Author: dogbytelab@gmail.com

Small increases in physical activity as part of our daily lives can bring long-term benefits to our health.

Some mornings, I really struggle to go out for a jog, but I force myself because I know it will be good for me. The protective effect that exercise can have not only the body, but our brain, memory and general wellbeing is something I’ve spoken to researchers a lot about recently.

But what has also become clear is that we don’t need to be doing intense workouts to see benefits.

New research shows that even small increases in activity can have a powerful impact on health and longevity. Just five minutes of moderate activity each day – such as brisk walking, cycling or climbing stairs – could prevent around one in ten premature deaths, which could help millions of individuals live longer.

While this doesn’t mean that just doing five minutes of exercise is enough to ensure you stay healthy, it is an indication that compared to doing nothing, this small increase in physical activity can bring improvements to overall health. For those who are already pretty active or relatively fit, doing five minutes more exercise will have a smaller effect.

But it shows the power of doing even just some very basic forms of exercise.

“Physical activity is something that is really beneficial for preventing high stress rates and high burnout rates,” says Nicole Logan, an assistant professor of kinesiology from the University of Rhode Island in the US. “We know that physical function, muscle strength, muscle quality, bone strength, these are really good predictors of later life mortality. So living longer and living healthier for longer.”

Live well for longer

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Increasing lifespan

The new research involved a large-scale analysis of data from 150,000 adults in the UK, US and Scandinavia.

“It was surprising that very small changes in physical activity of five minutes per day have such a large impact on reducing the risk for premature mortality,” says Ulf Ekelund, lead author of the research and a professor of physical activity and health at the Norwegian School of Sport. The findings reveal the health benefits of doing five minutes of exercise across the whole population rather than on an individual level, he says.  

Adults should still strive for the World Health Organization’s recommendation of 150 minutes of moderate-intensity exercise a week, Ekelund says. But the study shows that those who might struggle to go to the gym or join a sports club, can still benefit from adding more movement into their lives.

Reducing inactivity was also found to be beneficial. Cutting daily sitting time by 30 minutes was linked to a 7% reduction of early death across the population. This is especially important because physical inactivity is a leading cause of chronic disease and an earlier death.

Ekelund says that consistency is key. “Start slow and gradually build up the amount,” he says. The activity should be tailored to the individual’s preferences and ability.”

Exercise snacking

The study builds on many others that show how long-term health benefits from exercise do not require us to radically change our lifestyle. Simply adding movement into our daily life can have an outsized effect.

Muscle strengthening activities have also been shown to be beneficial. One US study found that individuals in their 60s and 70s who combined aerobic exercise with muscle-strengthening activities lived longer and had a lower risk of dying compared to those who did no exercise.

Other recent work shows that “exercise snacking” – which consists of short bursts of activity spread throughout the day – can improve heart health. A large authoritative analysis of existing research found that among older adults, it also helped with muscular endurance. Uptake was high too, with over 82% of participants continuing to take part, most likely because exercise snacking is easy to “integrate into daily routines”, the authors note. (Read more about how short bursts of activity can help you live for longer.)

Unlike a gym session, these “snacks” can be spread throughout the day as part of your normal routine. This can include anything that gets your heart rate up – be it vigorous hoovering, dancing to a song in your kitchen or running up and down your stairs faster than normal.

As Marie Murphy, professor of exercise and health at Ulster University in the UK, told the BBC’s Just One Thing podcast, smaller chunks of exercise increase how often we are stimulating our metabolism. “When we stop exercising, our metabolism keeps going a little bit quicker while we recover,” she said. “You still have that metabolic mill turning.”

Benefits of habit

Research shows that people respond positively when they are made more aware of the health benefits of exercise snacking, and that it could help address barriers to exercise.

Simple prompts can make a difference. Signs encouraging people to take the stairs instead of the lift or escalator, for example, can lead to more of them to do so.

According to Amanda Daley, professor of behavioural medicine at Loughborough University in the UK, it’s these small shifts that build meaningful change over time. “We just have these unconscious ways of doing things that mean that we’re more likely to do it,” she says. “You take the stairs because that’s you’ve learned. It’s a habit.”

Similarly, Daley suggests that a simple way to decrease sedentary behaviour is to park the car at least five minutes from your destination. She calls this type of approach “snacktivity” and in a small study, she and colleagues found that participants were receptive to the idea, finding it easier to implement than longer bouts of exercise.

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Or take walking. We can benefit from fewer steps in a day than is commonly believed, as the BBC has previously reported. One step-count study found that taking 2,517-2,735 steps per day reduces cardiovascular risk by 11% compared to taking only 2,000 steps.

