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Published on Leave a comment on Reduce Your Risk Of Diabetes By Eating Whole Grains, Fruits, and Vegetables

Want to reduce your risk of getting type 2 diabetes? Two large studies published in the British Medical Journal (BMJ)  found that eating fruits, vegetables, and whole grains really reduces the risk of type 2 diabetes.

The first study (which took data from 3 large American studies) found that persons eating the most whole grain foods (when compared to those eating the least) had a 29% lower risk in developing type 2 diabetes over the next 24 years. Whole grain foods included: whole grain breakfast cereal, oatmeal, dark bread, brown rice, bran, wheat germ, and popcorn. The good results were from eating just two servings a day of whole grains.

A European study didn't just ask people what they ate, but actually measured the level of plasma vitamin C and carotenoids (from fruits and vegetables eaten) in the blood. Those with higher values had a lower incidence of type 2 diabetes over a 10 year period, with the highest group having a 49% lower risk of type 2 diabetes.

Current guidelines recommend eating at least 5 servings of fruits and vegetables each day, which is equivalent to eating 400 g or more per day. Many people don't eat nearly enough servings, as was seen in the study. Fruit and vegetable intake in the study  was divided into 5 groups, with median consumption ranging from 274 g (lowest), 357 g, 396 g, 452 g, to 508 grams (highest) per day.

The good news was that increasing fruit and vegetable consumption by just 66 grams (3/4 cup) per day was associated with a 25% lower risk of developing diabetes. So even a small  increase in fruit and vegetable consumption could help prevent type 2 diabetes!

By the way, there are also other health benefits from eating whole grains. Higher consumption lowers the risk of developing several major chronic diseases, including cardiovascular disease, obesity, and some types of cancer.

From Science Daily: Higher fruit, vegetable and whole grain intake linked to lower risk of diabetes

Higher consumption of fruit, vegetables and whole grain foods are associated with a lower risk of developing type 2 diabetes, according to two studies published by The BMJ today.
...continue reading "Reduce Your Risk Of Diabetes By Eating Whole Grains, Fruits, and Vegetables"

Published on Leave a comment on Eat Fruits And Vegetables Every Day!

Another reason to eat fruits and vegetables daily - cognitive and memory functioning in later life. A large US study of 27,842 men found that a higher intake of fruits, vegetables, and orange juice for many years is linked to a lower risk of poor cognitive functioning in later years of life (70s and beyond). The study specifically looked at subjective cognitive function - a measure of earliest changes in cognitive functioning, including memory. This is the stage before "mild cognitive impairment". The study started in 1986 when the average age was 51 years, and continued till 2012. The men studied were all health professionals (e.g. dentists)

What was a high intake of fruits and vegetables? For vegetables: about 5.7 servings per day (while the lowest intake was 1.7 servings per day). For fruit: high intake was 3.1 servings per day (vs lowest intake was .5 servings per day). For fruit juice (orange juice): high intake was 1.5 servings per day (vs lowest intake was .1 servings per day). A serving of fruit is considered one cup of fruit or ½ cup of fruit juice. A serving of vegetables is considered one cup of raw vegetables or two cups of leafy greens.

The researchers found that green leafy vegetables, carotenoid-rich vegetables (esp. tomatoes and peppers), cantalope, berries, and orange juice to be especially protective. They point out that many antioxidant nutrients and bioactive substances (including vitamins A,B, C, and E, carotenoids, flavonoids, and polyphenols) are all found naturally in vegetables, fruits, and juices. These are thought to reduce brain oxidative stress, improve cognitive performance, and to prevent neuronal damage. In other words, all good things for the brain. From Science Daily:

Orange juice, leafy greens and berries may be tied to decreased memory loss in men

Eating leafy greens, dark orange and red vegetables and berry fruits, and drinking orange juice may be associated with a lower risk of memory loss over time in men, according to a study published in the November 21, 2018, online issue of Neurology, the medical journal of the American Academy of Neurology.  ...continue reading "Eat Fruits And Vegetables Every Day!"

