CNO Report 221
Release Date 26 2015
Draft Report Compiled by
Ralph Turchiano
In This Issue:
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Low levels of vitamin D may increase risk of stress fractures in active individuals
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Treating colon cancer with vitamin A
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Saline water better than soap and water for cleaning wounds, researchers find
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High fat/low carb diet could combat schizophrenia
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New ‘exercise hormone’ promotes physical endurance
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Face cream ingredient found to mimic life-extending effects of a calorie restriction diet
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Healthy reflections
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Fish oil helps transform fat cells from storage to burning
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New ‘exercise hormone’ promotes physical endurance
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Dietary cocoa flavanols improve blood vessel function in patients with kidney dysfunction
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Low zinc levels may suggest potential breast-feeding problems
Public Release: 14-Dec-2015
Low levels of vitamin D may increase risk of stress fractures in active individuals
Experts recommend active individuals who participate in higher impact activities may need to maintain higher vitamin D levels, reports The Journal of Foot & Ankle Surgery
Elsevier Health Sciences
Philadelphia, PA, Dec. 14, 2015 – Vitamin D plays a crucial role in ensuring appropriate bone density. Active individuals who enjoy participating in higher impact activities may need to maintain higher vitamin D levels to reduce their risk of stress fractures, report investigators in The Journal of Foot & Ankle Surgery.
The role of vitamin D in the body has recently become a subject of increasing interest owing to its many physiologic effects throughout multiple organ systems. Vitamin D is an essential nutrient that can behave as a hormone. It is obtained through diet and through the skin when exposed to the sun’s rays. It is essential for bone development and remodeling to ensure appropriate bone mass density. Low levels of vitamin D can lead to osteoporosis, osteomalacia, decreased bone mineral density, and risk of acute fracture.
Investigators tested the serum concentration of 25(OH)D, which is used to determine vitamin D status, in patients with confirmed stress fractures. “By assessing the average serum vitamin D concentrations of people with stress fractures and comparing these with the current guidelines, we wanted to encourage a discussion regarding whether a higher concentration of serum vitamin D should be recommended for active individuals,” explained lead investigator Jason R. Miller, DPM, FACFAS, Fellowship Director of the Pennsylvania Intensive Lower Extremity Fellowship, foot and ankle surgeon from Premier Orthopedics and Sports Medicine, in Malvern, Pennsylvania, and Fellow Member of the American College of Foot and Ankle Surgeons.
The investigators reviewed the medical records of patients who experienced lower extremity pain, with a suspected stress fracture, over a three-year period from August 2011 to July 2014. All patients had x-rays of the affected extremity and were then sent for magnetic resonance imaging (MRI) if no acute fracture had been seen, yet concern for the presence of a stress fracture remained based on the physical examination findings. Musculoskeletal radiologists independently reviewed all the MRI scans, and the investigators then confirmed the diagnosis of a stress fracture after a review of the images.
The serum vitamin D level was recorded within three months of diagnosis for 53 (42.74%) of these patients. Using the standards recommended by the Vitamin D Council (sufficient range 40 to 80 ng/mL), more than 80% of these patients would have been classified as having insufficient or deficient vitamin D levels. According to the standards set by the Endocrine Society (sufficient range 30 to 100 ng/mL), over 50% had insufficient levels.
“Based on these findings, we recommend a serum vitamin D level of at least 40 ng/mL to protect against stress fractures, especially for active individuals who enjoy participating in higher impact activities,” explained Dr. Miller. “This correlates with an earlier study of 600 female Navy recruits who were found to have a twofold greater risk of stress fractures of the tibia and fibula with a vitamin D level of less than 20 ng/mL compared with females with concentrations above 40 ng/mL
“However, vitamin D is not the sole predictor of a stress fracture and we recommend that individuals who regularly exercise or enjoy participating in higher impact activities should be advised on proper and gradual training regimens to reduce the risk of developing a stress fracture,” he concluded.
Public Release: 14-Dec-2015
Treating colon cancer with vitamin A
Ecole Polytechnique Fédérale de Lausanne
A leading cause of cancer deaths worldwide, colon cancer is famously resistant to treatment. There are many reasons for this, but one has to do with a group of persisting cancer cells in the colon that cause relapses. Conventional therapies against them are mostly ineffective. EPFL scientists have now identified a biological mechanism that can be exploited to counteract colon cancer relapses. The approach activates a protein that is lost in the persisting cancer cells. The researchers were able to reactivate it using vitamin A, thus eliminating the cancer cells and preventing metastasis. The study is published in Cancer Cell, and introduces a new way to treat colon cancer.