When it comes to how you exercise, there are numerous options. You could go rock climbing, join a dance class or try some something a little more vigorous like high-intensity interval training, which can improve blood sugar control and blood pressure, as well as reducing body fat. 

I’ve certainly had sore arms when carrying food shopping home instead of taking the car. But it seems that discomfort can be worth it.

So next time you’re waiting for your pasta to boil or watching TV, perhaps include a set of squats, leg kicks or press ups. These little “exercise snacks” all add up. They are certainly “snacks” you won’t ever need to feel guilty about.

While it’s widely known that chewing more improves digestion, research suggests it can also boost our brains and even help fend off Alzheimer’s.

For once chewing a shallot 722 times before swallowing it, Horace Fletcher was dubbed “The Great Masticator”. The American self-taught nutritionist believed food should be chewed “until it is completely liquefied” and it “practically swallows itself”. Fletcher even estimated that vigorous chewing could have saved the US economy of the early 20th Century more than half a million dollars a day (roughly $19.5m in today’s money), because the average person would have ingested half a pound (227g) less food daily.

Fletcher’s doctrine may have been a little extreme, “but in some aspects, he was actually right”, says Mats Trulsson, professor in the department of dental health at the Karolinska Institutet in Sweden.

Chewing more can provide a wide range of health benefits, from improving digestion and helping people consume fewer calories to alleviating stress and anxiety and improving cognition by solidifying memory skills and boosting attention span. As there is a correlation between tooth health and Alzheimer’s disease and dementia, some experts argue that improving patients’ dental health could even help reverse mental ageing.

The prehistory of chewing   

Like most animals, humans have “had teeth and jaws for millions of years,” says evolutionary and ecological biochemist Adam van Casteren at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. But they’ve gone through many changes throughout prehistory.      

The earliest hominins, who lived roughly six to seven million years ago, had teeth similar to those of apes today; especially helpful for eating “lots of large, fleshy fruit” abundant in the forest habitats that our early ancestors lived in, says Van Casteren. But as rainforests gave way to more woodlands, open habitats and even savannah-like ecologies, hominins had to contend with “more mechanically challenging foods”, says Van Casteren, such as seeds, nuts, and tubers. So they evolved to favour an increase in molar size, with bigger jaws and faces to house all those teeth, alongside the larger muscles needed to power them.

The theory is that chewing works like a pump, pumping blood to the brain – Mats Trulsson

With the development of tools, food processing, and agriculture, as well as fire to cook food, we also stopped needing such lengthy bouts of mastication, explains Van Casteren. Today, humans spend roughly 35 minutes chewing every day, compared to 4.5 hours for our closest ape relatives, chimpanzees and bonobos and 6.6 hours for gorillas and orangutans.

Despite these evolutionary changes, the purpose of chewing remains the same. “We mammals are such complicated chewers because we want to get as much energy out of our food to power our warm-blooded metabolisms,” says Van Casteren.

An important first step

At the most basic level, chewing breaks food down into small particles and moistens them with saliva so that they can be easily swallowed. “It’s the first phase of digestion,” says Andries van der Bilt, a pioneer in the field of oral physiology and chewing, who worked as a researcher at the University Medical Center Utrecht in the Netherlands for over three decades.

Not only does chewing increase saliva production and the amount of digestive enzymes like amylase that help break down food, it also triggers the gut and pancreas to secrete juices that will help process food further, too. “If you don’t chew, the gut is not prepared to handle food,” says Trulsson.

The act of breaking food particles into smaller pieces also increases their surface area, which means digestive juices can act on them more efficiently, says orofacial neuroscientist Abhishek Kumar, who works with Trulsson at the Karolinska Institutet. This is important for gut health. Bigger particles tend to linger in the gut longer, giving microorganisms more time to ferment them. This causes “feelings of bloatedness, fullness, constipation, and other symptoms”, Kumar says.

Improving absorption and feelings of fullness

The act of chewing helps release nutrients in food, allowing our bodies to absorb them more effectively. In a 2009 study, for instance, 13 healthy adults were asked to chew a small handful of almonds 10, 25, or 40 times. When researchers collected samples of participants’ poo, they discovered that the more people chewed, the less fat they excreted, suggesting that the absorption of energy from the nuts was up to a third higher. (In the early 1900s, in fact, Fletcher believed chewing more helps produce poo of superior quality – “quite dry” and smelling of a “hot biscuit”.)

What’s more, chewing 40 times left participants feeling fuller for longer. A separate 2013 study echoed this satiety link: when 21 participants chewed a chicken-nugget sized slice of pizza either 15 or 40 times before swallowing, those in the latter group experienced a significant reduction in hunger. They also had higher levels of CCK and GIP, two hormones that coordinate digestion in the gut, alongside suppressed levels of the “hunger hormone” ghrelin.

