Monday, March 30, 2015

Health Benefits of Leafy Green Vegetables

A diet that includes plenty of green, leafy vegetables may lower the risk of glaucoma

A healthy lifestyle, consisting of balanced nutrition, moderate exercise, and appropriate rest is an important part of your overall health and well-being and can help prevent illness too.

The best way to ensure that you're getting all of your essential vitamins and minerals is to eat a balanced diet that includes fruits and vegetables -- they are a primary source of carotenoids, which can have overall benefits for vision health. Certain fruits and vegetables with higher vitamin A and C content have been shown to reduce glaucoma risk as well. Some of the most helpful fruits and vegetables for healthy vision are: collard greens, cabbage, kale, spinach, Brussels sprouts, celery, carrots, peaches, radishes, green beans, and beets.

Because oxidative stress is associated with damage to the optic nerve in glaucoma, antioxidants may help to prevent further injury. Dietary sources of antioxidants include pomegranate, acai berries, cranberries, dark chocolate, black and green tea, bilberry, lycopene (from tomato products), dark green leafy vegetables like kale and spinach, and flax seeds.

Any specific nutritional deficiencies in your diet can be addressed with supplements that include Vitamins A, B-complex, C, and E as well as the minerals Magnesium, Calcium and Zinc. However, there is no convincing data that vitamin supplements help to prevent glaucoma. I recommend that patients take a general multivitamin if they are uncertain whether their daily nutritional needs are met.

While good nutrition plays a role in disease prevention and overall health, it is not a treatment for glaucoma. Certain herbs such as ginkgo and bilberry may even increase the risk of bleeding with glaucoma surgery. Given the breadth of nutritional supplements available over-the-counter, it is important to discuss with your eye doctor all prescription, herbal, vitamin, mineral, and over-the-counter remedies you currently take. Talk to your doctor about any other questions related to glaucoma and your diet, exercise, and lifestyle choices.

Eating your greens could enhance sport performance

Nitrate supplementation in conjunction with Sprint Interval Training in low oxygen conditions could enhance sport performance a study has found.

Researchers from the University of Leuven in Belgium carried out a study with twenty-seven moderately trained participants. These were given nitrate supplements ahead of Sprint Interval Training (SIT), which took the form of short but intense cycling sessions three times a week.

Nitrate is commonly found in diets rich in leafy green foods, like spinach and is important for the functioning of the human body, especially during exercising.

To assess differences in performance in different conditions, the study included workouts in normal oxygen conditions and in hypoxia conditions, which are low oxygen levels such as those found in high altitudes.

The observations published in Frontiers in Physiology were unexpected: after only five weeks, the muscle fiber composition changed with the enhanced nitrate intake when training in low oxygen conditions.

"This is probably the first study to demonstrate that a simple nutritional supplementation strategy, i.e. oral nitrate intake, can impact on training-induced changes in muscle fiber composition;" stated Professor Peter Hespel from the Athletic Performance Center at the University of Leuven.

For athletes participating in sports competitions which require energy production in conditions with limited amounts of oxygen, this study is particularly interesting. In fact, exercising at high altitudes has become a training strategy for many athletes, albeit the uncertainties about such methods.

In these conditions, performing intense workouts requires high input of fast-oxidative muscle fibers to sustain the power. Enhancing these muscle fiber types through nutritional intake could very well boost the performance in this type of events.

However, this remains a question mark for the time being. "Whether this increase in fast-oxidative muscle fibers eventually can also enhance exercise performance remains to be established;" said Professor Hespel.

He cautioned: "consistent nitrate intake in conjunction with training must not be recommended until the safety of chronic high-dose nitrate intake in humans has been clearly demonstrated".

In times where athletes push the limits of their bodies and thrive for ever greater performances, this is clearly only the beginning of the research into how athletes can improve their competitive edge through dietary supplements. Looking to the future, Professor Hespel suggested: "it would now be interesting to investigate whether addition of nitrate-rich vegetables to the normal daily sports diet of athletes could facilitate training-induced muscle fiber type transitions and maybe in the long term also exercise performance".  

Leafy greens are essential for feeding good gut bacteria

A critical discovery about how bacteria feed on an unusual sugar molecule found in leafy green vegetables could hold the key to explaining how 'good' bacteria protect our gut and promote health.

