Mechanism that triggers fat formation uncovered

Scientists at the Stanford University School of Medicine in California reveal a control mechanism for fatty tissue to increase intake of calories via a pathway switched on by a hormone and diet-responsive protein dubbed ADAMTS1. This discovery may help to unravel how high-fat diets, stress, and some steroid medications lead to obesity.
[3d image of fat cells]

The hormone ADAMTS1 has been suggested to control fat formation in response to high-fat diets and glucocorticoid medications.

Fat depots – sites where large quantities of mature fat cells are stored along with small amounts of stem cells – are distributed in various locations around the body. The findings – published in Science Signaling – piece together the puzzle of how the stem cells in these areas are triggered to change and develop into more fat cells.

Senior study author Dr. Brian Feldman, Ph.D., assistant professor of pediatrics, and colleagues found that stored mature fat cells secrete the hormone ADAMTS1, which subsequently toggles a “switch” that controls whether the surrounding stem cells differentiate into more fat cells ready to also store fat.

The research indicates that the production of ADAMTS1 hormone may increase fat formation as a result of a high-fat diet and taking glucocorticoid medications.

“Intuitively, people understand that when you eat more, you get fatter,” says Dr. Feldman. “You’re ingesting food, and some signal has to tell your body to make more fat. We didn’t know what was gating or triggering that process in vivo. This new research goes a long way to fill in the in-between steps.”

Previous studies have shown that while mature fat cells have a primary storage function, they also send and receive many hormone signals to help regulate metabolism.

The Stanford team conducted experiments using fat cells and fat stem cells in a lab, followed by mice and human studies to investigate the function of ADAMTS1.

Initially, the scientists aimed to identify genes that change activity in response to glucocorticoid medications. While glucocorticoid medications – such as prednisone and dexamethasone – are widely used to treat inflammatory conditions, they have adverse side effects of promoting obesity and type 2 diabetes.

The researchers set an objective to understand how obesity risk is increased through glucocorticoid medications.

High-fat diet decreased ADAMTS1 hormone, increased fat cells

Mice experiments showed that mature fat cells usually produce and secrete ADAMTS1. However, when mice were given glucocorticoids, the levels of the hormone dropped. When mice were genetically engineered to produce more ADAMTS1 than average, they were found to have smaller fat depots and fewer mature fat cells.

Laboratory experiments revealed that when purified ADAMTS1 was added to fat stem cells in a dish, the hormone blocked the glucocorticoid-induced differentiation from fat stem cells to mature fat cells, which suggests that ADAMTS1 typically acts as a signal outside of fat cells.

Upon reaching the fat stem cell, the researchers say that the hormone transmits instructions through signals inside the cell that overlap with the cells’ glucocorticoid response pathway. The team also points out that a cell-signaling molecule, called pleiotrophin, plays a crucial role in the pathway. Blocking the molecule’s signal appears to block the stem cells’ entire response to ADAMTS1.

Mice were provided with a high-fat diet to examine the effect of the diet on ADAMTS1 signal. As a result of the high-fat diet, the mice became fatter, and new fat cells matured in visceral fat tissue – the fatty tissue that surrounds the internal organs – with decreased ADAMTS1.

However, in contrast, increased ADAMTS1 and less fat cell maturation were seen in subcutaneous fat tissue – the fat under the skin.

These results are consistent with earlier studies that show that more visceral, but not more subcutaneous fat cells, mature when a high-fat diet is consumed. These findings suggest that the hormone is a significant regulator of the difference in mature fat cells between the two types of fat.

Finally, in humans who gained weight from a high-fat diet, the same responses were observed as in the mice experiments.

Fat formed during childhood affects lifelong obesity risk

The research provides an overview of how high-fat diets and both synthetic and natural stress hormones are linked to obesity. Stress hormones transmit a message via ADAMTS1 to mature more fat cells. “We think it is a signal that there may be hard times ahead, a trigger to store as much available energy as you can,” says Dr. Feldman.

Dr. Feldman notes that the same signals and processes take place when people consume a high-fat diet without being stressed or taking glucocorticoid medications. “We’ve basically seen that the glucocorticoid signal is embedded in the high-fat feeding pathway. Connecting those dots together was really exciting,” he adds.

While there may be other undiscovered hormones that influence maturation of fat cells, the potency of ADAMTS1 indicates that the hormone is a dominant signal and a major player, Dr. Feldman continues.

The findings may help understand how fat formation during childhood affects the risk of lifelong obesity.

“We know that fat is a critical endocrine organ, formed almost exclusively during childhood. The rate of fat formation in childhood has lifelong implications, and understanding how that’s controlled and regulated is very important.”

Dr. Brian Feldman, Ph.D.

The team is uncertain, however, of whether the findings could be used as a target for anti-obesity drugs. “If you block fat formation, extra calories have to go somewhere in the body, and sending them somewhere else outside fat cells could be more detrimental to metabolism,” explains Dr. Feldman.

“We know from other researchers’ work that liver and muscle are both bad places to store fat, for example. We do think there are going to be opportunities for new treatments based on our discoveries, but not by simply blocking fat formation alone,” he concludes.

Read about how restoring the omega-3 and omega-6 balance in the diet may curb obesity.

