Sunday, November 30, 2014

Tomato, Cooked or Raw, & Lycopene

According to the National Cancer Institute, one out of every six American men develops prostate cancer in his lifetime. In 1995, a study by Dr. Edward Giovannucci and colleagues at Harvard University found that men who consumed tomatoes or tomato products developed fewer cases of prostate cancer. Since then, researchers have sought to identify the component in tomatoes that provides this and other benefits.

Tomato Nutrients

Tomatoes contain significant amounts of vitamin E, fiber, antioxidant polyphenols, potassium and folate. Most tomato and prostate cancer research focuses on lycopene, the red pigment of tomatoes. The lycopene content of tomato products varies widely depending upon variety, ripeness of the fruit and processing methods, making it difficult to make dietary recommendations.
Lycopene in Foods

According to Harvard Medical School, one slice of raw tomato contains approximately 515 micrograms lycopene, while 2 tablespoons of tomato paste contains 13,800 micrograms of lycopene. That means tomato paste contains many times more lycopene than raw tomatoes. Because most research attributes the anticancer properties of tomatoes to lycopene, tomato paste appears to be the better source.
Lycopene Concentration

The higher water content of raw tomatoes reduces total lycopene concentration. Raw tomatoes contain approximately 94.5 percent water by weight, according to the USDA Nutrient Database. The processing of tomatoes to form tomato paste causes water loss, so lycopene becomes more concentrated.
Lycopene Structure

The structure of lycopene determines how much the body absorbs. Two primary forms of lycopene exist: a straight line -- the all-trans form -- and a chain with kinks -- the cis-isomer form. Processing of tomatoes to form tomato paste increases the amount of cis-lycopene. The smaller structure of the cis-lycopene isomer allows for easier absorption in the small intestine compared to all-trans lycopene. This means that when you eat tomato paste, more of the kinked form of lycopene accumulates in the body compared to its straight counterpart.

How Much Green Tea Should You Drink to Lose Weight?

Green tea alone does not cause weight loss -- only creating a calorie deficit can do that. According to an article published in the “Journal for Nurse Practitioners" in 2010, however, green tea can aid in weight-loss efforts by reducing appetite and boosting metabolism. Studies have not established an exact daily dose of green tea that will best support weight loss. You should drink at least 2 to 3 cups a day while staying under the upper limits of recommended caffeine intake.

Caffeine Intake
The caffeine found in green tea is partly responsible for its weight-loss effects. Caffeine is not without side effects, and too much can cause toxicity. A “Journal for Nurse Practitioners" article warned of the potential for people to abuse supplements that contain caffeine. Green tea contains about 25 milligrams of caffeine per 8 ounces. The upper limit of caffeine intake for healthy adults to avoid harmful effects is 300 to 400 milligrams daily. This limit may be different if you have a health condition, so it's important to speak with your doctor. Pregnant women should have no more than 200 milligrams of caffeine daily.

Avoiding Caffeine Toxicity
To stay within the upper limit of caffeine intake, do not exceed 12 to 16 8-ounce cups of green tea daily. Keep in mind that the strength at which tea is brewed affects its caffeine content. Using one tea bag counts as one cup of tea. If you desire stronger tea, count each tea bag used as an additional cup toward the upper limit.

Sufficient Doses of Polyphenols
The University of Maryland Medical Center recommends drinking 2 to 3 cups of green tea daily to get a sufficient dose of its health-promoting active ingredients. This includes 240 to 320 milligrams of polyphenols. These plant compounds are antioxidants, which means they protect cells from damage. They also may also increase your metabolism. A review and meta-analysis of studies on green tea's effects on weight loss, published in "NutriciĆ³n Hospitalaria" in 2014, concluded green tea does reduce fat mass slightly. You can't rely on green tea alone to lose weight, but it can aid in your overall efforts.

Side Effects and Precautions
Side effects of caffeine include increased heart rate, insomnia, nausea and vomiting, frequent urination, tremors, anxiety and depression. Consult with your doctor before drinking green tea if you have a medical condition. If you suffer from heart, kidney or liver problems, high blood pressure, diabetes, anemia, glaucoma, osteoporosis or anxiety, avoid drinking green tea. Green tea also interacts with certain medications, so talk with your doctor before drinking it if you're taking any medications. Birth control pills, blood thinners and others are known to interact with green tea.

source :