Eating purple potatoes could reduce the risk of developing colon cancer, according to a new study.
Pigs fed the vegetables found levels of a damaging protein that fuels tumours and other inflammatory bowel diseases were reduced by six times.
Researchers say other colorful fruits and vegetables, such as broccoli and red grapes, could bring the same beneficial effects.
The findings add to a body of research that suggests a ‘rainbow diet’ contains a cocktail of anti-inflammatory chemicals that can prevent chronic illnesses.
Understanding how these food compounds work at a molecular level could lead to new drugs for cancer and other potentially fatal conditions, said the team from Pennsylvania State University.
The study adds to a growing body of research that suggests plant based diets may prevent a variety of chronic diseases (stock photo)
Food scientist Professor Jairam Vanamala explained: ‘Ancient wisdom, as well as modern evidence, suggests plant based diets can potentially prevent a variety of chronic diseases, such as type 2 diabetes, heart disease and even cancer.
‘When you ‘eat from the rainbow’, like red grapes, purple potatoes, green broccoli, we are not providing one compound, we are providing a wide variety of compounds, thousands of them, that work on multiple pathways, and cause the self destruction of cancer stem cells.’
The study in pigs, which have a digestive system very similar to humans, found purple fleshed potatoes suppressed the spread of colon cancer stem cells – even as part of a high calorie diet.
They had six times less of a damaging protein called IL-6 (interleukin-6) which fuel tumours and other inflammatory bowel diseases compared to a control group on a normal diet.
Both uncooked and baked potatoes had similar effects.
Professor Vanamala said elevated levels are associated with other proteins, such as Ki-67, that are linked to the spread and growth of cancer.
‘What we are learning is food is a double edge sword – it may promote disease, but it may also help prevent chronic diseases, like colon cancer,’ he said.
‘What we don’t know is, “how does this food work on the molecular level?” This study is a step in that direction.’
His team said eating whole foods that contain macronutrients – substances humans need in large amounts such as proteins – as well as micro and phytonutrients like vitamins, carotenoids and flavonoids, may alter the IL-6 pathway.
SYMPTOMS OF BOWEL CANCER
The three main symptoms of bowel cancer are:
- Persistent blood in the stools – that occurs for no obvious reason or is associated with a change in bowel habit
- A persistent change in your bowel habit – which usually means going more often, with looser stools
- Persistent lower abdominal (tummy) pain, bloating or discomfort – that’s always caused by eating and may be associated with loss of appetite or significant unintentional weight loss
The symptoms of bowel cancer can be subtle and don’t necessarily make you feel ill.
However, it’s worth waiting for a short time to see if they get better as the symptoms of bowel cancer are persistent.
If you’re unsure whether to see your GP, try the bowel cancer symptom checker on the NHS Choices website.
Source: NHS Choices
Plant-based diet benefits
The findings, published in the Journal of Nutritional Biochemistry, reinforce recent research suggesting cultures with plant based diets tend to have lower bowel cancer rates than those that eat more meat.
Bowel cancer is the second leading cause of cancer related deaths in the US and a leading killer in many other Western countries, which tend to include more meat and less fruits and vegetables.
It is second only to lung cancer as the leading cause of death from the disease in both the UK and in Europe. Up to 16,000 people in the UK die from the disease every year.
Colourful plants, including the purple potato, contain bioactive compounds, such as anthocyanins and phenolic acids, that have been linked to cancer prevention, explained Professor Vanamala.
‘For example, white potatoes may have helpful compounds, but the purple potatoes have much greater concentrations of these anti inflammatory, anti oxidant compounds,’ he said.
‘We use the purple potato as a model and hope to investigate how other plants can be used in the future.
‘Instead of promoting a pill, we can promote fruits and vegetables that are very rich in anti inflammatory compounds to counter the growing problem of chronic disease.’
Currently, anti-IL-6 drugs are used against certain type of rheumatoid arthritis and are being considered to treat other inflammation-promoted chronic diseases like bowel cancer. But they are expensive and can cause side effects.
The diet approach to cancer treatment has also shown similar promise in mice, Professor Vanamala added.