Fletcherism

So-called “Fletcherism” became a curious diet fad that swept through parts of Europe and the US in the 1900s and was practised by many notable figures. Some Asian cultures also espouse good chewing, including traditional Chinese medicine. Japan’s health authorities once even introduced a Kamingu 30 campaign, encouraging citizens to chew every bite 30 times before swallowing.

Chewing more means you’re also likely to consume less food, according to two separate meta-analyses that reviewed nearly 50 studies.

That’s because it takes around 20 minutes for the body to adjust its production of hunger-related hormones and send signals to the brain that you’re full – and chewing buys you more time. It’s one reason why so many dieticians and doctors advocate slow and mindful eating over wolfing down a meal, especially if you’re trying to shed some pounds. A survey of 92 children in Brazil found that those who were obese “performed fewer mastication sequences and ate faster” compared to children of normal weight. 

One good way of slowing down your eating rate, in fact, is to eat more textured foods. Many studies recommend choosing solids over liquids (think oranges rather than orange juice), and high-viscosity foods over low-viscosity ones (oatmeal and flaxseeds instead of white rice or pasta).     

“The texture of food can affect how full we feel, and therefore potentially help those struggling with obesity to lose weight by reducing their food intake,” says Kumar.

A boost for brain health

Nutrition and digestion aside, researchers are increasingly uncovering that chewing plays an important role in other aspects of our wellbeing – especially brain health – as we get older. “There is growing interest in the ‘bite–brain axis,’ which proposes that mastication is directly linked to brain health,” says Kumar. Tooth loss, for instance, has also been linked with a higher risk of Alzheimer’s disease and dementia. 

Wouldn’t it be really cool if you can rehabilitate the brain by rehabilitating the dentition? – Mats Trulsson

Memory is affected, too. In a survey involving more than 28,500 people older than 50 across 14 European countries, participants with good chewing ability or those without dentures performed better on a battery of cognitive tests. They demonstrated significantly better word recall, verbal fluency, and numeracy skills than those with chewing problems. In one study of 273 healthy people between the ages of 55 and 80, scientists found that those who retained a greater number of their natural teeth had better semantic memory (linked to knowledge and facts of the world) and long-term memory. 

But why does chomping ability have anything to do with memory? Some researchers point to the multiple neural circuits connecting our chewing apparatus to the hippocampus – the region of the brain responsible for spatial learning and making new memories, which is one of the first to be damaged by Alzheimer’s. Others suggest that chewing, especially moderately hard substances, may increase blood flow to the brain, as Japanese researchers demonstrated in experiments with gum chewers. “The theory is that chewing works like a pump, pumping blood to the brain,” explains Trulsson. This keeps the brain sharp and working well, he says. 

To determine whether poor chewing ability can actually cause cognitive decline, and whether rehabilitation is possible, Trulsson’s team is currently running an experiment replacing patients’ missing teeth with implants and then studying their brain function before and up to a year after the procedure. MRI brain scans will also be used to examine if white matter lesions, a marker of poor brain vascular health, shrink with treatment.

“Wouldn’t it be really cool if you can rehabilitate the brain by rehabilitating the dentition?” says Trulsson, who has recruited over 80 patients for his trial so far.

Heightening alertness

In some instances, chewing has also been found to improve concentration in the general population. One meta-analysis, comprising 21 studies, detected a weak but statistically significant improvement in attention levels of gum-chewing participants compared to non-chewers during some cognitively demanding tasks. (This research was funded by gum manufacturer Mars Wrigley, suggesting a potential conflict of interest.)

In an unrelated study of 80 participants, chewing improved alertness levels by 10% during a series of cognitive tasks. Gum-chewers also performed better on an intelligence test.

Scientists “don’t really know exactly how it works,” but the link between chewing and heightened attention is fairly strong, says Trulsson. There’s a caveat, though: “The effect will probably not last for more than 15 to 20 minutes“, although researchers aren’t sure why.

Another experiment – in young adults who were asked to perform four computerised tasks simultaneously – also found significantly better alertness (nearly 20% higher) in gum chewers. Interestingly, this was accompanied by reductions in self-reported anxiety, stress and salivary cortisol levels (a common biomarker of stress).

Lowering stress

Outside the lab, chewing is a good stress-reliever too. When a group of Turkish researchers studied 100 nursing students preparing for mid-term exams, they found that students who chewed gum for at least 30 minutes daily experienced lower levels of stress, anxiety and depression. This was regardless of whether they began chewing gum 15 days or two days before their exams.

