The dairy debate

The white stuff is accused of causing allergies and even cancer. As an anti-dairy campaign is launched, Anastasia Stephens asks where the truth lies

Once given out free at schools, milk used to be a dietary staple. But all the evidence is that it's falling out of fashion. In the organic food shops of Notting Hill, the shelves are full of oat and soya milk, vegan cheeses and hemp-oil ice cream, suggesting that the produce of the humble cow is being squeezed out of the market.

Chris Martin and Gwyneth Paltrow threw it out years ago. As for Heather Mills-McCartney (below right), she credits a dairy-free diet with helping her to overcome a post-operative infection. Later this month, she will speak at the launch of a Vegetarian and Vegan Foundation campaign, White Lies, on "Why you don't need dairy".

If you're about to dismiss this as a fad, take note - dairy-free support is growing in academic circles, too.

But hasn't cow's milk always been a trusted and valuable source of nutrition? As nutritionists and scientists engage in the debate, which side should we be taking?

WHY DAIRY IS GOOD FOR US

IT'S PACKED WITH CALCIUM

It's often pointed out that we need milk to strengthen our bones. There's no arguing the fact that milk is very rich in calcium; cow's milk contains 120mg calcium per 100ml, making it nearly four times richer in this mineral than human milk (34mg per 100ml). According to the Dairy Council, a single glass of milk provides a child with half the daily requirement of calcium.

"Milk is one of the richest sources of calcium," says Dr Judith Bryans, the director of the Dairy Council. "But it's not just calcium in milk that is useful - milk and other dairy produce contains magnesium, protein and phosphorus, which are all bone-building nutrients."

IT MAY HELP TO PREVENT CANCER

This argument may be more complex than it appears. According to Dr Michelle Harvie, the author of The Genesis Breast Cancer Prevention Diet, providing the milk you drink is low fat, it could be cancer-protective. "Two large surveys in the US show that drinking almost a pint of low-fat milk or eating two portions of low-fat dairy foods a day reduces risk of breast cancer by 20 to 30 per cent," she says.

Any cancer-protective effect may be partly due to the vitamin D in milk, which helps to prevent tumour growth. Dairy products are also the main dietary source of the anti-cancer fat, conjugated linoleic acid (CLA). However, the amounts needed to result in an anti-cancer effect are about three times greater than the usual dietary intake.

IT PROVIDES 'GOOD' BACTERIA

For those who don't suffer from lactose intolerance or dairy allergies, live yogurt and unpasteurised milk are among the best sources of good gut bacteria, which improve digestion and boost immunity. "Studies have found that beneficial gut bacteria such as acidophilus help with the digestion of vitamins, boost immunity and kill pathogenic bacteria - and yogurt is an important source," says Dr Jane Flemming, a London GP.

By strengthening digestion and immunity, yogurt may also indirectly protect against allergies.

BUTTER IS BETTER

Butter is one of the most nutritionally misunderstood dairy products. "As a raw animal fat, butter is packed with fat-soluble vitamins, including A, D, E and K and other vital nutrients," says Dr Mary Enig, a US biochemist who specialises in this field. "It's especially rich in vitamin A, needed for growth, cell renewal, fertility and immunity. Butter gives you vitamin D, which is needed for a healthy brain and nervous system, and is also anti-cancer. Then there are other substances that are unique to butter, such as Wulzen factor, which helps to prevent arteries and joints from stiffening with age."

WHY WE SHOULD DO WITHOUT

IT'S NOT NATURAL

One of the main anti-dairy arguments is that drinking milk from another animals isn't natural. "Like other mammals, we're not designed to drink milk past weaning, which is why many people stop producing lactase, the enzyme that breaks down lactose, a milk sugar, after infancy," Dr Flemming points out.

This is why 10 per cent of Europeans, 90 per cent of Asians and 65 per cent of Africans are lactose intolerant. Unable to digest milk sugar, they suffer symptoms such as bloating, cramps, nausea and diarrhoea - unless they cut out dairy products completely.

IT CAN TRIGGER ILLNESS

The theory that our bodies aren't adapted to digest milk might explain other reactions. "We see hundreds of patients with symptoms such as achy joints, eczema and fatigue every year, and find that intolerance to milk and dairy products is high on the list of culprits," says Patrick Holford, the nutritionist and founder of the Institute for Optimum Nutrition. "Dairy is also one of the main food triggers for migraine sufferers."

