A dog's life

A group of Labrador dogs that enjoyed long lives on carefully planned diets, and under the care and scrutiny of nutritional scientists, has provided researchers with a unique life-long metabolic profile. The data reveal the relationship between diet, disease and longevity.

The first part of the study took more than fifteen years and was all done in the name of developing dog food. 48 puppies from seven litters were raised at a research centre in the US run by food company Nestl?, also a leading dog food producer. Animals were fed either a restricted or normal (control) diet and subjected to regular clinical assessment. Urine samples collected from each dog during these check-ups provided a metabolic record that UK scientists have used to study the biological process of aging and metabolism.

The dogs on the restricted diet lived about two years longer than those on the control diet. The last of the dogs died just over two years ago, and Jeremy Nicholson and his team at Imperial College London have now used updated analytical techniques on the old samples to measure life-long biochemical changes. They identified compounds in the urine samples using nuclear magnetic resonance (NMR) spectroscopy, catalogued age-related changes and compared the results from the two groups of animals. ’The link between longevity and a restricted diet has been appreciated for some time, but this is the first time it has been demonstrated in a larger animal,’ Nicholson told Chemistry World.

Nicholson said diet can induce changes in the microorganisms in our gut. This could influence the development of certain diseases in animals and humans, including obesity, which may be related to longevity. His group found that levels of gut microbial metabolites, like methylamines, cresols and other aromatic compounds, were different between the two groups of dogs. ’This is significant because altered gut microflora has already been linked to obesity in humans,’ he said.

The data enabled Nicholson’s team to revisit a long-term study that he said would be almost impossible to repeat. ’We can study these samples with state-of-the-art techniques, allowing us to discover more about the biology of these metabolic systems: why do gut microbes change and what do they do to our metabolism? Once we understand that, and how it links to disease, we can actually engineer the changes we want.’

Victoria Gill