Diet, nutrition have profound effects on gut microbiome
George Washington University, March 25, 2020
Nutrition and diet have a profound impact on microbial composition in the gut, in turn affecting a range of metabolic, hormonal, and neurological processes, according to a literature review by scientists from the George Washington University (GW) and the National Institute of Standards and Technology (NIST). The article is published in Nutrition Reviews.
Until recently, the human microbiome remained an understudied target for novel strategies to diagnose and treat disease. The prevalence of diseases that may involve disruption of the gut microbiome are increasing and there is currently no consensus in the scientific community on what defines a “healthy gut” microbiome.
The review from GW and NIST systematically assessed the current understanding of the interactions between nutrition and the gut microbiome in healthy adults.
“As we learn more about the gut microbiome and nutrition, we are learning how influential they are to each other and, perhaps more central to public health, the role they both play in prevention and treatment of disease,” said Leigh A. Frame, PhD, MHS, program director of the Integrative Medicine Programs at the GW School of Medicine and Health Sciences.
Through their review, the authors found that the bi-directional relationship between nutrition and the gut microbiome is emerging as more research is conducted on how microbiota utilize and produce both macro and micronutrients. The authors found that research has mostly focused on the benefits of dietary fiber, which serves as fuel for gut microbiota, and also found that, in contrast, protein promotes microbial protein metabolism and potentially harmful byproducts that may sit in the gut, increasing the risk of negative health outcomes.
“This review reveals that the measurement tools currently in our arsenal are ineffective for identifying the microbial and molecular signatures that can serve as robust indicators of health and disease,” said Scott Jackson, adjunct assistant professor of clinical research and leadership at SMHS and leader of the Complex Microbial Systems Group at NIST.
The authors suggest that future research must consider individual responses to diet and how the gut microbiome responds to dietary interventions, as well as emphasized function of the microbiome (what it does) over merely composition (what is there).
Too much salt weakens the immune system
University of Bonn (Germany),. March 25, 2020
A high-salt diet is not only bad for one’s blood pressure, but also for the immune system. This is the conclusion of a current study under the leadership of the University Hospital Bonn. Mice fed a high-salt diet were found to suffer from much more severe bacterial infections. Human volunteers who consumed an additional six grams of salt per day also showed pronounced immune deficiencies. This amount corresponds to the salt content of two fast food meals. The results are published in the journal Science Translational Medicine.
Five grams a day, no more: This is the maximum amount of salt that adults should consume according to the recommendations of the World Health Organization (WHO). It corresponds approximately to one level teaspoon. In reality, however, many Germans exceed this limit considerably: Figures from the Robert Koch Institute suggest that on average men consume ten, women more than eight grams a day.
This means that we reach for the salt shaker much more than is good for us. After all, sodium chloride, which is its chemical name, raises blood pressure and thereby increases the risk of heart attack or stroke. But not only that: “We have now been able to prove for the first time that excessive salt intake also significantly weakens an important arm of the immune system,” explains Prof. Dr. Christian Kurts from the Institute of Experimental Immunology at the University of Bonn.
This finding is unexpected, as some studies point in the opposite direction. For example, infections with certain skin parasites in laboratory animals heal significantly faster if these consume a high-salt diet: The macrophages, which are immune cells that attack, eat and digest parasites, are particularly active in the presence of salt. Several physicians concluded from this observation that sodium chloride has a generally immune-enhancing effect.
The skin serves as a salt reservoir
“Our results show that this generalization is not accurate,” emphasizes Katarzyna Jobin, lead author of the study, who has since transferred to the University of Würzburg. There are two reasons for this: Firstly, the body keeps the salt concentration in the blood and in the various organs largely constant. Otherwise important biological processes would be impaired. The only major exception is the skin: It functions as a salt reservoir of the body. This is why the additional intake of sodium chloride works so well for some skin diseases.
However, other parts of the body are not exposed to the additional salt consumed with food. Instead, it is filtered out by the kidneys and excreted in the urine. And this is where the second mechanism comes into play: The kidneys have a sodium chloride sensor that activates the salt excretion function. As an undesirable side effect, however, this sensor also causes so-called glucocorticoids to accumulate in the body. And these in turn inhibit the function of granulocytes, the most common type of immune cell in the blood.
