Does Echinacea Prevent colds? | BBC FUTURE

Echinacea is often advised for warding off the winter sniffles, says Claudia Hammond, but does it actually work?

• By Claudia Hammond | BBC FUTURE

5 November 2014

If you find yourself about to go down with a cold this winter, the chances are that at some point a friend will suggest you take echinacea. Some swear by it to ward off a cold when they feel the first stirrings of a sore throat. Others take it once a cold is full-blown, in the hope that it will speed their recovery. Native Americans have long valued echinacea for its medical properties, but in the 20th Century its use spread to many countries after it became popular in Germany. In today’s health food shops ­ you can see dozens of different kinds of preparations. The question is, does it work?

Every couple of years a new study is published showing that echinacea either does or doesn’t reduce your risk of contracting a cold. Part of the reason for this mixed picture is that it comes in so many forms. Of the nine different species, all from the daisy family, there are three which are often used medicinally - the pinky-purple echinacea purpurea, the pale purple coneflower and the slightly shorter echinacea angustifolia. To complicate things more, some preparations use the root, others the flower, the leaves or the whole plant and then it can be pressed for its juice, made into a tincture or dried and put into tablets. Different research studies use different preparations, making them hard to compare.

(Thinkstock)

No one is even agreed on exactly which ingredients in echinacea might prevent or aid recovery from a cold, or whether it’s the combination of ingredients that’s crucial. Echinacea contains four types of compounds which might boost the immune system: alkamides, glycoproteins, polysaccharides and caffeic acid derivatives, but not all these substances are found in every species of echinacea, nor in every part of the plant.

So does it make a difference to your chances of contracting a cold? After years of mixed results, in 2007 scientists at the University Of Connecticut in the US conducted a meta-analysis, combining and reanalysing the data from the 1600 participants in previous trials. The results seemed good news for echinacea fans, with newspapers proclaiming that supplements could halve your chances of getting a cold. The problem is that the plant is so versatile that the original studies involved not only different species of echinacea, but different parts of the plant, extracted in different ways. You could argue that this is like pooling the results of studies measuring different treatments, since chemically not every species of part of the plant is the same.

Full review

Then earlier this year came the most comprehensive review so far – a Cochrane review that scanned the literature and included only the very best studies. They looked for randomised controlled studies where people were given either echinacea or a placebo and neither they nor the staff administering the preparations knew which they were getting. From the 82 trials they assessed they ended up with 24 which fulfilled the criteria, mostly from the US and Germany. Still, they weren’t always convinced that the people wouldn’t guess what they were taking. One trial used capsules containing vegetable oil as a placebo. Another used the manufacturers’ own staff who might be familiar with the taste of their own product.

Various parts of echinacea are used for remedies and it's unclear which ones work best, if at all (Nomadic Lass/Flickr/CC BY-SA-2.0)

In some studies people were given echinacea and then deliberately exposed to a cold virus to see whether they became infected. In others, people had the echinacea on hand and were instructed to start taking it the moment they felt a tickle in their throat or starting sneezing.

Their results were slightly disappointing for those hoping to avoid colds in the future. They found that when you looked at these well-conducted trials, none of them showed on their own that echinacea prevented colds. But on a more positive note, when they pooled the results of the best studies, giving them a much larger group of people, those who took echinacea did turn out to be less likely to get a cold, even if only 10 to 20% less likely. The authors suggest that perhaps the reason that these effects didn’t show up in individual studies, is that they had such small numbers of people taking part in them. Of course with the pooled result there’s still the problem that the people in different studies took different forms of echinacea.  

Immune trigger

We also need to bear in mind that these studies all excluded people with an underlying illness. Not everyone wants to boost their immune systems. A healthy immune system has been described to me as a dog on a lead that’s out in the park. It’s straining at the leash ready to shoot off at any moment if it can get free. You want it to keep on walking at a steady pace with you, not to break free and go rushing off too far. Similarly, you want the immune system to work reliably, but not to go too far. Auto-immune diseases like multiple sclerosis and rheumatoid arthritis involve an immune system that has become too active and organisations such as the National Institute of Health in the US advise patients with these conditions not to take echinacea. 

So the next time you feel your throat getting a bit sore and fear you’re going down with a cold, you could try taking some echinacea, but bear in mind no one yet knows exactly which kind you should take. And until they do, then on average there’s an 80-90% chance you will still get the cold. It might make a difference, but only a small one.

http://www.bbc.com/future/story/20141104-does-echinacea-prevent-colds

What would happen if the world suddenly went vegetarian? | BBC FUTURE

Eliminating meat from our diets would bring a bounty of benefits to both our own health and the planet’s – but it could also harm millions of people.

