The path to a long life may be as short as the walk to your refrigerator or the local gym. That’s the message from scientists who are working on the cutting edge of aging research. Focused on diseases such as dementia, cancer and heart disease, this area of study has uncovered clues to how certain nutrients and specific exercise regimens can change the biological destinies of your cells. “You can tip your odds in favor of aging well if you follow what we’re learning is the healthy way to live,” says Trygve Tollefsbol, PhD, a senior scientist with the University of Alabama at Birmingham’s Comprehensive Center for Healthy Aging. In other words: Because of these discoveries, you may be able to rewrite your medical future.
A new way of looking at genes
We all learned in high school (but may have forgotten) that DNA provides genetic blueprints for the production of proteins that carry out the functions of each cell. In a discovery with huge implications, scientists have uncovered an additional cellular system: the epigenome, a complex network of switches or tags that govern whether genes are turned on or off. “Your DNA is wound really tightly around one of these protein switches,” explains Emily Ho, PhD, a principal investigator at the Linus Pauling Institute at Oregon State University. The epigenome tags physically mark your DNA in a way that affects how your genes operate. For instance, cells in your skin, eyes, teeth and hair contain exactly the same DNA. But they produce different features because, under the influence of these tags, some genes are “expressed” and others are “silent.”
Epigenetic changes—this turning on and off of genes—tend to occur more often as we grow older. Many of these changes influence the development of some age-related diseases by, for example, promoting or halting the production of substances the body uses to combat cancerous cells.
While you can’t change your genes, you have a shot at controlling epigenetic events. “You may be able to undo a harmful epigenetic change with the right lifestyle choices,” Ho says.
The case for broccoli
One nutrient at the center of epigenetics research is sulforaphane, which is found in cruciferous vegetables, such as broccoli, cauliflower, Brussels sprouts, kale and cabbage. Research at Oregon State and other academic labs has shown that sulforaphane inhibits a group of enzymes known as histone deacetylases (HDACs), which are involved in DNA wrapping and other tasks. Blocking HDACs can control inflammation and suppress tumor formation. In fact, a handful of cancer drugs already in human clinical trials use synthetic compounds to inhibit HDACs.
Emerging research suggests that a diet rich in broccoli and Brussels sprouts may help fend off cancer by reversing epigenetic events. In a 2007 study at the Johns Hopkins University School of Medicine, eight healthy women on their way to breast-reduction surgery were fed an extract of filtered broccoli sprouts (very young broccoli plants that taste a bit like radishes). When researchers later examined the women’s excised breast tissue, they found high levels of a tumor-fighting enzyme related to sulforaphane.
More recently, Ho’s research has shown that broccoli sprouts contain more sulforaphane than mature plants do and are thus a potentially more effective food for staving off unwanted epigenetic changes. “One cup of these sprouts may provide the benefits of 50 cups of broccoli,” Ho says. Tollefsbol recommends eating a cup of broccoli sprouts every day. You can buy them at farmers’ markets and natural food stores. Eat them raw as a snack or in a salad or sandwich. They can also be cooked in stir-fries.
Indian spice with an important kick
There’s another element of the epigenome that seems to be influenced by nutrition: microRNAs. These tiny molecules appear to regulate the process by which genes make vital proteins. Usually their expression and activity is perfectly normal, but sometimes they malfunction. “Recent evidence suggests that microRNAs can leave the tissue of origin and land in distant sites,” says Sharon Ross, PhD, a scientist in the Nutritional Science Research Group at the National Cancer Institute. This migration may play a role in the development of cancer.
Scientists are investigating the influence of nutrients on the concentration and activity of microRNA. In several recent studies, curcumin (which provides yellow color to the Indian spice turmeric) was shown to manipulate microRNA in a manner that helps suppress the proliferation of pancreatic- and lung-cancer cells. There’s also a wealth of data (from studies done in laboratories on isolated human cells) indicating that curcumin may decrease the proliferation of cancer cells, Ross says.
And it’s not just cancer that curcumin affects. In January a team of researchers from China and the U.S. Department of Agriculture’s Human Nutrition Research Center on Aging reported that curcumin reduces the expression of five genes known to regulate the aging process in fruit flies, which have a genetic profile similar to that of human beings.
When researchers fed elderly mice a diet high in a derivative of curcumin, they lived longer than mice that ate regular kibble. The scientists concluded that curcumin regulates protein expression so as to reduce oxidative stress, a type of cell damage caused by free radicals, pollution, smoking and other harmful forces. Oxidative stress has been implicated in many diseases, including cancer, Parkinson’s, Alzheimer’s and heart failure. How much curcumin should we eat to reap benefits? No one knows, because the appropriate studies have not yet been conducted on humans.