Granulocytes, like macrophages, are scavenger cells. However, they do not attack parasites, but mainly bacteria. If they do not do this to a sufficient degree, infections proceed much more severely. “We were able to show this in mice with a listeria infection,” explains Dr. Jobin. “We had previously put some of them on a high-salt diet. In the spleen and liver of these animals we counted 100 to 1,000 times the number of disease-causing pathogens.” Listeria are bacteria that are found for instance in contaminated food and can cause fever, vomiting and sepsis. Urinary tract infections also healed much more slowly in laboratory mice fed a high-salt diet.
Sodium chloride also appears to have a negative effect on the human immune system. “We examined volunteers who consumed six grams of salt in addition to their daily intake,” says Prof. Kurts. “This is roughly the amount contained in two fast food meals, i.e. two burgers and two portions of French fries.” After one week, the scientists took blood from their subjects and examined the granulocytes. The immune cells coped much worse with bacteria after the test subjects had started to eat a high-salt diet.
In human volunteers, the excessive salt intake also resulted in increased glucocorticoid levels. That this inhibits the immune system is not surprising: The best-known glucocorticoid cortisone is traditionally used to suppress inflammation. “Only through investigations in an entire organism were we able to uncover the complex control circuits that lead from salt intake to this immunodeficiency,” stresses Kurts. “Our work therefore also illustrates the limitations of experiments purely with cell cultures.”
New study: Cannabis helps fight resistant bacteria
University of Southern Denmark, March 25, 2020
Since the discovery of penicillin in 1928 by Sir Alexander Fleming, antibiotics have saved millions of lives from fatal infections world-wide. However, with time bacteria have developed mechanisms to escape the effects of antibiotics – they have become resistant.
With fewer antibiotics available to treat resistant bacterial infections, the possibility of entering a pre-antibiotic era is looming ahead.
Alternative strategies are being explored and helper compounds are attracting attention. Helper compounds are non-antibiotic compounds with the capability of enhancing the efficacy of antibiotics.
How to boost antibiotics
One such helper compound has been suspected to be cannabidiol (CBD); a cannabinoid from the cannabis plant. Now a research team from University of Southern Denmark, has published a scientific study proving the effect of CBD.
Janne Kudsk Klitgaard is Principal Investigator and corresponding author. First author is PhD student Claes Søndergaard Wassmann. The study is published in the journal Scientific Reports.
When we combined CBD and antibiotics, we saw a more powerful effect than when treating with antibiotics alone. So, in order to kill a certain number of bacteria, we needed less antibiotics, they say.
Bacteria clones spread globally
In the study, CBD was used to enhance the effect of the antibiotic bacitracin against Staphylococcus aureus bacteria; a major human pathogen that frequently causes community- and hospital-acquired disease.
Multidrug-resistant clones of this pathogen have spread globally. In some countries, treatment of bacterial infections with these resistant bacteria are difficult and the problem is projected to be an ever-larger problem in the future.
According to the researchers, the combination of CBD and antibiotics may be a novel treatment of infections with antibiotic resistant bacteria.
How do the bacteria die?
Three things happened with the Staphylococcus aureus bacteria, when the researchers treated them with the combination in their study:
The bacteria could no longer divide normally.
The expression of certain key genes (cell division and autolysis genes) in the bacteria was lowered.
The bacterial membrane became unstable.
Anti-resistance must be stopped
According to the researchers, overuse of antibiotics is the main cause of antibiotic resistance.
If we combine an antibiotic with a helper compound, that enhances the effect of the antibiotic, we need less antibiotic to achieve the same effect. This may contribute to the development of fewer resistant bacteria, says Janne Kudsk Klitgaard.
To stay positive, live in the moment—but plan ahead
North Carolina State University, March 25, 2020
A recent study from North Carolina State University finds that people who manage to balance living in the moment with planning for the future are best able to weather daily stress without succumbing to negative moods.
“It’s well established that daily stressors can make us more likely to have negative affect, or bad moods,” says Shevaun Neupert, a professor of psychology at NC State and corresponding author of a paper on the recent work. “Our work here sheds additional light on which variables influence how we respond to daily stress.”
Specifically, the researchers looked at two factors that are thought to influence how we handle stress: mindfulness and proactive coping.
Mindfulness is when people are centered and living in the moment, rather than dwelling in the past or worrying about the future. Proactive coping is when people engage in planning to reduce the likelihood of future stress.
To see how these factors influence responses to stress, the researchers looked at data from 223 study participants. The study included 116 people between the ages of 60 and 90, and 107 people between the ages of 18 and 36. All of the study participants were in the United States.
All of the study participants were asked to complete an initial survey in order to establish their tendency to engage in proactive coping. Participants were then asked to complete questionnaires for eight consecutive days that explored fluctuations in mindfulness. On those eight days, participants were also asked to report daily stressors and the extent to which they experienced negative mood.
