For many decades, scientists have known that low caloric intake is linked with greater longevity in humans and other organisms. The researchers were interested in exploring how fasting worked at the molecular level, specifically in the stem cells in the intestine.

Intestinal stem cells are responsible for maintaining the lining of the intestine, which typically renews itself every five days. When an injury or infection occurs, stem cells are key to repairing any damage. As people age, the regenerative abilities of these intestinal stem cells decline, making it more difficult to recover from gastrointestinal infections or other conditions that affect the intestine.

It’s been observed that the prevalence of both metabolic syndrome and vitamin D deficiency have been observed among postmenopausal women in India. But as yet, there has been no research linking the two conditions.

To see if there was a link, Indian researchers conducted a cross-sectional study of women in rural West Bengal. They randomly selected 222 postmenopausal women and assessed their serum vitamin D levels, blood pressure, waist circumference, fasting blood glucose, triglyceride levels and HDL cholesterol.

Results, published in the journal PLOS One found was that 70% of the participants suffered from either vitamin D insufficiency (51%) or deficiency (19%).

The prevalence of metabolic syndrome among the women studied was 46%. Among these women, 75% exhibited vitamin D insufficiency (22%) or deficiency (53%).

In addition, 68% of those with a waist circumference of 80cm or more were vitamin D-insufficient or deficient.

The same was observed in 84% of those with a fasting blood glucose measurement of 110mg/dl, 75% of those with a triglyceride level of 150mg/dl, 74% of those with HDL cholesterol level of below 50mg/dl, and 70% of those with a blood pressure of 130/85 or higher.

Potential risk factor

Metabolic syndrome affects nearly a quarter of the world’s adult population, and it is defined by a group of risk factors that put you on the road to diabetes and heart disease. The characteristic symptoms include obesity around the waistline and at least two of the following: high blood sugar levels, high blood pressure or high cholesterol. Sufferers usually also have excess fat in their liver.

The main cause of metabolic syndrome appears to be a diet high in fat or carbohydrate. However, observational studies have also linked metabolic syndrome to vitamin D deficiency, which affects 30-60% of the world’s population.

We’ve previously reported on an animal experiment, conducted by researchers from the US and China, in which boosting levels of circulating vitamin D in mice improved gut flora, which in turn improved the symptoms of metabolic syndrome in the animals.

Not all studies agree that there is a link between vitamin D and metabolic syndrome. However, referencing a broad range of previous studies, the authors of the current study conclude: “Vitamin D deficiency or insufficiency, therefore, may be one of the potential risk factors for developing metabolic syndrome in the studied population…”​

Future research should focus on other ethnicities to see if the association is as strong in these.

Ashwagandha (Withania somnifera​) is an adaptogenic herb used widely in Ayurvedic medicine. Supplements have grown in popularity in the mainstream market due to the herb’s ability to reduce stress and anxiety, decrease serum cortisol and stress-related food cravings, enhance memory and cognition, increase endurance and strength, support healthy sexual function, and in men increase natural testosterone.

In this small trial, published in the Journal of Alternative and Complementary Medicine, Indian researchers evaluated the effects of a commercial ashwagandha supplement (KSM-66, manufactured by Ixoreal Biomed) on thyroid hormone levels.

The double blind, randomised, placebo-controlled trial included 50 subjects who received either ashwagandha supplements (600 mg daily) or placebo for eight weeks. Results showed that the herbal supplement helped balance thyroid stimulating hormones (TSH), serum thyroxine (T4) and serum triiodothyronine (T3) – achieving change toward normalisation of 19%, 45% and 21% respectively.

“The results of the present study are in accordance with previous studies,” wrote the researchers. “The results indicate a possible role for ashwagandha in regulating HPT axis. The anti-stress and cortisol-lowering effect of ashwagandha may provide a suitable explanation for the current outcome.”​

A traditional healer​

Ashwagandha has a history of use in Ayurvedic medicine that dates back as far as 4,000 years to the teaching of renowned scholar Punarvasu Atreya, and in subsequent works that make up the Ayurvedic tradition.

While it has been studied for a variety of beneficial effects, very few modern studies have investigated on the herb’s beneficial effects on thyroid function. This is the first clinical study that supports the traditional claim of ashwagandha as a thyroid modulator.​

“The outcome of the present study highlights the beneficial role of ashwagandha root extract for normalizing thyroid hormone levels in subclinical hypothyroid patients; however, further studies are required to elucidate the underlying mechanisms of ashwagandha,” ​concluded the researchers.