The finding suggests that leafy greens are essential for feeding good gut bacteria, limiting the ability of bad bacteria to colonise the gut by shutting them out of the prime 'real estate'.

Researchers from Melbourne and the UK identified a previously unknown enzyme used by bacteria, fungi and other organisms to feed on the unusual but abundant sugar sulfoquinovose - SQ for short - found in green vegetables.

Each year, leafy green vegetables - such as spinach - produce the sugar on an enormous scale globally, comparable to the world's total annual iron ore production.

The research, published today in the journal Nature Chemical Biology, was led by Dr Ethan Goddard-Borger from the Walter and Eliza Hall Institute, Professor Spencer Williams from the Bio21 Institute and University of Melbourne, and Professor Gideon Davies from the University of York, UK.

Dr Goddard-Borger said the discovery could be exploited to cultivate the growth of 'good' gut bacteria. "Every time we eat leafy green vegetables we consume significant amounts of SQ sugars, which are used as an energy source by good gut bacteria," he said.

"Bacteria in the gut, such as crucial protective strains of E. coli, use SQ as a source of energy. E. coli provides a protective barrier that prevents growth and colonisation by bad bacteria, because the good bugs are taking up all the habitable real estate," Dr Goddard-Borger said.

"E. coli is a key bacterial coloniser needed by our gut. We speculate that consumption of this specific molecule within leafy greens will prove to be an important factor in improving and maintaining healthy gut bacteria and good digestive health."

Professor Williams said the team had revealed how bacteria extract the sugar from plants in order to fuel their growth. "We discovered the enzyme YihQ, which is used by bacteria to absorb and metabolise these sulfur-containing sugars as food," he said.

"Sulfur is critical for building proteins, the essential components of all living organisms. SQ is the only sugar molecule which contains sulfur, and 'digestion' of the molecule by bacteria releases sulfur into the environment, where it re-enters the global 'sulfur cycle' to be reused by other organisms."

Professor Williams said that the pathway was unusual, but abundant in biological organisms.

"This work answers a 50-year mystery that has surrounded how sulfur - an element essential for life on Earth - was used and recycled by living organisms," he said. "What is remarkable is that the YihQ enzyme was hiding in plain sight and is produced by the humble bacterium E. coli, present in nearly every biologist's laboratory."

The discovery also provides crucial insights that may one day be exploited to develop an entirely new class of antibiotics, Dr Goddard-Borger said. "New antimicrobial strategies are desperately needed as more and more bacteria acquire resistance to existing classes of antibiotics."

"We think it will be possible to use these widespread enzymes to enable highly specific delivery of antibiotics to harmful forms of E. coli and other pathogens, such as Salmonella, responsible for food poisoning, while leaving the good gut bacteria untouched."

Magnesium intake from dark, leafy greens or nuts may be beneficial in preventing pancreatic cancer

Indiana University researchers have found that magnesium intake may be beneficial in preventing pancreatic cancer.

Their study, "Magnesium intake and incidence of pancreatic cancer: The VITamins and Lifestyle study," recently appeared in the British Journal of Cancer.

Pancreatic cancer is the fourth leading cause of cancer-related death in both men and women in the United States. The overall occurrence of pancreatic cancer has not significantly changed since 2002, but the mortality rate has increased annually from 2002 to 2011, according to the National Cancer Institute.

"Pancreatic cancer is really unique and different from other cancers," said study co-author Ka He, chair of the Department of Epidemiology and Biostatistics at the IU School of Public Health-Bloomington. "The five-year survival rate is really low, so that makes prevention and identifying risk factors or predictors associated with pancreatic cancer very important."

Previous studies have found that magnesium is inversely associated with the risk of diabetes, which is a risk factor of pancreatic cancer. But few studies have explored the direct association of magnesium with pancreatic cancer; of those that did, their findings were inconclusive, said Daniel Dibaba, a Ph.D. student at the School of Public Health-Bloomington, who led the IU study.

Using information from the VITamins and Lifestyle study, Dibaba and the other co-authors analyzed an enormous trove of data on over 66,000 men and women, ages 50 to 76, looking at the direct association between magnesium and pancreatic cancer and whether age, gender, body mass index, non-steroidal anti-inflammatory drugs use and magnesium supplementation play a role.