When a colon-cancer patient receives treatment, e.g. chemotherapy, most of the cancer cells die off. But the genetic mutations that caused the cancer in the first place can survive in a specific group of cells of the colon. These are actually stem cells, meaning that they are premature cells waiting to grow into full-blown, normal cells of the colon. After cancer treatment ends, the surviving stem cells, still containing the cancerous mutations, can reappear and cause a relapse.
The lab of Joerg Huelsken at EPFL studied how differentiated colon cells come from stem cells in the gut. Using an array of different techniques, the team looked at cells, mouse models and samples from human patients.
Proteins and signaling pathways
The study focused on a protein called HOXA5, which belongs to a family of proteins that regulate the development of the fetus. These proteins are made during early development and work together to make sure that every tissue is correctly identified and that the fetus’s body and limbs are patterned properly. In the adult body, proteins like HOXA5 regulate the body’s stem cells to maintain both the identity and function of different tissues. Huelsken’s team found that in the gut, HOXA5 plays a major role in restricting the number of stem cells, as well as the cells that make them.
Like all proteins, HOXA5 originates from a specific gene. The study showed that the cancerous stem cells of the colon use a biological mechanism that blocks it. This mechanism is called a “signaling pathway” because it involves a domino of molecules, each activating the next one down the line. The purpose of a signaling pathway is to transmit biological information from one part of the cell to another, e.g. from the outer membrane all the way to the nucleus. By blocking the HOXA5 gene, the cancerous stem cells of the colon can grow uncontrollably and spread, causing relapses and metastasis.
Retinoids: a way to fight back
The researchers looked for ways to reverse the blocking of HOXA5. The answer came from vitamin A. This small chemical structure is called a retinoid, and it has been known to induce differentiation of stem cells in the skin. The EPFL scientists found that retinoids can re-activate HOXA5. In mice that had colon cancer, the treatment with retinoids blocked tumor progression and normalized the tissue. By turning the gene for HOXA5 back on, this treatment eliminated cancer stem cells and prevented metastasis in the live animals. The researchers got similar results with samples from actual patients.
The new study suggests that patients that may profit from this well-tolerated treatment can be identified based on their expression pattern for the HOXA5 gene. Retinoid differentiation therapy could be significantly effective against colon cancer, not only for treatment of existing disease but also as a preventive measure in high-risk patients.
Public Release: 15-Dec-2015
Saline water better than soap and water for cleaning wounds, researchers find
Findings may have important implications for the care of patients with open fractures worldwide
McMaster University
Hamilton, ON (Dec. 15, 2015) – Many scientific advances have been made in the delivery of care and infection prevention for open fractures, but the standard practice of wound cleaning with soap and water before surgery has remain the unchanged. Now, an international team of researchers led by McMaster University in collaboration with the Research Institute of the McGill University Health Centre has found that soap and water is actually less effective than just using saline water.
The findings, which were published in the New England Journal of Medicine, could lead to significant cost savings, particularly in developing countries where open fractures are particularly common.
As part of the study, 2,400 people with open arm or leg fractures had their wounds cleaned with either soap and water, or a saline water solution, and one of three different levels of water pressure. Patients were monitored to see who would need to have an additional operation within 12 months because of infection or problems with wound healing. The researchers found that very low water pressure was an acceptable, low-cost alternative for washing out open fractures, and that the reoperation rate was higher in the group that used soap.
“There has been a lot of controversy about the best way to clean the dirt and debris from serious wounds with bone breaks,” says Dr. Mohit Bhandari, principal investigator and a professor of surgery for the Michael G. DeGroote School of Medicine at McMaster. “All wounds need to be cleaned out — a process known as debridement — but evidence shows that cleaning wounds with soap was not better than just water, which was unexpected.”
“These findings may have important implications for the care of patients with open fractures worldwide since developing countries deal with a disproportionate number of cases,” adds one of the study’s co-authors, Dr. Edward Harvey, chief of Orthopaedic Trauma at the McGill University Health Centre and a professor of surgery at McGill University. “Most of the time we were using soap and water with a high pressure delivery system to clean the wound, but now we don’t, and that makes the best practice much cheaper.”
