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Published on Leave a comment on Beneficial Foods: Blackberries, Red Raspberries, and Black Raspberries

It seems that a lot has been written about the health benefits of some berries, such as blueberries, while other berries have been neglected. This study focused on red raspberries, black raspberries, and blackberries. While the study was done in Poland, it was pointed out that these berries are also commonly grown in the USA. Red raspberry, black raspberry, and blackberry fruits are abundant in dietary phytochemicals such as flavonols, phenolic acids, ellagitannins, vitamins C and E, folic acid, and β-sitosterol. Many of these bioactive compounds exhibit antioxidant activity. Anthocyanins and other phenolic compounds such as ellagitannins and ellagic acid, which distinguish raspberry from other berries, occur in high levels and are mainly responsible for their broad beneficial health properties (including anti-inflammatory, antimicrobial, and antiviral activities).

For these reasons, the researchers said that "raspberry and blackberry fruits can be regarded as natural functional foods". Another term for functional foods is nutraceutical, which is a food containing health-giving additives and having medicinal benefit. From Science Daily:

Looking for the best antioxidant fruit? Search no further than black raspberries

As far as healthy foods go, berries make the top of the list. They contain potent antioxidants, which decrease or reverse the effects of free radicals -- natural byproducts of energy production that can play havoc on the body and that are closely linked with heart disease, cancer, arthritis, stroke or respiratory diseases.

Unsurprisingly, the benefits of berries are extoled in one study after another....The research published now in Open Chemistry suggests that black raspberries grown in Central Europe show greater health benefits than their better known cousins -- raspberries or blackberries.

A group of researchers led by Anna Małgorzata Kostecka-Gugała measured the content of phenolics and anthocyanins in black raspberries, red raspberries and blackberries, assessing their antioxidant potential and health benefits. They were able to confirm that the antioxidant activity of natural products correlates directly with their health promoting properties.

It turns out that the amount of antioxidants in black raspberries was three times higher than the other fruits under investigation. Remarkably, the number was even higher for phenolics or the amount of anthocyanines -- with black raspberries topping their humble cousins by over 1000%. But most interestingly, black raspberries seem to be characterized by a higher content of secondary metabolites, which have been proved beneficial for human health.

Published on Leave a comment on Can Cruciferous Vegetables Fight Cancer?

Reading this recent study, I was struck by how the results are evidence for eating sulforaphane containing foods, such as kale, cauliflower, brussels sprouts, broccoli, and cabbage for health and preventing cancer (due to anti-tumor activity). It is debatable whether it is support for taking supplements (here a sulforaphane supplement called BSE), even though the researchers were testing the supplement. Seven days of taking a supplement without "serious adverse events" (but they did have minor ones such as "mild abdominal discomfort") is too short a length of time for any support for a product. The real test would be seeing what health effects, both positive and negative, are after a year or two of taking the supplement.

Numerous other studies have found that eating foods are linked to good health, while taking supplements are linked to various health problems. Some scientists speculate that it's because the doses in supplements are too high - that they're much higher than what is found in foods. Also, supplements may be missing important nutrients that are found in foods. Bottom line: eat real foods for health and and cancer prevention, including several servings a week of cruciferous vegetables (cauliflower, cabbage, garden cress,bok choy, broccoli, brussels sprouts and similar green leaf vegetables). From Futurity:

Can A Broccoli Sprout Pill Fight Cancer?

A compound in broccoli sprouts may not only help prevent cancer but also treat it. Sulforaphane is found in vegetables such as kale, cauliflower, and cabbage—and in particularly high concentrations in young broccoli sprouts. Sulforaphane also is available as a dietary supplement called BSE.

Researchers at the Texas A&M Health Science Center Institute of Biosciences and Technology, along with collaborators in Oregon, had previously found that sulforaphane could inhibit colon and prostate cancer cells in the laboratory. They’ve now shown that it seems to help humans as well. A paper published in the journal Clinical Epigenetics hints at the biological pathways involved and suggests BSE is generally safe.

