03:44am Sunday 24 September 2017

What we eat affects our jeans…and our genes

The study in human volunteers showed that whilst age had the biggest effects on these molecular changes, selenium and vitamin D status reduced the accumulation of epigenetic changes, and high blood folate and obesity increased them. These findings support the idea that healthy ageing is affected by what we eat.

Professor John Mathers and colleagues from Newcastle University working with researchers from the Institute of Food Research, led by Dr Nigel Belshaw, examined the cells lining the gut wall from volunteers attending colonoscopy clinic.

The study volunteers were free from cancer or inflammatory bowel disease and consumed their usual diet without any supplements. The researchers looked for specific epigenetic modifications of the volunteers’ genes that have been associated with the earliest signs of the onset of bowel cancer – an age-related disease. These epigenetic marks, known as DNA methylation, do not alter the genetic code but affect whether the genes are turned on or off. These methylation marks are transmitted when cells divide, and some have been associated with the development of cancer.

The investigators studied the relationship between the occurrence of these epigenetic marks at genes known to be affected in cancer, and factors including the volunteers’ age, sex, body size and the levels of some nutrients in the volunteers’ blood. The biggest influence on gene methylation was age. This fits with the fact that the biggest risk factor for bowel cancer is age, with risk increasing exponentially over 50 years old. 

The findings, published in the journal Aging Cell, showed that men tended to have a higher frequency of these epigenetic changes than women, which is consistent with men being at a greater risk of bowel cancer. Volunteers with higher vitamin D status tended to show lower levels of methylation, and a similar effect was observed for selenium status. Again, this is consistent with the known links between higher vitamin D and selenium and reduced bowel cancer risk.

The B vitamin folate is essential for health, but in this study, high folate status was associated with increased levels of epigenetic changes linked with bowel cancer. These findings are consistent with some epidemiological studies suggesting that excessive folate intakes may increase risk in some people. The researchers intend to investigate the mechanism for the observed effect of folate on DNA methylation in a follow-up study.

Obesity is also a risk factor for bowel cancer. This study found relationships between body size (height, weight and waist circumference) and epigenetic changes. How excess body weight induces these epigenetic changes, and the consequences for gut health, are currently being investigated at IFR and in Newcastle University.

The results of this study support the hypothesis that ageing affects the epigenetic status of some genes and that these effects can be modulated by diet and body fatness.

Reference: Nutritional factors and gender influence age-related DNA methylation in the human rectal mucosa, Aging Cell, doi: 10.1111/acel.12030

Key Facts:

  • Newcastle University is a Russell Group University
  • We rank in the top 20 of UK universities in The Sunday Times 2013 University Guide
  • Amongst our peers Newcastle is:
    • 10th in the UK for student satisfaction
    • In the UK’s top 12 for research power in Science and Engineering
  • 93% of our students are in a job or further training within six months of graduating (HEFCE 2012)
  • We have a world-class reputation for research excellence and are spearheading three major societal challenges that have a significant impact on global society. These themes are: Ageing and Health, Sustainability, and Social Renewal
  • Newcastle University is the first UK university to establish a fully owned international branch campus for medicine at its NUMed Campus in Malaysia which opened in 2011
  • Our International students put Newcastle University in world’s top 12 (ISB 2011)

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