Published on Leave a comment on Fruits, Vegetables, and Whole Grains Lower Inflammation

Chronic low-grade inflammation in humans is drawing a lot of interest because it is linked to so many diseases (diabetes, cancer, etc). Key ways to lower this inflammation appear to be losing weight (if overweight), exercising, not smoking, and eating a healthy diet rich in fruits, vegetables, whole grains, nuts, and seeds (thus lots of fiber). Research also shows that the type of diet a person generally eats has an effect on the composition of gut microbes (you want to feed beneficial microbes!). But which is more important for health and lowering inflammation - whole grains or fruits and vegetables or neither?

A recent study attempted to answer this question. They put 49 overweight or obese individuals, who typically ate low amounts of fruits, vegetables, and whole grains (less than 1 serving per day), into 1 of the following 3 groups for 6 weeks: 1) Whole grains (WG), 2) Fruits and vegetables (FV), and 3) a Control group (who ate refined grains). All persons were given 3 servings per day of "treatment" foods to eat at home, but the rest of their Western style diets stayed the same. The individuals did not all consume the same foods, but rather consumed their choice of foods from their group's food category.

The researchers collected blood and stool samples (both at the beginning of the study and after 6 weeks) to measure inflammation levels, and types of microbes and fatty acids in the gut. Inflammatory markers that they measured were: tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP), and high sensitivity C-reactive protein (hs-CRP).

The researchers found an increase in microbial diversity in the FV group (perhaps due to the new variety of fibers in the fruits and vegetables), but otherwise there were no significant changes in gut microbiome composition among the groups. [Note: but each group had only some dietary changes, not drastic changes]

The researchers found that whole grains and fruits and vegetables lowered markers of inflammation - but each treatment (FV or WG) lowered different types of inflammation markers. And note that for the fruit/vegetable group - the 3 servings per day, was still below government recommendations of 5 servings per day for adults. And the rest of their diet was the same Western diet that they normally ate. So the whole grains or fruits and vegetables were not major dietary changes. And yet there were positive changes - lowering of inflammation.

So the final answer is that it is best for your health  (and gut microbes) to eat a diet rich in fruits, vegetables, and also whole grains. And they didn't even mention legumes, nuts, and seeds - all high fiber foods with lots of micronutrients, and known to be good for beneficial gut microbes. So yes, eat them also. What was a serving in this study? 1 serving = 1 cup fruits or vegetables, and 1 serving = 1 oz of whole or refined grains.  ...continue reading "Fruits, Vegetables, and Whole Grains Lower Inflammation"

Published on Leave a comment on Eating Lots of Fruits and Vegetables Associated With a Lower Breast Cancer Risk Years Later

A decades long study (from the Harvard T.H. Chan School of Public Health) had results that many women may find reassuring - because there may be something they can do to increase their odds of preventing breast cancer. The study found that women who ate more than 5.5 servings of fruits and vegetables each day had an 11% lower risk of breast cancer than those who ate 2.5 or fewer servings daily.

While the findings support eating a variety of fruits and vegetables, they found that cruciferous (broccoli, cabbage, cauliflower) and yellow/orange vegetables (e.g. winter squash) appear to be especially beneficial in reducing the risk of breast cancer, especially those that are more aggressive tumors. The association between amount of fruits and vegetables eaten daily  and breast cancer appeared to be strongest 8 or more years before cancer diagnosis - meaning fruit and vegetable intake now appears to have effects many years later.

