Consuming lots of dairy could raise the risk of men developing prostate cancer, a review of evidence has suggested.
Experts at the Mayo Clinic analysed the results of 47 studies that delved into the link between diet and the disease.
They found men who regularly ate dairy were between seven to 76 per cent more likely to get prostate cancer.
However, some studies found no link or even the opposite. Critics said the review suffered from a number of ‘weaknesses’.
The research, based on tracking more than one million participants for up to 20 years, is not the first to suggest dairy is linked to prostate cancer.
However, the results on cheese, milk and butter have thrown up mixed results and the risk is thought to be small.
Experts at the Mayo Clinic analysed the results of 47 studies that delved into the link between diet and the disease
It is thought eating large quantities of dairy increases the amount of insulin-like growth factor (IGF) inside the body.
The protein interacts with cells and causes a ‘cascade of reactions’, according to the World Cancer Research Fund International.
Prostate Cancer UK says the link between the disease and dairy products ‘might be because of the calcium in them’ – but added that scientists don’t know for certain.
But the charity warns it is important to get 700mg of calcium – three glasses of milk – each day to ‘keep your bones healthy’.
The review, which analysed studies published since 2006, was published in the Journal of the American Osteopathic Association.
Dr John Shin, lead author, has now called for more trials to investigate the link between dairy products and prostate cancer.
Discussing the findings, he said: ‘Our review highlighted a cause for concern with high consumption of dairy products.’
The results did not say what amount of dairy was linked to an increased risk.
Results also showed men who stuck to plant-based diets were less likely to develop prostate cancer.
The American Institute for Cancer Research recommends a plant-based diet to slash the risk of cancer because of the ‘protective nutrients’.
The study found no link to an increased risk of prostate cancer from other animal-based foods, such as red and white meat or fish.
Dr Shin and colleagues pointed out the rate of prostate cancer is higher in Western countries, where people tend to consume more dairy.
More than 47,000 men each year are diagnosed with prostate cancer in Britain. The disease claims the lives of 11,000 people each year.
Figures show around 175,000 men are diagnosed with the killer disease each year in the US. Some 30,000 people die from it each year.
Professor Tom Sanders, an expert in nutrition and dietetics at King’s College London, said: ‘The methods used in this review suffer from a number of weaknesses.’
Dr David Montgomery, director of research at Prostate Cancer UK said: ‘This paper has reviewed some of the previous studies which looked at whether certain foods have an impact on prostate cancer risk.
‘The previous studies are of variable quality and have not consistently taken account of other factors beyond diet that could impact the results. We would not encourage anyone to avoid or increase intake of certain foods as a result of this study.
‘What we do know is that being overweight may increase your risk of being diagnosed with aggressive or advanced prostate cancer.
‘Eating a healthy, balanced diet and keeping physically active can help you stay a healthy weight, and so might help to lower your risk.
‘The main risk factors that men should be mindful of include being over 50, of black ethnicity, or having a family history of the disease, and anyone who has concerns about their risk should discuss this with their GP.’
How many people does it kill?
Prostate cancer became a bigger killer than breast cancer for the first time, official statistics revealed last year.
More than 11,800 men a year – or one every 45 minutes – are now killed by the disease in Britain, compared with about 11,400 women dying of breast cancer.
It means prostate cancer is behind only lung and bowel in terms of how many people it kills in Britain. In the US, the disease kills 26,000 each year.
Despite this, it receives less than half the research funding of breast cancer – while treatments for the disease are trailing at least a decade behind.
How quickly does it develop?
Prostate cancer usually develops slowly, so there may be no signs someone has it for many years, according to the NHS.
If the cancer is at an early stage and not causing symptoms, a policy of ‘watchful waiting’ or ‘active surveillance’ may be adopted.
Some patients can be cured if the disease is treated in the early stages.
But if it diagnosed at a later stage, when it has spread, then it becomes terminal and treatment revolves around relieving symptoms.
Thousands of men are put off seeking a diagnosis because of the known side effects from treatment, including erectile dysfunction.
Tests and treatment
Tests for prostate cancer are haphazard, with accurate tools only just beginning to emerge.
There is no national prostate screening programme as for years the tests have been too inaccurate.
Doctors struggle to distinguish between aggressive and less serious tumours, making it hard to decide on treatment.
Men over 50 are eligible for a ‘PSA’ blood test which gives doctors a rough idea of whether a patient is at risk.
But it is unreliable. Patients who get a positive result are usually given a biopsy which is also not foolproof.
Scientists are unsure as to what causes prostate cancer, but age, obesity and a lack of exercise are known risks.
Anyone with any concerns can speak to Prostate Cancer UK’s specialist nurses on 0800 074 8383 or visit prostatecanceruk.org
Source: Read Full Article