Potential benefits, according to the small pilot study in the International Journal of Food Sciences and Nutrition, were seen both in the short-term and long-term.

To test spirulina’s effects scientists at Ohio State University recruited 17 healthy men who were then randomly assigned to receive either placebo or 3g per day of spirulina for eight weeks. During the study researchers administered aerobic exercise tests and mathematical-based mental fatigue tests, and also asked the subjects to rate their own feelings of daily fatigue.

Results showed that performance improvements on the mental fatigue test were measurable four hours after the first supplementation with spirulina, and continued for eight weeks, compared to placebo.

What is more, according to the researchers the benefits seen for mental fatigue were “fairly large” and could not be accounted for by the men adapting to the test – since the men in the placebo group actually got worse as mental fatigue increased.

Physical benefits, but less long lived

Testing the men’s capacity for exercise the researchers observed that the spirulina group showed an increase calorie burn after one week, but this had disappeared after eight weeks. It is not known why this would be the case, but the small size of the study may have been influential.

Self-reported physical and mental fatigue was also improved after four hours in the spirulina group, and still evident after eight weeks.

Previous studies have come up with conflicting opinions about spirulina’s ability to battle fatigue. A Romanian study in which people with chronic fatigue symptoms were given 3g of spirulina daily, found no real benefit. But other studies have shown benefits. A small study of Taiwanese runners found that protected runners’ muscles during intensive training and increased their stamina. A Greek study also found that spirulina increased exercise performance and fat burning.

Professor Robert DiSilvestro from Ohio State’s Department of Human Sciences and corresponding author on the study, commented: “The biggest value of this study is that practical benefits were observed in what could be considered models for common situations for a healthy person. Most previous human studies on spirulina examined either people with health problems or used extreme stress such as very heavy exertion.”

The study was supported financially by Cyanotech – a producer of spirulina and other nutritional products derived from cyanobacteria and other algae.

The researchers recruited 38 overweight and obese people with an average age of 38 and randomly assigned them to receive a supplement with with 282 mg of EGCG and 80 mg of resveratrol per day or a placebo for 12 weeks.

Results showed that the polyphenol combination was associated with significant increases in oxidative capacity in muscle fibers, compared with placebo. Mitochondrial respiration was also found to be significantly increased following EGCG plus resveratrol supplementation.

In plain language the study, published in the American Journal of Clinical Nutrition, found that the supplements helped the body burn fat more efficiently.

article_box boxcols=’3′ boxfloat=’right’]What you need to know

» A small study has looked at the effect of a daily supplement of the polyphenols EGCG ad resveratrol in helping to control weight and improve metabolism.

» Just 12 weeks of the supplement improved mitochondrial capacity and fat oxidation in the participants, which the researchers say may play a role in long-term prevention of weight gain and preventing the worsening insulin resistance.[/article_box]

Dairy products contain calcium and minerals which can be good for bones, but new research has shown that dairy consumption may also have beneficial effects on metabolic health and can reduce risk of metabolic diseases such as obesity and type-2 diabetes.

Previous research has shown this to be particularly true of live or fermented products like yoghurt; but less so for sweetened products like ice cream.

The aim of a recent Canadian study in the journal Applied Physiology, Nutrition, and Metabolism was to determine associations between dairy intake and specific metabolic risk factors, including height-weight ratios, plasma glucose, plasma lipid profile, inflammatory markers and blood pressure, in a healthy population.

A total of 254 participants from the greater Quebec City metropolitan area were recruited; 233 participants (105 men and 128 women) met all the eligibility criteria for the study ‒ meaning subjects had healthy metabolic profiles.

The Laval University study showed that the average individual consumed 2.5 portions of dairy per day. However, nearly 45% of the population in this study did not meet Canada’s Food Guide recommendations of at least 2 portions of dairy products a day. These findings are supported by recent Canadian surveys that highlighted an under consumption of dairy products by Canadians.

Protective fats

Data suggest that trans-palmitoleic acid found in plasma may be potentially used to estimate dairy consumption. Trans-palmitoleic acid, is naturally present in milk, cheese, yoghurt, butter, and meat fat but cannot be synthesised by the body.

