If exercise figures on your list of New Year’s resolutions, move it to number one position, underscore it, asterisk it, diarise it and DO it, because staying active enables you to age optimally.

This was the finding of a study of amateur older cyclists by King’s College London published in The Journal of Physiology. Many of the 125 cyclists (aged 55 to 79) who participated had levels of physiological function that would place them at a much younger age compared to the general population, thereby debunking the common assumption that ageing automatically equates to frailty.

The study recruited 84 male and 41 female cycling enthusiasts to explore how the ageing process affects the human body, and whether specific physiological markers can be used to determine age. Participants were chosen to exclude the effects of a sedentary lifestyle, which can aggravate health problems and cause changes in the body that might appear to be associated with the ageing process. The male contingent had to be able to cycle 100 km in under 6.5 hours, while the females had to do 60 km in 5.5 hours. Smokers, heavy drinkers and those with high blood pressure or other health conditions were excluded.

Physiological profile

Participants underwent two days of laboratory testing at King’s. A physiological profile was established for each person, which included measures of cardiovascular, respiratory, neuromuscular, metabolic, endocrine and cognitive functions, bone strength, and health and wellbeing. Reflexes, muscle strength, oxygen uptake during exercise, and peak explosive cycling power were determined.

The study revealed the effects of ageing were far from obvious. People of different ages could have similar levels of function such as muscle strength, lung power and exercise capacity. While the maximum rate of oxygen consumption showed the closest association with age, even this marker could not identify with any degree of accuracy the age of any given person, which would be the requirement for any useful biomarker of ageing.

Overall, the study concluded that ageing appears to be a highly individual phenomenon. As people are so different, the team believes more studies are needed that follow the same healthy and exercising individuals over time to better understand the effects of ageing the body.

“Inevitably, our bodies will experience some decline with age, but staying physically active can buy you extra years of function compared to sedentary people,” comments Emeritus Professor Norman Lazarus, a member of the King’s team and a cyclist. “Cycling not only keeps you mentally alert, it also requires the vigorous use of many of the body’s key systems, such as muscles, heart and lungs which you need for maintaining health and for reducing the risks associated with numerous diseases.”

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by King’s College London.

An ongoing challenge for parents of children with autism is how they can help their child socialise with their non-autistic peers. Pamela Wolfberg PhD, a professor of special education and communicative disorders at San Francisco State University, believes the solution may lie in a different type of playgroup: one that focuses on collaborative activities rather than the more typical adult-directed activities.

A new study shows that Integrated Play Groups® (IPGs), developed by Wolfberg in the late 1980s, are effective in teaching children with autism the necessary skills to interact with other children and engage in symbolic play such as pretending. The adults help all the children engage in playful activities of mutual interest, but do not direct the play, because children learn more about how to play through interactions with other kids than they do from adults. However, Wolfberg stresses it’s still important for adults to play with kids in other situations.

Wolfberg and her research team studied 48 children with autism during free-play activities with kids they had not previously met on two occasions before they participated in an IPG program with children they knew, and once after. Following the IPG program, the children’s ability to interact with the kids they didn’t know and to engage in pretend play rose dramatically, indicating the IPGs were successful in providing them with transferable social and symbolic-play skills.

Restrictive play repertoire

Children with autism tend to have a “very restrictive play repertoire”, as Wolfberg describes it. They prefer individual play, have unusual interests and engage in repetitive activity. The goal of IPGs is to move children from engaging in very basic solo levels of play, such as simply banging something, to more symbolic play where they interact with other children.

Wolfberg says that in San Francisco, the earthquake-rescue theme is the most popular. One little boy had an affinity for banging things. The children came up with the idea of building cardboard blocks and having an earthquake. Playing the role of a construction worker, the boy was able to participate with the other kids, building something more elaborate and having a whole fantasy about it.

The success of IPGs is an opportunity for parents, educators and therapists seeking to help children with autism in socialising with their peers. In addition, the IPG model also teaches non-autistic children about autism and how to form friendships with kids who might play, communicate or relate differently.