“We have not seen any serious adverse events in healthy volunteers who consumed BSE pills for seven days,” says Praveen Rajendran, an assistant professor at Texas A&M University, although some people did experience mild abdominal discomfort.

In a separate clinical study, 28 human volunteers over the age of 50, who were undergoing routine colonoscopies, were surveyed for their cruciferous vegetable-eating habits. When their colon biopsies were examined, those who ate more servings were found to have higher levels of expression of the tumor suppressor gene p16 than those who ate few or no cruciferous vegetables.

This effect on p16 held even for people who didn’t eat these vegetables every single day, which may seem strange, as a single serving of sulforaphane is generally cleared from the body in less than 24 hours. “This hints at the possibility that epigenetic mechanisms are initially triggered by sulforaphane and its metabolites, and downstream mechanisms could be sustained, at least in the short-term, even after compounds are eliminated from the body.” In other words, eating vegetables containing sulforaphane may change your genes and help your body fight tumor growth.

However, it’s not all good news. In animal models, sulforaphane was shown to generally inhibit the development of colon cancer, but it’s a bit of a two-edged sword. Sulforaphane induces a protein called Nrf2, which has beneficial antioxidant and detoxifying effects—and is obviously good for fighting cancer. Later in the development of cancer, though, Nrf2 can also have a role in tumor growth and can even enhance the buildup of plaque in the arteries.

Published on Leave a comment on Early Pesticide Exposure Linked to Poorer Lung Function

 Just a few years ago the type of pesticide (organophosphate, for example chlorpyrifos) looked at in this study was commonly used everywhere - in schools, homes, agriculture. It was easy to buy in stores (e.g., Raid spray), and was considered "safer" than older pesticides. Over time problem after problem has been found with them - with the latest being decreased lung function in children exposed to organophosphates early in life.

Keep in mind that with all current pesticides we know very little about long-term effects, especially on developing fetuses and children, and so we should be very, very careful about using them and avoid unnecessary use. Yes, that means using them for harmless lawn weeds is an unnecessary use. Common lawn weeds can not give a person cancer, birth defects, health problems, or illnesses, but pesticides can. From Medical Xpress:

Weaker breaths in kids linked to early pesticide exposure

Taking a deep breath might be a bit harder for children exposed early in life to a widely used class of pesticides in agriculture, according to a new paper by researchers at the University of California, Berkeley. A new study has linked the levels of organophosphate pesticide metabolites in the urine of 279 children living in California's Salinas Valley with decreased lung function. Each tenfold increase in concentrations of organophosphate metabolites was associated with a 159-milliliter decrease in lung function, or about 8 percent less air, on average, when blowing out a candle. The magnitude of this decrease is similar to a child's secondhand smoke exposure from his or her mother.

"Researchers have described breathing problems in agricultural workers who are exposed to these pesticides, but these new findings are about children who live in an agricultural area where the organophosphates are being used," said study senior author Brenda Eskenazi, a professor of epidemiology and of maternal and child health. "This is the first evidence suggesting that children exposed to organophosphates have poorer lung function."

The children were part of the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal study in which the researchers follow children from the time they are in the womb up to adolescence. The researchers collected urine samples five times throughout the children's lives, from age 6 months to 5 years, and measured the levels of organophosphate pesticide metabolites each time. When the children were 7 years old, they were given a spirometry test to measure the amount of air they could exhale.

"The kids in our study with higher pesticide exposure had lower breathing capacity," said study lead author Rachel Raanan, who conducted the research while she was a postdoctoral scholar in Eskenazi's lab. "If the reduced lung function persists into adulthood, it could leave our participants at greater risk of developing respiratory problems like COPD (chronic obstructive pulmonary disease)."

The study did not examine the pathways for the children's exposure to pesticides, but the researchers did recommend that farmworkers remove their work clothes and shoes before entering their homes. They also suggested that when nearby fields are being sprayed with pesticides, children be kept away and, if indoors, windows should be closed. Pesticide exposure can also be reduced by washing fruits and vegetables thoroughly before eating.

