Study suggests link
A new study published in the journal, Ageing, has claimed that eating meat frequently could be linked with an increase in blood phosphate levels that contributes to faster ageing of body cells.
The study measured blood phosphate levels in 666 adults recruited from Glasgow. Participants estimated their own dietary intakes by filling out a 21-category food frequency questionnaire which asked whether they tended to eat certain foods daily, weekly or monthly. No portion sizes were recorded.
The researchers then correlated blood phosphate levels with markers of biological ageing including telomere length (a measure of cell ageing), inflammation, and DNA hypomethylation (a marker of DNA abnormalities). Higher phosphate levels in the blood were statistically associated with worse cell ageing.
However industry experts on the side of meat have questioned the conclusions of this study. Dr Carrie Ruxton, from the Meat Advisory Panel notes:
“The conclusion of this study – that eating red meat is somehow to blame for faster ageing – bears no relation to the evidence the researchers actually collected. I am amazed that Glasgow University should be willing to publicise this illogical piece of work.
Dietary phosphate comes from a wide variety of sources, including meats, fish, eggs, dairy products and vegetables, as noted by the authors themselves in the paper.
Therefore, using a cross-sectional ‘snapshot’ of diet and blood samples as was the case in this study, it is impossible to say which individual dietary component was responsible for people’s raised blood phosphate levels.
The dietary assessment only asked participants to record how often they ate a food – no data were collected on the amounts eaten. Again, this hampers any chance of linking diet with phosphate levels. To do this, you would need a controlled clinical trial which varied the amounts of phosphate-containing foods in the diet.
Looking at the authors’ theory that a higher meat intake in lower socio-economic groups contributed to faster ageing, national diet data actually show lower or similar intakes of red meat in less well-off groups of people. The National Diet and Nutrition Survey which has data on more than 6000 individuals reported that men in the two lowest socio-economic groups ate 84-85g of red and processed meat daily, while men in the two highest socio-economic groups ate 83-93g daily. For women the differences were 53-57g daily in the lowest two groups and 56-59g in the highest two groups. This means that the authors of the paper are wrong about differences in red meat intakes across socio-economic groupings.
Randomised controlled trials which vary lean red meat consumption have not found detrimental effects on markers of health. For example, a 4-month study in elderly women which delivered a red meat intake of 160g daily on 6 days of the week found a significant reduction in inflammation.
In conclusion, all this study can say is that higher blood phosphate levels are linked with faster cell ageing, and that red meat and blood phosphate are statistically correlated. It tells us nothing about the cause of high
phosphate levels, or the cause of faster ageing. The elementary theory that red meat is to blame is simply speculation and is not based on solid evidence.
Red meat is a valuable source of iron, selenium, B vitamins and vitamin D – all of which would be expected to support normal health."