SIRTUINS slowing down the ageing process
SIRTUINS ARE a family of seven proteins that play an essential role in our health, from DNA maintenance to mitochondrial biogenesis and cellular energy production.
In relation to protein, there are one of four main biological macromolecules, including lipids, carbohydrates, and nucleic acids. There are an estimated 80,000 to 400,000 types of proteins in the human body. More than 2,700 of these are a particular type of protein called enzymes, which catalyse chemical reactions to carry out important biological tasks, from digestion to replicating DNA.
Seven of these enzymes are sirtuins, SIRT1-SIRT7. They play such a critical role in health, from metabolism to gene expression, that researchers have described them as guardians of the genome and even the ‘magnificent seven.’
Sounds important and a little dramatic, right? Let us take a closer look at the role of sirtuins in your body to see why scientists are so interested.
According to Dr Orlando Thomas, medical doctor and functional medicine practitioner at Thomas Medical and Shockwave Centre, sirtuins are really quite miraculous in the work they perform to manage the many processes in our cells that are involved in ageing and the diseases associated with the ageing processes.
METABOLIC SENSORS
The scientific definition of sirtuins is NAD+-dependent histone deacetylases, a mouthful! What does it mean to be NAD+dependent? Sirtuins can only function in the presence of NAD+. In fact, they consume one molecule of NAD+ each time they do their work of deacetylation. “The relationship to NAD+ is important: NAD+ stands for nicotinamide adenine dinucleotide, a coenzyme found in all living cells that’s essential for cellular metabolism, mitochondrial function, and hundreds of other biological processes. The concentration of NAD+ is determined by the nutritional state of the cell and by other factors, like age; NAD+ levels decline with age,” Dr Thomas said.
“So, in their relationship with NAD+, sirtuins act as metabolic sensors, able to understand the metabolic state of the cell and act accordingly to help keep things in balance,” Dr Thomas added.
Deacetylation is how they do it. Sirtuins remove acetyl groups from other proteins – mainly histones, but also non-histone proteins, and in doing so they regulate gene transcription and protein activity.
“Sirtuins sense the metabolic state of the cell and then regulate gene expression or protein activity in response. Sirtuins are thought to do this mainly in response to stress of various kinds: genotoxic, metabolic, and even ageing. One challenge is that NAD+ levels and, consequently, sirtuin function actually decline with age, making it more difficult to respond to various stressors over time,” Dr Thomas said.
AGE-RELATED DISEASES
Studies have linked sirtuins to being able to help to repair DNA damage, as it is believed that they protect telomeres, the caps at the end of chromosomes within our DNA. They help to provide vital cellular energy, as they create new mitochondria, the power plant of our cell. Sirtuins also enhance the link between the nucleus and mitochondria so that the mitochondria functions more effectively.
Sirtuins go to work removing old, decaying parts of our cells, making everything ready for new growth.
Functional foods and nutraceuticals hold great promise for health and longevity promotion and prevention of age-related diseases. Certain foods have natural plant compounds which may be able to increase the level of the sirtuin proteins. Many of them are associated with the foods eaten in Japan and the Mediterranean diet.
These include kale, red wine, onions, soy, parsley, extra virgin olive oil, dark chocolate, turmeric, blueberries and coffee. Studies have linked ingredients such as fisetin, quercetin, resveratrol, pterostilbene to enhancing sirtuin activity. These can be found in capsule form to enable easy consumption.