The study involved patients across 41 sites in the United States, Canada, Australia, Norway and India. The majority of patients were men in their 40s with a lower extremity fracture, and the most common reason for the injury was a motor vehicle accident.
The researchers added that their findings may be particularly relevant for low and middle income countries where 90% of road traffic fatalities, and probably a similar proportion of open fractures, occur, according to the World Health Organization.
High fat/low carb diet could combat schizophrenia
James Cook University
Research by James Cook University scientists has found a diet favoured by body-builders may be effective in treating schizophrenia.
Associate Professor Zoltan Sarnyai and his research group from JCU’s Australian Institute of Tropical Health and Medicine (AITHM) have discovered that feeding mice a ketogenic diet, which is high on fat but very low on carbohydrates (sugars), leads to fewer animal behaviours that resemble schizophrenia.
The ketogenic diet has been used since the 1920s to manage epilepsy in children and more recently as a weight loss diet preferred by some body builders.
Dr Sarnyai believes the diet may work by providing alternative energy sources in the form of so-called ketone bodies (products of fat breakdown) and by helping to circumvent abnormally functioning cellular energy pathways in the brains of schizophrenics.
“Most of a person’s energy would come from fat. So the diet would consist of butter, cheese, salmon, etc. Initially it would be used in addition to medication in an in-patient setting where the patient’s diet could be controlled,” he said.
Schizophrenia is a devastating, chronic mental illness that affects nearly one per cent of people worldwide. There is no cure and medications used to alleviate it can produce side effects such as movement disorder, weight gain and cardiovascular disease.
But if the research findings can be translated into the effective management of schizophrenia they may offer a secondary benefit too.
The group’s paper, published online in the leading journal Schizophrenia Research, also shows mice on a ketogenic diet weigh less and have lower blood glucose levels than mice fed a normal diet.
“It’s another advantage that it works against the weight gain, cardiovascular issues and type-two diabetes we see as common side-effects of drugs given to control schizophrenia,” said Dr Sarnyai.
The JCU researchers will now test their findings in other animal schizophrenia models as they explore a possible clinical trial.
Public Release: 16-Dec-2015
New ‘exercise hormone’ promotes physical endurance
U. Iowa study shows that peptide released during exercise boosts muscle’s capacity for energy production and increases exercise tolerance
University of Iowa Health Care
A new study in mice shows that exercise causes muscle to release a peptide that builds the muscle’s capacity for energy production and increases physical endurance, allowing for longer and more intense exercise.
The findings establish that the peptide, called musclin, is an “exercise factor” — a hormone-like substance made by skeletal muscle in response to exercise and released into the bloodstream. The study shows that increased levels of circulating musclin trigger a signaling cascade that improves muscle performance and promotes production of mitochondria in muscle cells. The study was published online the week of Dec. 14 in the Proceedings of the National Academy of Sciences Early Edition.
“Exercise is an extremely powerful way to improve people’s health, but unfortunately, increasing physical activity can be really difficult in many circumstances,” says senior author Leonid Zingman, MD, associate professor of internal medicine at the University of Iowa Carver College of Medicine and a physician scientist at the Iowa City Veterans Affairs Medical Center. “We don’t want to replace exercise by using this exercise factor, but if we can learn more about the mechanism it might help us to increase exercise tolerance and make it easier for people to actually exercise. And if it is easier, people may exercise more.”
The scientists used genetic engineering to make mice that don’t have musclin. Although these animals look and act like wild type mice, they have lower exercise tolerance and are not able to exercise as long or as hard as wild type mice. However, infusing the musclin peptide back into these modified mice allows the animals to regain normal exercise capacity.
“The musclin infusion into the knockout mice was effective in rescuing the animal’s exercise capacity in just one week,” says first author, Ekaterina Subbotina, PhD, a post-doctoral scholar in Zingman’s laboratory.
The researchers also showed that infusion of wild type mice with musclin increased the animals’ voluntary treadmill activity; the mice ran faster and longer on the treadmill than wild type mice that received a placebo infusion of saline.
Further investigation showed that musclin signaling promotes production of mitochondria in muscle cells. Mitochondria are the cells’ power plants, producing the energy required for everything the cell does. The study links the increase in mitochondria to improved aerobic capacity in the mice.