By the way, the researchers found in earlier research that a higher fiber intake (especially during adolescence and early adulthood) was also associated with a lower beast cancer risk. Now let's see if these findings hold up over time in other studies. From Science Daily:

High fruit and vegetable consumption may reduce risk of breast cancer

Women who eat a high amount of fruits and vegetables each day may have a lower risk of breast cancer, especially of aggressive tumors, than those who eat fewer fruits and vegetables, according to a new study led by researchers from Harvard T.H. Chan School of Public Health. In their findings, cruciferous vegetables such as broccoli, and yellow and orange vegetables, had a particularly significant association with lower breast cancer risk.  ...continue reading "Eating Lots of Fruits and Vegetables Associated With a Lower Breast Cancer Risk Years Later"

Published on Leave a comment on Ten Portions of Fruits and Vegetables Daily?

 This past week a study was published linking 8 to 10 portions of fruits and vegetables per day with a lower risk of early death, cancer, heart disease, and stroke. This confirms other research linking many daily servings of fruits and vegetables with various health benefits. For example, the study findings discussed in the Nov. 2, 2016 post: "Eating lots of fruits and vegetables (more than 10 servings a day!)  is linked to better cognitive functioning in both normal weight and overweight adults (both young and older adults), and may delay the onset of cognitive decline that occurs with aging and also dementia."

This new study led by researchers from the Imperial College London reviewed 95 previous studies of the relationship between diet and health. They found that people who ate 10 portions of fruits and vegetables a day had nearly a third lower risk of premature death and stroke than those who ate very little or no fruits and vegetables. The researchers pointed out that as the amount of fruits and vegetables eaten daily went up, the health benefits also increased (lower risk of heart disease, stroke, cardiovascular disease, cancer), and the risk of premature death decreased - thus a dose related relationship. So better to eat some fruits and vegetables than none! A portion is about 80 grams, equivalent to a medium apple, 1 banana, or generally about 1/2 cup of vegetables or fruits.

From Science Daily: Eating up to ten portions of fruit and vegetables a day may prevent 7.8 million premature deaths worldwide

A fruit and vegetable intake above five-a-day shows major benefit in reducing the chance of heart attack, stroke, cancer and early death. This is the finding of new research, led by scientists from Imperial College London, which analysed 95 studies on fruit and vegetable intake....the greatest benefit came from eating 800 g a day (roughly equivalent to ten portions -- one portion of fruit or vegetables if defined as 80 g).

The results revealed that even a daily intake of 200 g was associated with a 16 per cent reduced risk of heart disease, an 18 per cent reduced risk of stroke, and a 13 per cent reduced risk of cardiovascular disease. This amount, which is equivalent to two and a half portions, was also associated with 4 per cent reduced risk in cancer risk, and 15 per cent reduction in the risk of premature death. Further benefits were observed with higher intakes. Eating up to 800 g fruit and vegetables a day -- or 10 portions -- was associated with a 24 per cent reduced risk of heart disease, a 33 per cent reduced risk of stroke, a 28 per cent reduced risk of cardiovascular disease, a 13 per cent reduced risk of total cancer, and a 31 per cent reduction in dying prematurely. This risk was calculated in comparison to not eating any fruit and vegetables. [Original study.]

Published on Leave a comment on Why Eat More Than Ten Servings of Fruits and Vegetables Daily?

  Eating lots of fruits and vegetables (more than 10 servings a day!)  is linked to better cognitive functioning in both normal weight and overweight adults (both young and older adults), and may delay the onset of cognitive decline that occurs with aging and also dementia. Overweight and obese older adults with a daily fruit and vegetable consumption of less than 5 servings generally had worse cognitive functioning. Higher levels of physical activity and higher daily fruit and vegetable consumption were both associated with better cognitive functioning. Cognitive functioning generally refers to a person’s ability to reason and think, the mental processes needed to gather and process information, and all aspects of language and memory.

