High Doses of Vitamin D Supplementation Has No Current Benefit in Preventing or Treating COVID-19

Natasha Meredith wrote . . . . . . . . .

Scientists from the UK, Europe and the USA, including experts from the University of Birmingham, have published a vitamin D consensus paper warning against high doses of vitamin D supplementation. According to the study, there is currently insufficient scientific evidence to show vitamin D can be beneficial in preventing or treating Covid-19. Its authors advise that the population adhere to Public Health England guidance on supplementation.

Following unverified reports that high doses of vitamin D (higher than 4000IU/d) could reduce the risk of contracting Covid-19 and be used to successfully treat the virus, a new report published in the journal BMJ, Nutrition, Prevention and Health, investigated the current scientific evidence base on the vitamin and its use in treating infections. Vitamin D is a hormone, produced in the skin during exposure to sunlight, and helps regulate the amount of calcium and phosphate in the body, which are needed to keep bones, teeth and muscles healthy.

Professor Sue Lanham-New, Head of the Department of Nutritional Sciences at the University of Surrey and lead author of the study, said: “An adequate level of vitamin D in the body is crucial to our overall health, too little can lead to rickets or the development of osteoporosis but too much can lead to an increase in calcium levels in the blood which could be particularly harmful.”

Examining previous studies in this field scientists found no evidence of a link between high dose supplementation of vitamin D in helping to prevent or successfully treat Covid-19 and cautioned against over supplementation of the vitamin, without medical supervision, due to health risks. Scientists concluded that assertions about the benefit of the vitamin in treating the virus are not currently supported by adequate human studies and are based on findings from studies that did not specifically examine this area.

Claims of a link between vitamin D levels and respiratory tract infections were also examined by scientists. Previous studies in this area have found that lower vitamin D status is associated with acute respiratory tract infections however limitations of the findings of these studies were identified. Findings from the majority of studies were based on data gathered from population groups in developing countries and cannot be extrapolated to populations from more developed countries due to external factors. Scientists believe that there is currently no firm link between vitamin D intake and resistance to respiratory tract infections.

Professor Judy Buttriss, Director General British Nutrition Foundation and co-author of the paper said: “In line with the latest Public Health England guidance on vitamin D, we recommend that people consider taking a vitamin D supplement of 10 micrograms a day during the winter months (from October to March), and all year round if their time outside is limited.

“Levels of the vitamin in the body can also be supplemented through a nutritionally balanced diet including foods that provide the vitamin, such as oily fish, red meat, egg yolk and fortified foods such as breakfast cereals, and safe sunlight exposure to boost vitamin D status.”

Professors Carolyn Greig and Martin Hewison from Birmingham University, are also co-authors on the paper. Professor Greig says: “Most of our vitamin D comes from exposure to sunlight, however for many people, particularly those who are self-isolating with limited access to sunlight during the current pandemic, getting enough vitamin D may be a real challenge. Supplementing with vitamin D is recommended but should be done under the current UK guidance.

“Although there is some evidence that low vitamin D is associated with acute respiratory tract infections, there is currently insufficient evidence for vitamin D as a treatment for COVID-19 and over-supplementing must be avoided as it could be harmful.”

Source: University of Surrey

Prenatal Supplement May Increase Blood Pressure at High Doses

Women who take high-dose folic acid supplements from pre-pregnancy through mid-pregnancy might increase their risk for potentially dangerous high blood pressure, according to new research.

The study, published Monday in the American Heart Association journal Hypertension, sought to answer questions about the safety of prenatal folic acid vitamin supplements.

Folic acid is the human-made form of folate, a form of vitamin B found in leafy green vegetables, fruits, beans and other foods. Everyone needs it, but because it protects unborn children against serious birth defects called neural tube defects, doctors often prescribe prenatal vitamins that contain folic acid of 400 micrograms or more per day.

In the study, researchers focused on how folic acid impacts pregnant women’s chances of developing two complications during pregnancy: gestational hypertension and preeclampsia, a more serious form of high blood pressure. Both complications can lead to poor fetal growth and stillbirth.

