To write about milk is to take your life in your hands. There is probably no
food that inspires more vehement accusations and counter-accusations than
the white stuff. Some are bound to be aired again in the coming days during
Food Allergy and Intolerance Week, as stories of bad reactions to milk are
used to promote the oat, soya and rice alternatives available.
In the blue corner we have cow’s milk as a cause of hosts of allergies, heart
disease and breast cancer, not to mention excess phlegm. In the red corner
we have milk as intrinsic to bone health, and protective against cancer,
diabetes and heart disease. Meanwhile, on the sidelines, there are those
advocating organic milk as nutritionally superior.
So should you aim for the milk moustache or never touch the stuff again? The
way to find out is to speak only to those with no direct links with
commercial organisations promoting any sort of milk, milk alternatives or
therapies. So that’s what I’ve done. The UK is the sixth-highest consumer of
fresh dairy products in the EU, getting through 129kg per head a year, a
figure virtually unchanged in a decade. Yet while sales of specialist
cheese, yoghurts and yoghurt drinks have soared, milk has plunged by a
third. Why? A perception that milk is fattening is one reason. It’s also an
easy food to omit from the diet, which is just as well given the huge number
of food scares surrounding milk.
Nutritional value
Let’s start with the facts. The calcium content of milk is its big
nutritional plus point. Calcium is vital to cell function and the health of
skeleton and bone, and especially important for children and teenagers who
need it for growth and bone mass. Teenagers need 1,000mg a day (a small
glass of milk contains about 300mg), with the adult daily requirement
dropping to 700mg; semi-skimmed milk contains 156mg per 100ml. Getting
enough calcium throughout your life, and increasing intake as you get older,
may slow age-related bone loss.
Ah yes, say the milk detractors, but there are lots of other dietary sources
of calcium; dark-green veg, seeds and bread (which is fortified with
calcium), for instance. True, but milk’s calcium is much more easily
absorbed by the body. “You’d have to eat 16 portions of spinach to get as
much calcium as your body gets from a 240ml glass of milk,” says Joanne
Lunn, of the British Nutrition Foundation. Try persuading your truculent
teen to eat 16 portions of spinach.
The joy of milk for parents is that it’s surreptitious nutrition, a food that
smuggles in protein and lots of B vitamins as well as calcium; for junior,
usually in bowls of cereal (a double whammy since most cereals are calcium
fortified). It’s also cheap; 81p a litre at Tesco, compared with £1.27 for a
litre of soya milk. Even those who don’t quaff milk by the glass still get
through a fair bit. “Add what you have in hot drinks, a matchbox-size piece
of cheese and a low-fat yog-hurt and you’re at 600mg,” says Catherine
Collins, the chief dietitian at St George’s Hospital, London. And if you
live in a hard-water area, a glass of Chateau Tap will add even more.
What about the downside? Detractors say that calcium’s bone benefits are
overstated. It’s true that calcium alone won’t do. A complex synergy of
exercise, hormones and vitamin D are also required for tip-top bone health.
Congestion
Then there’s that phlegmy feeling you can get in your mouth from
drinking milk. “That’s due to milk’s fat content,” says Collins. It has led
many, especially those with asthma, to cut out milk in the belief that it
creates mucus. But in an intriguing piece of research carried out by the
University of Adelaide, milk drinking was shown not to be associated with
increased mucus production in 60 brave volunteers deliberately infected with
colds.
Intolerance and allergies
What about the bloating and symptoms of intolerance that so many
experience with dairy and milk in particular? Dr George Lewith, who leads
the Complementary Medicine Research Unit at Southampton University, is
clear. “A few people have a bad time because of intolerance, but for most,
it is safe and good nutrition.” Milk detractors say human beings are not
designed to drink cow’s milk. In fact, humans are all born with the enzyme
needed to digest the lactose present in human milk and in other mammal
milks. Unusually for digestive enzymes it is produced in the gut. If our
diets do not include milk after weaning (as in much of Asia), the body
concludes that it is no longer needed, enzyme production ceases and
intolerance develops. Milk intolerance usually becomes apparent by the age
of 20, and the risk does not increase with age, though it can emerge
temporarily if the gut lining is damaged by antibiotics or infection.