For two separate groups of women undergoing elective gynaecological surgery in Korea, chewing on gum helped alleviate their pre-operative anxiety. It also had this effect on 73 Turkish children who were having an intravenous cannula inserted.

Chewing seems to be a natural reflex in stressful times, says Jianshe Chen, an oral processing researcher at Singapore’s Agency for Science, Technology and Research. “When some people are stressed, they start to chew unconsciously.” Teeth grinding or bruxism, which uses the same jaw muscles as chewing and affects roughly one in 10 adults, is commonly triggered by stress and anxiety.

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But the scientific data here is more contentious. Chen, for instance, says the evidence linking chewing to a calmer state of mind is “scattered”. We’re “still short of systematic studies” that confidently point to a strong association, he says. Another study, led by the same Korean researcher above, for instance, found that gum-chewing did little to alleviate the anxiety pregnant women felt as they were wheeled into the operating theatre for an elective caesarean section. It also failed to dent the stress levels of those working on an insolvable word puzzle.

One thing’s for sure, though – eating often elevates our mood. And chewing, a crucial part of this process, releases flavours in food, and combined with texture and aroma, makes “your eating experience much richer and more pleasant,” says Chen, who also studies the sensory perception of food. So, according to this logic, chewing your food better could boost your mental health, too. But rather than choosing sugary gum, you might want to consider chewing a healthy, textured snack before a stressful task.

Don’t overdo it, though. Unlike Fletcher, most experts don’t think there is a magic number for chewing. “Chew in a normal way until you feel it’s okay to swallow, which will be different for different people,” says Van der Bilt. “Just enjoy your food.”

Can the right foods really improve your chances of having a baby? Here are the facts.

Visit any online fertility chat room, and one of the main topics of debate will probably be what to eat to maximise your chances of conceiving. In addition to the wealth of supplements promoted as being fertility-boosting, there is also an array of foods that are supposed to help achieve a healthy pregnancy.

Amid all the myths and marketing, what is the actual evidence for using certain foods to enhance male and female fertility, and support the developing fetus?

For a start, when it comes to supporting a healthy pregnancy and fetus, certain nutrients really can make a difference – such as folic acid. When taken before and during pregnancy, it has been shown to help prevent both anencephaly, a birth defect of the baby’s brain, and spina bifida, which affects the baby’s spine.

Because these defects develop very early in the pregnancy, often before a woman knows she is pregnant, the US Centers for Disease Control and Prevention recommend that all women of reproductive age take 400 micrograms (mcg) of folic acid each day. Fortifying staple foods such as cereals with folic acid may offer even more powerful protection, because many pregnancies are unplanned. It is estimated that, in 2019, effective fortification programmes prevented 22% of potential cases of folic-acid-preventable spina bifida and anencephaly, worldwide.

Folic acid may have an additional benefit: when taken as a supplement by women trying to conceive, it may increase the chance of getting pregnant, though there is a need for further trials to confirm this.

What about other foods and supplements? Is there such a thing as a “fertility diet” that will maximise your chances of conceiving?

A study of couples undergoing IVF found that men’s meat consumption, and especially the type of meat they ate, affected the outcome

To answer that question, it helps to break down the main reasons for infertility. In the United States, after one year of having unprotected sex, 15% of couples are unable to conceive. There are many potential causes. On the female side, the ovaries may be unable to produce healthy eggs, or the egg may not be able to move from the ovaries to the womb – for example, due to blocked fallopian tubes. Even if the egg makes that journey successfully, it may then not attach to the lining of the womb, or not survive once it has attached.

On the male side, the quality of sperm cells is crucial for fertility. This includes their ability to move efficiently (motility), their shape and size (morphology), and how many there are in a given quantity of semen (sperm count). A range of factors can threaten sperm quality, including environmental problems such as pollution (read BBC Future’s report on the global decline in sperm quality). Even after tests, the cause of infertility may not always be clear: about 15% of infertility cases remain unexplained.

While no individual food or supplement will be a quick fix for any of these potential issues, experts say diet can play a beneficial role throughout the process of trying to conceive and beyond.

Most obviously, being well-nourished is crucial. The consequences of malnutrition can be devastating for prenatal health.

Arguably the best-known findings in this area come from a study of babies conceived during the so-called “Dutch Hunger Winter” of 1944; an eight-month famine that occurred when the Nazis cut off food supplies into the Netherlands at the end of World War II. The mothers-to-be were surviving on only 400 calories a day, a fraction of the intake necessary for a healthy pregnancy. The babies conceived during that time faced a range of adverse health consequences, including being shorter and thinner than those born before or after them, and having smaller heads. As adults, they had higher rates of obesity, diabetes and schizophrenia, and tended to die younger.