“This is what families want for their kids,” says Wolfberg. “This flips around the idea that kids with autism are incapable of socialising or incapable of pretending. They have the same innate drive to participate with peers and to engage in playful experiences, but … we have not been able to tap into their potential.”

Future research will look more closely at how IPGs can help children with autism better communicate with non-autistic peers, another challenge they face. Wolfberg also has been adapting the IPG model to be used in other countries.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials releasedby San Francisco State University.

The past three decades have seen a marked decline in physical activity among children, giving rise to public health implications that include a growing prevalence of obesity along with chronic diseases such as diabetes and hypertension.

New research presented in the December 2014 issue of Monographs of the Society for Research in Child Development broadens this focus to question whether physical activity also influences a child’s brain and cognitive development, and achievement in school. Past research indicates that while one reason behind diminishing physical activity in schools relates to a growing emphasis on student performance and academic testing, this may in fact be counter-productive as decreased physical activity is associated with decreased academic performance.

Physically active children tend to outperform their inactive peers in the classroom, and on tests of achievement. This new research helps clarify the reason: those who engage in more physical activity have larger brain volumes in the basal ganglia and hippocampus – areas associated with cognitive control (the control of thought, action, behaviour and decision-making) – compared to their less active class mates. Moreover, physically active children also have increased concentration and enhanced attention spans when compared to their less active peers. The findings on attention encompass children with special needs as well as typically developing children.

The authors found that fitness is related to a child’s ability to inhibit attention to competing stimuli when performing an activity, an ability that can help children stay focused and persevere to complete a task.

They also report on physical activity as an effective non-pharmaceutical intervention for children with attention-deficit/hyperactivity disorder (ADHD) and children with autism spectrum disorders.

“These results point to the important potential of approaches focusing on physical activity for strengthening children’s brain health and educational attainment,” notes lead author Dr Charles Hillman, professor of kinesiology and community health at the University of Illinois at Urbana-Champaign. “It’s important for state governments and school administrators to consider this evidence and promote physical activity in the school setting, which is where children spend much of their time.”

Hillman adds that the findings come not only from studies looking at variation in physical activity and fitness level as they occur spontaneously among children, but also from studies in which children are randomly assigned to physical-activity interventions, or to continue their ongoing activity levels. “This helps assure that the links between physical activity, brain development and achievement are actually caused by the differences in activity, rather than reflecting the characteristics of the children who choose to be more or less physically active.”

Australian physical activity guidelines

Australian guidelines for physical activity in children aged five to 17 recommend accumulating at least 60 minutes of moderate to vigorous intensity physical activity every day, including a variety of aerobic activities, with some vigorous intensity.

Additionally:

• Include activities that strengthen muscle and bone on at least three days a week.
• To achieve additional health benefits, engage in more activity – up to several hours per day.
• To reduce health risks, minimise sedentary time by limiting non-educational screen time to a maximum of two hours a day, and break up long periods of sitting as often as possible.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by Society for Research in Child Development.

That mindfulness meditation helps us feel better mentally has long been recognised. Now, for the first time, a new Canadian study published in the journal Cancer reveals practicing mindfulness meditation also influences key aspects of our biology.

A research team from Alberta Health Services’ Tom Baker Cancer Centre and the University of Calgary’s Department of Oncology has demonstrated that telomeres – protein complexes at the end of chromosomes – maintain their length in breast cancer survivors who practice meditation or are involved in support groups, while they shorten in a comparison group not involved in interventions. Shortened telomeres are associated with cell ageing and a number of diseases, whereas longer telomeres are thought to be protective against disease.

Eighty-eight breast cancer survivors, average age 55, who had completed their treatments for at least three months, were involved for the duration of the study. Most had ended treatment two years previously. To be eligible, the women also had to be experiencing significant levels of emotional distress.

