Life Extension Magazine October 2012
Defend Against DNA Destruction
By Alex Richter
As each second goes by, your DNA is being attacked by internal and environmental factors that can result in potentially lethal mutations.1
This accumulated DNA damage underlies most of the conditions that kill us, such as atherosclerosis, cancer, and Alzheimer's disease.2-5
Fortunately, there are steps that you can take to protect your DNA from the onslaught of around-the-clock damage.
Scientists have demonstrated that a special group of plant compounds known as xanthophylls have shown protective effects against DNA damage.6 These molecules have been researched for their ability to prevent DNA damage and reduce disease risk.
Xanthophylls have been shown to not only prevent deadly genomic damage but they simultaneously boost your body's natural DNA repair mechanisms which help it recover from damage that's already occurred.7,8
Widespread Impact of DNA Damage
The DNA molecule is extremely vulnerable to injury from internal and external sources.9,10 Oxygen radicals, toxins, and even sunlight all induce breaks, nicks, and other injuries to the delicate DNA strands.11 Without knowing it, you experience millions of such DNA "accidents" each day. Fortunately, your body has no fewer than five interrelated mechanisms for repairing that damage.9 Those mechanisms are so efficient and accurate that your cells and tissues remain stable and disease-free year after year.9 Periodically, even the most efficient and accurate repair systems make small errors. And these errors add up. Scientists now recognize that the ability to identify and repair DNA damage is the leading discriminator of who does and does not get cancer and probably many of the other diseases of aging.9,10,12
Xanthophylls Fight DNA Damage
Xanthophylls are concentrated in yellow, orange, and deep green leafy vegetables.13,14 Epidemiological studies show that people who consume large amounts of fruit and vegetables have lower rates of cancer and other DNA damage-related diseases.15,16 But studies that take a closer look show that supplying up to 8 servings of carotenoid-containing fruits and vegetables per day don't demonstrate a reduction in DNA damage or improvement in repair mechanisms.17 Eating 12 servings per day did produce some benefit particularly with regards to reduction of damaging inflammatory molecules, but most people can't sustain that level of vegetable consumption.18 True DNA protection seems to require supplementation to achieve higher levels of these valuable nutrients in your blood.
When human volunteers took capsules containing concentrated xanthophylls, they demonstrated a 40% reduction in markers of DNA damage in their white blood cells.19 Individually, lutein, zeaxanthin, and astaxanthin supplements each reduce oxidative stress and DNA destruction in both animal and human studies.20-23 Doses of 4 to 12 mg/day of xanthophylls, alone or in combination, have been reported to reduce DNA damage in various studies.24,25
Let's turn now to the compelling body of science that demonstrates how these three xanthophylls can work to prevent catastrophic age-related diseases such as cancer and eye disease by protecting DNA from damage.
Xanthophylls Prevent Cancer
Scientists estimate that poor nutrition and lifestyle habits may play a role in up to 80% of colon, breast, and prostate cancers and 33% of all other cancers, including inadequate intake of nutrients that prevent DNA damage and promote DNA repair.12,26 Large epidemiological studies consistently show that higher intake of foods rich in lutein, zeaxanthin, and astaxanthin reduce the risk of several different cancer types.16,27
Laboratory studies reveal the reasons for this impressive protection. When tumors are experimentally implanted into mice supplemented with xanthophylls, the rate of tumor growth and the final size of the tumors are reduced by as much as 40%, compared with unsupplemented animals.28-30 The number of tumors triggered by exposure to a carcinogenic chemical can be reduced by 55% in animals supplemented with xanthophylls such as lutein.29 It takes supplemented animals significantly longer to develop those artificial cancers.31-33 How do the xanthophylls exert their powerful anticancer actions?
They do it through a number of mechanisms that strike at different targets throughout the cancer development process:
- They block cancer initiation by limiting DNA damage and strengthening DNA repair mechanisms.12,26
- They suppress genes that promote tumor growth after cancer initiation.34
- They turn on genes that suppress tumor promotion.30
- They reduce inflammation that can promote cancer growth and spread.33-35
- They switch on cancer cells' defective suicide programming (apoptosis), helping to shrink existing cancers and prevent metastatic spread.30
- They slow the development of new blood vessels needed by a rapidly-growing tumor, starving it of its vital nutrient and oxygen supplies.30
Research has shown that supplementation with lutein, zeaxanthin, and astaxanthin boosts the immune system in ways that help it identify and destroy cancerous cells in their earliest stages.29,31 Most scientists today recognize that, after prevention of DNA damage, this kind of "immune-surveillance" is an essential and efficient means of preventing a full-blown cancer from emerging.35 The effects of the xanthophylls on skin cancer, the most common cancer in the United States, are especially prominent. Sunlight, and especially its ultraviolet rays, trigger high rates of DNA damage in skin cells that initiate certain types of skin cancer.36,37 Ultraviolet radiation weakens the immune system's anti-cancer surveillance mechanisms.33
People with the highest intake of lutein and zeaxanthin have a 53% lower risk of developing skin cancer compared to those with the lowest intake levels.38 Studies show that supplementation with xanthophylls reduces skin's unhealthy responses to ultraviolet light and enhances its resistance to cancer development.36,37 Increased survival time in an animal model of skin cancer has been demonstrated as a result of supplementation.37
Interestingly, lutein, zeaxanthin, and astaxanthin supplements reduce light-induced skin aging, again in large part because of their ability to combat age-promoting DNA damage.37 Their unique molecular structure seems to make them especially potent at taming the destructive effects of light bombardment on vulnerable tissues. Nowhere is that protection more essential than in the retina of the eye, as we'll see next.