Calorie restriction slows age-related epigenetic changes

Researchers found that calorie restriction slows age-related epigenetic changes in mice and monkeys. The findings suggest a mechanism for how calorie restriction extends lifespan.

Related image

Ok….lets feel better about aging!

Related image

Calorie restriction has been shown to extend lifespan in several different species, but the underlying reason isn’t known. During normal aging, epigenetic changes occur throughout cells in the body. These changes alter the way genes are switched on and off without changing the DNA sequence itself. Levels of one type of epigenetic modification, called DNA methylation, have been shown to roughly reflect a person’s age. To investigate whether caloric restriction affects DNA methylation, a team of scientists led by Dr. Jean-Pierra J. Issa at Temple University examined the epigenetic profiles of mice, rhesus monkeys, and humans at different ages. They then tested whether these changes were altered by a calorie-restricted diet in mice and monkeys.

The team first analyzed DNA methylation in blood from mice, rhesus monkeys, and humans at different ages. Each species showed similar changes in DNA methylation patterns as they aged. These changes are called methylation drift, or epigenetic drift. The rates of epigenetic drift were inversely correlated with lifespan. That is, the shorter the species lifespan, the faster the changes in DNA methylation. This finding suggests that DNA methylation helps regulate the effects of aging.

The team then tested whether a calorie-restricted diet could slow methylation drift by feeding a group of mice 40% fewer calories than controls starting when they were 0.3 years old until they were 2.7 to 3.2 years old. They also fed rhesus monkeys a diet with 30% fewer calories than controls starting at the age of 7–14 years old until they were 22 to 30 years old. The changes in DNA methylation patterns slowed for the animals fed a calorie-restricted diet. Monkeys on a calorie-restricted diet showed the same patterns of DNA methylation as monkeys who were 7 years younger but had eaten regular diets. This methylation age difference was even higher in mice.

The team then compared the rates of epigenetic drift to telomere shortening. Telomeres are molecular caps at the ends of chromosomes. Their length has previously been linked to the aging process. Calorie restriction had no measurable effect on telomere length. “The impacts of calorie restriction on lifespan have been known for decades, but thanks to modern quantitative techniques, we are able to show for the first time a striking slowing down of epigenetic drift as lifespan increases,” Issa says.

More studies are needed to better understand why age-related epigenetic changes occur faster in some people than others, and whether altering them could help prolong human life. The study was funded by National Institutes of Health’s (NIH) National Cancer Institute (NCI) and National Institute on Aging (NIA). Results appeared online on September 14, 2017, in Nature Communications.

Adapted from: Caloric restriction delays age-related methylation drift. Maegawa S, Lu Y, Tahara T, Lee JT, Madzo J, Liang S, Jelinek J, Colman RJ, Issa JJ. Nat Commun. 2017 Sep 14;8(1):539. doi: 10.1038/s41467-017-00607-3. PMID: 28912502.

Nutritional Nugget

Barely eat barley? This hearty whole grain can be used in soups, salads, risottos, or cooked like oatmeal for breakfast.

WOD Nugget

Jaded: Bored or lacking enthusiasm, typically after having had too much of something

Inspiration Nugget

The longer you wait for something, the more you appreciate it when it finally arrives. The harder you fight for something, the more priceless it becomes once you achieve it. The more pain you endure on your journey, the sweeter the arrival at your destination. Remember... all good things are worth waiting for and fighting for.

 

 

Calorie postings on menus cause more health mentions in online restaurant reviews

nihms786550f1.jpg

 

In 2008, New York City mandated all chain restaurants to post the calories of items on their menus. The intent was to induce consumers to choose healthier items in the restaurant. A forthcoming study in the INFORMS journal Marketing Science, a leading scholarly marketing publication, investigated whether the calorie posting on menus impacted consumer evaluations of the restaurant. The study found that once the calorie posting regulation was implemented, online reviews significantly increased. The result suggests that calorie posting can not only shift consumers towards healthier alternatives when inside a restaurant, but can also, potentially, redirect consumers towards healthier restaurants and food items.

The study, “The Effect of Calorie Posting Regulation on Consumer Opinion: A Flexible Latent Dirichlet Allocation Model with Informative Priors,” was co-authored by Dinesh Puranam of the University of Southern California, Vishal Narayan of the National University of Singapore, and Vrinda Kadiyali of Cornell University. The authors analyzed 761,962 restaurant reviews across 9,805 restaurants on an online restaurant review website in New York City from 2004 to 2012. Using text-mining methods, the authors examined the change in the mentions of health in reviews over time before and after the calorie posting rule went into effect. To rule out the possibility that the health mentions increase was simply due to increased public interest in health issues over time, they compared the change in topics discussed for chain restaurants, relative to non-chain restaurants which were not mandated by the rule to post calorie information. The authors found a significant increase in the proportion of reviews that discussed health for chain restaurants, relative to non-chain restaurants.

The authors also explored in greater detail the source of the increase in health topics. They found that it was largely driven by new reviewers who were previously not active in posting reviews, but began to post more reviews after the mandate. Puranam noted that “Interestingly, the increase in health discussion in opinions was not confined to restaurants in more affluent localities, commonly associated with more health-conscious consumers. This is an encouraging sign of the success of the rule across the socioeconomic divide — especially given the greater incidence of obesity among lower socioeconomic classes.”

New York City recently expanded the rule beyond chain restaurants to also include fine dining restaurants. Narayan noted that “our result that calorie posting on menus impacts online reviews is significant for this rule expansion since consumers are even more likely to consult reviews for fine dining restaurants than for chain restaurants that they habitually visit. Whether this will have an impact on the caloric content of items on fine dining restaurant menus of restaurants, of course, remains to be seen.”

Kadiyali cautioned that more work is needed to study whether the increased discussion of health topics actually do lead to a greater choice of healthier restaurants. “It is possible that the health-conscious consumers may choose healthier restaurants while the less health conscious may avoid them. In this case, health benefits across the population may be ambiguous. Nevertheless, our study suggests that online reviews are a useful place to look for potential changes in consumer behavior due to this rule,” she said.

Adapted from: Dinesh Puranam, Vishal Narayan, Vrinda Kadiyali. The Effect of Calorie Posting Regulation on Consumer Opinion: A Flexible Latent Dirichlet Allocation Model with Informative Priors. Marketing Science, 2017; DOI: 10.1287/mksc.2017.1048

Nutrition Tip of the Day

Instead of frying foods which can add a lot of extra calories and unhealthy fats, use healthier cooking methods that add little or no solid fat, like roasting, grilling, baking or steaming.

Daily Inspiration 

active-2548136_192360-min.jpg