– Those in the Mindfulness-Based Cancer Recovery group attended eight weekly, 90-minute group sessions that provided instruction on mindfulness meditation and gentle Hatha yoga, with the goal of cultivating non-judgmental awareness of the present moment. Participants were also asked to practice meditation and yoga at home for 45 minutes daily.
– Women assigned to the Supportive Expressive Therapy group met for 90 minutes every week for 12 weeks, where they were encouraged to talk openly about their concerns and their feelings. The objectives were to build mutual support and to guide them in expressing a wide range of both difficult and positive emotions, rather than suppressing or repressing them.
– The participants randomly placed in the control group attended one, six-hour stress-management seminar.

All involved in the study had their blood analysed and telomere length measured before and after their programs.

“It was surprising that we could see any difference in telomere length at all over the three-month period studied,” comments Dr Linda E. Carlson, PhD, principal investigator and director of research in the Psychosocial Resources Department at the Tom Baker Cancer Centre. “Further research is needed to better quantify these potential health benefits, but this is an exciting discovery that provides encouraging news.”

Whether the effect of these interventions is just short term or long lasting is yet to be determined.

One study participant who was placed in the mindfulness-based group describes her experience as life-changing. She admits to initial scepticism, considering it a “bunch of hocus-pocus”. Today, she practices mindfulness throughout the day and says it reminds her to become less reactive and kinder toward herself and others.

For those interested in learning more about mindfulness meditation, UCLA Mindful Awareness Research Centre offers free guided meditations.

Written for the Australian Traditional-Medicine Society (ATMS) from materials released by Alberta Health Services.

A joint study from King’s College London and the USA’s Cornell University published in the journal Cell, reveals our genetic makeup influences whether we are fat or thin by shaping which types of microbes thrive in our body.

By studying pairs of identical and fraternal twins at King’s Department of Twin Research, the researchers identified a specific, little-known bacterial family that is highly heritable and more common in people with low BMI. When this microbe was transplanted into mice, it protected against weight gain.

Previous studies have linked both genetic variation and the composition of gut microbes to metabolic disease and obesity, but notwithstanding these shared effects, it was presumed the relationship between human genetic variation and the diversity of gut microbes was negligible.

Researchers involved in this new study sequenced the genes of microbes taken from more than 1000 faecal samples from 416 pairs of twins. The abundances of specific types of microbes were found to be more similar in identical twins, who share 100 per cent of their genes, than in fraternal twins, who share on average only half of the genes that vary between people.

These findings demonstrate that genes influence the composition of gut microbes.

The type of bacteria whose abundance was most heavily influenced by host genetics was a family called Christensenellaceae, first described just two years ago. Members of this health-promoting bacterial family were more abundant in participants with low body weight than in those who were obese. Mice treated with this microbe gained less weight than untreated mice, suggesting that increasing the amounts of this microbe could help to prevent or reduce obesity.

“Until now, variation in the abundances of gut microbes has been explained by diet, the environment, lifestyle, and health,” says Ruth Ley, Associate Professor at Cornell University in the United States. “This is the first study to firmly establish that certain types of gut microbes are heritable: that their variation across a population is in part due to host genotype variation, not just environmental influences. These results will also help us find new predictors of disease and aid prevention.”

Professor Tim Spector, Head of the Department of Twin Research and Genetic Epidemiology at King’s College London, comments that the human microbiome represents an exciting new target for dietary changes and treatments aimed at combating obesity. “Twins have been incredibly valuable in uncovering these latest links, but we now want to promote the use of microbiome testing more widely in the UK through the British Gut Project. We want thousands to join up so we can continue to make major discoveries about the links between our gut and our health.”

Launched in October 2014 British Gut – the UK’s largest open-source science project to understand the microbial diversity of the human gut – is a collaboration between the Department of Twin Research at King’s College London and American Gut.

Although further research is needed, it’s hoped these findings may open the way for personalised probiotic therapies optimised to reduce the risk of obesity-related diseases based on a person’s genetic make-up.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by Kings College London.

If you’ve ever worked a swing shift (4pm to 12am) or graveyard shift (12am to 8am), you’re painfully aware of impact they have on your sleeping and eating patterns as a result of the disruption of the body’s circadian clock.

The primary circadian clock, which is responsible for these functions, is located in the brain. Circadian clocks are also located in other body tissues, including the liver, where the clock is charged with regulating blood glucose levels.

