A new study from Australia suggests that eating lots of red meat is linked to a higher risk of developing age-related macular degeneration (AMD), a leading cause of blindness in old age.
The study was the work of first author Dr Elaine Chong, who is from the Centre for Eye Research Australia based at the University of Melbourne, and colleagues, and is published on 1 April in the advance access issue of the American Journal of Epidemiology.
Chong and colleagues found that compared to those who ate it less than five times a week, people who ate red meat 10 times a week were nearly 50 per cent more likely to develop AMD in old age.
However, they also found that people who ate chicken at least three times a week were 50 per cent less likely to develop the condition.
AMD is where the middle part of the retina slowly breaks down, and the person gradually loses central vision, initially as blurring, then as fading colours. Although rarely resulting in complete blindness, AMD is still the leading cause of poor-sightedness and blindness among the over 60s and affects about half a million people in the UK.
Between 1990 and 1994 Chong and colleagues recruited 6,734 people aged from 58 to 69 who were living in in Melbourne, Australia. They got them to fill in information about their diets on food questionnaires at the start of the study: this included questions about how much meat they ate, of what type, and how often.
Over the follow up period (the study ended between 2003 and 2006), the researchers took digital macular photographs of the retina in both eyes of each participant and evaluated them for signs of AMD.
They then did statistical tests to find out the links between any signs of AMD and meat consumption, while adjusting for age, smoking, and other potential confounders.
The results showed that:
- At follow up, 1,680 participants had early stage AMD and 77 had late stage AMD.
- Higher red meat intake was positively associated with early AMD (ie more red meat linked to higher chance of having early AMD).
- The odds ratio for eating meat ten times a week or more versus eating it less than 5 times a week was a significant 1.47 (ie eating meat 10 times a week gave a person 47 per cent higher risk of AMD than if they ate it less than 5 times a week).
- Conversely, eating chicken 3.5 times a week or more was linked to 57 per cent lower risk of late AMD compared to eating it less than 1.5 times a week.
The researchers concluded that different types of meat appear to have different effects on the risk of developing AMD and helping people change their dietary habits could be a way to help them lower risk of developing AMD in old age.
“Red Meat and Chicken Consumption and Its Association With Age-related Macular Degeneration.”
Elaine W.-T. Chong , Julie A. Simpson , Luibov D. Robman , Allison M. Hodge , Khin Zaw Aung , Dallas R. English , Graham G. Giles , and Robyn H. Guymer.
American Journal of Epidemiology 2009 169(7):867-876.
Advance Access published on April 1, 2009.
DOI 10.1093/aje/kwn393
Click here for more information on AMD from the Royal National Institute of Blind People (RNIB, UK).
Sources: Journal article, RNIB.
Written by: Catharine Paddock, PhD