What Causes People to Age?
A number of theories have been proposed as to why we age. One is the oxidative stress theory, the idea that free radicals formed when cells are exposed to oxygen damage tissues. Another more recent theory is that aging is a failure of “autophagy.” Autophagy is the process cells use to clean up cellular “junk.” It’s a sort of self-cleaning system that reduces the build-up of cellular garbage that could cause cells not to function properly. According to Dr. Ana Maria Cuervo who has written numerous papers on this topic, in mice, old cells are restored to a more youthful state when autophagy is restored. Unfortunately, there’s not a simple switch to turn on healthy autophagy. Some people simply have a better clean-up system than others. On the other hand, she points out that diet appears to be a factor. Diets high in sugar and fat seem to overtax a cell’s clean-up system.
Aging and the Role of AGEs
Another contributor to aging is advanced glycation end products or AGEs. AGEs are formed when sugars crosslink with proteins and, to a lesser degree, with fats. Once formed, AGEs build-up inside blood vessels and tissues and contribute to blood vessel and tissue aging. Because diabetics have higher blood glucose levels, they form more AGEs. AGEs are believed to explain most of the complications of diabetes.
AGEs also form when you heat food to high temperatures, especially using dry cooking methods. Browning, grilling, barbecuing, roasting and frying all form AGEs. Animal-derived foods (meat) generate the most AGEs whereas high-carb foods form fewer. You can reduce the number of AGEs that form when you cook meat by marinating meat in an acidic marinade before preparing it.
Are There Ways to Prevent or Delay the Aging Process?
The good news is lifespan has already increased over the last 40 years. According to the National Institute on Aging, the average life expectancy has risen almost eight years since 1970. The average person could expect to reach the ripe age of 78 in 2008.
A number of small studies have looked at supplements and their effect on the aging process. Not surprisingly, antioxidant supplements have been the focus of considerable research. This is based on the idea that free radicals cause cell and tissue damage and this accelerates aging. Unfortunately, research doesn’t support the idea that supplemental antioxidants reduce the risk of age-related diseases in humans and taking them in supplement form may actually be harmful. One study showed smokers who took antioxidant vitamins and nutrients (vitamin C, vitamin E, selenium and beta-carotene) had a greater risk for developing lung cancer than those that didn’t.
On the other hand, fruits and vegetables are a good source of antioxidants, and research suggests that a diet rich in veggies and fruits lowers the risk for some types of cancer. How can you explain this? Antioxidants in whole foods are combined with a variety of other phytochemicals that work in synergy with each other. Isolating out a single antioxidant or antioxidants may have very different effects. A European study carried out in 2013 showed fruit and vegetable consumption was linked with reduced all-cause mortality. Some research also shows a diet rich in vegetables and fruits slows down cognitive decline associated with aging. Eat your fruits and veggies for a sharper brain!
Interestingly, exercise seems to make cells more resistant to free radical damage. One theory is exercise strengthens the body’s ability to defend itself against free radicals. Some research shows taking supplemental antioxidants prior to a workout may reduce this response and block some beneficial adaptations to exercise. More of a reason to get your antioxidants from food – not supplements.
Based on some theories of aging, free radicals aren’t such a bad thing. Calorie restriction and intermittent fasting has been studied in animals as a way to slow down aging. Restricting calories does extend the life of some animal species including mice and rats. How does it do this? One study found calorie restriction increases free radicals inside mitochondria, the energy-producing powerhouse of cells, but these free radicals seemed to increase the mitochondria’s antioxidant defense system as well, making cells more resistant to damage. It may also work by improving insulin sensitivity and metabolic health. Unfortunately, a more recent study found calorie restriction didn’t prolong life in rhesus monkeys, although it improved the metabolic health of these monkeys and delayed the onset of chronic diseases like diabetes, arthritis and heart disease.
Finally, a supplement called resveratrol may hold promise for slowing down the aging process. At least in animals, resveratrol, an ingredient in red wine, increases the activity of a protein called SIRT1 that seems to protect organisms against aging. So far, research shows it prolongs the lifespan of mice. Does it also do so in humans? Further research is needed.
The Bottom Line?
There’s still a lot we don’t know about the aging process. What is clear is that certain lifestyle habits like exercise and a diet of whole, unprocessed foods seems to lower the risk of a number of age-related diseases. Lifestyle matters when it comes to your health and how rapidly you age.
References:
National Institute on Aging. “Can We Prevent Aging?”
Clin Interv Aging. 2007 September; 2(3): 377-387.
Science Daily. “Experts confirm that fruit and vegetable consumption reduces the risk of mortality”
Ann Neurol. 2005 May;57(5):713-20.
Nutr Cancer. 1999;34(2):167-72.
National Institute on Aging. “NIH study finds calorie restriction does not affect survival” (2012)
Elsevier Connect. “Can We Delay Aging?”
Dermatoendocrinol. 2012 July 1; 4(3): 259-270.
Annual Review of Medicine. Vol. 46: 223-234.
J Am Diet Assoc. 2010 Jun;110(6):911-16.e12. doi: 10.1016/j.jada.2010.03.018.
Harvard Medical School. “New Study Validates Longevity Pathway”
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