DIET/Fruit and Vegetable

Teach Your Patients About Adequate Fruit and Vegetable Consumption

Increased consumption of fruits and vegetables is thought to increase health and reduce risk for cancer and cardiovascular disease. This trial was designed to quantify the impact of nutritional counseling vs.

behavioral dietary counseling on fruit and vegetable consumption in 271 patients at an inner-city health center. Patients randomized to the first intervention group received education about the importance of increasing fruit and vegetable consumption, with emphasis on how the biological elements of nutrients work to optimize health. Key to this intervention was the "five a day" recommendation - five servings of fruits and vegetables daily. Behavioral counseling was based on social learning theory and the "stage of change" model, which links positive behavior change with emotional readiness. To this end, each patient received personalized, specific advice tailored toward setting short- and long-term goals with regard to fruit and vegetable consumption.

Both interventions were performed by research nurses; all counseling sessions were audiotaped to ensure the two types of counseling remained distinct. Main outcome measures, assessed at baseline, eight weeks and one year, included self-reported daily fruit and vegetable intake (number of portions); plasma concentrations of alphatocopherol, beta-carotene and ascorbic acid; and 24-hour urinary potassium excretion, which are also markers associated with fruit and vegetable consumption.

Behavioral and nutritional counseling resulted in increases in fruit and vegetable consumption after 12 months, but more significantly in the behavioral group: 1.49 additional portions daily vs. 0.87 additional portions daily. The percentage of participants adhering to the "five a day" maxim also increased dramatically (42% vs. 27%, respectively). Moreover, plasma concentrations of beta-carotene and alphatocopherol increased in both groups. (Plasma beta-carotene more than doubled in both groups, while plasma alphatocopherol increased by 33% in the behavioral group vs. 28% in the nutrition group.)

The authors conclude that both interventions are feasible in primary care settings and could be adapted for group administration. They also note that because their findings involved individuals drawn from a low-income population (where fruit and vegetable intake is relatively low compared to higher-income populations), such interventions "may help address socioeconomic inequalities in health."

Tomatoes Lessen Prostate Cancer Risk

Tomatoes and tomato products are excellent sources of lycopene, an antioxidant with potent cancer-fighting abilities. Specifically, lycopene is believed to significantly reduce a man�s odds for prostate cancer.

Although studies have suggested preventive properties of these carotenoids, the data are inconclusive.

Following up on a previous six-year study, the authors of this study gathered data from the Health Professionals Follow-up Study of 40- to 75-year-old (at the 1986 baseline) health practitioners. A food-frequency questionnaire was completed by 47,365 subjects; food contributors to lycopene intake included tomatoes and tomato sauces (such as pasta sauce and salsa); pizza; watermelon; and grapefruit. Subjects were followed for an additional six years (1992 to 1998) for prostate cancer cases.

Consuming tomato sauces, which are considered the best source of bioavailable lycopene, more than twice per week reduced the odds for prostate cancer by 23%, compared to consuming them less than once per month. A higher estimated lycopene intake from all foods was also associated with a significant reduction in prostate cancer risk.

The authors conclude that these data confirm previous reports of a reduced risk for prostate cancer through consuming tomato products and other sources of lycopene. Tomato-product intake is recommended, and is consistent with other general dietary guidelines promoting high fruit and vegetable intake.

Grape Juice Helps Regulate Cholesterol

Moderate alcohol consumption induces increased high-density lipoprotein cholesterol formation and inhibited platelet aggregation. Some studies suggest that these benefits confer primarily to consumption of red wine rather than beer or other types of alcohol.

Flavanoids, the powerful antioxidants present in red wine, are also present in purple grape juice, an observation that spurred this study involving 15 adults with angiographically documented coronary artery disease (CAD). Subjects consumed approximately 21 ounces of purple grape juice twice daily for 14 consecutive days. Flow-mediated vasodilation (FMD), a measure of arterial dilation, was measured

using high-resolution ultrasonography, and susceptibility to increased low-density lipoprotein (LDL) oxidation was also measured.