Life-extending benefits of coffee and tea
Polyphenols are naturally occurring chemicals found mostly in plants. In addition to ameliorating oxidative stress, polyphenols may protect our DNA in a way that helps us live longer.
Using data collected from regions of the world where green tea is popular, researchers have shown that a polyphenol in the tea (it’s called -epigallocatechin-3-gallate) might provide protection from age-related diseases. For example, a 2008 study of elderly people on several Mediterranean islands found that as green and black tea consumption increased, the likelihood of diabetes declined.
Coffee, which also contains polyphenols, may be beneficial, too. In January 2013, the Tufts Nutrition Research Center released a study showing that older rats fed the equivalent of 10 cups of coffee performed better on tests of motor function and memory than did rats on the standard diet. Tufts University nutrition and genomics professor Jose Ordovas, PhD, says there’s good evidence coffee may have a “significant effect” on memory and cognition, but researchers are not sure that polyphenols are the main cause. Another possible factor is the caffeine in coffee, Ordovas notes.
Although scientists disagree about just how much coffee you should drink, a 2012 study sponsored by the National Institutes of Health suggests that more than one cup a day provides benefits. The research, which tracked more than 229,000 men and 173,000 women for 12 years, showed that drinking two or more cups of coffee a day was associated in men with a 10 percent lower risk of dying and in women with a 15 percent lower risk. If green tea is your beverage of choice, Tollefsbol suggests drinking two or three cups a day.
Protecting DNA with vitamin D and selenium
Another epigenetic phenomenon that plays into aging is DNA methylation. During this chemical process, hydrogen and carbon atoms are added onto DNA, altering its structure, which changes the way genes are expressed. Methylation usually works to our benefit—it’s vital for normal development and cell physiology—but evidence suggests methylation patterns become disturbed as we age.
Several diseases, including Alzheimer’s and cancer, have been tied to abnormal methylation, and that has prompted scientists to search for nutrients that can normalize the process. Last December a study coauthored by Nigel Belshaw, PhD, of the Institute of Food Research in Norwich, U.K., showed that people with low levels of vitamin D and the mineral selenium in their blood had higher rates of a particular type of methylation that increases the risk of colon cancer. Interestingly, “normal levels of selenium seemed to be more beneficial for women than men,” says Belshaw. The mineral has also been tied to a reduced risk of bladder cancer.
A variety of foods are rich in selenium, including seafood and Brazil nuts. You can easily meet the recommended daily allowance (RDA) of selenium, 55 micrograms, by eating three ounces of tuna (92 mcg) or six to eight Brazil nuts (544 mcg). The best source of vitamin D is sunshine, but there’s no harm in taking a supplement if you live in an area that gets little sunlight in the winter, says Belshaw. The RDA of vitamin D is 600 international units for women 70 and under.
Belshaw’s group also found a correlation between high body weight and a bad type of DNA methylation. “We know that obesity is a significant risk factor for colorectal cancer development,” he says. “So I would advise anyone obese to lose weight.”
Exercise and epigenetics
The Cooper Institute, a Dallas-based nonprofit research house, has been collecting data on 110,000 individuals for the past 40 years and recently embarked on a plan to identify biological markers associated with cardiovascular fitness.
There’s no doubt that fitness allows you to live longer and stay healthier. In February the Cooper Clinic published research in the Annals of Internal Medicines howing that high fitness is associated with a 36 percent reduced risk of developing dementia later in life. In May, Cooper scientists followed up with a study concluding that those who do aerobic exercise regularly have a 20 percent lower risk of being hospitalized for heart failure than do couch potatoes. “People who are fitter have lower mortality, from both cardiovascular and all causes,” says Laura DeFina, MD, the Cooper Clinic’s chief scientific officer. “Fitness appears to have an independent benefit outside of reducing your risks for hypertension and type 2 diabetes.”
Why? One clue can be traced to the epigenetic changes that take place when people work out. A study published last year in the journal Cell Metabolism showed that a onetime high-intensity exercise session (20 to 35 minutes on an exercise bike) changed the methylation status of genes in the muscle cells, setting the stage for muscle growth and improved metabolism (after exercising, you might burn more fat and sugar than usual during the day). Another report, which appeared this July in PLOS Genetics, determined that a six-month workout routine (for example, Spin or aerobics classes twice a week) produced beneficial changes in genes linked to type 2 diabetes and obesity.
So how much exercise is sufficient to produce these benefits? For now, researchers cite the standard advice for staying fit: 30 to 60 minutes of moderate-intensity exercise five days a week or 20 to 60 minutes of vigorous-intensity exercise three days a week.
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