As books that give answers go, there’s one classic that often gets
overlooked – the dictionary. So next time you’re wondering whether a £10
tub of the latest miracle food can really stave off cancer, diabetes
and heart disease, and get rid of a podgy belly in time for summer, run
your finger down to the word “miracle” where you will find this
definition: “an extraordinary and wondrous event” – so far so good –
“that cannot be explained by natural or scientific laws”.
“Whether it’s coconut oil, chia seeds or apple cider vinegar,” says
Duane Mellor, an assistant professor in dietetics at the University of
Nottingham and a spokesperson for the British Dietetic Association,
“there is no scientific evidence to suggest that if you top up your diet
with any ‘miracle’ or special food that you’ll get any of the promised
effects. The idea is almost entirely a marketing vehicle, but when
people read claims online, they start to think differently and can start
believing it.” One of the reasons people might believe the hype is
because as with any good miracle – or magic trick – the success lies in
smoke and mirrors. With miracle foods, while the magical health food
salesman is conjuring a few extra coins out of our pockets, we’re left
bamboozled by scientific terminology.
“Many products tend to be accompanied by all sorts of horrendous
scientific jargon, like ‘maintains cognitive function’,” says Mellor,
“which are watery, scientific-style claims that people tend to read as
being something meaningful to human health. Then there’s antioxidants
and free radicals, which are some of the most feared and misunderstood
words used.”
Free radicals are unstable elements that come spinning off any
oxygen-using chemical reaction in the body. They are unstable because
they are missing an electron and, in a bid to restabilise themselves,
they steal an electron from elsewhere. This could be from the fats in
cell membranes or from your DNA. The damage they do when bullying other
elements into handing over an electron is called oxidative stress, and
this can be associated with heart disease, cancer and diabetes.
Free
radicals, however, are also involved in beneficial processes. They help
to destroy invading bacteria and play a part in cell communication. To
limit their role to only those things that benefit us, our bodies make
things called antioxidants that, much like people standing outside
nightclubs handing out hugs and hot chocolate to pacify drunken
revellers, provide free radicals with the electrons they need so they
don’t cause damage elsewhere.
“But if you look at the antioxidants circulating in our bodies,” says
Mellor, “by far the most common are the ones we make ourselves –
glutathione and uric acid – followed by vitamins A, C and E, which we
get from normal food anyway. Many of the antioxidants in things like
chia seeds are there to stop the plant oils going rancid, or to protect
them from sunlight damage, and may not be that available to our bodies
anyway. So although the EFSA [European Food Safety Authority] allows
manufacturers to claim that their products are rich in antioxidants –
because they are – manufacturers are not allowed to claim any health
benefits. If you look carefully, it’s sort of legalese what they end up
claiming.”
Even when used as supplements, antioxidants don’t seem to provide any benefit. A large study published in the New England Journal of Medicine
that followed nearly 10,000 people over an average of four-and-a-half
years showed no benefit from vitamin E supplements in the prevention of
heart disease. Studies for other antioxidant supplements have been
equally discouraging.
Part of this confusion is because diet is complex. It’s tough to
tease apart the contribution of individual components because the
nutrients in many foods become available to us only when eaten as part
of a wider diet: studies have shown that only when we cook carrots can their beta-carotene become more available and; the lycopene in tomatoes is most readily available when they are eaten with oil.
But what about all the other vague claims about foods that can help
you lose weight, or support a healthy immune function, or lead to a
healthy heart? They all sound good and sort of make sense, don’t they?
According to Ali Khavandi, a cardiologist at the Royal United Hospital
in Bath, these claims are vague for a reason – they are based on
experiments carried out on animals or on human cells in a lab. They have
not been shown to have any effect on people, and until such
effectiveness is shown, he says, we should stay open-minded but cautious
about exaggerated claims.
“As doctors I think we’ve taken our eyes of the prize,” he says of
the importance of a healthy diet in avoiding the major chronic diseases
such as heart disease and diabetes. “For the past few years, at least
for heart doctors, I think we’ve been more interested in the sexier side
of preventing disease – new drugs, stents, and operation techniques –
and we’ve left the diet arena a little unmanned. It’s now been populated
by unqualified people and celebrity health gurus spreading
misinformation. As doctors I think we have an obligation to reassert an
authoritative voice when it comes to healthy eating.”
Yanking the spotlight back from celebrities and fad food products
might be a difficult task. “The problem,” says Khavandi, “is that the
message we try to get across – which is based on proper, robust evidence
that has been shown time and time again – is not very interesting to
people. They have heard it all before.”
The messages he is talking about include the fact that fruit and
vegetables are good for you. As are wholegrain cereals and nuts. For
fats, which you need, choose unsaturated fats such as olive oil and
those directly taken from marine sources such as oily fish. Neutral
foods, he says, are saturated fats like butter or coconut oil and
unprocessed red meats – eat these in moderation and they’re unlikely to
do any harm. Stay away from excess white-flour products, processed
meats, and trans fats such as vegetable oils and palm oils found in fast
foods.
Simple enough advice on the face of it, but with sensationalised
articles emerging daily about the benefits or dangers of specific foods,
people get confused and lose sight of the simple messages. A
complication nowhere more true than with cancer.