• By Rachel Nuwer | BBC FUTURE

27 September 2016

People become vegetarians for a variety of reasons. Some do it to alleviate animal suffering, others because they want to pursue a healthier lifestyle. Still others are fans of sustainability or wish to reduce greenhouse gas emissions.

No matter how much their carnivorous friends might deny it, vegetarians have a point: cutting out meat delivers multiple benefits. And the more who make the switch, the more those perks would manifest on a global scale.

But if everyone became a committed vegetarian, there would be serious drawbacks for millions, if not billions, of people.

“It’s a tale of two worlds, really,” says Andrew Jarvis of Colombia’s International Centre for Tropical Agriculture. “In developed countries, vegetarianism would bring all sorts of environmental and health benefits. But in developing countries there would be negative effects in terms of poverty.”

If vegetarianism was adopted by 2050, it would stave off about 7 million deaths per year, while veganism would knock that estimate up to 8 million (Credit: iStock)

Jarvis and other experts at the centre hypothesised what might happen if meat dropped off the planet’s menu overnight.

First, they examined climate change. Food production accounts for one-quarter to one-third of all anthropogenic greenhouse gas emissions worldwide, and the brunt of responsibility for those numbers falls to the livestock industry. Despite this, how our dietary choices affect climate change is often underestimated. In the US, for example, an average family of four emits more greenhouse gases because of the meat they eat than from driving two cars – but it is cars, not steaks, that regularly come up in discussions about global warming.

Most people don’t think of the consequences of food on climate change – Tim Benton

“Most people don’t think of the consequences of food on climate change,” says Tim Benton, a food security expert at the University of Leeds. “But just eating a little less meat right now might make things a whole lot better for our children and grandchildren.”

Marco Springmann, a research fellow at the Oxford Martin School’s Future of Food programme, tried to quantify just how much better: he and his colleagues built computer models that predicted what would happen if everyone became vegetarian by 2050. The results indicate that – largely thanks to the elimination of red meat – food-related emissions would drop by about 60%. If the world went vegan instead, emissions declines would be around 70%.

“When looking at what would be in line with avoiding dangerous levels of climate change, we found that you could only stabilise the ratio of food-related emissions to all emissions if everyone adopted a plant-based diet,” Springmann says. “That scenario is not very realistic – but it highlights the importance that food-related emissions will play in the future.”

Global vegetarianism might impact farmers in the developing world hardest (Credit: iStock)

Food, especially livestock, also takes up a lot of room – a source of both greenhouse gas emissions due to land conversion and of biodiversity loss. Of the world’s approximately five billion hectares (12 billion acres) of agricultural land, 68% is used for livestock.

If everyone became vegetarian by 2050, food-related emissions would drop by 60%

Should we all go vegetarian, ideally we would dedicate at least 80% of that pastureland to the restoration of grasslands and forests, which would capture carbon and further alleviate climate change. Converting former pastures to native habitats would likely also be a boon to biodiversity, including for large herbivores such as buffalo that were pushed out for cattle, as well as for predators like wolves that are often killed in retaliation for attacking livestock.

The remaining 10 to 20% of former pastureland could be used for growing more crops to fill gaps in the food supply. Though a relatively small increase in agricultural land, this would more than make up for the loss of meat because one-third of the land currently used for crops is dedicated to producing food for livestock – not for humans.

Both environmental restoration and conversion to plant-based agriculture would require planning and investment, however, given than pasturelands tend to be highly degraded. “You couldn’t just take cows off the land and expect it to become a primary forest again on its own,” Jarvis says.

Carnivorous careers

People formerly engaged in the livestock industry would also need assistance transitioning to a new career, whether in agriculture, helping with reforestation or producing bioenergy from crop byproducts currently used as livestock feed.

Some farmers could also be paid to keep livestock for environmental purposes. “I’m sitting here in Scotland where the Highlands environment is very manmade and based largely on grazing by sheep,” says Peter Alexander, a researcher in socio-ecological systems modelling at the University of Edinburgh. “If we took all the sheep away, the environment would look different and there would be a potential negative impact on biodiversity.”

Should we fail to provide clear career alternatives and subsidies for former livestock-related employees, meanwhile, we would probably face significant unemployment and social upheaval – especially in rural communities with close ties to the industry.

If meat dropped from menus, the economic effects worldwide would be profound (Credit: iStock)

“There are over 3.5 billion domestic ruminants on earth, and tens of billions of chickens produced and killed each year for food,” says Ben Phalan, who researches the balance between food demand and biodiversity at the University of Cambridge. “We’d be talking about a huge amount of economic disruption.”