Although the research focused primarily on the effect of exercise on musclin levels, even when mice were sedentary, mice that lack musclin had decreased exercise endurance compared to sedentary wild-type mice, suggesting that musclin may promote muscle health even during the low level exercise of normal everyday living.
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In addition to Zingman, who is also a member of Abboud Cardiovascular Research Center and the Fraternal Order of Eagles Diabetes Research Center at the UI, and Subbotina, the research team included UI scientists, Ana Sierra, Zhiyong Zhu, Siva Rama Krishna Koganti, Elizabeth Stepniak, Susan Walsh, Michael Acevedo and Denice Hodgson-Zingman. Santiago Reyes and Carmen Perez-Terzic at Mayo Clinic in Rochester, Minn., also were part of the team.
The study was funded in part by grants from the Department of Veterans Affairs, The National Institutes of Health, and the Fraternal Order of Eagles Diabetes Research Center at the UI.
Public Release: 16-Dec-2015
Face cream ingredient found to mimic life-extending effects of a calorie restriction diet
University of Liverpool
A commonly used skin care ingredient is one of several newly identified compounds that can mimic the life-extending effect of a starvation diet, new University of Liverpool research has revealed.
Calorie restriction, a reduction in calorie intake without malnutrition, has been found to slow down the ageing process in several animal models from worms to mammals, and developing drugs that can reproduce this effect, without the side effects, could have widespread human applications.
Now, using complex genetic data analysis and testing, scientists have shown for the first time that allantoin, which is found in botanical extracts of the comfrey plant and is an ingredient of many anti-ageing creams, can mimic the effect of calorie restriction and increase lifespan in worms by more than 20%.
Dr João Pedro de Magalhães, from the University’s Institute of Integrative Biology, who led the study said: “Calorie restriction has been shown to have health benefits in humans and, while more work is necessary, our findings could potentially result in human therapies for age-related diseases.”
To identify potential calorie restriction mimetic compounds, the team made use of existing molecular signatures from human cells treated with a variety of small-molecule drugs.
Using pattern-matching algorithms to make connections between drug compounds and calorie restriction effects, eleven potential compounds were identified. Five of these were then tested in nematode worms.
The researchers found that worms treated with allantoin, rapamycin, trichostatin A and LY-294002 not only lived longer, but also stayed healthier longer. Additionally, when the same compounds were tested in mutant worms they extended lifespan in a way expected from calorie restriction. Further molecular analysis of allantoin suggests it acts by a different mechanism from rapamycin, a well-known longevity drug.
PhD student Shaun Calvert, who carried out the work said: “Testing anti-aging interventions in humans is not practical, so developing computational methods to predict longevity drugs is of great use.
“We have shown so far that our compounds work in worms, but studies in mammalian models are now necessary. The next step for us is to understand the mechanisms by which allantoin extends lifespan, as this could reveal new longevity pathways.”
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The paper ‘A network pharmacology approach reveals new calorie restriction mimetic drugs in C. elegans‘ is published in the journal Aging Cell.
Public Release: 17-Dec-2015
Healthy reflections
Mirrors can make unhealthy foods less tasty
Cornell Food & Brand Lab
People often choose the unhealthy food because they think it is tastier. Aiming for solutions promoting healthy eating practices and ultimately combating obesity, this research shows that the presence of a mirror in a consumption setting can reduce the perceived tastiness of unhealthy food, which consequently reduces its consumption.
In a taste test study, 185 undergraduate students chose between a chocolate cake and a fruit salad and then evaluated its taste in a room with a mirror or with no mirrors around. Those who selected the chocolate cake evaluated it less tasty in the room with a mirror compared to those with no mirrors around. However, the presence of a mirror did not change the taste of the fruit salad.
Lead researcher Ata Jami of the University of Central Florida explains, “A glance in the mirror tells people more than just about their physical appearance. It enables them to view themselves objectively and helps them to judge themselves and their behaviors in a same way that they judge others.” He found that mirrors can push people to compare and match their behaviors with social standards of correctness. Accordingly, when one fails to follow the standards, he/she does not want to look at a mirror because it enhances the discomfort of the failure. Thus, the presence of a mirror induces a discomfort and lowers the perceived taste of the unhealthy food. This only holds true if the food is selected by the diner because then he/she feels responsible for the food choice. Eating healthy does not induce any discomfort and, as a result, mirror does not change the taste of healthy food.