“There is certainly no such thing as an anti-cancer diet,” says
Justin Stebbing, a consultant oncologist and professor of cancer
medicine and oncology at Imperial College London. “But I have patients
asking me things about these foods all the time.” He puts a finger on
why cancer-busting food is such an appealing concept. “As a patient,
disease makes you lose control. People immediately want to regain that
control and a very easy way for them to do that is by diet, and they can
get all sorts of things off the internet. We should understand that the
internet is a double-edged sword and if we’re looking for information
we should go to reputable sites.”
Such sites, says Stebbing, are NHS Choices, Cancer Research UK, Diabetes UK and the British Heart Foundation,
which all give clear, evidence-based dietary recommendations. Duane
Mellor has another simple rule of thumb for distinguishing cherrypicked
claims from bona fide scientific evidence. “The EFSA is very clear – and
very strict – about what health messages it allows companies to use in
the marketing,” he says.
“If you see a claim on a blog, and if it’s persuasive and looks good,
ask yourself why has the company not used it in their marketing? If the
product really did prevent cancer or heart disease, do you not think
it’d be plastered all over the packaging?”
Coconut oil: good in a Thai dish.Photograph: Zoonar GmbH/Alamy1. Coconut oil The claim:
Coconut oil is a saturated fat. While not the heart-clogging evil they
were once thought to be, it would take a leap of faith to proclaim that
they are good for you. A recent review of studies suggested that
saturated fats raise levels of both good and bad cholesterol. The oil is
predominantly a medium-chain triglyceride that, proponents state, might
carry benefits for weight loss, but this claim has not been shown in
human studies. Other suggestions for the benefits of coconut oil include
helping blood glucose regulation and preventing strokes and Alzheimer’s
– again, none of these benefits have been shown in people.
Dietetics professor Duane Mellor’s verdict: Probably best to enjoy a little coconut oil in a Thai dish occasionally rather than using it daily! Apple cider vinegar: save for your salads.Photograph: Bon Appetit/Alamy2. Apple Cider Vinegar The claim: Doubtless
a tasty condiment, but has been anecdotally linked with an
eye-wateringly long list of potential health benefits in areas
including: digestive disorders, sore throats, high cholesterol,
indigestion, preventing cancer, dandruff, acne, energy boosting, cramps,
and helping with blood sugar control. The EFSA, however, hasn’t
approved any of these claims. Many of the studies have been on animals
or in laboratories using human cells.
Mellor’s verdict: Vinegar is probably best kept as a
condiment. Use it on salads instead of high calorie oils and mayonnaise
and to add flavour to sauces to help reduce salt intake – it might
help, not because of anything it contains, but because it would be
replacing less-healthy foods.
Manuka honey: vague claims.Photograph: Dorling Kindersley ltd/Alamy3. Manuka Honey The claim: A
medical-grade version of this honey is used in sterile wrappings. As
with most honeys it has hydrogen peroxide, which gives it its antibiotic
qualities. It also has methylglyoxal, an antibacterial component, in
much higher quantities than found in other honeys. Studies have
suggested that manuka honey might help to ease symptoms of infections
such as coughs, but it’s not clear whether the honey is having an
antimicrobial effect or whether it is just soothing like all syrups.
Mellor’s verdiact: Any of the claims for eating
manuka honey, all of which have been rejected by regulators, are vague.
Any health benefits must be balanced against the very high quantities of
sugar compared with the very small amounts of these proposed active
compounds.
Spirulina: stick to fruit and vegetables.Photograph: Eskymaks/Alamy4. Spirulina The claim: This is another proposed miracle food for which regulatory agencies, this time the US National Institutes for Health,
say there is not enough scientific evidence to support any health
claims. Rejected claims include those relating to metabolic and heart
disorders (eg blood pressure control and diabetes), and also mental
health disorders such as anxiety, depression and ADHD. It does have
useful nutrients – calcium, niacin, potassium, magnesium, B vitamins,
iron, and essential amino acids – but the jury is out on whether your
body can use these nutrients in plant form.
Mellor’s verdict: Spirulina shouldn’t be relied on
as a source of nutrients. Rather than taking such supplements, it would
be better to spend your money on vegetables and fruit – this will help
to make your whole diet better rather than adding a supplement and not
thinking about the food you actually eat.
Chia seeds: no evidence of weight loss benefit.Photograph: Ruaridh Stewart/ZUMA Press/Corbis5. Chia seeds The claim: Packed
with antioxidants, but many of these are of plant origin so less likely
to be available to us. They have high omega-3 content, too, but our
bodies are not great at using omega-3 oils from plants – it’s best to
get these oils from oily fish such as salmon. But for people who don’t
eat fish, chia and other seeds can be a good substitute. Other potential
pluses are linked to their high protein and fibre content, which have
led some to suggest they might help you lose weight by reducing hunger.
However, two trials to date have shown no evidence of any benefit in
terms of weight loss or reduced risk of heart disease.
Mellor’s verdict: Chia seeds can add an interesting
texture to bread. Linseed and hemp seed are also rich in omega-3 fatty
acids, so chia is not unique and should be enjoyed more for its effect
on texture rather than any particular health effects.