Courtesy: Medical News Today

No Comments Nutrition

Vitamin A orange maize improves night vision

A new study has found that vitamin A-biofortified orange maize significantly improves visual functions in children.

The study was conducted among school-aged children (4 to 8 years old) in rural Zambia. Children who ate orange maize showed improved night vision within six months. Their eyes adapted better in the dark, improving their ability to engage in optimal day-to-day activities under dim light, such as during dusk and dawn. The study was published in The Journal of Nutrition.

“It shows that in populations that are vitamin A deficient, the eyes can respond well to a good source of vitamin A such as orange maize in a fairly short span of time,” says lead author Amanda Palmer of Johns Hopkins Bloomberg School of Public Health. “It also validates the importance of orange maize for tackling vitamin A deficiency as part of a food-based approach.”

Vitamin A deficiency occurs on a continuum. Severe vitamin A deficiency with blinding eye disease and a high risk of death from otherwise curable infections is at one end of the spectrum. But, less severe, incipient vitamin A deficiency – also an important underlying cause of child deaths – is more frequent and difficult to detect. According to the World Health Organization, lack of sufficient vitamin A blinds up to 500,000 children worldwide every year.

Impairment of the eyes’ ability to adapt to low-light conditions is one of the few measurable signs of vitamin A deficiency at its initial stages. In this study scientists used specialized portable equipment to confirm the benefit of eating vitamin A-rich orange maize in a population with marginal deficiency.

“It is an impressive advancement that with portable, more user-friendly equipment scientists are now able to accurately record the changing size of the pupils of the children’s eyes,” says Erick Boy, Head of Nutrition at HarvestPlus and a pediatrician by training. “In this study, the researchers documented how children’s eyes responded to different light conditions before and after a six-month feeding period. This used to be a much more cumbersome task until now.”

Testing for vitamin A deficiency is problematic because blood collection can prove difficult in rural settings. Levels of vitamin A in the blood may also be affected by other factors, such as infections. Rapid, reliable and non-invasive tools to measure the positive impact of nutritional interventions on the vision of those suffering from marginal deficiency were practically unavailable before this study.

Scientists in this study used a new device called a Portable Field Dark Adaptometer (PFDA). The PFDA is a set of goggles manufactured with a digital camera and flash inside. The goggles are connected to a desktop or laptop computer, which can accurately record the response of the pupil in each eye to changing light conditions.

The Johns Hopkins team is the first to use this device on a large scale.

“Until now, most of the tools and techniques used to measure night vision have relied on dark rooms, which are impractical in rural field settings. And, results were subjective,” says Palmer. “With PFDA we don’t need a tent or a dark room and it gives accurate results for people aged 3-4 years or older.” This randomized efficacy study was conducted in Zambia’s Mkushi District among children who were marginally vitamin A deficient. They were served two meals per day, six days a week for six months. Half of the children got meals made from biofortified orange maize, while the other half consumed white maize meals.

The children wore PFDA goggles to record pupil response. “We measured the responsiveness of the pupil to light and calculated the change in pupil size over a period of time. These goggles enabled us to monitor something that was not possible before,” says Palmer.

The biofortified orange maize used in this study was conventionally bred to have higher levels of beta-carotene, a naturally occurring plant pigment that the body converts into vitamin A with higher efficiency as the body stores of the vitamin decrease.

Article: Provitamin A Carotenoid-Biofortified Maize Consumption Increases Pupillary Responsiveness among Zambian Children in a Randomized Controlled Trial, Amanda C Palmer, Katherine Healy, Maxwell A Barffour, Ward Siamusantu, Justin Chileshe, Kerry J Schulze, Keith P West Jr., and Alain B Labrique, The Journal of Nutrition, doi: 10.3945/?jn.116.239202, published 19 October 2016.

Courtesy: Medical News Today

No Comments Nutrition

A new look at vitamin D challenges the current view of its benefits

Research in C. elegans shows the popular supplement engages longevity genes to increase lifespan and prevent the accumulation of toxic proteins linked to many age-related diseases.

A simple Google search for “what does vitamin D do?” highlights the widely used dietary supplement’s role in regulating calcium absorption and promoting bone growth. But now it appears that vitamin D has much wider effects – at least in the nematode worm, C. elegans. Research at the Buck Institute shows that vitamin D works through genes known to influence longevity and impacts processes associated with many human age-related diseases. The study, published in Cell Reports, may explain why vitamin D deficiency has been linked to breast, colon and prostate cancer, as well as obesity, heart disease and depression.

“Vitamin D engaged with known longevity genes – it extended median lifespan by 33 percent and slowed the aging-related misfolding of hundreds of proteins in the worm,” said Gordon Lithgow, PhD, senior author and Buck Institute professor. “Our findings provide a real connection between aging and disease and give clinicians and other researchers an opportunity to look at vitamin D in a much larger context.”