Data indicated impaired FMD at baseline and increased FMD following ingestion of grape juice. Decreased susceptibility to LDL oxidation was also noted with consumption of grape juice. The authors conclude: "Improved endothelium-dependent vasodilation and prevention of LDL oxidation are potential mechanisms by which flavanoids in purple grape products may prevent cardiovascular events, independent of alcohol content."

Fighting Cardiovascular Disease: Purple Grape Juice as Effective as Wine?

Recent studies have proven that moderate red wine consumption reduces the risk of coronary ischemia and provides antioxidants that protect against cardiovascular disease. Researchers wanted to know if these same benefits could be provided by the consumption of purple grape juice, without the effects of alcohol.

The purpose of this study was to determine the effects of purple grape juice on blood platelet function and the production of nitric oxide, a factor associated with inhibiting cardiovascular disease.

The method involved an in vitro test, in which blood samples were incubated with juice, and a clinical evaluation using 20 subjects. The subjects, aged 20 to 45, were given purple grape juice for 14 consecutive days to confirm the relevance of previous results.

The study found that aggregation (blood clotting) was inhibited and nitric oxide production increased, thereby increasing antioxidant effects in both the in vitro and human subject samples. Results were dose-dependent: when more purple grape juice was administered to a subject, the effects of the juice were enhanced.

The findings of this study indicate that it is possible to obtain the health benefits of red wine without having to consume alcohol. The beneficial properties in both red wine and purple grape juice appear to come from the presence of flavonoids, which are concentrated in the skins, seeds and stems of purple grapes. 

Not Enough Fruits and Vegetables on the Table

Substantial evidence suggests that consistent consumption of fruit and vegetables may prevent cancer and other chronic diseases. Current U.S. dietary guidelines recommend daily consumption of five servings of fruits and vegetables, but whether or not these guidelines translate into actual dietary trends among U.S.

adults remains unclear.

This study evaluated fruit and vegetable consumption in 16 states from 1990-1996. Data from telephone surveys, including questions on dietary intake and participation in leisure-time physical activities, were used to stratify respondents based on various sociodemographic and health-related characteristics.

Results indicated that only 22% of the study population reported adequate intake of fruits and vegetables over the six-year period (19% in 1990, 22% in 1994, and 23% in 1996). The proportion increased among those participating in leisure-time physical activity and those with normal weight, but remained almost the same among inactive people, and dropped among the obese.

The authors note that progress in fruit and vegetable intake over the study period was "encouraging." However, the relatively insignificant change from 1994-1996 emphasizes the need for increased education efforts, particularly targeting those people who are overweight and/or participate in little or no physical activity.

Broccoli Compound May Suppress Growth of Breast Cancer Cells

Sulforaphane is a chemical compound abundant in green vegetables such as broccoli and brussel sprouts. Previous research has shown that sulforaphane can inhibit the growth of cancerous tumors in animals, and can induce apoptosis, or programmed cell death, in colon cancer cells.

A new study published in the Journal of Nutrition suggests that sulforaphane may also slow the spread of breast cancer cells.

In the study, researchers treated samples of a malignant tumor in a laboratory setting with various concentrations of a sulforaphane solution (SUL). The cells were observed every few hours to determine rates of mitosis, or cellular division. The scientists found that within 48 hours, sulforaphane "inhibited cell proliferation" and "induced significant inhibiation of DNA synthesis" in the tumor cells. It appeared to do so by disrupting the action of certain protein microtubules in the cells, which are vital for successful cell division.

The scientists concluded that their study "is the first to report the effectiveness of SUL as an inhibitor of human mammary carcinoma proliferation and to provide confirmatory evidence of a recently identified novel mechanism of SUL action." They recommended that future studies be conducted "to ascertain the implications of SUL intake as a result of either the consumption of cruciferous vegetables in the diet or potential chemoprevention strategies directed toward persons deemed to be at high risk for developing malignancy."