The study looked at 4,853 Chinese women who took folic acid supplements, including 1,161 women who developed gestational hypertension and 161 who developed preeclampsia. After adjusting for various factors, the women who took high-dose folic acid supplements – 800 mcg or more – from pre-pregnancy through mid-pregnancy had a 32% higher risk of developing gestational hypertension compared to those who didn’t take folic acid supplements.

The risk for gestational high blood pressure “remained robust,” the authors said, even for women of normal weight, without diabetes, and with no family history of high blood pressure. However, no significant association was found between folic acid supplements and preeclampsia.

“Given the efficiency of folic acid supplement use with a daily dose of 400 micrograms, our findings suggest that high-dose folic acid for long duration should be avoided for (most) women planning or capable of pregnancy,” said the study’s lead author, Nianhong Yang.

Until now, few studies have looked at potential adverse consequences of folic acid, she said.

“More attention should be paid to the impact of folic acid supplementation on gestational and long-term health, especially on the optimal dose and timing of supplementation,” said Yang, a professor who studies nutrition and safety at Tongji Medical College in Wuhan, China.

Yang said the study had several limitations, including a lack of measurements of a specific kind of folate in the blood and information about how different genetic factors influence the way folic acid is metabolized in the body. She called for future studies that explore how unmetabolized folic acid might affect the health of mothers and their children.

Dr. Rossana Orabona, who was not involved in the study and is a researcher in obstetrics and gynecology at the University of Brescia in Italy, said the work was limited by a lack of information about vitamins B6 and B12, autoimmune disorders and levels of homocysteine, an amino acid used to test for vitamin deficiency and heart disease.

The study “is important because it is the first to hypothesize a negative cardiovascular effect of high-dose FA during pregnancy,” she said.

Orabona, who wrote an editorial to accompany the new study, said further research is needed to clarify how folic acid and gestational high blood pressure are impacted by the immune system, and how genetic differences influence folate breakdown, high levels of amino acids in the blood and other factors.

“Adequate evidence is still needed to clarify the relationship between folic acid intake and cardiovascular outcomes in pregnancy.”

Source: American Heart Association

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Better Sleep? Prebiotics Could Help

Lisa Marshall wrote . . . . . . . . .

Think dietary fiber is just for digestive health? Think again.

Specific fibers known as prebiotics can improve sleep and boost stress resilience by influencing gut bacteria and the potent biologically active molecules, or metabolites, they produce, new CU Boulder research shows.

The research could ultimately lead to new approaches to treating sleep problems, which affect 70 million Americans.

“The biggest takeaway here is that this type of fiber is not just there to bulk up the stool and pass through the digestive system,” said Robert Thompson, a postdoctoral researcher in the Department of Integrative Physiology and lead author of the study, published March 2, in the journal Scientific Reports. “It is feeding the bugs that live in our gut and creating a symbiotic relationship with us that has powerful effects on our brain and behavior.”

Food for our bugs

Most people are familiar with probiotics, friendly bacteria present in fermented foods like yogurt and sauerkraut. More recently, scientists have taken an interest in prebiotics—dietary compounds that humans cannot digest but serve as nourishment for our microbiome, or the trillions of bacteria residing within us. While not all fibers are prebiotics, many fibrous foods such as leeks, artichokes, onions and certain whole grains are rich in them.

For the study, the researchers started adolescent male rats on either standard chow or chow infused with prebiotics and tracked an array of physiological measures before and after the rats were stressed.

As reported in the researchers’ previous study, those on the prebiotic diet spent more time in restorative non-rapid-eye-movement (NREM) sleep. After stress, they also spent more time in rapid-eye-movement (REM) sleep, which is believed to be critical for recovery from stress.

While rats eating standard chow saw an unhealthy flattening of the body’s natural temperature fluctuations and a drop in healthy diversity of their gut microbiome after stress, those fed prebiotics were buffered from these effects.

The new study sheds light on how prebiotics can help bust stress.

