Damage to DNA is ultimately what causes our bodies to age and is at the root of degenerative diseases including cancer and cardiovascular disease. Understanding what causes or accelerates DNA damage, what has the potential to slow it down or increase the repair pathways and what other factors influence our susceptibility to DNA damage, has the potential to make an enormously important contribution to health over the lifespan.
This area of science is growing at an exponential rate with advances in the techniques used to measure DNA damage. We know that as we age the level of DNA damage rises substantially. The questions being asked are what cause some people to have far greater levels of damage than others? Is there a threshold of damage above which aging and risk of disease is accelerated? The word ‘exposome’ has been coined to describe the exposure factors that influence this process. These can be lifestyle, environmental and dietary factors. The future of anti-aging and nutrition will almost certainly include designing an exposome that minimises DNA damage.
“The questions being asked are what cause some people to have far greater levels of damage than others?”
Nutritional effects on DNA damage were first observed in the 1960s, with the observation that deficiencies of two B group vitamins – folate and vit B12 – increased damage. Today our knowledge has increased exponentially and several nutrients have been shown to be important. Folate however stands out as key. In fact the DNA damage as a result of folate deficiency is similar to that induced by unsafe doses of ionizing radiation!
Other nutrients and phytochemicals that have been shown to be important include vitamin C, vitamin E, selenium, carotenoids, polyphenols, choline, zinc, magnesium, niacin, vitamin A, magnesium, calcium, vitamin D, vitamin K and the omega-3 fatty acids. What is important however, is to understand the optimal intake of each of these nutrients. More is not always better. For example beta-carotene has been shown to be protective up to a certain level of intake, above which it actually increases damage. This is true not just for beta-carotene. The temptation to simply take high dose supplements of ‘anti-aging’ nutrients is potentially very dangerous and may be doing more harm than good.
“What is important however, is to understand the optimal intake of each of these nutrients. More is not always better.”
Some research has been done in this area and indicates that optimal levels may also be different for specific age groups and populations. It is likely that the optimal amounts are somewhat higher than the current RDIs. A group at the CSIRO lead by Dr Michael Fenech showed that supplementation with 3.5 times the RDI of folic acid and vit B12 reduced the measured DNA damage marker by 25% in young adults with an increased susceptibility to chromosomal damage.
Gene variants have been identified that indicate our efficiency to process certain nutrients. For example the MTHFR gene is involved in folate usage. Currently available genetic testing can identify whether a person has one of the variants of this gene that makes them less efficient at using folate. Such gene testing is in its infancy and while many tests are now available, there remain questions over how results are interpreted. However it seems certain that this is where we are heading, where truly individualized nutrition advice can be tailored to our genes.
For now what we can certainly do is try to optimise our intake of foods rich in nutrients such as folate to give us the best chance of protection and aging well. Our current dietary guidelines are very general with regards to fruit and vegetables, advising only a total number of serves with no differential given to type. If, for example, we consider the folate content of plant foods it varies from very little in a banana (although bananas are fabulous for other nutrients including potassium) to excellent levels in spinach, broccoli and legumes. It is quite possible to consume your recommended 5&2 serves of vegetables and fruit, yet still fall short on folate. The concept of dietary recommendations for optimal genome health is reckoning.
“It is quite possible to consume your recommended 5&2 serves of vegetables and fruit, yet still fall short on folate
So where will you find folate in plentiful supply? In fortified breakfast cereals, liver, legumes (beans and lentils), leafy greens, asparagus, mushrooms, broccoli, Brussels sprouts and avocado.
But it’s not just diet; other lifestyle factors play an equally, and often greater role. These include smoking, alcohol intake, exercise, sleeping hours (7 or more, or less than 7), daily working hours (9 or more, or less than 9), mental stress, and whether or not breakfast was consumed. Studies to date seem to show that the most important factors are sleep, exercise, working hours and nutrition.
In summary from what we currently know the best ‘anti-aging’ strategy to minimise DNA damage is:
- don’t smoke
- drink alcohol in moderation
- eat a nutrient-dense diet including plenty of foods high in the nutrients identified above (especially folate)
- engage in regular exercise
- avoid working excessively long work hours
- get enough sleep.
Fortunately this advice is nicely in line with our Get Lean nutrition and healthy lifestyle recommendations. So while the future may hold more specific advice tailored for individuals, by truly adopting a Get Lean lifestyle you know you’re giving your body the best chance of aging well!
This article was originally published on Dr. Joanna McMillan’s site.