Study provides links to human disease

The study shines a light on protein homeostasis, the ability of proteins to maintain their shape and function over time. It’s a balancing act that goes haywire with normal aging – often resulting in the accumulation of toxic insoluble protein aggregates implicated in a number of conditions, including Alzheimer’s, Parkinson’s and Huntington’s diseases, as well as type 2 diabetes and some forms of heart disease. “Vitamin D3, which is converted into the active form of vitamin D, suppressed protein insolubility in the worm and prevented the toxicity caused by human beta-amyloid which is associated with Alzheimer’s disease,” said Lithgow. “Given that aging processes are thought to be similar between the worm and mammals, including humans, it makes sense that the action of vitamin D would be conserved across species as well.”

Postdoctoral fellow Karla Mark, PhD, led the team doing the experiments. She says the pathways and the molecular network targeted in the work (IRE-1/XBP-1/SKN-1) are involved in stress response and cellular detoxification. “Vitamin D3 reduced the age-dependent formation of insoluble proteins across a wide range of predicted functions and cellular compartments, supporting our hypothesis that decreasing protein insolubility can prolong lifespan.”

Clinicians weigh in

“We’ve been looking for a disease to associate with vitamin D other than rickets for many years and we haven’t come up with any strong evidence,” said Clifford Rosen, MD, the director of the Center for Clinical and Translational Research and a senior scientist at the Maine Medical Center Research Institute studying osteoporosis and obesity. “But if it’s a more global marker of health or longevity as this paper suggests, that’s a paradigm shift. Now we’re talking about something very different and exciting.”

“This work is really appealing and challenging to the field,” said Janice M. Schwartz, MD, a professor of medicine and bioengineering and therapeutic sciences the University of California, San Francisco, and a visiting research scientist at the Jewish Home in San Francisco. She has studied vitamin D supplementation in the elderly. “We focus on vitamin D and the bones because that’s where we can measure its impact. I believe that vitamin D is as crucial for total body function and the muscles as it is for bones. Vitamin D influences hundreds of genes – most cells have vitamin D receptors, so it must be very important.”

Current recommendations and controversies

How much vitamin D do humans need and how do they best get it? The issue is confusing with disagreement rampant among experts. The Institute of Medicine’s (IOM) latest recommendations (from 2011) pertain only to vitamin D’s role in bone health and fracture reduction. Experts concluded that evidence for other proposed benefits of vitamin D was inconsistent, inconclusive, or insufficient to set recommended intakes. The IOM recommends a daily intake of 600 International Units (IU) for people between 1 and 70 years old, and 800 IU daily for those older. The upper limit – the levels above which health risks are thought to increase – was set at 4,000 IU per day for adults. Excess vitamin D can raise blood levels of calcium which leads to vascular and tissue calcification, with subsequent damage to the heart, blood vessels and kidneys.

Many vitamin D researchers and some health organizations, including the Endocrine Society and the International Osteoporosis Foundation, disagreed with the IOM’s recommendations for daily intake, instead recommending supplementation of 800 to 2,000 IU per day, at least for people known or likely to have low blood levels. The disagreement highlights another difficulty: measuring blood levels of vitamin D is problematic given a lack of standardization and reliability among labs. Blood levels of the precursor to the active vitamin D are measured in nanograms per milliliter (ng/mL) in the U.S. Many researchers and expert groups have argued that a blood level of at least 30 ng/mL is optimal; some call for optimum levels to be set at 40 or 50 ng/mL. But the IOM report concluded that blood levels starting at 20 ng/mL would be adequate for bone health in the vast majority of people.

Universal supplementation?

Based on problems with laboratory standards and a lack of agreed-upon meaning of results, both Rosen and Schwartz agree that the costs of universal testing for vitamin D levels would outweigh the benefits. Instead, both recommend universal supplementation of between 800 – 1000 IU of vitamin D daily for adults. “It’s safe, there’s no reason for anyone not to take it,” said Schwartz, who has written about vitamin D for the popular press.

Schwartz says older adults may be particularly prone to vitamin D deficiency because the skin’s ability to manufacture vitamin D from sun or UV light exposure declines with age, adding that the elderly are less likely to spend time in the sun, are more likely to have diets lacking in sources of vitamin D, and may suffer from gastrointestinal disorders that make it harder to absorb vitamin D. Others prone to vitamin D deficiency include those with darker skin and those who live in higher latitudes where the sun’s angle is low in the sky.

Bringing it back to aging

Given adequate funding, senior author Lithgow plans to test vitamin D in mice to measure and determine how it affects aging, disease and function – and he hopes that clinical trials in humans will go after the same measurements. “Maybe if you’re deficient in vitamin D, you’re aging faster. Maybe that’s why you’re more susceptible to cancer or Alzheimer’s,” he said. “Given that we had responses to vitamin D in an organism that has no bone suggests that there are other key roles, not related to bone, that it plays in living organisms.”

Lithgow gave a shout out to the tiny, short-lived nematode worms which populated this study. “Working in these simple animals allows us to identify novel molecular pathways that influence how animals age,” he said. “This gives us a solid starting point to ask questions and seek definitive answers for how vitamin D could impact human health. We hope that this work will spur researchers and clinicians to look at vitamin D in a larger, whole-person context that includes the aging process.”

The work was supported by funding from the Larry L. Hillblom Foundation, the Glenn Foundation for Medical Research and grants from the National Institutes of Health: UL102417, R01AG029631-01A1, R21AG048528, R01AG029631, PL1 AG032118, 1S10 OD016281.