This research suggests that placing a mirror in dining rooms and other eating spaces so that diners can see themselves eat, can be an effective way for individuals and restaurants to encourage healthier eating practices.
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This article is published in the inaugural issue of the Journal of the Association for Consumer Research entitled “The Behavioral Science of Eating.” This issue has been edited by Brian Wansink of Cornell University and Koert van Ittersum of the University of Groningen.
Public Release: 17-Dec-2015
Fish oil helps transform fat cells from storage to burning
Kyoto University shows how fish oil can improve fat metabolism in mice
Kyoto University
Kyoto, Japan — Researchers have found that fish oil transforms fat-storage cells into fat-burning cells, which may reduce weight gain in middle age.
The team explains in Scientific Reports that fish oil activates receptors in the digestive tract, fires the sympathetic nervous system, and induces storage cells to metabolize fat.
Fat tissues don’t all store fat. So-called “white” cells store fat in order to maintain energy supply, while “brown” cells metabolize fat to maintain a stable body temperature. Brown cells are abundant in babies but decrease in number with maturity into adulthood.
A third type of fat cell — “beige” cells — has recently been found in humans and mice, and has been shown to function much like brown cells. Beige cells also reduce in number as people approach middle age; without these metabolizing cells, fat continues accumulating for decades without ever being used.
The scientists investigated whether the number of these beige cells could be increased by taking in certain types of foods.
“We knew from previous research that fish oil has tremendous health benefits, including the prevention of fat accumulation,” says senior author Teruo Kawada. “We tested whether fish oil and an increase in beige cells could be related.”
The team fed a group of mice fatty food, and other groups fatty food with fish oil additives. The mice that ate food with fish oil, they found, gained 5-10% less weight and 15-25% less fat compared to those that did not consume the oil.
They also found that beige cells formed from white fat cells when the sympathetic nervous system was activated, meaning that certain fat-storage cells acquired the ability to metabolize.
“People have long said that food from Japan and the Mediterranean contributes to longevity, but why these cuisines are beneficial was up for debate,” adds Kawada. “Now we have better insight into why that may be.”
Public Release: 17-Dec-2015
Dietary cocoa flavanols improve blood vessel function in patients with kidney dysfunction
American Society of Nephrology
Highlight
· Ingesting a drink rich in cocoa flavanols improved blood vessel function and reduced diastolic blood pressure in patients with kidney failure.
· Heart disease is the leading cause of death in patients with chronic kidney disease.
Washington, DC (December 17, 2015) — Consuming a beverage containing cocoa flavanols improves blood vessel function in patients with kidney failure, according to a study appearing in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN). The findings suggest that the plant-derived compounds may benefit the cardiovascular health of patients with poor kidney function.
Individuals with failing kidneys are at increased risk of developing heart problems, and they’re more likely to die from cardiovascular causes than from any other cause. Lifestyle and dietary modifications to maintain vascular health or reduce disease risk might help protect patients’ heart health, but there are currently limited diet-based therapeutic approaches to counteract cardiovascular disease in patients with kidney failure.
Tienush Rassaf, MD (University Hospital Essen, Germany) and his colleagues tested the potential of cocoa flavanols, a subgroup of plant-derived polyphenols that are present in cocoa and have been shown to have beneficial effects on blood vessel function in individuals with normal kidney function.
The team randomized 57 dialysis patients to ingest either a test beverage rich in cocoa flavanols (900 mg per day) or a control beverage that was free of cocoa flavanols but matched the nutrient content of the test beverage in all other aspects. After 30 days, the investigators found that cocoa flavanol ingestion was well-tolerated by patients and it improved blood vessel function and reduced diastolic blood pressure. No effects were observed in the group that consumed the control beverage.
“Impressively, the degree of reversion of vessel dysfunction was comparable to the effects observed through administering statins or making dietary and lifestyle changes,” said Dr. Rassaf. “Whether this approach also leads to a reduction in mortality is not clear and has to be investigated.”
In an accompanying editorial, Carmine Zoccali, MD and Francesca Mallamaci, MD (CNR-IFC, in Italy) noted that “the burden of cardiovascular disease in dialysis patients is so devastating that a promising intervention like cocoa flavanols deserves full attention by the nephrology community.” They added that if the findings are confirmed in additional studies, they may represent a turning point in patient care.