“We know that this combination of dietary fibers helps promote stress robustness and good sleep and protects the gut microbiome from disruption. With this new study, we wanted to try to identify the signal,” said senior author and Integrative Physiology Professor Monika Fleshner, director of the Stress Physiology Laboratory.

Using a technology called mass spectrometry to analyze the rats’ fecal samples, the researchers measured metabolites, or bioactive small molecules produced by bacteria as food is broken down.

They found rats on the prebiotic diet had a substantially different “metabolome”, or make-up of metabolites. Theirs was higher in dozens of them, including fatty acids, sugars and steroids which may, via gut-brain signaling pathways, influence behavior. The rats’ metabolome also looked different after stress.

For instance, the rats on the standard chow diet saw dramatic spikes in allopregnanolone precursor and Ketone Steroid, potentially sleep-disrupting metabolites, while those on the prebiotic diet saw no such spike.

“Our results reveal novel signals that come from gut microbes that may modulate stress physiology and sleep,” said Fleshner.

In search of a better sleeping pill

While prebiotic dietary fiber is certainly healthy, it’s uncertain whether just loading up on foods rich in it can promote sleep. The rats were fed very high doses of four specific prebiotics, including: galactooligosaccharides, which are present in lentils and cabbage; polydextrose (PDX) an FDA-approved food additive often used as a sweetener; lactoferrin, found in breast milk; and milk fat globular protein, abundant in dairy products.

“You’d probably have to eat a whole lot of lentils and cabbage to see any effect,” said Thompson.

Prebiotic supplements already abound on natural food store shelves. But Fleshner said it’s too soon to say whether a supplement or drug containing such compounds would be safe and effective for everyone. Depending on what their microbial make-up is, different people might respond differently.

“These are powerful molecules with real neuroactive effects and people need to exercise some caution,” she said.

Human studies are already in the works at CU Boulder.

Ultimately, Fleshner believes what they are learning in her lab could lead to a new class of options for people who can’t sleep but don’t like taking narcotics.

“Armed with this information, we might be able to develop a targeted therapeutic that boosts the molecules that buffer against stress and tamps down the ones that seem to disrupt sleep,” she said. “It’s exciting to think about.”

Source: University of Colorado Boulder

Omega-3 Supplements Do not Protect Against Cancer

Omega-3 fats do not protect against cancer – according to new research from the University of East Anglia.

Increased consumption of omega 3 fats is widely promoted globally because of a common belief that it will protect against, or even reverse, diseases such as cancer, heart attacks and stroke.

But two systematic reviews published today find that omega 3 supplements may slightly reduce coronary heart disease mortality and events, but slightly increase risk of prostate cancer. Both beneficial and harmful effects are small.

If 1,000 people took omega 3 supplements for around four years, three people would avoid dying from heart disease, six people would avoid a coronary event (such as a heart attack) and three extra people would develop prostate cancer.

The sister systematic reviews are published today in the British Journal of Cancer and the Cochrane Database of Systematic Reviews.

Omega 3 is a type of fat. Small amounts are essential for good health and can be found in the food that we eat including nuts and seeds and fatty fish, such as salmon.

Omega 3 fats are also readily available as over-the-counter supplements and they are widely bought and used.

The research team looked at 47 trials involving adults who didn’t have cancer, who were at increased risk of cancer, or had a previous cancer diagnosis, and 86 trials with evidence on cardiovascular events or deaths.

More than 100,000 participants were randomised to consume more long-chain omega-3 fats (fish oils), or maintain their usual intake, for at least a year for each of the reviews.

They studied the number of people who died, received a new diagnosis of cancer, heart attack or stroke and/or died of any of the diseases.

Lead author Dr Lee Hooper, from UEA’s Norwich Medical School, said: “Our previous research has shown that long-chain omega 3 supplements, including fish oils, do not protect against conditions such as anxiety, depression, stroke, diabetes or death.