A new study from University of Utah researchers, published in Diabetes News Journal online, reveals that dietary iron plays an important role in the liver’s circadian clock.

Study leader Judith A. Simcox, Ph.D., a University of Utah postdoctoral fellow in biochemistry, describes iron as being like the dial that sets the timing of the clock. “Discovering a factor, such as iron, that sets the circadian rhythm of the liver may have broad implications for people who do shift work,” she comments.

Food intake sets the liver’s circadian clock. During sleep, this clock helps maintain a constant blood glucose level, but causes it to spike just before you wake up. When the clock in the liver gets out of synch with the clock in the brain, this may contribute to metabolic diseases, says senior author of the study, Donald A. McClain, M.D., Ph.D., University of Utah professor of medicine (endocrinology) and biochemistry.

In order to identify external signals that set the circadian clock in the liver, McClain and Simcox fed iron to mice as part of their natural eating cycle. They noted that dietary iron increases the cellular concentration of haem, an oxygen-carrying iron compound found in haemoglobin. When haem binds to a circadian protein–a substance, whose function Simcox likens to that of a cog in a mechanical clock, the protein’s activity increases and causes the liver to optimally control blood glucose levels.

While increased activity of a circadian protein is healthy when it occurs in the liver’s natural clock cycle, when it occurs at a time that is out of synch with the circadian clock – such as during a graveyard shift – this may lead to abnormal blood glucose levels.

Eating iron-rich food at night could exacerbate the lack of synchronisation between the clock in the liver and the main clock in the brain. By tending to flatten the circadian variation of metabolism, high iron in tissues may also interfere with the normal day-to-night fluctuations associated with a healthy metabolic system.

Numerous studies have found shift workers experience higher incidences of obesity, diabetes and other metabolic disorders. Their risk for cardiovascular disease, stroke and cancer also is higher. In 2007, a World Health Organization subcommittee declared shift work is probably carcinogenic.

More research is needed to see how the results of this study could affect dietary recommendations for everyone, but especially for shift workers. The investigators are quick to point out that too little iron is also unhealthy. Ultimately, they hope their studies define an optimal range of iron that is much narrower than the current “normal” range.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by the University of Utah

Added sugars in processed foods could have more impact on high blood pressure, heart disease and stroke than added salt, according to an analysis of published evidence in the online journal Open Heart. The findings prompted the authors to recommend that dietary guidelines should emphasis the role played by added sugars in the fight to curb the prevalence of cardiovascular disease.

Cardiovascular disease is the number-one cause of premature death in the developed world, with high blood pressure the prime risk factor, accounting for almost 350,000 deaths in the US in 2009 and costing more than US$50bn every year. In Australia in 2011/12, 32 per cent of adults over 18 had high blood pressure.

A key strategy for normalising blood pressure has historically focused on reducing salt intake. However, the potential benefits of this approach are debatable, say the authors, with average reductions in blood pressure tending to be relatively small.

Moreover, some evidence suggests three to six grams of salt daily may be necessary for optimal health, and that an intake of less than three grams is potentially harmful.

The authors point out that most salt in the diet comes from processed foods, which also happen to be loaded with added sugars. They say compelling evidence from basic science, population studies, and clinical trials implicates sugars generally, and fructose in particular, as a contributor to overall cardiovascular risk through a variety of mechanisms.

High fructose corn syrup dangers

High fructose corn syrup – the most frequently used sweetener in processed foods, especially fruit-flavoured and fizzy drinks – is especially problematic. Internationally, sugar-sweetened beverage consumption has been implicated in 180,000 deaths annually.

Until relatively recently, sugar consumption was just a few kilograms annually, whereas current estimates suggest that average consumption in the US is 34 to 69 kilograms a year; in Australian, that figure is 108 kilograms.

The evidence suggests:

• People whose dietary intake of added sugars accounts for at least a quarter of their total daily kilojoules have almost triple the cardiovascular disease risk of those who consume less than 10 percent.
• A daily intake of more than 74 grams of fructose is associated with a 30 percent greater risk of blood pressure above 140/90, and a 77 percent increased risk of blood pressure above 160/100.
• A high-fructose diet is also linked to an unfavorable blood fat profile, higher fasting blood insulin levels, and a doubling in the risk of metabolic syndrome.