But even the best-laid plans probably wouldn’t be able to offer alternative livelihoods for everyone. Around one-third of the world’s land is composed of arid and semi-arid rangeland that can only support animal agriculture. In the past, when people have attempted to convert parts of the Sahel – a massive east-to-west strip of Africa located south of the Sahara and north of the equator – from livestock pasture to croplands, desertification and loss of productivity have ensued. “Without livestock, life in certain environments would likely become impossible for some people,” Phalan says. That especially includes nomadic groups such as the Mongols and Berbers who, stripped of their livestock, would have to settle permanently in cities or towns – likely losing their cultural identity in the process.

Plus, even those whose entire livelihoods do not depend on livestock would stand to suffer. Meat is an important part of history, tradition and cultural identity. Numerous groups around the world give livestock gifts at weddings, celebratory dinners such as Christmas centre around turkey or roast beef, and meat-based dishes are emblematic of certain regions and people. “The cultural impact of completely giving up meat would be very big, which is why efforts to reduce meat consumption have often faltered,” Phalan says.

Worldwide vegetarianism by 2050 would lead to a global mortality reduction of up to 10%

The effect on health is mixed, too. Springmann’s computer model study showed that, should everyone go vegetarian by 2050, we would see a global mortality reduction of 6-10%, thanks to a lessening of coronary heart disease, diabetes, stroke and some cancers. Eliminating red meat accounts for half of that decline, while the remaining benefits are thanks to scaling back the number of calories people consume and increasing the amount of fruit and vegetables they eat. A worldwide vegan diet would further amplify these benefits: global vegetarianism would stave off about 7 million deaths per year, while total veganism would knock that estimate up to 8 million. Fewer people suffering from food-related chronic illnesses would also mean a reduction in medical bills, saving about 2-3% of global gross domestic product. 

Even the best-laid plans probably wouldn’t be able to offer alternative livelihoods for everyone (Credit: iStock)

But realising these projected benefits would require replacing meat with nutritionally appropriate substitutes. Animal products contain more nutrients per calorie than vegetarian staples like grains and rice, so choosing the right replacement would be important, especially for the world’s estimated two billion-plus undernourished people. “Going vegetarian globally could create a health crisis in the developing world, because where would the micronutrients come from?” Benton says.

All in moderation

But fortunately, the entire world doesn’t need to convert to vegetarianism or veganism to reap many of the benefits while limiting the repercussions.

Instead, moderation in meat-eating’s frequency and portion size is key. One study found that simply conforming to the World Health Organization’s dietary recommendations would bring the UK’s greenhouse gas emissions down by 17% – a figure that would drop by an additional 40% should citizens further avoid animal products and processed snacks. “These are dietary changes that consumers would barely notice, like having a just-slightly-smaller piece of meat,” Jarvis says. “It’s not this either-or, vegetarian-or-carnivore scenario.”

Certain changes to the food system also would encourage us all to make healthier and more environmentally-friendly dietary decisions, says Springmann – like putting a higher price tag on meat and making fresh fruits and vegetables cheaper and more widely available. Addressing inefficiency would also help: thanks to food loss, waste and overeating, fewer than 50% of the calories currently produced are actually used effectively.

“There is a way to have low productivity systems that are high in animal and environmental welfare – as well as profitable – because they’re producing meat as a treat rather than a daily staple,” Benton says. “In this situation, farmers get the exact same income. They’re just growing animals in a completely different way.”

In fact, clear solutions already exist for reducing greenhouse gas emissions from the livestock industry. What is lacking is the will to implement those changes.

http://www.bbc.com/future/story/20160926-what-would-happen-if-the-world-suddenly-went-vegetarian

Faecal bacteria found in ice from three major UK coffee chains

BBC Watchdog investigation of iced water samples from Caffè Nero, Starbucks and Costa Coffee found faecal coliform bacteria

Nicola Davis

@NicolaKSDavis

Wednesday 28 June 2017 12.43 BST

All three coffee chains have responded to the findings, saying they are taking steps in the matter. Photograph: Yui Mok/PA

Ice from three major coffee chains in the UK has been found to contain faecal bacteria.

An undercover investigation revealed that iced water obtained from high street outlets Caffè Nero, Starbucks and Costa Coffee all contained faecal coliform bacteria, with a positive test found for seven out of 10 samples from Costa and three out of 10 samples from the other two chains.

All three chains have responded to the findings by the BBC’s Watchdog programme, saying that they are taking steps in the matter.

Rob Kingsley, an expert in food-borne pathogens and a research leader at Quadram Institute Bioscience said the findings were extremely concerning. 

“Coliforms are an indicator of faecal contamination which means that essentially anything which is in faeces could be in that ice,” he said, meaning other, more dangerous bacteria could be present. “It is an indicator that somewhere there has been some kind of breakdown in hygiene or the source of the water used for this ice.” 

Asked whether the public should give iced drinks a wide berth, Kingsley demurred but added “I would certainly think twice about eating something which may contain faecal contamination at that level, where it is detectable.”

