According to findings published in a recent issue of the journal Science, there is a tantalizing possibility of predicting who might hope for a longer life. The findings also cast doubt on the accuracy of tests that offer to predict a person’s risk of chronic diseases such as Alzheimer’s.
Several teams of researchers have identified gene patterns linked with extreme old age. But the researchers, led by Paola Sebastiani and Thomas Perls at Boston University, US, say theirs provides the greatest accuracy yet.
The researchers studied around 1,000 people who lived to be 100 or more and matched them to 1,200 other people to identify the genetic patterns more common in the 100-year-olds, using an approach called a genome-wide association study. To their surprise, the longest-lived people had many of the same genes linked with diseases as everyone else. Their old-age genes appeared to cancel out the effects of the disease genes.
“A lot of people might ask, ‘well who would want to live to 100 because they think they have every age-related disease under the sun and are on death’s doorstep, and certainly have Alzheimer’s’, but this isn’t true,” Perls told reporters in a phone briefing. “We have noted in previous work that 90% of centenarians are disability-free at the average age of 93. We had long hypothesized that to get to 100 you have to have a relative lack of disease-associated variants. But in this case we’re finding that not to be the case.”
They identified 19 patterns among around 150 genes and said these patterns predicted with 77% accuracy who would be in the extreme old-age group.
“Some signatures correlate with the longest survival, other signatures correlate with the most delayed age of onset of age-related diseases such as dementia or cardiovascular disease or hypertension,” Sebastiani says.
The researchers stress that having these genes is unlikely to give a person a free pass to smoke, drink and overeat.
Sebastiani says Seventh Day Adventists have an average life expectancy of 88, eight years more than their average US contemporaries.
“They get there by virtue of the fact that they have a religion that asks them to be vegetarian, they regularly exercise, they don’t drink alcohol, they tend to manage their stress well through religion and time with family, and they don’t smoke,” she says. “It really does speak to the incredible importance of lifestyle factors.”
“The methodology that we developed can be applied to other complex genetic traits, including Alzheimer’s disease, Parkinson’s, cardiovascular disease and diabetes,” Sebastiani says.
Choose your drinks with care
This is a perfect time of year to take a beverage inventory: what you drink, how much and how to maintain a reasonable intake of fluids—ones that will supply your body with much-needed water without adding to your fat stores.
Chances are the summer heat will tempt you to grab whatever cold liquid might be handy, and many of today’s most popular choices are loaded with sweet calories that actually increase the body’s need for water. The effects of dehydration can be subtle, with an array of confusing symptoms that can leave people feeling fatigued, irritable and unproductive, often with side effects of headache and muscle cramps. Athletes, whether amateur, recreational or professional, often fail to drink enough to compensate for the fluid they lose through sweat and respiration, and as a result they may not perform up to par. Even the totally sedentary are at risk when high heat, dry air (air conditioning in the summer, heating in the winter) or high altitudes increase their bodies’ water needs.
For the elderly, who often restrict their liquid intake for fear of having to get to a bathroom quickly, dehydration is commonplace and can be downright dangerous.
Despite their caffeine, which is a mild diuretic, coffee, tea and other caffeinated beverages can count towards your daily liquid intake, though not as completely as the equivalent amount of water.
Alcohol, however, definitely increases the body’s water need and cannot be included in your liquid intake unless the drinks are prepared with plenty of unsweetened non-alcoholic mixers.
The most recent national nutrition survey found that sugar-sweetened sodas are the single largest source of calories in the American diet: 7.1%. Yet they supply nothing but water that is of value to the body. And their sugar content actually increases the body’s water needs. The average American now consumes about a gallon of soda a week, and most of it is not the sugar-free diet variety.
Think green tea is good for you? The scientific evidence certainly suggests that, with antioxidants and about 40mg of caffeine in each cup, it can boost metabolism, among other health benefits. The research findings were based on plain green tea, with perhaps a teaspoon (16 calories) of sugar.
©2010/THE NEW YORK TIMES
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