The York University researchers found that fruit and vegetable consumption, physical activity, and BMI or body mass index (normal, overweight, obese) all appear to interact in how a person mentally functions (cognitive functioning), especially as they age. The ideal goal as one ages is to preserve the mind. It appears that eating lots of fruits and vegetables daily (10 or more servings), being physically active (this includes daily walks), and being a healthy weight help with this goal. It helps to also be highly educated (or read books?) so that the brain has a "cognitive reserve",

Why is daily fruit and vegetable consumption (FVC) good for cognitive functioning and the brain? Studies find that daily consumption of fruits and vegetables is strongly associated with a reduced risk of cardiovascular disease, cancer, diabetes and age-related declines. They appear to be "protective" against cognitive decline. The study researchers point out that fruits and vegetables contain high quantities of vitamin C and E, fiber, micronutrients, flavonoids, beta-carotenes and other classes of phytochemicals. These are important in various ways: "they modulate detoxifying enzymes, stimulate the immune system, modulate cholesterol synthesis, and act as antibacterial, antioxidant or neuroprotective agents." NOTE: A serving of fruit is generally 1 medium fruit or 1/2 cup of fruit. A serving of vegetables is 1 cup of raw leafy greens or 1/2 cup of other vegetables. From Medical Xpress:

Healthy living linked to higher brain function, delay of dementia

It's tempting to dip into the leftover Halloween treats, but new research out of York University has found eating plenty of fruits and vegetables, combined with regular exercise, leads to better cognitive functioning for younger and older adults, and may delay the onset of dementia. York U post-doctoral fellow Alina Cohen and her team, including Professors Chris I. Ardern and Joseph Baker, looked at cross-sectional data of 45,522 participants, age 30 to 80+, from the 2012 annual component of the Canadian Community Health Survey.

What they found was that for those who are normal weight or overweight, but not obese, eating more than 10 servings of fruit and vegetable daily was linked to better cognitive functioning. When moderate exercise was added, those eating less than five servings, reported better cognitive functioning. Higher levels of physical activity were linked to the relationship between higher daily fruit and vegetable consumption and better cognitive performance. Those with higher body mass indexes, low activity levels and fruit and vegetable consumption were associated with poorer cognitive functioning.

More details from the original study in the Journal of Public Health: Physical activity mediates the relationship between fruit and vegetable consumption and cognitive functioning: a cross-sectional analysis

Results: Higher BMIs, lower PA [physical activity] and FVC [fruit and vegetable consumption] were associated with poorer cognitive functioning. Additionally, PA statistically mediated the relationship between FVC and cognitive function (Sobel test: t = −3.15; P < 0.002); and higher education levels and daily FVC were associated with better cognitive function (P < 0.001). Conclusion: Higher PA levels were associated with better cognitive functioning in younger and older adults. Also, higher daily FVC and education levels were associated with better cognitive scores.

Individuals who were normal weight or overweight and reported a FVC of >10 servings per day reported better cognitive functioning scores than those who reported <10 servings, as well as those individuals with obesity . As well, both active and inactive individuals who reported a FVC of >10 servings per day had better cognitive scores than those who consumed fewer servings. However, in those who were moderately active, individuals with a daily FVC of <5 or 5–10 servings reported better cognitive functioning than those with a daily FVC of 10 or more servings; this may have resulted because of underestimations of the number of servings of fruits and vegetables actually consumed... Thus, increasing FVC and PA levels as well as having a healthy BMI may aid in the delay of cognitive decline.

Results also indicated that higher education levels along with a daily FVC of five or more servings were associated with better cognitive functioning. Education may be assisting in the process of delaying cognitive decline by increasing cognitive reserve, the ability of the human brain to cope with damage by using different brain processes to retain the ability to function well. Cognitive reserve is developed through intellectual stimulation and translates into a higher volume of connections between neurons and stronger rates of cerebral blood flow.

