the scientists observe that there are likely other components of fruits and vegetables that are equally important to good health.

Note: Cooked tomatoes and tomato products such as spaghetti sauce are better sources of lycopene than fresh, raw tomatoes because heating makes more lycopene available for digestion.