Of those followed, 151 participants developed pancreatic cancer. The study found that every 100-milligrams-per-day decrease in magnesium intake was associated with a 24 percent increase in the occurrence of pancreatic cancer. The study also found that the effects of magnesium on pancreatic cancer did not appear to be modified by age, gender, body mass index or non-steroidal anti-inflammatory drug use, but was limited to those taking magnesium supplements either from a multivitamin or individual supplement.

"For those at a higher risk of pancreatic cancer, adding a magnesium supplement to their diet may prove beneficial in preventing this disease," Dibaba said. "While more study is needed, the general population should strive to get the daily recommendations of magnesium through diet, such as dark, leafy greens or nuts, to prevent any risk of pancreatic cancer."

Eating green leafy vegetables keeps mental abilities sharp


"Losing one's memory or cognitive abilities is one of the biggest fears for people as they get older," said Martha Clare Morris, Sc.D., assistant provost for community research at Rush University Medical Center and leader of the research team. "Since declining cognitive ability is central to Alzheimer's disease and dementias, increasing consumption of green leafy vegetables could offer a very simple, affordable and non-invasive way of potentially protecting your brain from Alzheimer's disease and dementia."

The researchers tracked the diets and cognitive abilities of more than 950 older adults for an average of five years and saw a significant decrease in the rate of cognitive decline for study participants who consumed greater amounts of green leafy vegetables. People who ate one to two servings per day had the cognitive ability of a person 11 years younger than those who consumed none.

When the researchers examined individual nutrients linked with slowing cognitive decline, they found that vitamin K, lutein, folate and beta-carotene were most likely helping to keep the brain healthy.

"Our study identified some very novel associations," said Morris, who will present the research at the American Society for Nutrition (ASN) Annual Meeting during Experimental Biology 2015. "No other studies have looked at vitamin K in relation to change in cognitive abilities over time, and only a limited number of studies have found some association with lutein." Other studies have linked folate and beta-carotene intake with slower cognitive decline.

To conduct the study, Morris' research team gathered data from 954 participants from the Memory and Aging Project, which aims to identify factors associated with the maintenance of cognitive health. The participants, whose age averaged 81, reported their daily food and beverage intake by answering a detailed 144-item questionnaire at the beginning of the study. The researchers computed the total daily nutrients by combining the nutrient content for each food consumed with the number of servings eaten each day. They followed participants for 2 to 10 years, assessing cognition annually with a comprehensive battery of 19 tests and adjusted for age, sex, education, smoking, genetic risk for Alzheimer's disease and participation in physical activities when estimating the effects of diet on cognitive decline.

"With baby boomers approaching old age, there is huge public demand for lifestyle behaviors that can ward off loss of memory and other cognitive abilities with age," said Morris. "Our study provides evidence that eating green leafy vegetables and other foods rich in vitamin K, lutein and beta-carotene can help to keep the brain healthy to preserve functioning."

In addition to green leafy vegetables, other good sources of vitamin K, lutein, folate and beta-carotene include brightly colored fruits and vegetables.

The researchers would like to expand their research to explore the mechanisms of how nutrients in leafy green vegetables are acting on the brain.

Lettuce is rich in antioxidants, as it contains compounds like phenolic acids, flavonoids, anthocyanins, and vitamins A and C

Antioxidants provide long-term protection against the chain reactions of free radical processes, in other words, of the molecules that are capable of causing cell damage and generating various diseases. Free radicals harm our body by causing, in the best of cases, ageing and, in the worse, serious diseases. Lettuce is rich in antioxidants, as it contains compounds like phenolic acids, flavonoids, anthocyanins, and vitamins A and C, among other things.

Green, semi-red and red leaves

To conduct this research, which started in 2011 and in which researchers of the UPV/EHU and the University of Pisa (Italy) have been participating, the compounds of three lettuce varieties were analysed: the green-leaf 'Batavia', the semi-red-leaf 'Marvel of Four Seasons', and the red-leaf 'Oak Leaf'. Using Electron Paramagnetic Resonance (EPR) techniques, they were able to observe the behaviour of the kinetics of the compounds of each variety. And the results show that the green-leaf lettuce contains water-soluble, antioxidant compounds that act at a slow and intermediate speed, the red-leaf one has compounds with intermediate and rapid kinetics, and the semi-red-leaf one has three kinds of compounds, with a rapid, intermediate and slow speed.