The researchers found that engaging in proactive coping was beneficial at limiting the effect of daily stressors, but that this advantage essentially disappeared on days when a participant reported low mindfulness.
“Our results show that a combination of proactive coping and high mindfulness result in study participants of all ages being more resilient against daily stressors,” Neupert says. “Basically, we found that proactive planning and mindfulness account for about a quarter of the variance in how stressors influenced negative affect.
“Interventions targeting daily fluctuations in mindfulness may be especially helpful for those who are high in proactive coping and may be more inclined to think ahead to the future at the expense of remaining in the present.”
The paper, “Thinking Ahead and Staying in the Present: Implications for Reactivity to Daily Stressors,” is published in the journal Personality and Individual Differences. First author of the paper is Melody Polk, an undergraduate at NC State. The paper was co-authored by Emily Smith and Ling-Rui Zhang, graduate students at NC State. The work was done with support from NC State’s College of Humanities and Social Sciences.
Astaxanthin ameliorated neuron deficits and Alzheimer disease-related pathological progression in hippocampus of mouse model of the disease
University of Toyama (Japan), March 25, 2020
According to news reporting from Toyama, Japan, research stated, “Growing evidence suggests that oxidative stress due to amyloid b (Ab) accumulation is involved in Alzheimer’s disease (AD) through the formation of amyloid plaque, which leads to hyperphosphorylation of tau, microglial activation, and cognitive deficits. The dysfunction or phenotypic loss of parvalbumin (PV)-positive neurons has been implicated in cognitive deficits.”
Our news editors obtained a quote from the research from University of Toyama: “Astaxanthin is one of carotenoids and known as a highly potent antioxidant. We hypothesized that astaxanthin’s antioxidant effects may prevent the onset of cognitive deficits in AD by preventing AD pathological processes associated with oxidative stress. In the present study, we investigated the effects of astaxanthin intake on the cognitive and pathological progression of AD in a mouse model of AD. The AppNL-G-F/NL-G-F mice were fed with or without astaxanthin from 5-to-6 weeks old, and cognitive functions were evaluated using a Barnes maze test at 6 months old. PV-positive neurons were investigated in the hippocampus. Ab42 deposits, accumulation of microglia, and phosphorylated tau (pTau) were immunohistochemically analyzed in the hippocampus. The hippocampal anti-oxidant status was also investigated. The Barnes maze test indicated that astaxanthin significantly ameliorated memory deficits. Astaxanthin reduced Ab42 deposition and pTau-positive areal fraction, while it increased PV-positive neuron density and microglial accumulation per unit fraction of Ab42 deposition in the hippocampus. Furthermore, astaxanthin increased total glutathione (GSH) levels, although 4-hydroxy-2,3-trans-nonenal (4-HNE) protein adduct levels (oxidative stress marker) remained high in the astaxanthin supplemented mice.”
According to the news editors, the research concluded: “The results indicated that astaxanthin ameliorated memory deficits and significantly reversed AD pathological processes (Ab42 deposition, pTau formation, GSH decrease, and PV-positive neuronal deficits). The elevated GSH levels and resultant recovery of PV-positive neuron density, as well as microglial activation, may prevent these pathological processes.”
Fish oil, vitamin B12 supplementation associated with lower plasma homocysteine
Zhejiang University (China), March 16, 2020.
The Asia Pacific Journal of Clinical Nutrition published the finding of researchers at Zhejiang University in Hangzhou, China of a reduction in plasma homocysteine levels following supplementation with vitamin B12 and/or fish oil.
“No study has reported the effect of vitamin B12 in combination with fish oil on plasma homocysteine, ferritin, CRP and other cardiovascular disease risk factors in Chinese,” announce Duo Li and colleagues in their introduction to the article.
Thirty men and women were randomly assigned to receive 1000 micrograms (mcg) vitamin B12, 2 grams fish oil, or 2 grams fish oil plus 1000 mcg vitamin B12. Plasma vitamin B12, lipids, ferritin (a biomarker of iron status), C-reactive protein (CRP), total homocysteine and other factors were measured before treatment and after four and eight weeks of supplementation.
Among those who received fish oil alone or fish oil plus vitamin B12, triglycerides, CRP and ferritin significantly decreased after four and eight weeks of supplementation. Homocysteine was lowered by 22% in the vitamin B12 group, 19% in the fish oil group and 39% among those who received both supplements for eight weeks.
