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Tag: orange juice

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Citrus paradisi (Grapefruit, pink) white bg.jpgWill these research results hold up over time? It is known that certain fruits (citrus fruits and juices) and vegetables contain photosensitizing chemicals called psoralens, and the researchers suspected that a high intake of citrus products over time could make individuals more susceptible to melanoma than people who rarely ate citrus fruits. During more than 2 decades of following more than 100,000 persons they found 1840 melanomas , And yes, even though there were relatively few melanomas, they did find a dose-dependent relationship between citrus product consumption and melanoma risk, specifically that ingesting citrus fruit 1.6 or more times per day had a 36% higher risk for melanoma than people who ate it less than twice per week. But this association was only with whole grapefruit and orange juice, and weirdly, not with consumption of grapefruit juice or whole oranges. Before people panic, remember that citrus fruits have all sorts of great health benefits and should be eaten. From Science Daily:

Can orange juice, grapefruit raise your melanoma risk?

People who enjoy a glass of orange juice or some fresh grapefruit in the morning may face a slightly increased risk of melanoma—the least common but most deadly form of skin cancer. That's the finding from a study of more than 100,000 U.S. adults followed for about 25 years. Researchers discovered that those who regularly consumed orange juice or whole grapefruit had a higher risk of developing melanoma, compared to people who avoided those foods.

Experts were quick to stress that the findings, reported online June 29 in the Journal of Clinical Oncology, do not prove that citrus foods help cause skin cancer. It is plausible, however, that certain compounds in citrus explain the association, said senior researcher Dr. Abrar Qureshi, chair of dermatology at Brown University and a dermatologist at Rhode Island Hospital, in Providence.

Citrus foods contain particular "photoactive" chemicals—namely, psoralens and furocoumarins—that are known to make the skin more sensitive to the sun when they're applied topically, Qureshi said."You'll see children get a sunburn in spots where a citrus popsicle dripped down the chin, for example," Qureshi explained.

But even if citrus foods potentially make some people susceptible to sunburn, it's not orange juice that should be avoided, Qureshi said. "The citrus can't hurt you without the excessive sun exposure," he pointed out. So the message remains the same, Qureshi said: Protect your skin from soaking up too many rays by staying in the shade, using sunblock and wearing a hat. "I don't think the general public should make any changes based on this study," said Berwick, a professor of dermatology at the University of New Mexico in Albuquerque. 

For the study, the researchers analyzed data from two long-running studies of U.S. health professionals. Every couple of years, the participants answered detailed surveys on their health and lifestyle. Over about 25 years, more than 1,800 people developed melanoma and the risk was higher among those who regularly drank orange juice or ate whole grapefruit. That was true, the researchers found, even when several other factors were taken into account—including people's reports of their overall sun exposure and history of bad sunburns.

People who had orange juice at least once a day were about 25 percent more likely to develop melanoma than those who drank the juice less than weekly. Similarly, people who ate whole grapefruit at least three times a week had a 41 percent higher melanoma risk, versus those who never ate it. On the other hand, there was no connection between melanoma risk and either whole oranges or grapefruit juice, the researchers found.

Qureshi did offer a potential explanation for why only orange juice and whole grapefruit may be tied to melanoma risk."There are different types of these photoactive compounds in different parts of the fruit," he said. So, it's possible that not all citrus fruits are alike when it comes to melanoma risk. Plus, Qureshi said, heat—like that used in pasteurizing juice—neutralizes the photoactive compounds. That might help explain why grapefruit juice was not connected to melanoma risk.

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More reasons to eat a variety of foods - each food will contribute something different, and the effects may be subtle. Here are two healthy foods from plants: orange juice and shiitake mushrooms. From Medical Xpress

Orange juice could help improve brain function in elderly people

Drinking orange juice could help improve brain function in elderly people, according to new research from the University of Reading.The study saw a group of 37 healthy adults (mean age 67 years) consuming 500 ml (just under a pint) of orange juice, daily over an eight week period. At the beginning and end of the eight weeks their memory, reaction time and verbal fluency was measured. These were then combined into one overall score known as 'global cognitive function'. The adults showed an 8% overall improvement in global cognitive function after orange juice consumption compared to a control drink (matched for taste and calories) given during a different eight week period. Although subtle, these improvements are significant. ."

