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A summary of the latest clinical trials using fruit and vegetables to prevent disease. Current dietary guidelines in Canada recommend that adults eat 7-10 servings of fruit and vegetables daily. Here are some reasons to eat them today!

Apples

An apple a day could, in fact, keep the doctor away! Investigators at the University of Reading, UK, are collaborating with the FEM-IASMA Research and Innovation Centre, Italy, to examine the effects of apples on cardiovascular risk and gut health. Due to their high level of polyphenols and fiber, apples have been linked with a reduced risk of cardiovascular disease.

The current trial will assess the effect of regular apple consumption on cholesterol, vascular function and gut micro biota profile. Participants will include two apples per day in their regular diet, for a total of eight weeks. A second group of participants will consume 110ml of apple juice instead of eating two whole apples. At the end of the eight weeks the two groups will be compared using outcome measures that include; changes in blood lipid levels, blood pressure and other markers of cardiovascular disease and type 2 diabetes.

The investigators’ goal is to assess whether consuming apples on a regular basis can have a positive effect on cholesterol levels, vascular functioning and gut microbiota, thereby increasing cardiovascular health, and reducing the risk of cardiovascular disease.

 

ClinicalTrials.gov “Effect of Apples on cardioVascular Risk And Gut Health (AVAG)” Available from: http://clinicaltrials.gov/ct2/show/NCT01988389?term=NCT+01988389&rank=1 Last Accessed: Nov 20, 2013.

 

Blueberries

Blueberries have recently gained popularity as a ‘super food’. They are high in polyphenols which are important for promoting health and proper functioning of many systems in the body, including the cardiovascular system. A study underway at Florida State University, USA, will assess the effect of daily incorporation of blueberries into the diet on cardiovascular health.

Included in this study will be post-menopausal women with pre-hypertension. For eight weeks, participants will incorporate 50g of freeze-dried blueberry powder into their regular diet twice a day, for a total of 100g per day. At the end of the study, participants who were taking the blueberry supplement will be assessed for measures of cardiovascular function, including blood pressure, compared to participants who did not take the blueberry supplement.

The investigators aim to provide support for the notion that eating blueberries will reduce blood pressure and improve vascular function in their participants. Their hope is to provide a basis for alternate, safe, approaches in the prevention of hypertension long before there is a need for drug prescription.

 

ClinicalTrials.gov “Blueberry Consumption Improves Vascular Function and Lowers Blood Pressure in Post-Menopausal Woman with Pre-hypertension” Available from: http://clinicaltrials.gov/ct2/show/NCT01686282?term=NCT01686282&rank=1 Last Accessed: Nov 20, 2013.

 

Purple Vegetables

A study currently underway at the University of Guelph in Ontario, Canada, is assessing the effect of a diet high in purple vegetables in men with increased risk of cardiovascular disease and type 2 diabetes. The basis of the research is the thought that richly colored purple vegetables contain higher levels of polyphenols, such as anthocyanins, compared to lighter colored vegetables.

Study participants will be including 200-300g of raw carrots or cooked potatoes per day into their regular diet for twelve weeks. There will be a total of four groups of participants consuming; orange carrots, purple carrots, white potatoes or purple potatoes. Participants will be assessed at six and twelve weeks for measures of diabetes and cardiovascular disease. These will include: blood pressure, body composition, insulin resistance, and circulating biomarkers of cardiovascular disease and type 2 diabetes. In addition, metabolites of polyphenols will be measured in both the blood and urine.

Overall the study will assess the health benefits of replacing light colored vegetables with purple colored vegetables, which are high in polyphenols, in reducing the risk of cardiovascular disease and type 2 diabetes.

 

ClinicalTrials.gov “Effects of Purple Vegetables on Cardiovascular Disease (CVD) Risk Factors” Available from: http://clinicaltrials.gov/ct2/show/NCT01564498?term=NCT+01564498&rank=1 Last Accessed: Nov 20, 2013.

 

Green Vegetables

A trial planned by the University of Wisconsin, United States, aims to determine the effects of cruciferous vegetables on breast cancer risk. Cruciferous vegetables are those belonging to the mustard family and include: mustard greens, various cabbages, broccoli, cauliflower and brussel sprouts. Study participants will consume 40g of the cruciferous vegetables broccoli and brussel sprouts, daily for eight weeks. These participants will be compared to two other study groups. The first group will take Cruciferous CompleteTM supplements (2 capsules, 3 times daily) instead of eating the vegetables; the second will take placebo pills.

After the eight week study period, risk of breast cancer will be assessed by measuring the urinary concentration of estrogen metabolites. A ratio of 2 to 16αhydroxyestrogens (2:16) is a proposed biomarker of chemoprevention from breast cancer. The investigators suggest that the supplements will increase the 2:16 ratio in comparison to either the brussel sprouts plus broccoli or placebo groups. Overall, they suggest that cruciferous vegetables should have a preventive effect on breast cancer, as indicated by an increase in urinary estrogen metabolite ratio.

 

ClinicalTrials.gov “Green Vegetables and Women’s Health” Available from: http://clinicaltrials.gov/ct2/show/NCT01726127?term=NCT+01726127&rank=1 Last Accessed: Nov 20, 2013.

 

Written by Deborah Tallarigo, PhD

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