For those who do have access to sufficient food, it is still important to obtain the right mix of nutrients. While discussions around beneficial foods often focus on female fertility, there has been a growing awareness of how diet can also affect male fertility.

A 2015 study of couples undergoing IVF found that men’s meat consumption, and especially the type of meat they ate, affected the outcome, as measured by fertilization rates. Eating more poultry had a positive impact on fertilisation rates, whereas eating processed meat (such as bacon and sausages) had a negative impact. Men who ate the least processed meats, averaging fewer than 1.5 servings a week, had an 82% chance of achieving pregnancy with their partner – while men who ate the most processed meats, with an average of 4.3 servings a week, had just a 54% chance.

5:05What external factors affect male fertility and why.

Even after conception, the father’s diet may indirectly affect the unborn child.

A study led by researchers at The University of Queensland in Australia has shown that what fathers eat has a lasting effect on the future health of their unborn children. The team analysed dietary data from almost 200 couples receiving antenatal care at Australia’s largest maternity hospital, the Mater Mothers’ Hospital in Brisbane. The study found that the men’s dietary intake strongly influenced that of the women, and that in turn impacted the developing baby. Other studies suggest that a father’s weight can have an intergenerational effect, influencing the weight of the child.

“Men’s health and nutrition for fertility is overlooked, but it is so important,” says Shelley Wilkinson, a dietician who was one of the authors of the University of Queensland study and now works at Lifestyle Maternity, a private clinic in Australia that specialises in fertility support. “It can actually impact their grandchildren’s health.”

Wilkinson also highlights the importance of tackling any changes as a couple. “If one person is meeting the dietary guidelines, the other person is more likely to be as well,” she says. “We should be focusing on supporting women as well as men to make healthy changes. Otherwise, we’re losing half the battle.”

One beneficial change can be to increase the amount of fat in the couple’s diet – as long as it’s the right kind of fat. Healthy fats are found in nuts, seeds, salmon, avocado and olive oil. However, trans fatty acids – which can come from natural or industrial sources, and are for example found in margarine, doughnuts, fried food and other processed food – are associated with a higher risk of infertility.

A diet rich in plants may also be beneficial. Researchers at Harvard School of Public Health assessed the diets of a group of 18,555 women over eight years, as they attempted a pregnancy or became pregnant. Consuming plant-based protein like legumes, instead of animal-based proteins like red meat, was associated with a more than 50% lower risk of ovulatory infertility, they found.

We need to support women as well as men to make healthy changes. Otherwise, we’re losing half the battle – Shelley Wilkinson

The authors of a 2021 review of research on the possible link between diet and female fertility concluded that, while their recommendations focused on women, “diet and nutritional patterns are undoubtedly significant for both male and female fertility”.

The researchers gave a detailed overview of the effects of individual nutrients and the foods that contain them. They also emphasised the importance of involving a clinical dietician in the care of couples planning a pregnancy. Broadly speaking, their summary recommended foods such as vegetables, fruit, whole-grain pasta and whole-grain bread (for carbohydrates); sources of healthy fat such as oily fish; and legumes, eggs and lean meat for protein. They also pointed out the important role of certain nutrients that may sometimes be overlooked: these include iodine, which helps the proper development of the fetus and the expectant mother’s thyroid function.

For alcohol, the advice is clear and consistent across the research. The CDC states: “there is no known safe amount of alcohol use during pregnancy or while trying to get pregnant.” This goes for all types of alcohol, including all wines and beer. The advice is to avoid it altogether.

If you have any concerns or questions about your diet and how it might affect your fertility, the best step is to consult your healthcare provider. And while certain foods do appear to play a positive role in fertility, it’s important not to overstate their power. Infertility is complex, as are its cause. Worrying over one’s diet can cause unnecessary stress as well as feelings of guilt and shame. Those struggling to conceive can rest assured that the problem is unlikely to be rooted in one specific thing they did or did not eat.

Wilkinson says that people with fertility issues are often searching for a single fertility-promoting food – but it is better to aim for an overall healthy eating pattern. “In the fertility chat rooms, there’s a lot of talk about pineapple being some kind of magic fertility food for if you’re trying to fall pregnant. However, there is no single food or supplement that works like that.”

* All content within this article is provided for general information only, and should not be treated as a substitute for the medical advice of health care professionals.

Disclaimer: The BBC is not responsible or liable for any diagnosis or actions taken by a user based on the content of this site. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. Always consult your own GP if you’re in any way concerned about your health or the health of your child.

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