Article: Vitamin D Promotes Protein Homeostasis and Longevity via the Stress Response Pathway Genes skn-1, ire-1, and xbp-1, Karla A. Mark, Kathleen J. Dumas, Dipa Bhaumik, Birgit Schilling, Sonnet Davis, Tal Ronnen Oron, Dylan J. Sorensen, Mark Lucanic, Rachel B. Brem, Simon Melov, Arvind Ramanathan, Bradford W. Gibson, Gordon J. Lithgow, Cell Reports, doi: 10.1016/j.celrep.2016.09.086, published 25 October 2016.

Courtesy: Medical News Today

No Comments Nutrition

Are There Any Health Benefits to Drinking Alkaline Water?

Alkaline water is the opposite of acidic water. It has a higher pH level than plain water.

Claims of health benefits have helped increase the popularity of alkaline diets and sales of machines that turn water alkaline. Ionizing machines are one example of these products, which can cost over a thousand dollars.

But what scientific evidence lies behind drinking alkaline water? Are there any proven health benefits?

What is alkaline water?

Alkaline water has a high pH:

a pH balance chart showing 1-13 /acid to alkaline

pH is said to be an abbreviation of “power of hydrogen.”
  • Neutral is a pH of 7.0
  • Regular water from rainfall is usually slightly acidic, just below neutral on the pH scale
  • Acidic, or basic, water is below a pH of 7.0, down to zero
  • Vinegar is around pH 3, lemon juice is around pH 2, and battery acid is around pH 1
  • Alkaline water is above pH 7
  • Baking soda is between pH 8 and 9, and Milk of Magnesia is between pH 10 and 11

The pH of water is changed by chemicals and gases. Carbon dioxide from the air increases acidity, for example. This is why rainwater’s pH is below neutral.

Water that is too high or too low in pH has adverse effects. Water that is too alkaline has a bitter taste. It can cause deposits to encrust pipes and appliances. Highly acidic water may corrode metals or even dissolve them.

How to get alkaline drinking water

Machines called ionizers make water alkaline, but they are expensive.

Bottled mineral water tends to be neutral or slightly alkaline. Some manufacturers may state the pH level of their bottled waters.

Sparkling waters are acidic. Carbonation introduces carbon dioxide, which lowers the pH.

Alkaline water and bone health

A man drinks from a bottle of water

Bottled mineral water may be slightly alkaline.

Some research has been done into effects of alkaline intake on bones. A study published in Bone found an effect on bone resorption. Bone resorption is the process where old bone cells are broken down and replaced by new ones.

Less bone resorption and more mineral density result in better bone strength.

The study examined a very small number of people, though. Only 30 women took part in the research.

The authors concluded “that a bicarbonate- and calcium-rich alkali mineral water decreased bone resorption more than a calcium-rich acidic mineral water.”

They called for more work to be done, to see if the benefit of less bone resorption was long-term and could improve bone mineral density.

Large review of evidence

Another study, published in Nutrition Journal, looked at an alkaline diet rather than alkaline drinking.

The review looked into whether an acidic diet could cause osteoporosis, a disease marked by weak and brittle bones.

Reviewing the background to the study, the authors noted a high number of claims being made on the Internet. These claims suggested “that alkaline diets and related commercial products counteract acidity, help the body regulate its pH, and thus prevent disease processes.”

The review used high-quality evidence to conclude that acid from the modern diet does not cause osteoporosis. It also concluded that an alkaline diet or alkaline supplements or salts do not prevent osteoporosis.

Alkaline water and cancer

A review of the effects of alkalis on cancer was published in the journal BMJ Open.

The review assessed thousands of studies. However, the authors found only one proper, randomized test of acid in the diet and cancer of the urinary bladder.

They found no studies about alkaline water and cancer in humans. The review did find some other types of study of alkaline water, “none of which supported the promotions that suggest alkaline water supports good health.”

They found only harms from alkaline water, including:

  • Restricting the release of stomach acids
  • Reducing gall bladder emptying
  • Poisonous reactions
  • Heart problems

The alkaline diet, said the authors, is promoted to correct “the acid state that the modern diet creates.” The alkaline diet includes more fresh fruits and vegetables and reduced protein intake.

“The marketing of the alkaline diet promotes not only a diet, but also the sale of related supplements and water alkalinizer machines through almost every media medium, including websites, books, and videos,” the authors wrote, adding:

“In our experience, patients with cancer are approached by salespeople who are promoting water alkalinizers as a way to treat their cancer.”

The overall conclusion of the paper was there was no evidence to support the use of the alkaline diet:

“Despite the promotion of the alkaline diet and alkaline water by the media and salespeople, there is almost no actual research to either support or disprove them.”

Alkaline water and acid reflux

Two men and two women in conversation at the gym whilst holding drinks

Maintaining hydration is important for everyone.

Acid reflux disease is when the contents of the stomach, which are acidic, splash back up the food pipe.

Acid reflux that keeps happening for a long time can cause damage and a disease known as gastroesophageal reflux disease, or GERD.

A study published in Annals of Otology, Rhinology & Laryngology found that drinking alkaline water might be worth further study as a supplement to other treatment for reflux disease.