The authors noted that although organophosphate pesticides are still widely used, most residential uses of organophosphate pesticides in the United States were phased out in the mid-2000s. In California, use of organophosphates in agriculture has also declined significantly from 6.4 million pounds in 2000, when the study began, to 3.5 million pounds in 2013, the year with the most recent pesticide use data. 

Published on Leave a comment on What is “Seeding” the Microbiomes of Babies Born By C-section?

The mother is an important source of the first microbiome for infants by "seeding" the baby's microbiome - from the vaginal birth and then breastfeeding. However, research finds that infants born by C-section acquire bacteria commonly found on skin (Staphylococcus, Corynebacterium, and Propionibacterium) rather than the bacteria acquired during a vaginal birth.

This study examined the source of the skin-type bacteria found on C-section babies. The researchers analyzed the dust from operating rooms (which they collected right after C-sections) and found that it contains deposits of human skin bacteria and human skin flakes. The researchers point out that "Humans shed up to 37 million bacterial genomes into the environment per hour." Operating rooms are occupied by humans, lack natural ventilation, and even though they are regularly cleaned, the humans using the operating rooms shed bacteria and skin flakes. From Microbiome:

The first microbial environment of infants born by C-section: the operating room microbes

Newborns delivered by C-section acquire human skin microbes just after birth, but the sources remain unknown. We hypothesized that the operating room (OR) environment contains human skin bacteria that could be seeding C-section born infants. To test this hypothesis, we sampled 11 sites in four operating rooms from three hospitals in two cities. Following a C-section procedure, we swabbed OR floors, walls, ventilation grids, armrests, and lamps....The bacterial content of OR (operating room) dust corresponded to human skin bacteria, with dominance of Staphylococcus and Corynebacterium. Diversity of bacteria was the highest in the ventilation grids and walls but was also present on top of the surgery lamps. 

We conclude that the dust from ORs, collected right after a C-section procedure, contains deposits of human skin bacteria. The OR microbiota is the first environment for C-section newborns, and OR microbes might be seeding the microbiome in these babies. 

In the present study, we used 16S rRNA gene sequencing to show that OR dust, collected right after a C-section procedure, contains bacteria similar to human skin microbiota. Previous studies using culture-dependent methods also showed that over 85 % of air samples from ORs had skin-like bacteria which were mostly coagulase-negative staphylococci and Corynebacterium. These airborne skin-bacteria could be from individuals present during C-section but could also be shed by cleaning personnel between operations.

In our study, 30 % of samples failed to yield sufficient DNA sequences to be analyzed. While there are no published data on the microbiota in operating rooms using 16S rRNA gene sequencing, very few bacteria (average 3.3–3.5 CFU/10 cm2) were detected in ORs after regular decontamination using standard culturing methods, consistent with the low sequence numbers in our study.

In addition, we found that the microbiota of OR samples was more similar to human skin microbiota than oral microbiota and that OR dust contains deposits of human skin flakes. These results reveal that while the use of surgical masks has limited effectiveness at curtailing oral microbial shedding, skin flakes from individuals present during C-section and/or from cleaning personnel between operations could be a more influential factor contributing to the structure of OR microbiota.

Our SourceTracker analysis results suggest that the OR microbes could play a role in seeding infants born by C-section. C-section born infants, in particular, may be solely receiving this inoculum, while vaginally born infants have exposure to vaginal bacteria. The results of these further studies could be relevant to the possible effects on the priming of the immune system by skin bacteria from environmental sources as the primordial inoculum seeding the infant microbiome. This might be relevant to the increased risk of immune diseases observed in C-section born infants.

Published on Leave a comment on When Do Football Players Recover From Concussions?

New research showed that eight days after a concussion, the concussed athletes (football players) looked and felt like they had recovered (clinical recovery), but MRIs showed that there were still neurophysiological abnormalities (significant blood flow decrease) in their brains. They did not look at if and when the blood flow returned to normal, but that research also needs to be done.