This fatty acid has been recently shown to have health-promoting effects. In this study, that trans-palmitoleic acid level in blood was related to lower blood pressure in men and women, and to lower body weight in men.

Dairy intake was also associated with lower blood glucose and blood pressure in the population studied, thought the design of the study prevented the scientists from making a definite link between dairy and these health outcomes.

You only need a little

In a different study a daily small serving of dairy food was found to reduce the risk of heart disease or stroke, even in communities where such foods have not traditionally formed part of the diet.

The sutdy which involved nearly 4000 Taiwanese people found that daily intake may not be necessary and that people only needed to eat small amounts to gain the benefits. Those who included dairy food in their diet only three to seven times a week were at lower risks of death from cardiovascular disease, especially stroke. No protective effect was seen in this study against cancer.

The optimal frequency for dairy consumption was 5 times a week and a serving was the equivalent of 8 grams of protein: i.e. a cup of milk, or 45 grams of cheese

“A little is beneficial and a lot is unnecessary,” commented lead researcher Emeritus Professor Mark Wahlqvist from Monash University’s Department of Epidemiology and Preventive Medicine and the Monash Asia Institute

• Click here for information on Non-dairy sources of calcium

Researchers questioned 58 women about the previous day’s stressors before giving them a meal consisting of 930 calories and 60 grams of fat.

The scientists then measured their metabolic rate – how long it took the women to burn calories and fat – and took measures of blood sugar, triglycerides, insulin and the stress hormone cortisol.

The most common reported stressors were interpersonal in nature: arguments with co-workers or spouses, disagreements with friends, trouble with children or work-related pressures.

On average, the women in the study who reported one or more stressors during the previous 24 hours burned 104 fewer calories than nonstressed women in the seven hours after eating the high-fat meal – a difference that could result in weight gain of almost 11 pounds in one year.

The stressed women also had higher levels of insulin, which contributes to the storage of fat, and less fat oxidation – the conversion of large fat molecules into smaller molecules that can be used as fuel. Fat that is not burned is stored.

“This means that, over time, stressors could lead to weight gain,” said Jan Kiecolt-Glaser, professor of psychiatry and psychology at The Ohio State University and lead author of the study. “We know from other data that we’re more likely to eat the wrong foods when we’re stressed, and our data say that when we eat the wrong foods, weight gain becomes more likely because we are burning fewer calories.”

The research is published in the journal Biological Psychiatry.

Not just saturated fat

The research meal consisted of eggs, turkey sausage, biscuits and gravy – roughly equivalent in calories and fat to a loaded two-patty hamburger and French fries at a fast-food restaurant. Participants were required to eat the entire meal within 20 minutes.

“This is not an extraordinary meal compared to what many of us would grab when we’re in a hurry and out getting some food,” said Kiecolt-Glaser, also director of the Institute for Behavioral Medicine at Ohio State.

For comparison some of the women received a meal that was high in a different kind of fat: sunflower oil containing monounsaturated fat, which is associated with a variety of health benefits.

“We suspected that the saturated fat would have a worse impact on metabolism in women, but in our findings, both high-fat meals consistently showed the same results in terms of how stressors could affect their energy expenditure,” said Martha Belury, professor of human nutrition at Ohio State and a co-author of the study.

After they ate their meal, the women’s metabolic rate was tested for 20 minutes of every hour for the next seven hours.

This showed that  the participants burned fewer calories over the seven hours after the meal when they had a stressor in their life the day before the meal.

In addition the stressors’ effects of increasing insulin had a time element: Insulin spiked soon after the high-fat meal was consumed and then decreased to roughly match insulin levels in nonstressed women after another 90 minutes.

Depression – an added complication

A history of depression alone did not affect metabolic rate, but depression combined with previous stressors led to a steeper immediate rise in triglycerides after the meal. Triglycerides are a form of fat in the blood, and high levels are considered a risk for cardiovascular disease.

“With depression, we found there was an additional layer. In women who had stress the day before and a history of depression, triglycerides after the meal peaked the highest,” Kiecolt-Glaser said. “The double whammy of past depression as well as daily stressors was a really bad combination.”

The researchers are reluctant to extend these findings to men because men tend to have more muscle than women, which would affect their metabolic rate, Belury said.