It found that alkaline water at pH 8.8 stops an enzyme that is connected to reflux disease. It also appeared to reduce the acidity of the stomach contents.

The work was done in a laboratory rather than in humans. More research would be needed to support these findings.

Summary of health benefits to drinking alkaline water

There is no good evidence that drinking alkaline water is good for health or treats any medical conditions.

It may be wise to think twice about claims that alkaline diets or water are especially good for people.

Why is hydration important?

Getting enough fluid to keep the water balance of our bodies is vital for life.

Bodies are made up of water to about two-thirds of body mass. People start to dehydrate if they stop taking in water.

The body uses and loses water through sweating, urination, and so on. If not enough water is taken in, cells become deprived of nutrients very quickly. Blood pressure also starts to fall if there is not enough water to maintain a healthy blood volume.

Some people are more at risk from the effects of water loss than others. Dehydration in the very young or very old, for example, becomes dangerous quickly.

Courtesy: Medical News Today

No Comments Nutrition

Cranberry extract disrupts spread of hard-to-treat bacteria

New research reveals fresh clues on the infection-fighting properties of cranberries. Researchers in Canada showed how cranberry extract rich in a particular type of compound successfully disrupted cell-to-cell communication in bacteria responsible for hard-to-treat infections.

The study shows cranberry extract rich in a particular group of compounds may help stop the spread of a bacterium that causes infections in hospital patients and people with weak immune systems.

The team – from McGill University in Montreal and INRS-Institut Armand-Frappier in Laval, both in Canada – reports the discovery in the journal Scientific Reports.

Previous studies have already shown that cranberries contain proanthocyanidins (PACs), a class of compound that fends off illness through various antibacterial properties.

For example, they can stop certain bacteria from sticking onto the wall of the bladder and causing a urinary tract infection.

However, the team behind the new study also wanted to find out if cranberry compounds can control the virulence of bacteria, and therefore reduce the severity of an infection.

They suggest their findings not only give fresh clues on how PACs in cranberries fight bacteria, but they could also lead to new approaches to infection control.

Cranberry compounds disrupt bacterial cell communication

For their study, the team used fruit flies – a useful model for studying human infections at the level of cells and molecules.

They found severity of bacterial infection was reduced in fruit flies fed on cranberry extract rich in PACs, compared with cranberry-free fruit flies. The cranberry-fed flies also lived longer.

Further investigation revealed the cranberry PACs disrupt a cell communication process called “quorum sensing” that forms an essential link in a chain of events involved in the spread and severity of chronic bacterial infections.

The research focuses on a bacterium called Pseudomonas aeruginosa, which can cause infections in hospital patients and people with weak immune systems.

Patients on breathing machines, fitted with catheters, or with burns or surgical wounds are potentially at risk for serious, life-threatening infections.

Implications for antibiotic resistance

Pseudomonas infections are generally treated with antibiotics. However, because of increasing antibiotic resistance, these and other hospital-acquired bacterial infections are becoming harder to treat.

In the United States, there are an estimated 51,000 healthcare-associated P. aeruginosa infections every year. Of these, around 13 percent are multi-drug resistant, and about 400 deaths are due to these infections.

In their paper, the researchers discuss the relevance of their findings to the problem of drug resistance. They found that while the cranberry PACs disrupted bacterial quorum sensing, this did not kill the cells – it just disrupted their communication and spread.

They suggest this could be important because one reason conventional antibiotics lead to drug resistance is because they kill bacteria – which they note poses “strong selective pressure in any environment.”

However, the authors also point out it would be “naive to presume” that by disrupting quorum sensing one would not be placing any selective pressures that might lead to resistance against drugs that work using this mechanism.

Nonetheless, the findings are still useful in that they “expand our strategies for combating pathogen resistance by identifying novel anti-microbial and anti-virulence agents,” they conclude.

“This means that cranberries could be part of the arsenal used to manage infections and potentially minimize the dependence on antibiotics for the global public.”

Co-senior author Prof. Nathalie Tufenkji, McGill University

The study was funded by the Natural Sciences and Engineering Research Council of Canada, the Wisconsin Cranberry Board, and the Cranberry Institute.

Learn how cranberry capsules, but not necessarily juice, can help reduce risk of urinary tract infection.

Courtesy: Medical News Today

No Comments Nutrition

How sweet it is: Artificial sweeteners in blood

A recent study by investigators at the National Institute of Diabetes, Digestive and Kidney Diseases at the National Institutes of Health measured how much artificial sweetener is absorbed into the blood stream by children and adults after drinking a can of diet soda. Results of this study are published in Toxicological & Environmental Chemistry.

The team measured the artificial sweeteners sucralose and acesulfame-potassium, which are found in a wide range of packaged foods and beverages. These artificial sweeteners, also including saccharin and aspartame, have received a lot of attention lately because it has been found that they are not inert chemicals with a sweet taste, but active substances that can affect the metabolism.

Despite their approval as food additives following the submission of detailed safety data to the United States Food and Drug Administration (FDA), concerns about their safety and especially about their long-term health effects remain. Artificial sweetener use is increasing worldwide because it is universally accepted that high sugar consumption promotes a variety of health problems, including obesity and diabetes. The food industry responds to the consumer demand, and increasingly replaces sugar with artificial sweeteners in order to provide tasty goods with lower sugar content. Most consumers expect that weight loss will result from switching to artificial sweeteners (because they contain no or fewer calories), but paradoxically the opposite may happen.

