The present nested case-control study was designed to investigate whether the association between carotenoid consumption and risk of breast cancer is related to mammographic density. High breast density as measured by mammography has been reported to be a powerful indicator of increased breast cancer risk. The study included 604 breast cancer cases and 626 cancer-free controls in the Nurses' Health Study for whom circulating carotenoid (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin) levels had been measured and mammograms obtained prospectively. Using a computer-assisted method to determine mammographic density, circulating carotenoids were not found to be associated with mammographic density. However, mammographic density significantly influenced the association between total circulating carotenoids and risk of breast cancer (P heterogeneity = 0.008). Total circulating carotenoid levels were found to be inversely associated with overall breast cancer risk (P trend = 0.01). Among women in the highest third of mammographic density, total circulating carotenoids were associated with a 50% lower risk of breast cancer (odds ratio = 0.5; 95% confidence interval = 0.3 - 0.8). Similarly, among these women, high levels of circulating alpha-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin were found to be associated with a significant 40% to 50% reduction in risk of breast cancer (P trend < 0.05). On the other hand, no such inverse association was observed between circulating carotenoids and breast cancer risk among study participants with low mammographic density. The authors conclude that plasma levels of carotenoids may play a role in reducing risk of breast cancer, especially among women with high breast density.

The present study was designed to investigate the impact of food irradiation on certain nutrients and quality attributes in thirteen vegetables. Irradiation is used to improve the microbial safety, while maintaining the quality, of fresh fruits and vegetables. Irradiation at 1 kGy (a dose that potentially inactivates E. coli) was performed on the following fresh-cut vegetables: spinach, tomatoes, cilantro, parsley, green onions, carrots, broccoli, red cabbage, celery, and iceberg, romaine, green and red leaf lettuce. The appearance of irradiated vegetables was found to be comparable to nonirradiated samples except that irradiated carrots, celery, cilantro, and green onions were found to have higher appearance scores. No differences were observed in the instrumental texture between irradiated and nonirradiated samples. The aroma of several of the irradiated vegetables was significantly better than non-irradiated controls after 14 days of storage, because the controls had higher levels of decay. Irradiation with 1 kGy did not affect the vitamin C content of most of the vegetables. However, irradiated green and red leaf lettuce were found to have 24% to 53% lower vitamin C content than nonirradiated lettuce. The authors conclude that most fresh-cut fruits and vegetables tested can tolerate up to 1 kGy irradiation without significant losses in any quality attributes.

The current study was designed to assess the impact of lifestyle in first-degree relatives with a family history of cancer in Nagoya, Japan. 1,988 gastric, 2,455 breast, 1,398 lung and 1,352 colorectal cancer patients and 50,706 outpatients without cancer were selected from 1988 to 1998. The cancer patients and controls were evaluated for lifestyle factors, including diet, physical exercise habits, and smoking and drinking status. Frequent intake of fruits, raw vegetables, carrots, pumpkin, cabbage and lettuce, as well as frequent physical exercise, were found to be correlated with decreased risk of all four sites of cancer, while smoking increased the risk of gastric and lung cancer. The authors conclude that there was no appreciable influence of family history of cancer on lifestyle-related risk factors for gastric, breast, lung, and colorectal cancer. Habitual smoking enhanced, while frequent physical exercise and raw vegetables intake reduced cancer risk, regardless of the family history of cancer.

The present study was designed to investigate the effects of lettuce intake on lipid metabolism and antioxidant protection in the rat. Rats fed a 20% lettuce diet for three weeks were found to have decreased LDL/HDL cholesterol ratios and markedly lower liver cholesterol levels (41% decline). At the same time, fecal total steroid excretion was elevated (44% increase) and apparent absorption of dietary cholesterol was significantly depressed (37% decline). The lettuce diet also resulted in an improvement of the vitamin E/TG ratio in plasma and limited lipid peroxidation in the heart. In further experimentation, lettuce intake also significantly increased both post-prandial ascorbic acid and post-prandial α-tocopherol plasma levels, contributing to improved plasma antioxidant capacity within two hours of consumption. The authors conclude that lettuce consumption increases the total cholesterol end-products excretion and improves antioxidant status. Regular consumption of lettuce should contribute to improve protection against cardiovascular diseases.

The current study evaluated the phenolic profiles and antioxidant and antiproliferative activities of 10 common vegetables. The vegetables were selected on the basis of per capita consumption in the U.S. Broccoli was found to have the highest total phenolic content, followed by spinach, yellow onion, red pepper, carrot, cabbage, potato, lettuce, celery, and cucumber. Red pepper was found to have the greatest total antioxidant activity, followed by broccoli, carrot, spinach, cabbage, yellow onion, celery, potato, lettuce, and cucumber. The phenolics antioxidant index was used to evaluate the quality and quantity of phenolic contents in these vegetables and was calculated from the corrected total antioxidant activities by eliminating the contribution of vitamin C. Antiproliferative activities were evaluated using HepG(2) human liver cancer cells. Spinach was found to have the highest inhibitory effect on proliferation, followed by cabbage, red pepper, onion, and broccoli. On the basis of these results, the authors proposed a bioactivity index for dietary cancer prevention to provide a simple reference for consumers to choose vegetables in accordance with their beneficial activities.

In the current study, 198 Mexico City women aged 21 to 79 years with breast cancer were individually age matched to 198 women with no breast disease from 1994 to 1995. Information on socioeconomic characteristics and diet was obtained by interview and a questionnaire was used to estimate the level of consumption of 95 foods. The effect of selected foods on risk of breast cancer was estimated using logistic regression models. The adjusted odds ratio for the consumption of more than one slice of onion per day and breast cancer was 0.27 (95% confidence interval = 0.16-0.47), and had a statistically significant trend (p < 0.001). This protective effect remained after adjustment for known breast cancer risk factors. For premenopausal women, there was also a protective and significant effect associated with the intake of lettuce and spinach and nonsignificant protective effects for apples and herbal tea.