As Dr Pérez-López, researcher of the Department of Plant Biology and Ecology of the UPV/EHU's Faculty of Science and Technology, stressed, "the fact that there are compounds that act at different speeds does not mean that some are better or worse than others. If we eat foods that can generate free-radical activity, there will be some compounds that act to eliminate them more quickly. But at the same time, it is also important that our bodies should acquire foods with antioxidants that have slower kinetics so that the latter will continue to act over a longer period of time. That is why people say that it is very interesting to mix different types of lettuce because they have different, complementary characteristics".

Boosting the properties

Having determined the kinetics of the antioxidants, the research is currently continuing with the aim of achieving a nutraceutical improvement of these three varieties of lettuce. The research group is now trying to boost the effect of the specific compounds in each variety by subjecting the plants to short stresses. These compounds perform defence functions in plants. So if conditions that are not the normal ones are applied to them (such as watering them with salinated water, subjecting them to high lighting intensity or working with raised concentrations of CO2), these defences will become intensified and, as a result, the antioxidant qualities of the plants will be boosted.

"What matters in this process is not to lose productivity, and that is why we apply short-intensity stresses. With excessive stress, we could reach a point in which plant growth is reduced, and we are not interested in achieving greater quality at the cost of a reduction in size. The aim is to maintain production and achieve greater quality in this production," pointed out Dr Usue Pérez-López.

Leafy greens can prevent the ill-effects of toxins in foods like peanut butter

Not only are the vitamins and minerals good for you, but eating greens could also save your life, according to a recent study invoving scientists from Lawrence Livermore National Laboratory (LLNL).

LLNL researchers Graham Bench and Ken Turteltaub found that giving someone a small dose of chlorophyll (Chla) or chlorophyllin (CHL) — found in green leafy vegetables such as spinach, broccoli and kale — could reverse the effects of aflatoxin poisoning.

Aflatoxin is a potent, naturally occurring carcinogenic mycotoxin that is associated with the growth of two types of mold: Aspergillus flavus and Aspergillus parasiticus. Food and food crops most prone to aflatoxin contamination include corn and corn products, cottonseed, peanuts and peanut products, tree nuts and milk.

Bench and Turteltaub, working with colleagues from Oregon State University and an industry partner, Cephalon Inc., found that greens have chemopreventive potential.

Aflatoxins can invade the food supply at anytime during production, processing, transport and storage. Evidence of acute aflatoxicosis in humans has been reported primarily in developing countries lacking the resources to effectively screen aflatoxin contamination from the food supply. Because aflatoxins, particularly aflatoxin B1 (AFB1), are potent carcinogens in some animals, there is interest in the effects of long-term exposure to low levels of these important mycotoxins on humans.

The study used AMS to provide aflatoxin pharmacokinetic parameters previously unavailable for humans, and suggest that chlorophyll and chlorophyllin co-consumption may limit the bioavailability of ingested aflatoxin in humans, as they do in animal models, according to Bench.

Exposure to environmental carcinogens has been estimated to contribute to a majority of human cancers, especially through lifestyle factors related to tobacco use and diet. Notable examples are the tobacco-related carcinogens; heterocyclic amines produced from sustained, high-temperature cooking of meats; and the fungal food contaminants aflatoxins.

The team initially gave each of three volunteers a small dose of carbon 14 labeled aflatoxin (less than the amount that would be found in a peanut butter sandwich.) In subsequent experiments the patients were given a small amount of Chla or CHL concomitantly with the same dose of carbon 14 labeled aflatoxin.

By using LLNL’s Center for Accelerator Mass Spectrometry, the team was able to measure the amount of aflatoxin in each volunteer after each dosing regimen and determine whether the Chla or CHL reduced the amount of aflatoxin absorbed into the volunteers.

“The Chla and CHL treatment each significantly reduced aflatoxin absorption and bioavailability,” Bench said.