It is not the first food outlet to be shown to have high levels of such bacteria in its ice: last year the BBC programme Rip Off Britain found high levels of faecal bacteria in ice from a KFC restaurant in Birmingham, prompting the chain to launch an investigation. However, ice from a handful of coffee shops tested at the same time, including Costa and Caffè Nero, was not found to be cause for concern. 

“This time we have tested 10 coffee shops of the three different chains, so we tested more places,” said Margarita Gomez Escalada, a microbiologist and senior lecturer at Leeds Beckett University who carried out the analysis for both BBCprogrammes.

Gomez Escalada said that it was most likely that ice was contaminated by being touched by unclean hands, but added that ice machines and ice buckets might have compounded the issue if they were not properly cleaned.

“The levels allowed by law of bacteria in tap water are super low, so we would find say maybe 10 microorganisms per millilitre – we found hundreds per millilitre,” she added.

The analysis, said Gomez Escalada, looked at both the total bacteria count, and the faecal bacteria count. While some samples showed high levels of total bacteria but not faecal bacteria, some showed high levels of both.

“The fact that we have found so many bacteria, it just increases the risk [of getting sick],” she said. “Some of the bacteria we identified were actually what we call opportunistic pathogens, which are bacteria that to healthy people do not often cause disease, but they cause disease to people [whose] immunity is reduced.” 

Gomez Escalada admitted that other pathogens might also have been present in the samples, but would not have been picked up in the analysis.

But Tony Lewis, head of policy at the Chartered Institute of Environmental Health who has seen the BBC’s findings urged caution, pointing out that the sample size for the investigation was small.

“Given that there are tens of thousands of coffee shops around the UK, we have to put this into context,” he said. “The samples that the BBC have got indicate a problem, or problems, in respect to the Costa and the Caffè Nero and the Starbucks that they sampled – but at the end of the day the public should not panic about this. You can’t generalise from the small sample size that we have got here.”

Lewis added that, of all the bacteria found in the samples, some would have been “good bacteria”, but he added that some species were associated with disease.

“Yes, the overall levels [of bacteria] in some instances are high, the numbers of the pathogens – they shouldn’t be there at all,” he said. “We would not expect to see pathogens present –f we would not expect to see faecal coliforms present.”

But Lewis said that the public should not give up their iced coffees. “It is not something to panic over,” he said, adding that the companies take hygiene seriously and have taken action, and environmental health had been notified. “The public should be reassured, this will have been dealt with.”

Gomez Escalada said that the issue of ice needs to be tackled, pointing out that while microbial levels in water are carefully controlled, ice is often overlooked. “No one looks at the ice,” she said.

https://www.theguardian.com/world/2017/jun/28/faecal-bacteria-found-ice-three-major-uk-chains-caffe-nero-starbucks-costa-coffee

Is Sparkling Water bad For You? | BBC FUTURE

We’re often warned to go easy on sparkling water, as it may be detrimental to our gut, bones and teeth. But is there any truth in this?

• By Claudia Hammond | BBC FUTURE

14 September 2015

We all know by now that drinking sweet, fizzy drinks all day isn’t a good idea. The combination of a high sugar content coupled with acidity caused by the carbonisation that makes it fizzy, isn’t good. Anyone who has tried leaving coins in a glass of cola overnight knows that they come up shiny and clean. The reason is that phosphoric acid in the drink removes the oxide coating that has built up on the coin. So one alternative is to drink water. “Still or sparkling?” they say to you in restaurants. If you’re not brave enough to say “tap” then sparkling can seem like a nice change.

The chances are though, that if you’re in a group at least one person will say sparkling water is bad for you, but is there any evidence for that claim?

Let’s start with the stomach. Fizzy water is made by adding carbon dioxide under pressure. The result is that water contains the weak acid, carbonic acid. If you gulp it down it can of course give you hiccups or indigestion. But what if you drink it at a more measured pace? Is there any truth in the idea that it harms your stomach?

(Credit: Getty Images)

Quite the reverse, it appears. In a small but double-blinded randomised trial, patients with frequent dyspepsia or constipation were assigned to drink either still or sparkling water for 15 days. Then they were given a series of tests. Both conditions improved in the people drinking sparkling water and showed no improvement in those drinking tap water.

If you drink a lot of sparkling water you might find you feel bloated, but researchers in Japan have found that this side-effect could be put to good use. They had a group of women fast overnight and then slowly drink either still or sparkling water. They found that 900ml of gas was released from just 250ml of water, so not surprisingly the women’s stomachs distended slightly and the had the perception of feeling full, even though they hadn’t eaten. They didn’t feel uncomfortable and so fizzy water has been suggested as a way of avoiding overeating, because it makes you feel fuller.

Bone problems?