Published on Leave a comment on Diet May Affect Body’s Biological Age

This study found that people with high red meat intake, combined with low fruit and vegetable intake and a poor overall diet (which was found most frequently in males of low socioeconomic status) had biological markers indicating accelerated aging and poor renal function (early indicators of chronic kidney disease). Bottom line: eat less red meat, more whole grains, more fruits and vegetables for your health. From Medical Xpress:

Too much red meat and too few vegetables may increase your body's biological age

A diet containing too much red meat and not enough fruit and vegetables could increase your body's 'biological age' and contribute to health problems. Research led by the University of Glasgow and published today in Aging, has found that a moderate increase in serum phosphate levels caused by red meat consumption, combined with a poor overall diet, increases biological age (miles on the clock) in contrast to chronological age (years of age).
The study, which looked at participants from the most deprived to the least deprived in the NHS Greater Glasgow Health Board area, also demonstrates that deprived males were the worst affected.

Data from the study suggests that accelerated biological ageing, and dietary derived phosphate levels among the most deprived males, were directly related to the frequency of red meat consumption. Researchers believe that excess red meat particularly affects this group because of their poor diet and "sub-optimal fruit and vegetable intake".
The research, led by the Institute of Cancer Sciences in collaboration with the Karolinska Institutet (Stockholm, Sweden), also found that high phosphate levels in deprived males correlated with reduced kidney function and even underlying mild to moderate chronic kidney disease.

Phosphate is naturally present in basic foodstuffs, including meats, fish, eggs, dairy products and vegetables. Intestinal absorption of naturally occurring phosphate is minimally regulated, as absorption is efficient, hence high supplementation results in markedly elevated levels of serum phosphate, which can have adverse health consequences. Indeed high phosphate levels, as a consequence of dietary intake, have already been linked to higher all-cause and cardiovascular mortality risk, premature vascular ageing and kidney disease.

The researchers observed significant relationships between serum phosphate and biological age markers, including DNA content and telomere length. (Original study.)

Published on Leave a comment on Could Apigenin Be Considered a Brain Food?

The important thing learned from this study (though it was done in the laboratory and not directly on humans) is that it supports that apigenin (in the same chemical group as flavonoids) is important for neuron formation and for strengthening connections between brain cells. Flavonoids are known to positively affect memory and learning, and to preserve and enhance brain function. Apigenin is found in many fruits and vegetables, but common sources are parsley, celery, celeriac, thyme, chamomile, grapefruit, onions, oranges, red wine, and spices such as rosemary, oregano, thyme, basil, and coriander. Another good reason to eat a variety of fruits and vegetables. From Medical Xpress:

Plant compound found in spices and herbs increases brain connections

Brazilian researchers from D'Or Institute for Research and Education (IDOR), Federal University of Rio de Janeiro (UFRJ) and Federal University of Bahia (UFBA) have demonstrated in laboratory that apigenin, a substance found in parsley, thyme, chamomile and red pepper, improves neuron formation and strengthens the connections between brain cells.

Previous experiments with animals had already shown that substances from the same chemical group as the apigenin, known as flavonoids, positively affect memory and learning. Many studies highlight the potential of flavonoids to preserve and enhance brain function. While the effectiveness of flavonoids for brain health is not an entirely new concept, this research is the first to show the positive effects of apigegin directly on human cells and the first to unraveling its mechanism.

The scientists observed that just by applying apigenin to human stem cells in a dish they become neurons after 25 days - an effect they would not see without the substance. Moreover, the neurons that were formed made stronger and sophisticated connections among themselves after being treated with this natural compound."Strong connections between neurons are crucial for good brain function, memory consolidation and learning", says neuroscientist from IDOR and UFRJ Stevens Rehen, leader author of the paper published today atAdvances in Regenerative Biology.

The research team conducted by Rehen demonstrated that apigenin works by binding to estrogen receptors, which affect the development, maturation, function, and plasticity of the nervous system. This group of hormones is known to delay the onset of psychiatric and neurodegenerative disorders such as schizophrenia, depression, Alzheimer's and Parkinson's disease. However, the use of estrogen-based therapies is limited by the increased risk of estrogen-dependent tumors and cardiovascular problems.