It is very disturbing to look at both this research and also the finding that the off-season is not enough for high school football players to recover from the repeated hits (not concussions, but sub-concussive hits) that they receive during the football season (Nov. 24, 2015 post). Do student football players really know and understand the dangers to their brains from the repeated hits and also concussions that occur in football? From Medical Xpress:

Reduced blood flow seen in brain after clinical recovery of acute concussion

Some athletes who experience sports-related concussions have reduced blood flow in parts of their brains even after clinical recovery, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA). The results suggest a role for MRI in determining when to allow concussed athletes to return to competition.

Decisions to clear concussed athletes to return to action are typically based on symptoms and cognitive and neurological test results. However, there is increasing evidence that brain abnormalities persist beyond the point of clinical recovery after injury. To find out more, researchers from the Medical College of Wisconsin in Milwaukee studied concussed football players with arterial spin labeling, an advanced MRI method that detects blood flow in the brain.

Dr. Wang and colleagues studied 18 concussed players and 19 non-concussed players. They obtained MRI of the concussed players within 24 hours of the injury and a follow-up MRI eight days after the injury and compared results with those of the non-concussed players. Clinical assessments were obtained for both groups at each time point, as well as at the baseline before the football season.

The concussed players demonstrated significant impairment on clinical assessment at 24 hours post-injury, but returned to baseline levels at eight days. In contrast to clinical manifestation, the concussed players demonstrated a significant blood flow decrease at eight days relative to 24 hours post-injury, while the non-concussed players had no change in cerebral blood flow between the two time points.

"In eight days, the concussed athletes showed clinical recovery," Dr. Wang said. "However, MRI showed that even those in clinical recovery still had neurophysiological abnormalities. Neurons under such a state of physiologic stress function abnormally and may become more susceptible to second injury." "For years, we've relied on what athletes are telling us," Dr. McCrea said. "We need something more objective, and this technology may provide a greater measurement of recovery."

Published on Leave a comment on The Appendix Has A Purpose

This new study gives further support for the role of the appendix as a "natural reservoir for 'good' bacteria". The researchers found that a network of immune cells (innate lymphoid cells or ILCs)  safeguard the appendix during a bacterial attack and help the appendix "reseed" the gut microbiome. They also said that a person's diet, such as the proteins in leafy green vegetables, could help produce ILCs. Note that while it is thought that this applies to humans, the research was done on mice. From Medical Xpress:

Immune cells make appendix 'silent hero' of digestive health

New research shows a network of immune cells helps the appendix to play a pivotal role in maintaining the health of the digestive system, supporting the theory that the appendix isn't a vestigial—or redundant—organ.

The research team....found that innate lymphoid cells (ILCs) are crucial for protecting against bacterial infection in people with compromised immune systems. By preventing significant damage and inflammation of the appendix during a bacterial attack, ILCs safeguard the organ and help it to perform an important function in the body, as a natural reservoir for 'good' bacteria.

"Popular belief tells us the appendix is a liability," she said. "Its removal is one of the most common surgical procedures in Australia, with more than 70,000 operations each year. However, we may wish to rethink whether the appendix is so irrelevant for our health. "We've found that ILCs may help the appendix to potentially reseed 'good' bacteria within the microbiome—or community of bacteria—in the body. A balanced microbiome is essential for recovery from bacterial threats to gut health, such as food poisoning."

Professor Belz said having a healthy appendix might even save people from having to stomach more extreme options for repopulating—or 'balancing out'—their microbiomes. "In certain cases, people require reseeding of their intestines with healthy bacteria by faecal transplant—a process where intestinal bacteria is transplanted to a sick person from a healthy individual," Professor Belz said. "Our research suggests ILCs may be able to play this important part in maintaining the integrity of the appendix.

