There are two kinds of people in the world — those who ignore food expiration dates and those who don't. You can slice off a piece of mold from that block of cheese, but that doesn't mean you should. Researchers at Harvard University suggest when it comes to food, you are what you eat; eating old food can accelerate aging and shorten your lifespan.

Vadim Gladyshev, Harvard professor of medicine, and his colleagues, noted human youthfulness begins to fade from cell damage, wear and tear on DNA's protein process, a lack of aerobic respiration, and slower enzyme function. This leads the body to become weak, which leads to deterioration, and eventually death, The researchers believe the consumption of old food may significantly contribute to the damage.

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“This damage is generated by nearly every cellular process. So over time, we have many, many ‘damage forms,’ millions or billions, and as a function of age, they accumulate," said Gladyshev, in a statement.

In the study, published in Science Advances, researchers sought to test the effect of old food on cellular aging by feeding different types of old food to yeast, fruit flies, and mice in a series of experiments.

In yeast, the researchers formulated a cell-culture medium composed of extracts from young yeast cells and another of extracts from old ones, and then grew new yeast cells on each medium to see which set would live longer. The same basic procedure was replicated in fruit flies and mice as they collected 5,000 freshly dead flies that had lived an average of 45 days, and sacrificed 5,000 others that were three to five days old. They prepared two diets: one of young flies and the other using old ones. Lastly, the mice were fed diets of skeletal muscle, or meat, from young and old farmed red deer (three years old versus 25) that replaced the normal mouse diet — insects, carrion, worms, and many others.

The findings were considered a little unexpected for the researchers; old food consistently lowered lifespans of each sample by 10 percent. However, in the mouse study, the old diet shortened only female animals' lifespans.

Gladyshev explains because they had limited deer meat, they only tested 60 mice, rather than two or three times that amount. Moreover, they recognized mice had normal diets prior to the experiment, suggesting there may not have been enough time for the new diets to have a full effect.

The researchers interpret this to mean that damage accumulation may be only one of many contributing factors in aging, and that this damage caused by internal molecular changes may have a stronger effect than damage via diet. They do believe they're on the right track to identifying the components that contribute to cell damage.

“That shows us that these age-related changes that accumulate are truly deleterious, and that provides a fundamental insight into the aging process,” said Gladyshev.

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Now, they hope to discover how the aging process can be slowed down. In other words, they want to know how to restructure cellular metabolism so this damage can occur at a slower rate.

“Aging is the most important biological question," he said.

Age is linked to several diseases; for example, if cancer is eliminated, there are still other age-related diseases, like diabetes, Alzheimer's, sarcopenia, cardiovascular disease, among many others that affect how fast we age on a cellular level. Learning how to slow down the aging process can help deal with the effects of these diseases by delaying their appearance.

Avoiding common triggers of a shortened lifespan, like eating expired food, can reduce how fast our cells age, and boost your life expectancy.

Below are three more unusual things that may unexpectedly shorten your lifespan.

No Sense Of Humor

Laughter may be the best medicine, especially when it comes to aging. A study in Psychosomatic Medicine found women with a strong sense of humor were found to live longer in spite of illness, especially cardiovascular disease and infection. The findings show that for women, high scores on humor's cognitive component were associated with 48 percent less risk of death from all causes, a 73 percent lower risk of death from heart disease, and an 83 percent lower risk of death from infection.

A link in men was only found for the risk of death from infection; those with a high humor score had a 74 percent reduced risk. Gender differences could be due to a slight decline in humor scores as men aged.

Not Getting Along With Your Co-workers

People who have friendly exchanges with coworkers are more likely to live longer than their less social peers. A study in Health Psychology found friendly and supportive co-workers lowered stress levels and reduced blood pressure and cholesterol, with this effect being most pronounced among those between the ages of 38 and 43. Those who were more likely to cause arguments and not distribute the workload equally, had a higher risk of dying.

Not Drinking

Despite popular belief, moderate drinking can help extend your lifespan. A study in Alcoholism: Clinical and Experimental Research found abstaining from alcohol does tend to increase one's risk of dying, even when you exclude former problem drinkers. More surprisingly, mortality rates are higher for non-drinkers than those of heavy drinkers. Moderate drinking can help protect against heart disease, and decreases the likelihood of Alzheimer’s and dementia through improved neuron function in the brain

No Sex

If you're under a dry spell, or have chosen not to have sex ever again, you could live a shorter life. A study in the British Medical Journal found men who didn’t have sex at least once a month, experienced twice the mortality rate of those who had sex once a week. It seems sex has a protective effect on men’s health, concluded the researchers.

Source: Lee SG, Kaya A, Avanesov AS et al. Age-associated molecular changes are deleterious and may modulate life span through diet. Science Advances. 2017.

See Also:

8 Causes Of Death That Made US Life Expectancy Fall For The First Time In 23 Years

Life Expectancy Around The World: In Which Countries Do People Live The Longest?