Of particular concern is that UK and US teens may be consuming added sugars up to 16 times the recommended limit.

The authors would like to see more stringent recommendations about daily intake of added sugars in dietary guidelines, along with specific recommendations about fructose. They emphasise that naturally occurring sugars found in fruit and vegetables are not harmful to health: eating fruit and vegetables is almost certainly beneficial.

“The evidence is clear that even moderate doses of added sugar for short durations may cause substantial harm,” the authors caution.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by BMJ.

An expert panel convened by the US National Sleep Foundation is making new age-based recommendations on how much sleep we need.

These new guidelines, published in the journal Sleep, include a broader range of what constitutes a good night’s sleep. For example, the expert panel recommends teens aged 14 to 17 get 8 to 10 hours of sleep per night, where the previous guideline had a narrower recommended range of 8.5 to 9.5 hours.

Lydia DonCarlos PhD, a professor in the Department of Cell and Molecular Physiology of Loyola University Chicago Stritch School of Medicine, and other experts in disciplines including sleep, anatomy, physiology, paediatrics, neurology, gerontology and gynaecology examined – in a scientifically rigorous process – 320 studies reporting sleep-duration findings for healthy people, effects of reduced or prolonged sleep duration, and health consequences of too much or too little sleep.

DonCarlos is a neuro-endocrinologist who studies how hormones affect the structure of the brain. Hormones produced by the hypothalamus, which is responsible for regulating hormone production, govern body temperature, hunger, stress responses, sex drive, circadian rhythms and sleep.

In addition to serving on the National Sleep Foundation expert panel, DonCarlos serves on the National Institutes of Health’s Neuroendocrinology, Neuroimmunology, Rhythms and Sleep (NNRS) study section, which reviews applications for research grants.

“We still have a great deal to learn about the function of sleep,” says DonCarlos. “We know it’s restorative and important for memory consolidation. But we don’t know the details of what the function of sleep is, even though it is how we spend one-third of our lives.”

These are the sleep-time recommendations from the National Sleep Foundation expert panel:

• Newborns (0-3 months): Sleep range narrowed to 14-17 hours each day (previously 12-18)
• Infants (4-11 months): Sleep range widened two hours to 12-15 hours (previously 14-15)
• Toddlers (1-2 years): Sleep range widened by one hour to 11-14 hours (previously 12-14)
• Pre-schoolers (3-5): Sleep range widened by one hour to 10-13 hours (previously 11-13)
• School-age children (6-13): Sleep range widened by one hour to 9-11 hours (previously 10-11)
• Teenagers (14-17): Sleep range widened by one hour to 8-10 hours (previously 8.5-9.5)
• Younger adults (18-25): Sleep range is 7-9 hours (new age category)
• Adults (26-64): Sleep range remains 7-9 hours.
• Older adults (65 or more): Sleep range is 7-8 hours (new age category).

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by the National Sleep Foundation.

My 13-year-old daughter has lovely long, brown hair, but suffers terribly with dandruff and the ends of her hair are very dry. She has an oily scalp and skin, and her hair needs washing very regularly because of the oil. She can’t use fragrances on her skin as she gets eczema from it, although essential oils have been fine for her. Any suggestions?
Naturopath and western herbalist Teresa Mitchell-Paterson responds:

Firstly, at age 13 we have to suspect hormones are involved, and hormonal imbalances with skin and hair that develop in both sexes lead to excess sebum production. These hormonal changes are referred to as adrenarche, as opposed to menarche, because it’s an influence of androgen (male) hormones in young females.

Other contributors are:

• Incorrect diet
• Lack of nutrients
• Condition of the gut flora
• Appropriate hair care

All are intertwined, so each issue needs to be addressed.

Testing

Because those androgens promote excess production of sebum, you may choose to see your GP to have serum levels of dehydroepiandrosterone sulphate tested.