"We found ILCs are part of a multi-layered protective armoury of immune cells that exist in healthy individuals. So even when one layer is depleted, the body has 'back ups' that can fight the infection. "In people who have compromised immune systems—such as people undergoing cancer treatment—these cells are vital for fighting bacterial infections in the gastrointestinal system. This is particularly important because ILCs are able to survive in the gut even during these treatments, which typically wipe out other immune cells."

Professor Belz has previously shown that diet, such as the proteins in leafy green vegetables, could help produce ILCs."ILCs are also known to play a role in allergic diseases, such as asthma; inflammatory bowel disease; and psoriasis," she said. "So it is vital that we better understand their role in the intestine and how we might manipulate this population to treat disease, or promote better health."

Drawing of colon seen from front (appendix is colored red). From Wikipedia.

Published on Leave a comment on Loneliness Is a Health Risk

Loneliness or social isolation is a health risk that can increase the risk of chronic illness and premature death. Why?  Loneliness leads to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells. Essentially, lonely people had a less effective immune response and more inflammation than non-lonely people. The study was part of the Chicago Health, Aging, and Social Relations Study (CHASRS) and followed 144 people over 10 years. From Science Daily:

Loneliness triggers cellular changes that can cause illness, study shows

Loneliness is more than a feeling: For older adults, perceived social isolation is a major health risk that can increase the risk of premature death by 14 percent.

Now a team of researchers, including U Chicago psychologist and leading loneliness expert John Cacioppo, has released a study shedding new light on how loneliness triggers physiological responses that can ultimately make us sick. The paper.... shows that loneliness leads to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells. The study examined loneliness in both humans and rhesus macaques, a highly social primate species.

Previous research from this group had identified a link between loneliness and a phenomenon they called "conserved transcriptional response to adversity" or CTRA. This response is characterized by an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses. Essentially, lonely people had a less effective immune response and more inflammation than non-lonely people.

For the current study, the team examined gene expression in leukocytes, cells of the immune system that are involved in protecting the body against bacteria and viruses. As expected, the leukocytes of lonely humans and macaques showed the effects of CTRA--an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses. But the study also revealed several important new pieces of information about loneliness' effect on the body.

Next, the team investigated the cellular processes linking social experience to CTRA gene expression in rhesus macaque monkeys at the California National Primate Research Center, which had been behaviorally classified as high in perceived social isolation. Like the lonely humans, the "lonely like" monkeys showed higher CTRA activity. They also showed higher levels of the fight-or-flight neurotransmitter, norepinephrine.

Previous research has found that norepinephrine can stimulate blood stem cells in bone marrow to make more of a particular kind of immune cell--an immature monocyte that shows high levels of inflammatory gene expression and low levels of antiviral gene expression. Both lonely humans and "lonely like" monkeys showed higher levels of monocytes in their blood.

Taken together, these findings support a mechanistic model in which loneliness results in fight-or-flight stress signaling, which increases the production of immature monocytes, leading to up-regulation of inflammatory genes and impaired anti-viral responses. The "danger signals" activated in the brain by loneliness ultimately affect the production of white blood cells. The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks.

Published on Leave a comment on Brains of Teen Football Players Don’t Fully Heal During the Off Season

This past week there was discussion of the number of high school football players that die annually while playing football (at least 5). But the bigger risk - because it involves so many players - is the damage to brains that occurs from concussions and from just being hit in football. The response from football enthusiasts is that there are safeguards now - that football players don't play after a concussion until they "heal" (show no obvious symptoms). But do they really heal? And much of the damage is from repeated hits, without having a concussion (sub-concussive blows or hits), what about the damage from that?

This study found that repeated head hits in football can cause changes in brain chemistry and metabolism, even in high school players not diagnosed with concussions. And even after the lengthy off-season (somewhere between two and five months after the season has ended)—the majority of players are still showing that they had not fully recovered. The researchers also made it clear that 2 weeks is not enough time to heal from a concussion. Scary long-term implications - what is happening to brains that never truly heal from past seasons as the players start playing in the next season? From Futurity:

High School Football: Teen Brains Don't Heal During Offseason

Brain scans of high school football players taken before, during, and after the season raise concerns they don’t fully recover from repeated head hits. The researchers used an imaging technique called proton magnetic resonance spectroscopy (1H MRS) to study the brains of 25 high school football players and compared them to the brains of teenagers involved in non-contact sports. The findings suggest repeated head hits in football can cause changes in brain chemistry and metabolism, even in players not diagnosed with concussions. 

