Lactose
is found in milk and is
derived from two sugars:
galactose and glucose. In
regions where milk forms
a significant part of the
adult diet, lactose
intolerance is fairly rare.
Most people of European
descent can drink milk
without any issues.
Lactose is often added to
foods and medications.BBC SCIENCE FOCUS MAGAZINE COLLECTION 63According to Michael Mosley, you
could miss out on nutrients by
avoiding glutenand start producing hydrogen. The downside of
t h is test is t hat it ca n produce severe d ia r rhoea.
Instead, you may prefer the stool acidity test,
which is as straightforward as it sounds. You
provide stool samples and if your stools are
acidic, you are intolerant to lactose.EAT UP
If you are neither lactose intolerant nor a
vegan, then there is a considerable downside
to avoiding dairy products. Cow’s milk is
incredibly nutritious (it has to feed a growing
calf). It’s rich in proteins and fatty acids, but
also calcium, vitamin D, vitamin B12, potassium
and phosphorus, all of which are good for bones.
Those of you who have been persuaded (as
I once was) that low-fat dairy is somehow
‘healthier’ should also bear in mind that low-
fat versions are missing out on a wide range
of healthy fatty acids and fat-soluble vitamins.
Individuals who are looking to follow a
healthy diet will find that their wallets are
considerably lighter after the weekly food shop
if they fill their trolleys with free-from foods. So
unless you have been diagnosed with a genuine
i ntolera nce or a l ler g y, t hen a va r ied d iet w it h lot s
of fruit and veg is still the best way to maintain
optimum health.Unlike most people in the world, those
of European descent continue being able to
enjoy milk and other dairy products when
they are adults because their bodies produce a
digestive enzyme called lactase, which breaks
down lactose.
If, like 75 per cent of the world’s population,
you lose this enzyme as you grow older, then
lactose will hang around in your digestive
system, where it will be fermented by bacteria,
leading to the production of lots of gas. If you
are genuinely lactose intolerant then an hour
or so after eating dairy products you are likely
to experience flatulence (wind), diarrhoea, a
bloated stomach, cramps and stomach rumbling.
The easiest way to find out if you are lactose
intolerant is through an exclusion diet, along
the lines of the gluten exclusion diet described
earlier. There are also other, more exotic and
expensive ways to find out. These include a
hydrogen breath test and a stool acidity test.
For the breath test you have to fast overnight,
then swallow a fixed amount of lactose. Your
breath is then analysed over the next couple
of hours. If your body is unable to break down
lactose then your gut bacteria will feed on itWe are encouraged to either
avoid milk altogether or
try other variants, such as
almond milk and soya milk
ADVERTISING ARCHIVES, ALAMY, BBC ILLUSTRATION: ACUTE GRAPHICS
by DR MICHAEL MOSLEY (@DrMichaelMosley)
Dr Mosley is a presenter on BBC Two’s Trust me, I’m a
Doctor and the author of The Clever Guts Diet.Gluten-free foods are
popular, but check the
labels carefully – some are
packed with salt and sugar