True allergies are a different matter. “Milk allergy prevalence is highest in
infancy, at about 5 per cent,” says Professor John Warner, of Imperial
College and a specialist in paediatric allergy. “But most of these infants
get better spontaneously.” He says that parents who substitute with goat
milk are giving something equally allergenic because the same allergens are
present. Soya milk, he says, causes even more allergies.
Does avoiding milk in pregnancy, during breast-feeding or in the first year
help to prevent children developing asthma and eczema? “Women should eat a
sensible balanced diet, not eliminating anything,” says Warner. “Weaning
shouldn’t be delayed and should include diverse foods as these are more
likely to lead to tolerance.”
According to a long-running Finnish study, prolonged exclusive breast-feeding
increases the risk of babies developing allergies. This adds weight to the
belief that exposure to disease and bacteria at key points in early life are
more important factors in determining the onset of allergies than milk.
Breast cancer
Breast cancer rates are low in Japan, which is not a nation of milk
drinkers, so people conclude that milk must be cancer-causing. But it is the
saturated-fat content of our diets and obesity that’s the problem. People
who develop cancer have higher blood levels of a protein called IGF1. Cows
given bovine growth hormone (somatotropin) to increase milk yields have more
IGF1 in their milk, as does milk from cows that have recently calved. Breast
cancer cells contain IGF1, which leads you to conclude that drinking milk
containing high IGF1 levels causes cancer. Sounds worrying, but let’s unpick
this. First, growth hormone use in dairy cows is banned in Europe. Secondly,
the evidence that IGF1 can survive eating and cross into the bloodstream is
limited. In any case, even if it could, humans beings produce IGF1, too,
with our gut alone churning out industrial quantities. Three pints of milk
contain less than 1 per cent of the IGF1 produced by our gut. Finally,
humans vary in their level of IGF1 and in levels of a partner protein that
mops it up. Some people are naturally always going to have higher levels
than others. Since IGF1 has properties that prevent aberrant cells
committing suicide, that may be the link, not milk. On the other hand,
reviews of more than 5,000 cases of colon cancer suggest that milk drinking
is protective.
Heart disease and diabetes
Professor Peter Elwood, Professor of Epidemiology at Cardiff
University, thinks that people who say there is a link between milk and
heart disease have misread the evidence; it’s not the milk that’s the
problem, but milk with too much fat. He points to an overview of the ten big
cohort studies that cover this area (a cohort is a group of people whose
health is followed over a long period). They point to milk protecting
against cardiovascular disease, as despite causing a rise in cholesterol,
the calcium reduces blood pressure. Professor Elwood also says the Cardia
study into the diseases that affected 3,000 young adults over their lifetime
included data on dairy consumption and symptoms of the metabolic syndrome
(obesity, high blood pressure, abnormal glucose control). Those who were
overweight at the start were significantly less likely to develop the full
metabolic syndrome the more dairy products they ate.
Going organic
Is organic mik better nutritionally? Yes, it contains more omega-3
fatty acids, but these aren’t as beneficial as those in oily fish. And you
would have to drink gallons to benefit. Is there anything wrong with the
dairy milk alternatives such as rice and soya milk? No, if you prefer to
drink them, fine.
Here’s the advice. If you like milk, drink it, but not too much of it (because
too much of anything isn’t good) and choose skimmed or semi-skimmed. Get
your kids to drink more. If you prefer the taste of organic, fine. If milk
upsets you, avoid it. Simple really.
Vivienne Parry is a science writer and broadcaster. She is working on a
new series of Am I Normal? for Radio 4
Healthy bones: cost of calcium
20p for a glass of milk
£5.60 for 16 portions of spinach
BOTH CONTAIN 300mg OF CALCIUM
Is it an allergy?
- A true food allergy causes an antibody response, causing itching and swelling.
Milk, peanuts and shellfish can cause true allergies.
- A food intolerance produces a less specific effect — unpleasant symptoms such
as diarrhoea — because your digestive system doesn’t seem to be coping.