“We are seeing damage not just to neurons, but also to the vasculature and glial cells in the brain,” says Eric Nauman, professor of mechanical engineering, basic medical sciences, and biomedical engineering at Purdue University. “I was particularly disturbed that when you get to the offseason—we are looking somewhere between two and five months after the season has ended—the majority of players are still showing that they had not fully recovered.”

The 1H MRS data provide details about the blood flow, metabolism, and chemistry of neurons and glial cells important for brain function. The data also revealed a “hypermetabolic response” during the preseason, as though the brain was trying to heal connections impaired from the previous season. “We found that in the preseason for the football players in our study, one part of the brain would be associating with about 100 other regions, which is much higher than the controls,” says Thomas Talavage,  professor of electrical and computer engineering and biomedical engineering and co-director of the Purdue MRI Facility.

“The brain is pretty amazing at covering up a lot of changes. Some of these kids have no outward symptoms, but we can see their brains have rewired themselves to skip around the parts that are affected.”

One of the research papers shows that knowing a player’s history of specific types of hits to the head makes it possible to accurately predict “deviant brain metabolism,” suggesting that sub-concussive blows can produce biochemical changes and potentially lead to neurological problems, which indicates a correlation between players taking the heaviest hits and brain chemistry changes.

The data shows that the neurons in the motor cortex region in the brains of football players produced about 50 percent less of the neurotransmitter glutamine compared to controls. “We are finding that the more hits you take, the more you change your brain chemistry, the more you change your brain’s ability to move blood to the right locations,” Nauman says.

“Recent proton magnetic resonance spectroscopy studies argue that the recommended two-week window of rest is insufficient for full metabolic recovery after concussion,” Nauman says. “Those returning to play prior to full recovery could incur a second concussion with symptoms and metabolic changes more lasting than the first.”

Published on Leave a comment on How a Sneeze Travels Through a Room

 Cold and flu season will soon be here, so it's time to review sneeze basics. Here's a nice little study looking at where our sneeze germs wind up - answer: basically all over the room within a "high propulsion sneeze cloud". From Medical Xpress;

Ah-choo! Sneeze 'cloud' quickly covers a room, study finds

Just in time for cold and flu season, a new study finds the average human sneeze expels a high-velocity cloud that can contaminate a room in minutes. Researchers at the Massachusetts Institute of Technology (MIT) came to that conclusion by analyzing videos of two healthy people sneezing about 50 times over several days.

It's well known that sneezes can spread infectious diseases such as measles or the flu, because viruses suspended in sneeze droplets can be inhaled by others or deposited on surfaces and later picked up as people touch them. But it wasn't clear how far sneeze droplets can spread, or why some people are more likely to spread illness through sneezes than others. In a prior study, the team led by MIT's Lydia Bourouiba found that within a few minutes, sneeze droplets can cover an area the size of a room and reach ventilation ducts at ceiling height.

In their latest new study, they discovered how sneeze droplets are formed within what they called a "high-propulsion sneeze cloud." The findings are slated for presentation Monday at the annual meeting of the American Physical Society in Mobile, Ala.

"Droplets are not all already formed and neatly distributed in size at the exit of the mouth, as previously assumed in the literature," Bourouiba said in a society news release. Rather, sneeze droplets "undergo a complex cascading breakup that continues after they leave the lungs, pass over the lips and churn through the air," said Bourouiba, who is head of MIT's Fluid Dynamics of Disease Transmission Laboratory.

Published on Leave a comment on Breast Milk and Preserving Sight In Preemies

Another excellent reason to breastfeed premature infants - to increase the odds of preventing retinopathy of prematurity (ROP), which is the reason preemies can go blind. It occurs when blood vessels in the retinas of premature infants start to grow out of control. If the abnormal growth continues, the retinas detach, and this can cause blindness.