But the findings do offer one more motivation to keep healthful foods nearby.

“We know we can’t always avoid stressors in our life, but one thing we can do to prepare for that is to have healthy food choices in our refrigerators and cabinets so that when those stressors come up, we can reach for something healthy rather than going to a very convenient but high-fat choice,” Belury said.

For the study, published online in the journal Psychoneuroendocrinology, researchers from the University of California at San Francisco (UCSF) spent a year studying a group of 61 healthy women; 33 were chronically stressed women caring for a spouse or parent with dementia, and 28 were women with low stress.

The women also reported their consumption of high sugar, high fat foods.

“Chronic stress can play an important role in influencing biology, and it’s critical to understand the exact pathways through which it works.” said Kirstin Aschbacher, PhD, an assistant professor in the UCSF Department of Psychiatry and lead author.

When a calorie isn’t just a calorie

“Many people think a calorie is a calorie, but this study suggests that two women who eat the same thing could have different metabolic responses based on their level of stress. There appears to be a stress pathway that works through diet – for example, it could be similar to what we see in animals, where fat cells grow faster in response to junk food when the body is chronically stressed.”

The researchers evaluated key biological markers associated with elevated metabolic risk including waistline measurements, assessments of abdominal fat deposits. They also tested participants’ insulin resistance – a key driver of metabolic syndrome – and used blood tests to measure levels of hormones and a blood test to measure stress hormones and oxidative (free radical) damage to lipids and cell RNA, a marker that has predicted higher rates of death from diabetes.

Oxidative damage of the genome is also an important outcome because it is one factor that can contribute to faster cellular ageing.

The devastating impact of stress

What they found was that more frequent high-fat, high-sugar consumption with a larger waistline, more abdominal fat, higher oxidative damage, and more insulin resistance, but only among the group of women exposed to chronic stress,”

But, adds Aschbacher. “The chronically stressed women didn’t report eating more high sugar, high fat foods than the low stressed women; however, they did have higher levels of a stress-related biomarker, peripheral Neuropeptide Y (NPY).”

A new pathway

Based on what is known from animal studies, stress triggers greater peripheral NPY which, in combination with junk food, creates larger abdominal fat cells, and these cells may be more prone to metabolic dysregulation.

While this stress-junk food pathway has been well mapped out with rodents and primates, this study is the first to suggest the same pathways may be at work in chronically stressed humans, according to the researchers.

“Diet appears to be a critical variable that can either amplify or protect against the metabolic effects of stress,” said senior author Elissa Epel, ” but we still don’t know the details of how much it takes.” Their next study, she says, will specifically feed high stress people a consistently high sugar diet and monitor its effects.

More studies on the way

Metabolic syndrome is a cluster of abnormalities – increased blood pressure, a high blood sugar level, excess body fat around the waist and abnormal cholesterol levels – that occur together, increasing a person’s risk of heart disease, stroke and diabetes.

“The medical community is starting to appreciate how important chronic stress is in promoting and worsening early disease processes,” said Aschbacher. “But there are no guidelines for ‘treating’ chronic stress. We need treatment studies to understand whether increasing stress resilience could reduce the metabolic syndrome, obesity or diabetes.”

An international consortium of researchers report that overweight people with fewer bacterial species in their intestines are more likely to develop complications, such as cardiovascular diseases and diabetes. In addition, a gut with decreased bacterial richness appears to function entirely differently to the healthy variety with greater diversity.

Says lead researcher Jeroen Raes from the University of Brussels: “This is an amazing result with possibly enormous implications for the treatment and even prevention of the greatest public health issue of our time.”

Diversity is the key

Gut bacteria strengthens our immune system, produces vital vitamins and communicates with the nerve cells and hormone-producing cells within the intestinal system. The researchers add that gut bacteria also produces a variety of “bioactive substances” which enter the bloodstream, affecting our biology.

The gut needs a wide diversity of intestinal bacteria in order to maintain all these processes. In the current study people who were overweight were more likely to have low diversity in their gut flora.

The bacterial link

In this current study researchers took a closer look at the intestinal flora of 169 obese Danes and 123 non-obese Danes. The results were published in the journal Nature.