Orange juice is a major source of a group of naturally occurring plant phytochemicals known as flavonoids, being particularly rich in a sub-class of flavonoids, known as flavanones. Recent studies from the School of Chemistry, Food and Pharmacy have shown that flavonoids may improve memory through the activation of signalling pathways in the hippocampus, a part of the brain that is associated with learning and memory. 

Previous Reading research has shown that other flavonoid rich foods such as blueberries are beneficial for cognition. Research is still ongoing to determine the exact mechanisms by which flavonoids may exert benefits to the brain. Several mechanisms haveboosting immune systbeen proposed such as improved blood flow in the brain and protecting neurons against oxidative damage and increasing the efficiency with which neurons transmit signals.

This study was published in April 2015, from Science Daily:  Mushrooms boost immunity, suggests research

Could a mushroom a day help keep the doctor away? A new University of Florida study shows increased immunity in people who ate a cooked shiitake mushroom every day for four weeks.... 52 healthy adults, age 21 to 41, came to the Gainesville campus, where researchers gave them a four-week supply of dry shiitake mushrooms. Participants took the mushrooms home, cleaned and cooked them. Then they ate one, 4-ounce serving of mushrooms each day during the experiment. Through blood tests before and after the experiment, researchers saw better-functioning gamma delta T-cells and reductions in inflammatory proteins.

"If you eat a shiitake mushroom every day, you could see changes in their immune system that are beneficial," said Percival, an Institute of Food and Agricultural Sciences faculty member. "We're enhancing the immune system, but we're also reducing the inflammation that the immune system produces."

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Good news for those people who enjoy drinking a glass of orange juice each day. From NPR News:

What's More Nutritious, Orange Juice Or An Orange? It's Complicated

We all could probably eat more fruits and vegetables. But if forced to choose between whole fruit or a glass of juice, which one seems more healthful? The general advice is to opt for the fruit, since juices are stripped of the fiber – which most us don't get enough of — in whole fruit. And let's face it: Most juice contains a lot of sugar, which most of us consume too much of.

So our interest was piqued when we spotted a study suggesting that, when it comes to oranges, juice might actually unlock more carotenoids and flavonoids – both beneficial phytonutrients — than an equivalent amount of fruit.

To figure that out, German and Saudi researchers started with a big batch of fresh navel oranges. They analyzed the fruit in three forms: peeled segments, a mashed-up puree and as juice, both fresh-squeezed and pasteurized. They found that levels of vitamin C and carotenoids were basically the same in the juice and the unprocessed fruit, while levels of flavonoids were significantly lower.

But then the scientists threw their orange test foods into in a test tube model designed to mimic digestion, and that's when things got interesting: Much more of the carotenoids and flavonoids were released from the orange juice than from the fruit slices or mush. The differences were striking: Carotenoid release went up from nearly 11 percent in the fruit to 28 percent in the fresh juice, and up to 39.5 percent in the pasteurized juice. Meanwhile, flavonoids were boosted nearly five-fold in juice compared to fruit.

The findings, which appear in the Journal of Agricultural and Food Chemistry, are scientifically intriguing. For example, the researchers suspect heat may have something to do with the extra carotenoids released in pasteurized juice....That said, the new study "is in line with other studies that have found that nutrients in some fruits and vegetables are more bioavailable when the produce is chopped, mashed, juiced or prepared with oils," Blumberg notes in an email to The Salt.

Indeed, there's a whole avenue of research that is challenging our understanding of how to unleash the nutrition fixed inside fruits and veggies. For instance, as we've reported, we get more beta-carotene from tomatoes when we add a little fat like olive oil, and gently cooking carrots can coax them to release more nutrients. And while cooking broccoli for too long can destroy its antioxidants, chopping it is ideal.