Pregnant and breastfeeding women who don’t eat sufficient protein put their sons at greater risk of prostate cancer, experts warn
- Experts believe diet can alter levels of oestrogen and testosterone in later life
- Sex hormone changes are believed to be a factor in the growth of men’s tumours
- Every year there are 47,000 new cases of prostate cancer diagnosed in the UK
Pregnant and breastfeeding women who do not eat enough protein put their sons at greater risk of developing prostate cancer, according to new research.
Experiments in male rats found those exposed to just a third of the normal amount of protein were more vulnerable to the disease later in life.
That’s because it altered levels of oestrogen and testosterone – reducing the latter six times in old age.
Alterations to the sex hormones are believed to be a major factor in the growth of the most common tumour in men.
Risk: Experts believe diet can alter levels of oestrogen and testosterone in later life
Professor Luis Justulin Junior, who led the study, said: ‘Our previous research showed exposure in the womb to a low-protein diet impairs prostate development.
‘Our latest published study proves that this effect observed postnatally increases the incidence of prostate disease when the individuals concerned are older.’
In the new study, published in The Journals of Gerontology: Series A, pregnant rats were fed a diet with only six per cent protein – a third of the usual amount.
The pregnant rats were then divided into three groups – two of which got the six per cent protein diet, either only during pregnancy or while breastfeeding.
By the time male offspring were 18 months old – in their 70s or 80s in human years – 33 per cent exposed to little protein had prostate cancer.
This rose to 50 per cent among those whose mothers ate little protein while lactating.
But no cases of prostate cancer were found in the the third group – whose mothers were fed the standard diet with at least 17 per cent protein when they were in the womb and during three weeks of breastfeeding.
You are what you eat: Sex hormone changes are believed to be a factor in men’s tumours
An analysis on the animals’ prostates in all three groups found all had the potential to become cancerous.
The previous study, reported last year in General and Comparative Endocrinology, described some of the impairments caused in offspring by a maternal low-protein diet.
Prof Justulin said: ‘Generally speaking, these animals had low birth weight, less developed organs, and altered hormone levels.
‘However, around the twenty-first day after birth, we began to see accelerated growth to try to make up for the deficit.’
In a recently-published study, researchers collected blood from males at three weeks and 18 months of age. They found an imbalance between female and male hormone levels between the offspring of mothers fed a low-protein diet and the offspring of the control group.
They had two and a half times less oestrogen in old age and, even more significantly, about six times as little testosterone.
Prof Justulin said: “Our prior research showed pups exposed in the womb to a low-protein diet were born small but that as young adults they no longer displayed differences compared with controls in terms of size, prostate volume or hormone levels.
“In our new study, the differences reappeared as they aged. It is as if aging were a second insult to the organism, considering the first was the low-protein diet in the initial stage of development.”
Researchers are now testing the theory exposure to altered hormone levels in old age fuels tumours.
Prof Justulin said: ‘We observed this in the prostate, but other studies show low birth weight induced by maternal undernourishment is correlated with altered insulin levels and increased incidence of metabolic syndrome and heart disease.’
WHAT IS PROSTATE CANCER?
How many people does it kill?
Prostate cancer became a bigger killer than breast cancer for the first time, official statistics revealed earlier this 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