“In summary, supplementation of fish oil alone or in combination with vitamin B12 decreased plasma concentrations of homocysteine, ferritin and CRP,” Dr Li and associates conclude. “Oral supplementation with vitamin B12 in combination with fish oil had a synergistic effect on lowering plasma concentrations of homocysteine.”
Analysis predicts purified fish oil could prevent thousands of cardiovascular events
University of California at Irvine, March 25, 2020 –
Researchers from the University of California, Irvine have conducted a statistical analysis that predicts more than 70,000 heart attacks, strokes and other adverse cardiovascular events could be prevented each year in the U.S. through the use of a highly purified fish oil therapy.
Led by Nathan D. Wong, PhD, professor and director of the Heart Disease Prevention Program in the Division of Cardiology at the UCI School of Medicine, the abstract of the statistical analysis was accepted by the American College of Cardiology and is slated to be presented at the upcoming ACC.20/World Congress of Cardiology virtual conference taking place March 28-30. The analysis utilizes data from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES), and inclusion criteria from a multinational clinical trial led by investigators from Harvard University called REDUCE-IT, which was published in the New England Journal of Medicine in January of 2019.
The REDUCE-IT trial showed patients with known cardiovascular disease or diabetes and multiple risk factors who have elevated triglyceride levels and are at increased risk for ischemic events benefitted substantially from icosapent ethyl, a highly purified fish oil therapy, which lowered cardiovascular events, including heart attacks and strokes, by 25 percent. Positive results were not found in other trials, possibly due to mixtures with other omega-3 fatty acids such as DHA, or inadequate dosages according to Wong.
“Our analysis extends the findings of the REDUCE-IT trial by estimating its potential impact on the U.S. population,” said Wong. “By using inclusion criteria and cardiovascular disease event rates from the REDUCE-IT trial and applying it to data on US adults from NHANES, we were able to estimate the beneficial impact icosapent ethyl could have on preventing initial and total cardiovascular events in eligible U.S. adults with cardiovascular disease or diabetes and multiple risk factors.”
Wong’s analysis is the first to project the findings of REDUCE-IT to the overall U.S. population.
“When you consider that for every 21 patients treated with icosapent ethyl you can spare a cardiovascular event, you begin to see the implications of our results,” said Wong.
Icosapent ethyl is a purified stable eicosapentaenoic acid (EPA) which was recently approved by the Federal Drug Administration (FDA) in conjunction with maximally tolerated statin therapy to reduce the risk of cardiovascular events in certain adults with elevated triglyceride levels. The only drug of its kind to show such an effect, icosapent ethyl, is currently marketed under the name Vascepa® by Amarin Pharma. The EPA therapy has also gained the support of several major societies, which have incorporated it in various guidelines, scientific statements and advisories, including the American Diabetes Association, American Heart Association, National Lipid Association, and the European Society of Cardiology/European Atherosclerosis Society.
Eating pecans had significant effect on biomarkers of heart disease and type 2 diabetes
Pecan-rich diet significantly improved insulin sensitivity in adults who are overweight or obese
Tufts University, March 22, 2020
A new study published in Nutrients shows that eating just 1.5 ounces of pecans – one small handful – every day may protect adults at risk for developing cardiovascular disease (CVD) and type 2 diabetes (T2D). Conducted by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, this study found that incorporating pecans into a typical American diet significantly improved insulin sensitivity and had a significant effect on markers of cardiometabolic disease in otherwise healthy overweight and obese adults with excess belly fat.
While a growing body of evidence has linked tree nuts such as pecans to reduced risk of CVD, this is the first study to look at the effects of pecan consumption on factors other than blood lipid levels and specifically those related to T2D. Obesity is a risk factor for T2D, and both obesity and T2D increase CVD risk.
“Pecans are naturally high in monounsaturated and polyunsaturated fats, so replacing a portion of the saturated fat in the diet with these healthier fats can explain some of the cardio-protective effects we observed,” said lead researcher, Diane McKay, Ph.D. “But pecans also contain a number of bioactive plant compounds as well as vitamins and essential minerals that all likely contributed to this benefit. What’s really interesting is that just one small change – eating a handful of pecans daily – may have a large impact on the health of these at-risk adults.”
In this placebo-controlled crossover study of 26 men and women (average age 59 years), all meals were provided to carefully control their food intake. For four weeks at a time, subjects ate either a control diet with no nuts or the same diet with pecans substituted for 15 percent of the total calories. Both the control diet and the pecan-rich diet were low in fruits, vegetables and fiber. Calorie levels, as well as protein, carbohydrate, and total fat, were kept the same.