And you might have heard people deliberately letting fizzy drinks go flat and then drinking them if they’re dehydrated after a stomach upset or vomiting or even a hangover. But a review of this practice in children with acute gastroenteritis found there’s little evidence that it works and that compared with rehydration powders – specifically constituted to contain replacement salts and sugars in the right proportions – such drinks contain far lower levels of sodium and potassium than you’d find in rehydration drinks. So it’s better to stick to the real thing.

Surely any acid, even a weak one, is going to erode the enamel on our teeth?

But if sparkling water doesn’t damage your stomach, how about your bones?  Does it weaken them? Again, the evidence so far suggests not. A small, Canadian study published in 2001 found that teenagers who drank lots of fizzy drinks (not sparkling water) had less calcium in their bones, but they couldn’t tell whether this was a problem with the drinks themselves or that it was because people who drank them might favour them instead of milk.

The Framingham Heart study began in 1948 and followed a group of people over many years to discover more about the risk factors for heart disease. Now some of their offspring are taking part in the Framingham Osteoporosis Study which involves extensive testing every four years by researchers from Tufts University in Boston. In 2006, the team examined the relationship between bone density and fizzy drinks. They looked in detail at the different types of drink consumed by more 2,500 taking part in the study.

Some people have warned that any sparkling drink - even water - can be bad for us (Credit: Getty Images)

They found that the women (but not men) who drank cola-flavoured fizzy drinks three times a week had hip bones with a lower average bone mineral density. Other carbonated drinks made no difference. The authors hypothesise that the effect is probably down to caffeine and to the actions of phosphoric acid (not found in sparkling water) that are not yet well understood. It’s possible that it might somehow block calcium absorption – but no one yet knows how. Ten years later there is still disagreement over how diet affects bone health.

So as far as bones and stomachs go, so far drinking sparkling water seems to be fine. But how about teeth? Surely any acid, even a weak one, is going to erode the enamel on our teeth? Maybe not. Very little research has been done on sparkling water in particular, but much more has been done on other fizzy drinks. Barry Owens from the University of Tennessee College of Dentistry, Memphis, USA conducted a study back in 2007 comparing different fizzy drinks. In his study, cola-based drinks came out as most acidic, followed by diet-based cola drinks, followed by coffee.

Cumulative effect

He argues that it’s not just the initial pH of a drink that matters, but how strongly the drink retains that acidity in the presence of other substances, because in a real-life mouth saliva is present, as well as other foods which might affect the levels of acidity. This is known as the buffering capacity. A review of different drinks puts them in the following order for their buffering capacity. Non fruit-based carbonated drinks such as cola came out as the most acidic (with diet versions doing slightly better), followed by fruit-based fizzy drinks, fruit juice and then coffee. In other words, some fizzy drinks can damage the hardness of the enamel.

By taking slices of enamel and immersing them in different soft drinks for six, 24 and 48 hours, Poonam Jain at Southern Illinois University School of Dental Medicine demonstrated that the enamel does begin to erode. Some argue that this isn’t very like real life because we don’t keep a drink in our mouth for that length of time. But over the course of many years, even a few seconds each slurp adds up.

The eroding effects of sweet fizzy drinks add up over time (Credit: Getty Images)

A case study published in 2009 of a 25-year-old bank worker whose front teeth wore out after four years of drinking half a litre of cola a day, followed by three years where he upped that to a litre-and-a-half each day and added in some fruit juice, is enough to frighten anyone. But it also depends on how you drink it. This man was described as “holding the drink in the mouth for several seconds and tasting before swallowing”. In Sweden researchers compared short-sipping, long-sipping, gulping, nipping (whatever that might be) and sucking. They found that the longer a drink stayed in the mouth, the more noticeable the drop in pH in that person’s mouth. In other words, the more acidic the mouth becomes. But if you drink through a straw the drink goes straight to the back of your mouth and there’s less opportunity for damage.

But what about sparkling mineral water? At the University of Birmingham, Catriona Brown put extracted human teeth without signs of erosion into jars for 30 minutes with different kinds of flavoured sparkling water to see what happened. The teeth had been coated in varnish, apart from a half-a-centimetre-diameter test area which was left unvarnished. They found the effect of the drinks on the teeth was the same and sometimes greater than the effect of orange juice, a drink which is already known to soften tooth enamel. Lemon and lime, and grapefruit were the most acidic flavours, probably because they use citric acid to give the nice taste.

Sparkling water turns out to be only 1% as acidic as sugary sodas, research suggests (Credit: Getty Images)

So flavoured mineral waters shouldn’t be considered as harmless as water, but how about sparkling water with no added flavours?  Studies on this are few and far between. But in 2001, the Birmingham team examined seven different brands of mineral water, again pouring them over extracted teeth to see what happened. They found sparkling waters had a pH of between 5 and 6 (so not as acidic as some cola drinks which can be as high as 2.5), compared with still water which was neutral at 7. In other words, they are a weak acid, as suspected. But when it came to the erosive potential of that weak acid on the teeth, the effect was 100-times less than that of some other kinds of fizzy drinks. Of course the mouth itself is a different environment from a jar, but so far the evidence for harm doesn’t seem to be very strong.