Researchers believe apigenin can be used as an alternative approach on future treatments for neurodegenerative diseases as well as in neuronal differentiation strategies in laboratory. "We show a new path for new studies with this substance", points out Rehen. "Moreover, flavonoids are present at high amounts in some foods and we can speculate that a diet rich in flavonoids may influence the formation of neurons and the way they communicate within the brain."

Published on Leave a comment on Vegetables and Fruits Linked to Eye Health

A new study that tracked people more than 20 years found that a diet high in carotenoids - found in brightly colored fruits and vegetables (such as carrots, orange peppers, spinach, broccoli) - is linked to lower levels of macular degenaration (an age linked vision ailment).

Note that the link is found with real foods and not supplements (the researchers did not look at supplements). From Medical Xpress:

Carrots do help aging eyes, study shows

Your parents may have told you, "Eat your carrots, they're good for your eyes," and a new study suggests they were on to something. Pigments called carotenoids—which give red or orange hues to carrots, sweet potatoes and orange peppers, or deep greens to produce like spinach, broccoli and kale—may help ward off the age-linked vision ailment known as macular degeneration, researchers said.

Age-related macular degeneration (AMD) is one of the most common causes of vision loss, especially in the elderly. It affects the macula, the center part of the retina, and can lead to declines in sharp central vision and even blindness, experts say. 

Scientists have already linked a variety of factors to the condition including genetics, smoking and nutrition, said Bernstein, who was not involved in the new study. Prior research has produced mixed findings about links between carotenoids and macular degeneration, the researchers said. 

In the new study, Wu's team looked at data from health surveys that tracked people aged 50 and older—more than 63,000 women and almost 39,000 men—from 1984 or 1986 until 2010. Participants were all nurses and other health professionals. Overall, about 2.5 percent of study participants developed either intermediate or advanced forms of the eye condition during the years of the study.

Wu's team found that people who consumed the very highest levels of carotenoids known as lutein and zeaxanthin had a 40 percent lower risk of the advanced form of AMD compared to those who ate the veryleast. " Other carotenoids, including beta cryptoxanthin, alpha carotene and beta carotene, may also play protective roles," Wu added. People who consumed the very highest amount of these carotenoids—found in foods such as carrots and sweet potato—had a 25 to 35 percent lower risk of the advanced form of the illness, the findings showed.

Researchers did not find any link between the carotenoids and the intermediate form of macular degeneration, however. Lutein is found in eggs and dark leafy vegetables including broccoli, kale and spinach, Bernstein said. Zeaxanthin is harder to find in the diet, he said, but you can get it from corn, orange peppers and goji berries. Wu noted that both lutein and zeaxanthin concentrate in the macula, where they are thought to protect it from damage from oxygen and light.

Bernstein cautioned that the study has some weaknesses. It's based on people's recollections of their diets, he said, and doesn't examine the levels of the carotenoids that actually made it into their bodies and eyes. Still, he praised the research.... However, he said, a diet high in fruits and vegetables is important, especially colorful vegetables. Consume several servings a day, he advised.

Published on Leave a comment on Lots of Diverse Bacteria On Fresh Produce

 There has been tremendous concern in recent years over pathogenic bacteria (such as Salmonella and Escherichia coli) found on raw fruits and vegetables. But what about nonpathogenic bacteria? Aren't some of the benefits of eating raw fruits and vegetables the microbes found on them? What actually is on them?

The following research using modern genetic analysis (16 S rRNA gene pyrosequencing) is from 2013, but very informative and the only study that I could find of its kind. The results suggest that humans are exposed to substantially different bacteria depending on the types of fresh produce they consume, with differences between conventionally and organically farmed varieties contributing to this variation.

While each of the 11 produce types studies harbored different microbial communities, the most common (abundant) across all samples were: Enterobacteriaceae [30% (mean)], Bacillaceae (4.6%), and Oxalobacteraceae (4.0%). Earlier studies also suggested that non-pathogenic microbes may interact with and inhibit microbial pathogens found on produce surfaces. Bottom line: eat a variety of raw fruits and vegetables to get exposed to a variety of non pathogenic microbes.