Public Release: 21-Dec-2015
Looking for the next superfood? When in Europe, search no further than black raspberries
Antioxidant properties of raspberry and blackberry fruits grown in Central Europe
De Gruyter Open
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. It is usually the exotic Goji, Acerola or Acai berries that make the headlines as Superfoods, but for the health-savvy European consumer the native homegrown species could be even more alluring. The current study from the University of Agriculture in Krakow shows what’s in store for Old Continent foodies in the berries department. 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 Ma?gorzata Kostecka-Guga?a 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.
The Central Europe-grown variety of black raspberries showed greater health benefits than raspberries and blackberries. As there is no significant difference fruits collected in either summer or autumn they should remain a solid staple on our diet throughout the seasons.
Public Release: 22-Dec-2015
Low zinc levels may suggest potential breast-feeding problems
Penn State
Zinc levels in breast milk may be able to serve as an indicator of breast function during lactation, according to Penn State health researchers.
In previous studies, Shannon L. Kelleher and colleagues found that the protein ZnT2 is critical for secreting zinc into breast milk, and women who have mutations in the gene that encodes ZnT2 have substantially lower milk zinc levels, leading to severe zinc deficiency in exclusively breast-fed infants.
They had also found that in mice the deletion of ZnT2 alters milk composition and profoundly impairs the ability of mice to successfully nurse their offspring.
Now the researchers have found that genetic variation resulting in either loss or gain of function may be common in women and in some cases is associated with indicators of poor breast function. They suggest that by identifying women with abnormally low levels of zinc in breast milk, they may be able to more quickly recognize mothers who might have trouble breast-feeding.
In the current study, the researchers found that of 54 breast-feeding women, 36 percent had at least one non-synonymous single nucleotide polymorphism (SNP) — or mutation — in the protein ZnT2, and that genetic variation was associated with abnormal levels of zinc in their breast milk. Twelve previously unknown variants of ZnT2 were identified in the participants, and five of these variants were statistically associated with abnormal zinc levels in breast milk.
“We had no idea that genetic variation in ZnT2 would be so common,” said Kelleher, associate professor of cellular and molecular physiology and pharmacology, College of Medicine.
The protein ZnT2 transports zinc in specific tissues of the body, including the mammary glands. Women who have mutations, or SNPs, in ZnT2 may have difficulty breast-feeding because zinc is necessary for the growth of mammary glands and the function of mammary epithelial cells and secretion pathways. Even if they do successfully breast-feed, their breast milk will likely contain a lower than normal amount of zinc, which can cause severe zinc deficiency in exclusively breast-fed infants. Infants who don’t receive enough zinc in their diet are in danger of immunological and developmental problems.
In the current study, among the 36 percent of breast-feeding women found to have at least one genetic variant in ZnT2, all had an abnormally low or high level of zinc in breast milk. However, abnormal zinc levels did not automatically imply a problem with ZnT2, indicating that other factors remain to be identified. The researchers report their results in the current issue of the Journal of Mammary Gland Biology and Neoplasia.
The participants were sorted into four groups, according to breast milk zinc levels — from low to high. In the group with the lowest levels of zinc, researchers identified ZnT2 variants in 79 percent of the women; in the group with the highest levels, 29 percent of the women had ZnT2 variants.
“Importantly, among the subjects with ‘normal’ milk (zinc levels), no variants in ZnT2 were detected,” the researchers wrote.
The researchers also looked at the women’s ratio of sodium to potassium (Na/K) in the milk because this ratio is known to be an indicator of breast dysfunction, including infection and inflammation of the breast. In this study, 12 percent of women had the most common ZnT2 variant, T288S, and had a significantly higher Na/K ratio compared with women who had no variation in ZnT2, while another 9 percent of women with a different, less common ZnT2 variant, D103E, had a higher Na/K ratio than women with no variation in ZnT2, although this was not significant due to the fewer number of women in the study with this variant.
The researchers noted that this observation points to genetic variation of ZnT2 as a modifier of breast function.
While further research is needed to better understand how genetic variation affects milk zinc levels and breast function, these findings are an important step in identifying breast-fed infants who are at risk for zinc deficiency before they become deficient as well as identifying women who might have trouble breast-feeding.
research.