So if you want a change from plain old water, then although it’s mildly acidic, so far there isn’t strong evidence to suggest that it’s harmful to your bones, your stomach or your teeth. But if you want to play safe and keep it away from your teeth, when you answer the question “still or sparkling”, perhaps you should also ask for a straw. 

http://www.bbc.com/future/story/20150911-is-sparkling-water-really-bad-for-you

The secret to a long and healthy life? Eat less

Permanently cutting the daily calories you consume may turn out to have a profound effect on your future life, according to some tantalising scientific studies.

• By Alex Riley
• • | BBC FUTURE

1 June 2017

In a restaurant setting sometime in the not-too distant future, a man and a woman are on their first date. After the initial nerves subside, all is going well.

The man is 33, he says, has been single for most of those years, and, although he doesn’t mention it, knows he is looking to settle down and have a family. The woman replies that she is 52, has been married, divorced, and has children in their early 20s. He had no idea – she looked his age, or younger.

This is a dream of Julie Mattison from the National Institute on Ageing (NIA) in the United States. She envisions a time when chronological age ticks by with every year, but biological age can be set to a different timer, where elderly doesn’t mean what it does now.

It sounds far-fetched, but our society has already made great strides towards that goal, thanks to advances in medicine and improvements in healthy living. In 2014, for instance, the United States Health Interview Survey reported that 16% of people aged between 50 and 64 were impaired every day with chronic illness. Three decades earlier that number was 23%. In other words, as well as benefiting from longer lifespans, we are also experiencing longer “healthspans” – and the latter is proving to be even more malleable. To paraphrase and update a speech from John F Kennedy given at the first White House Conference on Ageing in 1961, life can indeed be added to years, rather than just years added to life.

Healthspan is proving to be even more malleable than lifespan  

So, what do we need to do to enhance the length and quality of our lives even more? Researchers worldwide are pursuing various ideas, but for Mattison and colleagues, the answer is a simple change in diet. They believe that the key to a better old age may be to reduce the amount of food on our plates, via an approach called “calorie restriction”. This diet goes further than cutting back on fatty foods from time-to-time; it’s about making gradual and careful reductions in portion size permanently. Since the early 1930s, a 30% reduction in the amount of food consumed per day has been linked to longer, more active lives in worms, flies, rats, mice, and monkeys. Across the animal kingdom, in other words, calorie restriction has proven the best remedy for the ravages of life. And it’s possible that humans have just as much to gain.

High calorie foods can be hard to avoid today (Credit: Getty Images)

The idea that what a person eats influences their health no doubt predates any historical accounts that remain today. But, as is often the case for any scientific discipline, the first detailed accounts come from Ancient Greece. Hippocrates, one of the first physicians to claim diseases were natural and not supernatural, observed that many ailments were associated with gluttony; obese Greeks tended to die younger than slim Greeks, that was clear and written down on papyrus.

Spreading from this epicentre of science, these ideas were adopted and adapted over the centuries. And at the end of the 15th Century, Alvise Cornaro, an infirm aristocrat from a small village near Venice in Italy, turned the prevailing wisdom on its head, and on himself.

If indulgence was harmful, would dietary asceticism be helpful? To find out, Cornaro, aged 40, ate only 350g (12oz) of food per day, roughly 1000 calories according to recent estimates. He ate bread, panatela or broth, and eggs. For meat he chose veal, goat, beef, partridge, thrush, and any poultry that was available. He bought fish caught from the local rivers.

Restricted in amount but not variety, Cornaro claimed to have achieved “perfect health” up until his death more than 40 years later. Although he changed his birthdate as he aged, claiming that he had reached his 98th year, it is thought that he was around 84 when he died – still an impressive feat in the 16th Century, a time when 50 or 60 years old was considered elderly. In 1591, his grandson published his posthumous three-volume tome entitled “Discourses on the Sober Life,” pushing dietary restriction into the mainstream, and redefining ageing itself.

With an additional boost of health into the evening of life, the elderly, in full possession of their mental capacities, would be able to put decades of amassed knowledge to good use, Carnaro claimed. With his diet, beauty became the aged, not the youthful.

Longevity trials

Cornaro was an interesting man but his findings are not to be taken as fact by any branch of science. Even if he was true to his word and did not suffer ill health for nearly half a century, which seems unlikely, he was a case study of one – not representative of humans as a whole.

But since a foundational study in 1935 in white rats, a dietary restriction of between 30-50% has been shown to extend lifespan, delaying death from age-related disorders and disease. Of course, what works for a rat or any other laboratory organism might not work for a human.