“These large systematic reviews included information from many thousands of people over long periods. This large amount of information has clarified that if we take omega 3 supplements for several years we may very slightly reduce our risk of heart disease, but balance this with very slightly increasing our risk of some cancers. The overall effects on our health are minimal.

“The evidence on omega 3 mostly comes from trials of fish oil supplements, so health effects of oily fish, a rich source of long-chain omega 3, are unclear. Oily fish is a very nutritious food as part of a balanced diet, rich in protein and energy as well as important micronutrients such as selenium, iodine, vitamin D and calcium – it is much more than an omega 3 source.

“But we found that there is no demonstrable value in people taking omega 3 oil supplements for the prevention or treatment of cancer. In fact, we found that they may very slightly increase cancer risk, particularly for prostate cancer.

“However this risk is offset by a small protective effect on cardiovascular disease.

“Considering the environmental concerns about industrial fishing and the impact it is having on fish stocks and plastic pollution in the oceans, it seems unhelpful to continue to take fish oil tablets that give little or no benefit.”

Source: EurekAlert!

Fish Oil Supplements Tied to Improved Male Fertility

Linda Carroll wrote . . . . . . . . .

Men who consume fish oil supplements, which are high in omega-3 fatty acids, might get a boost in fertility, a new study suggests.

After examining data from nearly 1,700 young men, researchers determined that fish oil supplement consumption was associated with a higher sperm count, larger testes and improved levels of hormones that contribute to male fertility, according to the report published in JAMA Network Open.

While all men could benefit from adding omega-3 fatty acids to their diets, the biggest impact would be in those with poor sperm quality, said study coauthor Tina Kold Jensen, a professor at Rigshospitalet and the University of Southern Denmark, in Odense.

That’s because these types of fatty acids are essential to fertility, Jensen said in an email.

“The composition of the sperm cell membrane with rich fatty acid content is critical for proper sperm function,” Jensen explained. “The sperm cell membrane plays a critical role in the key fertilization events. Omega-3 in the sperm membrane increases as the sperm matures and it cannot be synthesized . . . in humans and needs to come from diet.”

To explore the possibility that fish oil and other nutrients might impact male fertility, Jensen and her colleagues approached men between January 1, 2012 and December 31, 2017 who were undergoing physical exams as part of Denmark’s military conscription procedures.

The men were invited to participate in a study of testicular function and those who signed on were given an appointment for an examination and compensated with 500 Danish krone ($74.23).

During their appointments, the men filled out a questionnaire, underwent a physical exam, delivered a semen sample and had blood drawn. They were asked about diet, vitamins or dietary supplements, lifestyle and health issues, and specifically about testicular health issues, such as inguinal hernias, and about sexually-transmitted diseases.

The men were also asked about alcohol consumption, tobacco and marijuana use, and whether their mothers had smoked during pregnancy.

When Jensen and her colleagues analyzed their data, they found that men who had consumed fish oil supplements on fewer than 60 days in the past three months had semen volume that was 0.38 mL higher than those who took no supplements. Men who consumed fish oil on 60 or more days during that period had semen volume that was 0.64 mL higher than men not using the supplements.

Similarly, compared to those who did not take supplements, testicular size in men who consumed fish oil on fewer than 60 days was 0.8 mL larger and among those who consumed it for 60 days or more it was 1.5 mL larger.

Men who consumed fish oil also had higher numbers of sperm than those who did not take the supplements. In addition, they had higher percentages of sperm that swam straight ahead, as opposed to in circles, for example, and that had healthier shapes overall.

The new study is interesting since it looked at men from the general population who were young and healthy, said Albert Salas-Huetos, a researcher in the urology, andrology and IVF unit at the University of Utah in Salt Lake City, who wrote an editorial accompanying the new study.

“Because it’s an observational study you can’t say that there is a causal relationship between fish oil supplements and testicular function,” Salas-Huetos said. “But it’s a good starting point that might (spur) others to do a well-designed randomized controlled trial.”

Until such a study is done, no recommendations can be made about fish oil and fertility, Salas-Huetos said.

Source: Reuters

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