“What makes this study unique among prevention trials is, that we were able to administer a microdose of radio-labeled aflatoxin to assess the actions of the carcinogen directly in people. There was no extrapolation from animal models which often are wrong,” Turteltaub said.

Green leafy vegetables reduce diabetes risk

Eating more green leafy vegetables can significantly reduce the risk of developing type 2 diabetes, finds research published August, 2010 on

The authors, led by Patrice Carter at the University of Leicester, say there is a need for further investigation into the potential benefits of green leafy vegetables.

In the last two decades there has been a dramatic increase in the number of individuals developing type 2 diabetes worldwide.

Diets high in fruit and vegetables are known to help reduce both cancer and heart disease, but the relationship between fruit and vegetable intake and diabetes remains unclear, say the authors.

The researchers also note that previous research found that in 2002, 86% of UK adults consumed less than the recommended five portions of fruit and vegetables per day, with 62% consuming less than three portions. The study says that "it was estimated that inadequate consumption of fruit and vegetables could have accounted for 2.6 million deaths worldwide in the year 2000."

Patrice Carter and colleagues reviewed six studies involving over 220,000 participants that focused on the links between fruit and vegetable consumption and type 2 diabetes.

The results reveal that eating one and a half extra servings of green leafy vegetables a day reduces the risk of type 2 diabetes by 14%. However, eating more fruit and vegetables combined does not significantly affect this risk. Only a small number of studies were included in the meta-analysis and the benefit of fruit and vegetables as a whole for prevention of type 2 diabetes may have been obscured.

The authors believe that fruit and vegetables can prevent chronic diseases because of their antioxidant content. Green leafy vegetables such as spinach may also act to reduce type 2 diabetes risk due to their high magnesium content.

The authors argue that "our results support the evidence that 'foods' rather than isolated components such as antioxidants are beneficial for health … results from several supplement trials have produced disappointing results for prevention of disease."

In conclusion, they believe that offering tailored advice to encourage individuals to eat more green leafy vegetables should be investigated further.

In an accompanying editorial, Professor Jim Mann from the University of Otago in New Zealand, and Research Assistant Dagfinn Aune from Imperial College London, are cautious about the results and say the message of increasing overall fruit and vegetable intake must not be lost "in a plethora of magic bullets," even though green leafy vegetables clearly can be included as one of the five portions of fruit and vegetables per day.

They argue that given the limited number of studies, "it may be too early to dismiss a small reduction in risk for overall fruit and vegetable intake or other specific types of fruits and vegetables and too early for a conclusion regarding green leafy vegetables.

Eating green leafy vegetables reduces risk of diabetes

Eating just one more serving of green leafy vegetables or three more servings of fruit a day reduces the risk of developing Type II diabetes, according to results of data analysis performed by researchers in the Tulane School of Public Health and Tropical Medicine and the Harvard School of Public Health. The research team also found that one serving of fruit juice a day increased the risk of Type II diabetes in women.

Tulane epidemiologist Dr. Lydia Bazzano says, “Based on the results of our study, people who have risk factors for diabetes may find it helpful to fill up on leafy greens like lettuces, kale and spinach and whole fruits, like apples, bananas, oranges and watermelon rather than drink fruit juices, which deliver a big sugar load in a liquid form that gets absorbed rapidly.”

Bazzano, an assistant professor of epidemiology, cautioned that since this is one of the first studies to separate fruit juice consumption from fruits as a whole, the association between juice and diabetes must be confirmed by additional research.

She and her team analyzed 18 years worth of diet and health data from 71,346 nurses who participated in the Nurses’ Health Study from 1984 to 2002. The women were all between 38 and 63 years old and diabetes-free when the study began. Approximately 7 percent of the participants developed diabetes over the course of the study.

The researchers determined that the association between fruit and green leafy vegetable consumption and lowered diabetes risk remained after other factors, such as family history, cigarette smoking and weight, were analyzed. However, they found that women who ate more fruits and green leafy vegetables also were likely to be older, non-smokers and more physically active.

In addition to emphasizing the importance of eating whole fruits and green leafy vegetables to prevent diabetes, the team also recommends replacing refined grains and white potatoes with whole fruit or green leafy vegetable servings. White flours and potatoes have been associated with an increased risk of diabetes.

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