It may sound obvious, but what you choose to put in your trolley can have a profound effect on the length and quality of your life (Credit: Getty Images)

Long-term trials, following humans from early adulthood to death, are a rarity. “I don’t see a human study of longevity as something that would be a fundable research programme,” says Mattison. “Even if you start humans at 40 or 50 years old, you’re still looking at potentially 40 or 50 more years [of study].” Plus, she adds, ensuring that extraneous factors – exercise, smoking, medical treatments, mental wellbeing – don’t influence the trial’s end results is near impossible for our socially and culturally complex species.

That’s why, in the late 1980s, two independent long-term trials – one at NIA and the other at the University of Wisconsin – were set up to study calorie restriction and ageing in Rhesus monkeys. Not only do we share 93% of our DNA with these primates, we age in the same way too.

Slowly, after middle age (around 15 years in Rhesus monkeys) the back starts to hunch, the skin and muscles start to sag, and, where it still grows, hair goes from gingery brown to grey. The similarities go deeper. In these primates, the occurrence of cancer, diabetes, and heart disease increases in frequency and severity with age. “They’re an excellent model to study ageing,” says Rozalyn Anderson, a gerontologist from the University of Wisconsin. 

Sherman is the oldest Rhesus monkey ever recorded, nearly 20 years older than the average lifespan for his species in captivity  

And they’re easy to control. Fed with specially made biscuits, the diets of the 76 monkeys at the University of Wisconsin and the 121 at NIA are tailored to their age, weight, and natural appetite. All monkeys receive the full complement of nutrients and minerals that their bodies crave. It’s just that half of the monkeys, the calorie restricted (or CR) group, eat 30% less.

They are far from malnourished or starving. Take Sherman, a 43-year-old monkey from NIA. Mattison says that since being placed on the CR diet in 1987, aged 16, Sherman hasn’t shown any overt signs of hunger that are well characterised in his species.

Rhesus monkeys given a stricter, low calorie diet lived longer (Credit: Getty Images)

Sherman is the oldest Rhesus monkey ever recorded, nearly 20 years older than the average lifespan for his species in captivity. As younger monkeys were developing diseases and dying, he seemed to be immune to ageing. Even into his 30s he would have been considered an old monkey, but he didn’t look or act like one. 

The same is true, to varying extents, for the rest of his experimental troop at NIA. “We have a lower incidence of diabetes, and lower incidence of cancer in the CR groups,” says Mattison. In 2009, the University of Wisconsin trial published similarly spectacular results.

Not only did their CR monkeys look remarkably younger – with more hair, less sag, and brown instead of grey – than monkeys that were fed a standard diet, they were healthier on the inside too, free from pathology. Cancers, such as the common intestinal adenocarcinoma, were reduced by over 50%. The risk of heart disease was similarly halved. And while 11 of the ad libitum (“at one’s pleasure,” in Latin) monkeys developed diabetes and five exhibited signs that they were pre-diabetic, the blood glucose regulation seemed healthy in all CR monkeys. For them, diabetes wasn’t a thing.   

Overall, only 13% of the monkeys in the CR group had died of age-related causes in 20 years. In the ad libitum group, 37% had died, nearly three times as many. In an update study from the University of Wisconsin in 2014, this percentage remained stable.

The results show that ageing itself is a reasonable target for clinical intervention and medical treatment – Rozalyn Anderson  

“We have demonstrated that ageing can be manipulated in primates,” says Anderson. “It kind of gets glossed over because it’s obvious, but conceptually that’s hugely important; it means that ageing itself is a reasonable target for clinical intervention and medical treatment.”

If ageing can be delayed, in other words, all of the diseases associated with it will follow suit. “Going after each disease one at a time isn’t going to significantly extend lifespan for people because they’ll die of something else,” says Anderson. “If you cured all cancers, you wouldn’t offset death due to cardiovascular disease, or dementia, or diabetes-associated disorders. Whereas if you go after ageing you can offset the lot in one go.”

Calorie restriction involves a permanent reduction in a diet (Credit: Getty Images)

Eating less certainly seemed to help the monkeys, but calorie restriction is much tougher for people out in the real world. For one, our access to regular, high-calorie meals is now easier than ever; with companies like Deliveroo and UberEats, there is no longer a need to walk to the restaurant anymore. And two, gaining weight simply comes more naturally to some people.

“There’s a huge genetic component to all of this and its much harder work for some people than it is for others to stay trim,” says Anderson. “We all know someone who can eat an entire cake and nothing happens, they look the exact same. And then someone else walks past a table with a cake on it and they have to go up a pant size.”

Ideally, the amount and types of food we eat should be tailored to who we are – our genetic predisposition to gaining weight, how we metabolise sugars, how we store fat, and other physiological fluxes that are beyond the scope of scientific instruction at the moment, and perhaps forever.