Given this background, the authors performed a study to extend previous investigations into plasma concentrations of sucralose and acesulfame-potassium. Artificial sweetener concentrations were measured among adults following ingestion of various doses of sucralose with or without acesulfame-potassium, both in diet soda and mixed in seltzer or plain water. Results obtained in adults were then compared with measurements obtained in children.

The study comprised 22 adults aged 18-45 and 11 children aged 6-12 with no known medical conditions and who were not using any medications, enrolled in a randomized same-subject crossover study. The protocol was approved by the Institutional Review Board of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

The results of the study demonstrate that, compared to adults, children had double the concentrations of plasma sucralose after ingestion of a single twelve ounce can diet soda. The same research team previously found that these artificial sweeteners were also present in breast milk when mothers ingested foods, drinks, medicines or other products that contained artificial sweeteners. Since infants have less ability to clear substances from their blood stream via the kidneys (lower glomerular filtration rate up to age 2 years), the authors speculate that the infants’ artificial sweetener blood levels may be proportionately even higher.

These results are important because early life exposure to artificial sweeteners may influence a child’s future taste preferences, diet and metabolic fate. Since it is known that children generally prefer more sweetness than adults, they are especially vulnerable to the intense sweetness provided by artificial sweeteners.

The findings of this study also highlight the fact that some people absorb relatively small amounts of artificial sweeteners and some exorbitantly high amounts. Overall, this study will help others with the design and interpretation of crucial future research to better understand what artificial sweeteners do to our health.

Article: Plasma concentrations of sucralose in children and adults, Kristina I. Rother et al., Toxicological & Environmental Chemistry, doi: 10.1080/02772248.2016.1234754, published online 17 October 2016.

Courtesy: Medical News Today

No Comments Nutrition

Restoring evolutionary fatty acid balance may curb obesity

Many organizations and scientists consider the ever-increasing 600 million people around the globe who are obese to be a result of an imbalance between energy intake and expenditure. However, new research suggests that to prevent and manage obesity in the world’s population, omega-6 and omega-3 fatty acids need to be rebalanced in the food chain.
[Foods containing omega fatty acids]

The imbalance between omega-3 and omega-6 in the diet, not solely energy intake and expenditure, is suggested to play a significant role in obesity.

Nutrition policies that have centered on the mismatch between “calories in and energy out” in the belief that all calories are equal, have “failed miserably over the past 30 years,” disputes Dr. Artemis Simopoulos, of the Center for Genetics, Nutrition, and Health in Washington, D.C., and Dr. James DiNicolantonio, of Saint Luke’s Mid America Heart Institute in Kansas.

Drs. Simopoulos and DiNicolantonio note – in an editorial published in the online journal Open Heart – that humans evolved on a diet that had equal amounts of omega-6 and omega-3 fatty acids. This intrinsic balance is critical to babies’ development during pregnancy and breast-feeding, and in preventing and managing chronic diseases.

Now, this 1:1 ratio has been replaced by an omega-6 to omega-3 ratio of 16:1. This substantial ratio difference has emerged as a consequence of significant changes in the food supply over the last 100 years.

Food technology and modern agriculture have led to production of vegetable oils – such as sunflower, safflower, cottonseed, soybean, and corn – rich in omega-6 fatty acids, and a swap in animal feeds from grass to grain. Traditionally, animals grazed on grass containing omega-3, whereas the grains, corn, and soy that they are now fed are high in omega-6.

The change in oils and animal feed has increased levels of linoleic acid and arachidonic acid – two types of omega-6. Linoleic acid levels have soared in the diet from oils and arachidonic acid from meat, eggs, and dairy.

High dietary intake of omega-6 has several adverse outcomes, according to researchers. The high levels of omega-6 can lead to increased white fatty tissue and chronic inflammation, which are both hallmarks of obesity and linked to type 2 diabetes, heart disease, metabolic syndrome, and cancer.

Omega-6 can also prevent the browning of white fatty tissue to “good” energy-burning brown fatty tissue and can increase the risk of blood clotting.

Substituting meat for fish, changing cooking oils may rebalance fats

While the body needs both omega-3 and omega-6, the balance between the two is crucial, say the researchers. Fatty acids act directly on the nervous system, influencing food intake and sensitivity of the hormones involved in blood sugar control and appetite suppression.

Omega-3 and omega-6 are metabolically and functionally different. Previous studies have linked omega-3 fatty acids to a decrease in the development of fatty tissue and weight loss, while high concentrations of omega-6 have been associated with an increased risk of weight gain

The authors point out that different populations metabolize fatty acids differently, which makes them more or less at risk of the consequence of an imbalance. The authors write:

“The time has come to return the omega-3 fatty acids in the food supply and decrease the omega-6 fatty acids by changing the cooking oils and eating less meat and more fish. The composition of the food supply must also change to be consistent with the evolutionary aspects of diet and the genetics of the population.”

