A glass of milk a day reduces the risk of bowel cancer

A large British study has revealed new evidence that people with more calcium in their diet – the equivalent of a glass of milk a day – may help reduce their risk of bowel cancer.

Researchers analyzed the diets of more than half a million women over the age of 16 and found that dark leafy vegetables, bread and plant-based milks containing calcium also had a protective effect.

They also found more evidence that excessive consumption of alcohol and processed meat had the opposite effect, increasing the risk of disease.

Cancer charities say eating a healthy, balanced diet, being a healthy weight and stopping smoking are the best ways to reduce your risk of bowel cancer.

A recent study found that dairy products “probably” reduced the risk of colorectal (bowel) cancer.

This studyfrom the University of Oxford and Cancer Research UK, suggests this is due to calcium, whether from dairy or non-dairy foods.

• an extra 300 mg of calcium per day in the diet, or a large glass of milk, reduces your risk by 17%

“This highlights the potential protective role of dairy products, largely due to calcium, in the development of bowel cancer,” said lead researcher Dr Keren Papier, from Oxford.

Breakfast cereals, fruit, whole grains, carbohydrates, fiber, and vitamin C have also been shown to reduce cancer risk, but only slightly.

It is already well known that eating too much processed meat and red meat probably increases your risk of bowel cancer, just like alcohol.

This study provides more evidence of this link:

• Drinking an extra large glass of wine per day, or 0.7 oz (20 g) of alcohol, increases your risk by 15%
• eating 1 ounce more of red and processed meat per day, such as a slice of ham, increases your risk by 8%

It’s difficult to quantify exactly what these percentages mean, because everyone’s risk of bowel cancer is different depending on their lifestyle, diet, habits and genetics.

Calcium is an important mineral for strengthening bones and keeping your teeth healthy, but there is growing evidence that it also protects against certain cancers.

Milk, yogurt and cheese contain a lot of calcium. Dairy products are one of the main sources in the British diet (we love our cereals in the morning).

It is also present in other foods such as soy and rice drinks, white bread, nuts, seeds and fruits like dried figs, kale and canned sardines, and it is also present in lactose-free milk.

The study indicates that calcium may protect against bowel cancer “because it is able to bind to bile acids and free fatty acids in the colon, thereby reducing their potentially carcinogenic effects.”

There are around 44,000 cases of bowel cancer each year in the UK, making it the fourth most common cancer.

Although most cases concern elderly people, cancer rates increase among young adults under 50 – but there is no clear reason for this.

Experts say poor diet and obesity could be among the factors involved.

Symptoms of bowel cancer include:

• a change in your bowel habits, such as looser stools, more frequent bowel movements, or constipation
• bleeding from your butt or finding blood in your poop
• lose weight when you haven’t tried to
• unexplained fatigue or shortness of breath

The advice is to speak to your doctor if you notice any of these.

This is an observational study, not a trial, so it cannot categorically prove that calcium or any other food protects against cancer or makes it more likely.

However, the researchers say the study is “the largest to date on diet and bowel cancer”, giving them confidence that they are on the right track. The results are also consistent with the findings of previous studies.

More than 12,000 women in the study developed bowel cancer, and nearly 100 food products and nutrients in their diets were studied to assess potential links.

Janet Cade, a nutrition expert from the University of Leeds, said the paper “provides important evidence that overall diet may influence colorectal cancer risk.”

Professor Andrew Prentice, of the London School of Hygiene & Tropical Medicine, questions whether, in light of the study results, calcium supplements might have a protective effect, although he says “the jury is out.” disagree on this point.

The take-home message from Professor Tom Sanders, of King’s College London, is that “drinking above the alcohol intake limits (more than 14 units per week) increases the risk of colorectal cancer in women, but what to drink about half a pint of cow’s milk a day is probably protective.”

Dr Lisa Wilde, from the charity Bowel Cancer UK, says someone is diagnosed with bowel cancer “every 12 minutes” and half of all bowel cancers could be prevented by to a healthier lifestyle.

“If you don’t drink cow’s milk, there are other ways to get calcium, for example from broccoli or tofu, while reducing your risk of bowel cancer,” she says.