Excess sebum  production is also related to higher-sugar diets and slow detoxification of the hormones.

Diet

Diet is the difficult part because teenagers tend to eat with their peers and consume large amounts of sugar and/or foods that increase insulin: pizza, pasta, carbonated drinks, lollies, etc.

• High glycaemic index (GI) foods drive quite a high level of insulin growth factors from about age 15 to 35, and sometimes earlier. So we need to encourage teenagers – as best we can – to consume whole grains. If they’re having pizza they can order a wholegrain base, and wholegrain pasta made from wheat, spelt and other grams is now readily available.
• Encourage consumption of low-starch vegetables – typically those you find in salads – along with green beans, radish, cucumber, cabbage and broccoli. So five servings a day, plus two serves of fruit, which aligns with Australian dietary guidelines.

Eating whole grains and low-starch vegetables reduces insulin production, which in turn reduces female oestrogen changing to androgen hormones via the aromatisation process.

• Milk and other dairy products need to be reduced because casein and lactose have an influence on insulin growth factors. This, too, is a bit tricky because teens need to get sufficient calcium. One option is to swap dairy products with soy or almond alternatives containing added calcium, and/or to eat high-calcium foods such as tahini.
• Include some lean, hormone-free sources of protein. This is another important factor because androgen hormones in animals can actually transfer to humans through the meat we consume.
• It’s also important to lighten the liver’s load by reducing saturated fats and hydrogenated fats, which means no chips, no deep-fried foods. Teenagers love their chips, so consider an air fryer, which works by producing the Maillard reaction (browning). The chips come out crunchy and crisp exactly as they would if fried. Or make oven fries tossed in a little olive oil.
• A diet low in essential fatty acids has been proven to result in skin problems – and particularly dandruff. So use good olive oil, have fish oil supplements or cod liver oil, have oily fish three times a week, and eat avocados. Alternatively, supplement with vitamins A, D and E.

Mineral deficiency

The brittle and dry hair your daughter is experiencing is linked to mineral deficiency. Because our soils are lacking in minerals, a mineral supplement may be beneficial. While some speculate that silica is the main mineral for skin and hair, the reality is all minerals assist in hair growth and prevent brittleness. However, silica is important because it’s present throughout the skin and hair. Silica-rich foods include cucumber, mango, rhubarb, green beans, oranges, almonds, oats and apples. Silica is also present in our water supply.

Good flora

Gut flora is easily disrupted in teenagers for many reasons. Imbalanced gut flora affects the skin as well as the gut: if lactobacillus is missing or overwhelmed in the gastrointestinal tract, there can be a lack of it on the skin.

Personal-care products containing sodium laureth sulphate (SLS) also disrupt the natural skin bacteria.

A lack of good flora can lead to a growth of fungus on the scalp, and this is what causes the dandruff. Scientists have isolated a number of different fungi that grow on the scalp, one of which is the genus Malassezia, which has many species. Candida albicans can also be found in scrapings from dandruff.

Improving gut flra counteracts this:

• Avoid pickles and yeasty foods such as Vegemite and soy sauce.
• Eat clean as discussed earlier.
• Probiotics repopulate gut flora, which then migrate to the skin. Either use a probiotic supplement before bed, or eat 60mls plain yoghurt with live bacterial content. Kefir is an alternative, perhaps with some fruit to make it more interesting.
• Fermented foods contain lactic acid, which helps that gut to produce its own flora.

Hair care

I advise my patients to massage a little coconut oil into their scalp, as trials have shown it to be 100 per cent successful in repelling candida albicans. We know it’s really good for getting rid of fungus and it seems to work very well for dandruff. You do need to rinse it off in the morning, though, or else scrape your hair back into a pony tail.

Avoid scrubbing the scalp when shampooing because this can irritate the scalp, which causes more oil. The more you irritate the scalp this way, and strip your head of oil by using products containing SLS and washing the hair too often, the more the fungus grows and the more sebum is produced.

So choose an SLS-free shampoo, or alternatively use a beaten egg white, which foams a little and does not strip your hair of its natural oil. It’s also very nourishing and the albumen and the proteins in the egg benefit your hair.