IT MAY PROMOTE CANCER

Perhaps more worrying is research suggesting that dairy products could promote cancer. Supporting this is The China Study, one of the largest epidemiological studies ever conducted. Collating the results, Professor Colin Campbell, Professor Emeritus of nutritional biochemistry at Cornell University in the US, found that rural Chinese, who eat a virtually dairy-free diet, have an incredibly low rate of breast cancer - one in every 10,000.

It's a trend that makes sense when you consider modern milking methods. To get the most milk, cows are now milked during and after pregnancy, a time when oestrogens and growth factors in milk are at their highest. Researchers from Princeton University in New Jersey and elsewhere are concerned that growth factors such as insulin-like growth factor 1 (IGF-1) may act on cancer cells like oxygen to a spark - to trigger uncontrolled growth.

The theory convinces Professor Jane Plant, a geologist, who claims to have cured herself of breast cancer by cutting out dairy. "Despite chemotherapy, my cancer had recurred five times and I was given weeks to live when I cut dairy from my diet," Plant says. "I watched a tumour in my neck shrink from the size of a small boiled egg to nothing in six weeks." But this is a sample of one. Professor Plant is not a professor of medicine, and many who are are quick to dismiss her theories.

IT'S ACTUALLY NOT GOOD FOR BONES

Evidence is emerging that cheese and milk may not strengthen bones as previously thought. Of 37 studies recently reviewed by the American Academy of Pediatrics, 27 failed to show that consuming dairy products affected bone density.

"The review found that [these] 27 studies showed no relationship between dairy and bone health," says Juliet Gellatley, the director of the Vegetarian and Vegan Foundation. "In the remaining 10, the effects on bone health were small."

Nutritional researchers say calcium from dairy isn't well absorbed because of how it affects the acid-alkaline balance of the body. "The body works best in a slightly alkaline environment, but the protein in cheese has a very acidifying effect," says Patrick Holford, a nutritionist. "Calcium, however, is alkaline and is used to neutralise the acid. The body channels calcium from cheese or bone into the bloodstream to do just this. Because calcium is needed for this, it's not deposited as bone."

Anyway, diet may not be the most effective way to keep bones strong. Research shows that physical exercise is the single most critical factor for maintaining healthy bones, as well as lifestyle factors such as cutting out caffeine, alcohol and smoking - all habits that leach minerals out of bone. "African Bantu women who are physically active eat almost no dairy products at all; they have a relatively low calcium intake, mainly from vegetable sources," Gellatley points out. "Osteoporosis is virtually unknown among them."

The Vegetarian and Vegan Foundation hosts White Lies; the argument against dairy, at Lecture Theatre 1, New Hunt's House, Guy's and St Thomas' Hospital Campus, off Great Maze Pond, London SE1, at 7pm on 24 May; tickets £5 (0117-970 5190). For the pocket-size guides 'It's Easy to be Dairy Free' and 'How to be Dairy Free' (with 20 recipes), contact the Vegetarian and Vegan Foundation (0117-970 5190; www.vegetarian.org.uk)

How to stay healthy without milk

There are plenty of non-dairy sources of calcium. The major ones are dark green leafy vegetables such as broccoli, kale, spring greens, cabbage, bok choy and watercress.

Dried fruits, such as figs (250mg calcium per six figs) will also increase your calcium intake. Eat them alongside seeds and nuts, particularly almonds and brazils, sesame seeds and tahini (which contains a massive 680mg of calcium per 100g), and you'll definitely be covering your calcium RDA (800mg).

Pulses, including soya beans, kidney beans, chick peas, baked beans, broad beans, lentils, peas and calcium-set tofu (500mg calcium per 250g) are also good sources of calcium.

Most nutritionists agree that pulses, tofu and regular servings of fish can amply make up the protein content in any dairy-free diet.

There's also an extensive range of dairy substitutes to choose from. Milk alternatives range from soya to oat and rice milk, and there's a range of non-dairy cheeses made from soya and tofu.

Many margarines are dairy free. Good brands include Pure and Suma, which make soya and sunflower spreads, and Biona, which makes an organic olive spread.

You can also find dairy-free yogurts and ice creams, and even chocolate, made from dairy substitutes such as soya and hemp.