According to Raes “We were able to distinguish between two groups based on their intestinal flora: people with a large richness of bacterial species in their intestines and people with a fewer bacterial species. A species-rich bacterial flora appeared to function differently compared to the poorer variety. It was surprising to see that obese and non-obese people were found in both groups.”

The scientists found that the group with lower species richness in their intestinal flora was more susceptible to developing obesity-related conditions and chronic inflammation.

In addition, the obese people in this group were more at risk of cardiovascular conditions than the obese people in the other group. These are important results that suggest that it is not only weight gain and dietary habits that play a role in the development of medical complications in obese people.

Chicken and egg?

Metabolic conditions have become an epidemic partly due to the modern sedentary lifestyle and the and easy access to large amounts of energy-dense food. It is expected that obesity will increase tremendously all over the world; from 400 million obese people in 2005, to more than 700 million in 2015.

Some people appear to be more vulnerable to putting on weight than others and many studies over the years have examined the possible cause of this.

The researchers say they do not know whether lack of intestinal bacteria is the cause of obesity, or whether obesity causes a decrease in intestinal bacteria.

However, previous research has also suggested a link between gut bacteria and obesity. A study from the Cedars-Sinai Medical Center in Los Angeles, for example, found that certain types of bacteria in the gut cause it to take more calories from food, therefore leading to weight gain.

Dietary measures

Another finding of the international study was that a quarter of the participants had 40% fewer gut bacteria genes and correspondingly fewer bacteria than average.

Extrapolated to the entire population this suggests that a low number and diversity of gut bacteria could play a major role in health problems.

They say they cannot yet explain fully why some people have fewer intestinal bacteria compared with others, but they believe our diet may be a contributing factor.

They point to a 2012 study from a French research team, which revealed that a group of overweight participants who followed a low-fat diet for 6 weeks and who had fewer intestinal bacteria at the beginning of the diet, showed an increase in gut bacteria in both variety and amount.

“Our intestinal bacteria are actually to be considered an organ just like our heart and brain, and the presence of health-promoting bacteria must therefore be cared for in the best way possible. Over the next years, we will be gathering more knowledge of how best to do this.”

People have widespread exposure to perfluorinated chemicals (PFCs), which are used to manufacture items such as carpets, non-stick pans, stain resistant fabrics and paper coatings and in conventional skin-smoothing cosmetics (where it is listed on the label as polytetrafluoroethylene, or PTFE). Teflon and Scotchguard are arguably the most well-known PFC products.

These chemicals break down very slowly and take a long time to leave the body.

For this study, researchers analysed data from more than 1,100 people who took part in the 2007-2008 and 2009-2010 US National Health and Nutrition Examination Survey. The study looked at levels of four different PFCs as well as participants’ thyroid function.

Even after adjusting for potential confounding variables such as age, sex, race, alcohol consumption, smoking, and urinary iodine, the researchers found that women with elevated serum levels of one type of PFC, perfluorooctanoate (PFOA), were more likely to have higher levels of the thyroid hormone triiodothyronine (T3).

The researchers also observed increases in levels of T3 and thyroxine (T4) in women who had elevated concentrations of another PFC, perfluorohexane sulphonate (PFHxS), in their serum. In addition, those levels increased inappropriately; that is, without the pituitary gland having signalled the thyroid to generate more hormones, the researchers say.

In contrast, men whose blood contained elevated levels of PFHxS tended to have lower levels of T4 compared with other individuals in the cohort.

Greater risk of hypothyroidism

Along with finding that having higher levels of PFCs in the body can alter thyroid function in both men and women, the researchers also found that PFCs may increase the risk of mild hypothyroidism in women.

Hypothyroidism occurs when the thyroid gland does not produce enough hormones. This can lead to symptoms such as fatigue, mental depression, weight gain, feeling cold, dry skin and hair, constipation and menstrual irregularities.

The study was published in the Journal of Clinical Endocrinology & Metabolism.

“Our study is the first to link PFC levels in the blood with changes in thyroid function using a nationally representative survey of American adults,” study co-author Dr. Chien-Yu Lin, of En Chu Kong Hospital in Taiwan, said in a journal news release.

“Although some PFCs . . . have been phased out of production by major manufacturers, these endocrine-disrupting chemicals remain a concern because they linger in the body for extended periods,” Lin said. “Too little information is available about the possible long-term effects these chemicals could have on human health.”