“The scientific evidence to balance the omega-6 to omega-3 ratio is robust and necessary for normal growth and development, prevention and treatment of obesity and its comorbidities including diabetes, cardiovascular disease, and cancer,” they add.

Drs. Simopoulos and DiNicolantonio say that these objectives can be accomplished by studies focusing on the metabolism of nutrients, genes, and their function.

“It is the responsibility of the governments and international organizations to establish nutrition policies based on science and not continue along the same path of focusing exclusively on calories and energy expenditure, which have failed miserably over the past 30 years,” they conclude.

Read about how omega-3 may help prevent environmentally induced lupus.

Courtesy: Medical News Today

No Comments Nutrition

New guideline on calcium and vitamin D supplementation

A new evidence-based clinical guideline from the National Osteoporosis Foundation (NOF) and the American Society for Preventive Cardiology (ASPC) says that calcium with or without vitamin D intake from food or supplements that does not exceed the tolerable upper level of intake (2,000 to 2,500 mg/d) should be considered safe from a cardiovascular standpoint. Obtaining calcium from food sources is preferred, but supplements can be used to address dietary shortfalls. The guideline is published in Annals of Internal Medicine.

Calcium supplements have been recommended for persons who do not consume adequate calcium from their diet as a standard strategy for preventing osteoporosis-related fractures. Conflicting reports have suggested that calcium intake, particularly from supplements, may have either beneficial or harmful effects on cardiovascular outcomes. To update the evidence on calcium and vitamin D, investigators from the Tufts University School of Medicine reviewed randomized trials and prospective cohort studies published since their last evidence report in 2009. Their findings were used to inform the joint clinical guideline from NOF and ASPC.

A total of 31 studies were included in the review. Of the four randomized trials reviewed, none found a statistically significant difference in risk for cardiovascular events or mortality between groups receiving supplements of calcium alone or calcium plus vitamin D compared to those receiving placebo. None of the 27 cohort studies included in the review conclusively linked total, dietary, or supplemental calcium intake levels to cardiovascular disease and cerebrovascular disease, mortality, or all-cause mortality. Because excessive calcium intake is nearly impossible to achieve via diet, safety of supplementation had been an area of concern. Of the three supplementation-specific trials included in the review, none found a statistically significant effect of calcium supplementation on cardiovascular disease outcomes. Based on this moderate-quality evidence, the review team concluded that calcium intake from food or supplement sources at levels within the recommended tolerable range should be considered safe for generally healthy adults.

Guideline: Lack of Evidence Linking Calcium With or Without Vitamin D Supplementation to Cardiovascular Disease in Generally Healthy Adults: A Clinical Guideline From the National Osteoporosis Foundation and the American Society for Preventive Cardiology, Stephen L. Kopecky, MD; Douglas C. Bauer, MD; Martha Gulati, MD; Jeri W. Nieves, PhD; Andrea J. Singer, MD; Peter P. Toth, MD, PhD; James A. Underberg, MD; Taylor C. Wallace, PhD; Connie M. Weaver, PhD, Annals of Internal Medicine, doi: 10.7326/M16-1743, published 25 October 2016.

Evidence Review: Calcium Intake and Cardiovascular Disease Risk: An Updated Systematic Review and Meta-analysis, Mei Chung, MPH, PhD; Alice M. Tang, SCM, PhD; Zhuxuan Fu, MPH; Ding Ding Wang, MPH; Sydne Jennifer Newberry, MS, PhD, Annals of Internal Medicine, doi: 10.7326/M16-1165, published 25 October 2016.

Editorial: Calcium Supplements and Cardiovascular Disease Risk: What Do Clinicians and Patients Need to Know? Karen L. Margolis, MD, MPH; JoAnn E. Manson, MD, DrPH, Annals of Internal Medicine, doi: 10.7326/M16-2193, published 25 October 2016.

Courtesy: Medical News Today

No Comments Nutrition

Dietary intake and function in amyotrophic lateral sclerosis: Are they associated?

Is what you eat associated with better function and respiratory function for patients with amyotrophic lateral sclerosis (ALS) soon after diagnosis?

A new article published online by JAMA Neurology used data from a study of ALS progression to examine associations between nutritional intake, function and respiratory function at the time of study entry for patients who had ALS symptoms for 18 months or less.

ALS is a severe neurodegenerative disorder that causes atrophy, paralysis and eventually respiratory failure. The median survival time for ALS ranges from 20 to 48 months, although 10 percent to 20 percent of patients can live longer than 10 years.

There is interest in the potential role of nutrition and environmental factors in the pathogenesis (development) of ALS and in disease progression.

The current analysis by Jeri W. Nieves, Ph.D., of the Mailman School of Public Health at Columbia University, New York, and coauthors included 302 patients (178 of them men; average age about 63) with ALS. The analysis relied on nutrient intake reported using a food questionnaire; rating scores were used to measure function; and respiratory function was measured using the percentage of predicted force vital capacity (FVC). Higher rating scores and a higher percentage of FVC indicated better function.

Antioxidant nutrients, foods high in carotenoids, fruits, and vegetable intake appear to be associated with better ALS function at baseline, according to the results.

Authors note their study results cannot establish cause and effect. Also, the study relied on a food questionnaire and those may not always represent a true daily diet.