But a predisposition to obesity can be used as a guide to life choices rather than an inevitability. “I personally have a genetic history of obesity running through my family, and I practice a flexible form of caloric restriction,” says Susan Roberts a dietary scientist at Tufts University in Boston. “I keep my BMI at 22, and [have calculated] that that requires eating 80% of what I would eat if my BMI was at 30 like every other member of my family.” Roberts stresses that it isn’t hard – she follows her own weight management programme using a tool called iDiet to help her eat less but avoid feeling hungry or deprived of enjoyment. If this wasn’t possible, she adds, she wouldn’t practise calorie restriction.

Not only has Roberts seen the problems of obesity first-hand in her family, she knows the benefits of CR better than most. For over 10 years she has been a leading scientist in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy trial, also known as Calerie. Over two years, 218 healthy men and women aged between 21 and 50 years were split into two groups.  In one, people were allowed to eat as they normally would (ad libitum), while the other ate 25% less (CR). Both had health checks every six months.

Unlike in the Rhesus monkey trials, tests over two years can’t determine whether CR reduces or delays age-related diseases. There simply isn’t enough time for their development. But the Calerie trials tested for the next best thing: the early biological signs of heart disease, cancer, and diabetes.

Published in 2015, the results after two years were very positive. In the blood of calorie-restricted people, the ratio of “good” cholesterol to “bad” cholesterol had increased, molecules associated with tumour formation – called tumour necrosis factors (TNFs) – were reduced by around 25%, and levels of insulin resistance, a sure sign of diabetes, fell by nearly 40% compared to people who ate their normal diets. Overall, the blood’s pressure was lower.

Significant health benefits may be garnered in an already healthy body, but further trials are needed  

Admittedly, some benefits may come from weight-loss. Earlier trials from Calerie had included people that were obese as well as those with a healthy body mass index (BMI) of 25 or below, and slimming down would have certainly improved the welfare of the heavier participants. “One thing that’s been very clear for a long time is that being overweight or obese is bad for you,” says Roberts. Diseases and disorders previously thought to be age-associated diseases are now popping up in the obese population, she adds.

But the latest results suggested that significant health benefits can be garnered in an already healthy body – a person who isn’t underweight or obese. That is, someone whose BMI lies between 18.5 and 25.

Despite these results, evidence from further trials will be needed before someone with an already healthy BMI should be advised to reduce their calorie intake. (And anyone wanting to change their diet would be advised to consult a medical professional beforehand.)

Elderly life need not be one of disease and illness (Credit: Getty Images)

In the meantime, the scientists will be hoping that their rhesus macaques may help us to understand exactly why calories restriction may have these effects. With nearly 30 years of data on lives and deaths, and blood and tissue samples, from nearly 200 monkeys, the work at NIA and the University of Wisconsin aim to shine a light into the black box of calorie restriction, illuminating just how it delays ageing.

With less food, is the metabolism forced to be more efficient with what it has? Is there a common molecular switch regulating ageing that is turned on (or off) with fewer calories? Or is there an as of yet unknown mechanism underpinning our lives and deaths? The importance of monkeys like Sherman far outspans their lives.

Calorie restriction may be one of the most promising avenues for improving health and how long it lasts in our lives

Answers to such questions might be long in coming. “If I cloned 10 of myself and we all worked furiously, I don’t think we’d have it solved,” says Anderson. “The biology is inordinately complicated.” It’s a worthwhile undertaking – understand how CR works and other treatments could then be used to target that specific part of our biology. Ageing could be treated directly, that is, without the need of calorie restriction. “And I think that’s really the golden ticket,” says Anderson.

Although lacking a neat explanation, calorie restriction is one of the most promising avenues for improving health and how long it lasts in our lives. “There was nothing in what we saw that made us think caloric restriction doesn’t work in people,” says Roberts, from the Calerie trial. And, unlike drug-based treatments, it doesn’t come with a long list of possible side effects. “Our people were not hungrier, their mood was fine, their sexual function was fine. We looked pretty hard for bad things and didn’t find them,” says Roberts.

One expected issue was a slight decrease in bone density that is often tied to gradual weight loss, says Roberts. But as a precaution, volunteers were provided with small calcium supplements throughout the trial.

Even with such promising findings, “this [the Calerie trial] is the first study of its kind, and I don’t think that any of us would feel confident in saying, ‘okay, we’re going to recommend this to everyone in the world,’” says Roberts. “But it’s a really exciting prospect. I think that delaying the progression of chronic diseases is something that everyone can get behind and get excited about, because nobody wants to live life with one of those.”

http://www.bbc.com/future/story/20170601-the-secret-to-a-long-and-healthy-life-eat-less