From Science Daily: Diverse bacteria on fresh fruits, vegetables vary with produce type, farming practices

Fresh fruit and vegetables carry an abundance of bacteria on their surfaces, not all of which cause disease. In the first study to assess the variety of these non-pathogenic bacteria, scientists report that these surface bacteria vary depending on the type of produce and cultivation practices. The results are published March 27 in the open access journal PLOS ONE by Jonathan Leff and Noah Fierer at the University of Colorado, Boulder.

The study focused on eleven produce types that are often consumed raw, and found that certain species like spinach, tomatoes and strawberries have similar surface bacteria, with the majority of these microbes belonging to one family. Fruit like apples, peaches and grapes have more variable surface bacterial communities from three or four different groups. The authors also found differences in surface bacteria between produce grown using different farming practices.

The authors suggest several factors that may contribute to the differences they observed, including farm locations, storage temperature or time, and transport conditions. These surface bacteria on produce can impact the rate at which food spoils, and may be the source of typical microbes on kitchen surfaces. Previous studies have shown that although such microbes don't necessarily cause disease, they may still interact with, and perhaps inhibit the growth of disease-causing microbes. The results of this new research suggest that people may be exposed to substantially different bacteria depending on the types of produce they consume.

Excerpts of the actual study from PLoS One:  Bacterial Communities Associated with the Surfaces of Fresh Fruits and Vegetables

Fresh fruits and vegetables can harbor large and diverse populations of bacteria. However, most of the work on produce-associated bacteria has focused on a relatively small number of pathogenic bacteria....Our results demonstrated that the fruits and vegetables harbored diverse bacterial communities, and the communities on each produce type were significantly distinct from one another. However, certain produce types (i.e., sprouts, spinach, lettuce, tomatoes, peppers, and strawberries) tended to share more similar communities as they all had high relative abundances of taxa belonging to the family Enterobacteriaceae when compared to the other produce types (i.e., apples, peaches, grapes, and mushrooms) which were dominated by taxa belonging to the Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria phyla. ...Taken together, our results suggest that humans are exposed to substantially different bacteria depending on the types of fresh produce they consume with differences between conventionally and organically farmed varieties contributing to this variation.

Fresh produce, including apples, grapes, lettuce, peaches, peppers, spinach, sprouts, and tomatoes, are known to harbor large bacterial populations [1]–[7], but we are only just beginning to explore the diversity of these produce-associated communities. We do know that important human pathogens can be associated with produce (e.g., L. monocytogenes, E. coli, Salmonella), and since fresh produce is often consumed raw, such pathogens can cause widespread disease outbreaks [8]–[11]. In addition to directly causing disease, those microbes found in produce may have other, less direct, impacts on human health. Exposure to non-pathogenic microbes associated with plants may influence the development of allergies [12],and the consumption of raw produce may represent an important means by which new lineages of commensal bacteria are introduced into the human gastrointestinal system. 

Although variable, taxonomic richness levels differed among the eleven produce types with richness being highest on peaches, alfalfa sprouts, apples, peppers, and mushrooms and lowest on bean sprouts and strawberries (Fig. 1). Bacterial communities were highly diverse regardless of the produce type with between 17 and 161 families being represented on the surfaces of each produce type. However, the majority of these families were rare; on average, only 3 to 13 families were represented by at least two sequences per produce type.

Furthermore, pairwise tests revealed that the community composition on the surface of each produce type differed significantly from one another. Still, certain produce types shared more similar community structure than others. On average, tree fruits (apples and peaches) tended to share communities that were more similar in composition than they were to those on other produce types, and produce typically grown closer to the soil surface (spinach, lettuce, tomatoes, and peppers) shared communities relatively similar in composition. Surface bacterial communities on grapes and mushrooms were each strongly dissimilar from the other produce types studied.