“Those responsible for nutritional care of the patient with ALS should consider promoting fruit and vegetable intake since they are high in antioxidants and carotenes,” the study concludes.

Article: Association Between Dietary Intake and Function in Amyotrophic Lateral Sclerosis, Jeri W. Nieves, PhD et al., JAMA Neurology, doi:10.1001/jamaneurol.2016.3401, published online 24 October 2016.

Courtesy: Medical News Today

No Comments Nutrition

Drinking an ice slurry/water mix helps body cope with exertion in hot weather

New research from the University of Montana demonstrates a unique relationship between fluid volume and fluid temperature during arduous work in the heat. The study, published in Wilderness & Environmental Medicine, indicated that an ice slurry/water mixture was as effective as ambient water even when consumed in half the quantity. Investigators also emphasized the importance of rest.

“While the common approach to managing health in hot environments centers around maintaining hydration, limited attention is devoted to managing heat production from hard work or play,” explained lead investigator Brent C. Ruby, PhD, FACSM, Director of the Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula. “It should be obvious that as the temperature rises, so does the body’s need for proper fluid intake patterns. This ensures that blood and sweat volume can be maintained to continually enable heat loss through evaporative cooling (good old fashioned sweating). However, coaches, trainers, clinicians, medics, and safety officers continually emphasize the importance of proper hydration without providing sound guidance and attention to proper management of heat production from the working muscle. ”

Existing research indicates that fluids should be consumed to avoid more than an acute 2% body mass loss (reflecting modest dehydration) that is known to hinder performance and increase the risk of heat-related injury. Currently, the accepted minimum hydration rate is 2 grams of water per kilogram of body mass. However, controversy surrounds the link between moderate lapses in hydration status and risk for heat-related injury.

While these guidelines attempt to dictate how much water should be consumed, there is no existing recommendation for the optimal temperature of the water. In order to better understand how water temperature influences the body, investigators had subjects exercise in 88° F air temperatures (with 50% relative humidity) for three hours.

“While these guidelines serve as just that, ‘guidelines,’ constant access to body weight scales for repeated measures of nude body weight is impractical for nearly all sport or occupational settings. Reducing the emphasis on fluid volume, allowing cold fluid access, and emphasizing the need to rest adequately during the training session or workshift should become common practice,” stated Dr. Ruby.

During the trial, participants were randomly given one of three treatments: ambient temperature water at a rate of 2g·kg-1 of body mass; ice slurry (2/3 shaved ice and 1/3 water) at a rate of 2g·kg-1 of body mass; or the ice slurry mixture, but at a reduced rate of 1g·kg-1 of body mass. Each 2g·kg-1 body weight drink was provided at 10-minute intervals.

Several parameters indicating the physiological and thermoregulatory challenge during the three-hour exercise trials were measured. Investigators found the ice slurry, even at amounts that resulted in a 2% body mass loss, faired just as well as when subjects were provided the full amount of room temperature water. “There were no differences in rectal temperature, heart rate, physiological strain index, skin temperature, sweat loss, or rating of perceived exertion during three hours of exercise in the heat when participants were provided half the volume of fluid in the form of the ice slurry in comparison to ambient temperature water,” said Dr. Ruby.

While a reduced amount of ice slurry was just as effective as regular water, when the ice slurry was provided at the full rate, participants demonstrated significantly improved thermoregulation. Rectal and skin temperatures, heart rate, and overall all physiological strain were lower at the end of the exercise period, making the full amount of ice slurry the most effective liquid for managing thermoregulation and physiological responses.

“We want to emphasize that the temperature of fluids delivered will alter the physiological and thermoregulatory response during work in the heat. Consuming ambient temperature water did not improve the physiological or thermoregulatory responses compared to the one-half volume ice slurry/water mixture,” noted Dr. Ruby.

Previous studies have pointed to cold water as being a more effective method of hydration, but this new information reveals that temperature may be as important as volume. This means that people exercising or working in very hot conditions may be able to carry and drink less water if they are able to keep it ice cold. “Military training and operations, wildland fire suppression, and varied athletic/recreational pursuits require people to work or exercise in hot environments for extended periods of time. These activities also mandate the self-transport or frequent resupply of fluid to sustain performance for the duration of the work shift or event,” added Dr. Ruby. “For these individuals the weight of fluid that must be carried increases the metabolic demand and subsequent heat production, posing hindrances to completing the job or event.”

As more people become active outdoors and with temperatures on the rise, it is vital that we figure out the most effective ways to manage heat stress and remain safe in all conditions. This new study reveals that consuming an ice slurry mixture may offer protective effects against heat stress. “Individuals working in hot environments should be mindful of both the volume and temperature of the fluid they consume,” concluded Dr. Ruby. “Further research should be done to determine impact that exchanging fluid temperature for fluid volume has on exercise performance.”

Article: Thermoregulation During Extended Exercise in the Heat: Comparisons of Fluid Volume and Temperature, Walter S. Hailes, MS; John S. Cuddy, MS; Kyle Cochrane, MS; Brent C. Ruby, PhD, Wilderness & Environmental Medicine, doi: 10.1016/j.wem.2016.06.004, published September 2016.

Courtesy: Medical News Today

No Comments Nutrition