Sadly, an ROP epidemic occurred in the 1940s and early 1950s when hospital nurseries began using excessively high levels of oxygen in incubators to save the lives of premature infants. During this time, ROP was the leading cause of blindness in children in the US. In 1954, scientists funded by the National Institutes of Health determined that the relatively high levels of oxygen routinely given to premature infants at that time were an important risk factor, and that reducing the level of oxygen given to premature babies reduced the incidence of ROP.

Nowadays ROP is a leading cause of childhood blindness in developed countries. A large US study found that in extremely preterm infants with a gestational age of 22 to 28 weeks, the incidence of ROP was 59% (96% at 22 weeks and 32% at 28 weeks). ROP is considered a  multifactorial disease, and risk factors such as prematurity, low birth weight, oxygen therapy, and oxidative stress have been associated with its development.

This recent study was a meta-analysis of five studies (of 2208 pre-term infants), and it found that the overall incidence of ROP was reduced among infants fed human breast milk compared with those fed formula. The best results in preventing severe ROP was in babies fed exclusively breast milk (up to 90% reduction) or mainly human breast milk feeding. It is thought that breast milk may protect against the development of ROP because of its antioxidant and immune-protective properties.  Note that studies involving donor milk were not included because past studies did not find any advantage for donor milk over formula. This may be possibly related to loss of the breast milk microbes (breast milk normally contains up to 700 species of bacteria) during processing (pasteurizing/heat treatment of milk for 30 minutes) and storage of donor milk. From NPR:

Mother's Milk May Help Prevent Blindness In Preemies

If Stevie Wonder had been born three decades later, we might never have gotten "Superstition" and "Isn't She Lovely" — but the musician might never have gone blind, either. Born premature, Wonder developed retinopathy of prematurity, an eye disease that afflicts more than half of babies born before 30 weeks of gestation.Though treatments were developed in the 1980s, about 400 to 600 U.S. children and 50,000 children worldwide still go blind every year from the condition. Now a study suggests that number could be slashed by more than half if all those preemies received their mothers' milk.

The study, actually a combined analysis of five studies from 2001 through 2013, found that preemies receiving human milk from their mothers had 46 to 90 percent lower odds of retinopathy of prematurity (ROP), depending on how much milk they received and how severe the ROP was. The studies were observational, so they cannot show that breast milk directly caused the lower risk.

Of the infants who develop ROP, most recover and develop well without treatment, but about 10 percent develop severe ROP, increasing their risk of blindness, Chiang said. About half of those infants need treatment, which will prevent blindness in 80 to 90 percent of them.

The new research analyzed the outcomes of 2,208 preterm infants based on whether they received exclusive human milk, any human milk, mainly human milk (more than 50 percent), exclusive formula, any formula or mainly formula. The study did not include donor milk, so all the milk was the mother's pumped or hand-expressed breast milk.

Infants who exclusively received breast milk had 89 percent reduced odds of severe ROP compared to infants who received any formula. Infants who received a mixture of breast milk and formula had roughly half the odds of developing severe ROP compared to infants exclusively receiving formula. The analysis included a very large older study that had found no reduced risk for ROP from breast milk, but most infants in that study received less than 20 percent breast milk.

Until the 1940s and 1950s, ROP did not exist because infants born prematurely rarely survived, Chiang said. As doctors learned to how to keep these tiny babies, usually little more than 3 pounds at birth, alive, they discovered that the blood vessels in their retinas would often start to grow out of control. If the abnormal growth continued, their retinas detached, causing blindness.

The cause of ROP isn't entirely understood, but scientists believe oxidative stress can stimulate the abnormal growth of the blood vessels. Providing preemies with oxygen is often key to their survival, but that oxygen exposure might lead to ROP, according to Jianguo Zhou, a neonatologist in Shanghai, and lead author of the study.