Battle of the bottle

Could suspicions of a link between milk and ovarian cancer sound the death knell for the UK's once-essential pinta? Joanna Moorhead reports

We've been drinking it for thousands of years, and for longer than any of us can remember it has been promoted as one of the healthiest foodstuffs around. But increasingly, milk is in the firing line. Could insidious, cancer-causing substances really lurk within our daily pinta, packed as we know it is with vitamins and minerals and all-round goodness?


And there's more. Papers have already been published on a possible link between dairy products and the development of breast and prostate cancers; high-fat milk products are known to raise levels of cholesterol, a contributory factor in heart disease. Lactose intolerance, which blights the lives of many through nausea and diarrhoea, is on the increase. And there have been suggestions of a link between high dairy intake and the development of type 1 diabetes in children who already have a genetic predisposition to the disease.

There are snorts of derision at this over at the Dairy Council, where everyone remains convinced of milk's health-giving qualities. But not everyone is so confident: at Bristol Royal Infirmary, Jeff Holly, professor of clinical science, believes the tide is turning, and that the newest research is just one block in what will eventually become a large wall of evidence that, pure and spotless though it might look, milk has its bad side too.

"There's a convergence today that's questioning how healthy milk really is," says Holly. "I'm cautious because we don't want these studies to be exaggerated, but a lot of researchers are looking at a lot of questions ... We're piecing together a big jigsaw, and it could be that milk is a part of the answer to the puzzle.

"What we've seen in recent years is that it's been implicated in more and more studies - and while people might say, 'Surely it can't be bad, we've been drinking it for centuries,' the fact is that, in evolutionary terms, it hasn't been part of our diet for that long. The proportion of our diet made up of dairy products has increased over the years, and the way milk is produced in recent years has changed a lot, and that could all be part of the problem.

"There's definite evidence from parts of the world where dairy products aren't any part of the diet that it has some role in the development of cancers. Japan, for example, had no dairy consumption until 50 years ago, and over the years, as consumption has gone up, so too has the incidence of breast and prostate cancer."


But it's all speculation, so far. Not that they're taking any chances at the Bristol Cancer Help Centre, which now tells those seeking advice on combating cancer to cut dairy products right out of their diet. Their stance, which has been much influenced by the experience of Jane Plant, a scientist who believes she has overcome breast cancer thanks to a dairy-free diet, is that, while they don't want to make people worried or fearful, the weight of evidence against milk - certainly for those who already have cancer - is mounting. "There are lots of theories and we need more work to be done on them," says Liz Butler, nutritionist at Bristol. "As well as the growth hormone theory, there's another theory that the lactose in milk could be upsetting the natural balance of hormones or could be toxic to the cells in some areas of the body, such as the ovaries. Or the high levels of calcium in milk could be the problem, maybe by blocking the body's use of vitamin D, which is known to have a protective effect against cancer."

Unsurprisingly, the milk industry isn't taking all this lying down. The case for the cow, it says, is cast-iron. The number of people with milk intolerance has been exaggerated, and in any case milk intolerance is a condition of childhood and most people grow out of it. The evidence on a link with breast cancer is far from clear: a recent review of 45 studies found the relationship unproven, and the World Cancer Research Fund has described existing research as "inconsistent". On heart disease, milk, far from helping cause the problem, can in fact have a preventive effect; eating three servings of dairy foods a day, alongside plenty of fruit and vegetables, can lower your risk of heart disease to the same degree as being on medication. And cancer, too, might actually be prevented, not caused, by milk: it contains cancer-inhibiting nutrients and - last but certainly not least - there's good research showing colorectal cancer can be reduced in those who get their calcium through low-fat foods.

At the British Nutrition Foundation, Brigid McKevith says what people who are worried about milk need to remember is that the human race has evolved and adapted over countless years; milk may be the food a cow makes to feed its young, but drinking it has enhanced human health for countless years (archaeologists have apparently found pottery shards proving that ancient Britons were downing pints as long as 6,000 years ago). What's very clear, she says, is that we have become dependent as a society on milk for the calcium, protein and various other micro-nutrients beneficial to our health; as a society, we'd stop drinking it at our peril.

Not convinced? Well, watch this space. There are lots of scientists out there poring over all aspects of our milk-drinking habit and its benefits (or otherwise). This is a debate they'll be arguing over until the cows come home.

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