Use a minuscule amount of coconut oil as a conditioner. Rub a quarter teaspoon of the oil onto your hands and smooth it through the ends of your hair to condition it before drying.

Other factors

Hypothyroidism may be implicated, so use iodised salt. Vitamin B6 on its own, 50mgs, helps manage hormonal condition.

Finally, stress must be reduced because the Malassezia globosa form of fungus is associated with neurogenic responses – stress, in other words. Stress can also cause hair to lose its shine, and become a little greasy and sticky. Moreover, it increases the release of glucose, which then increases our insulin growth factors.

A new study by researchers at the Salk Institute for Biologic Studies suggests that confining kilojoule consumption to an eight-to-12 hour period – as past generations did – might stave off high cholesterol, diabetes and obesity.

The results, published in Cell Metabolism, add to mounting evidence suggesting that when we eat matters as much to our health as what we eat.

In 2012, Salk Institute associate professor Satchidananda Panda showed that mice fed a high-fat diet, which they could access for just eight hours a day, were healthier and slimmer than mice given 24-hour access to the same food. This despite the two groups consuming the same number of kilojoules.

This latest study reveals the benefits of time restriction are more profound than initially believed, and that in animal models it can actually reverse obesity and diabetes. The authors demonstrated that time restriction better synchronises the function of hundreds of genes and gene products in the body with the predictable time of eating.

These days, most of the advice is… ‘you have to eat a healthy diet’, ” says Panda. “But many people don’t have access to healthy diets. So the question is, without [such] access, can they still practise time-restricted feeding and reap some benefit?”

To determine just how forgiving time-restricted feeding is, Panda and his team fed almost 400 mice, ranging from normal to obese, various types of diets with differing length-of-time restrictions. They found the benefits of time-restricted feeding showed up regardless of the mouse’s weight, type of diet and length of the time restriction (to some degree).

Image: Courtesy of the Salk Institute for Biological Studies

• Mice whose diets were restricted within a time frame developed less body fat.
• Large fat droplets (white, left panel) accumulated in brown adipose tissue of mice freely fed a high-fat diet.
• The tissue of mice fed the same diet in a nine-hour time window (right) was less fat-filled.
• Regardless of whether their diets were high in fat, fat and sucrose, or just fructose, mice that were given time restrictions of nine to 12 hours, and consumed the same amount of daily kilojoules as their unrestricted counterparts, gained less weight than the controls.
• Variations in the time window in which the mice were allowed to eat a high-fat diet – including nine, 10 and 12-hour periods – all resulted in similarly lean mice. However, for a 15-hour group, the benefits conferred by time restriction became more modest.
• Some of the time-restricted mice were given a respite on weekends, allowing them free access to high-fat meals for the two days. These mice had less fat mass, and gained less weight, than the mice given a freely available, high-fat diet the whole time. In fact, mice that were freely fed just on weekends looked much the same as mice given access to food nine or 12 hours a day for seven days a week, suggesting this diet can withstand some temporary interruptions.
• Researchers restricted the food access of mice that had already become obese by eating a freely available high-fat diet over a nine-hour period. Although they continued to consume the same number of kilojoules, their body weight dropped by five percent within a few days. And importantly, eating this way prevented the mice from further weight gain – by about 25 percent by the end of the 38-week study – compared to the group kept on the freely available high-fat diet.
• When the group compared mice given a more balanced diet, they found the time-restricted mice had more lean muscle mass than the unfettered group.
• A comprehensive analysis of the blood metabolites in time-restricted mice revealed that multiple molecular pathways that go awry in metabolic disease are turned back to normal, and protective pathways are dialed up.

“It’s an interesting observation that although the mice on a normal diet did not lose weight, they changed their body composition,” Panda comments. “That brings up the question: what happens? Are these mice maintaining muscle mass that might have been lost with free feeding, or are they gaining muscle mass?”

Next steps include looking more in-depth at these molecular pathways, as well as investigating the effects of time-restricted eating in humans.

Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by the Salk Institute for Biological Studies