There seems to be an evolving controversy in science in the race to discover anti-aging drugs before researchers reveal anti-aging foods. Apparently, a gene’s action may help explain why restricting diet lengthens life in animals, according to the August 18, 2010 Eurekalert! news release, “Discovery may aid search for anti-aging drugs.” Check out the latest study, “Genes encoding longevity: from model organisms to humans.”
In the Sacramento area, UC Davis has been researching nutrition for years. For example, there have been studies this year at UC Davis on the anti-aging properties of strawberries. See the UC Davis Strawberry Study site at the UC Davis Nutrition Department. The University of California – Davis and Baylor College of Medicine teamed up to study the effects of fresh vegetable juices on weight loss and lowering blood pressure.
Interestingly, there seems to be a ‘race’ of sorts between finding foods that play a role in anti-aging, helping to switch on genes that slow down aging, and at the same time in a variety of universities another ‘race’ to find an anti-aging drug based on experiments of restricting calories, but not nutrition in animals.
A few months ago, UC Davis nutrition scientists also ran a 15-week study to test whether diets that contain potatoes would be useful in weight loss or maintaining current body weight and how these diets affect your blood sugar. Check out the UC Davis Department of Nutrition – Potato Study.
According to the August 18, 2010 news release, “Discovery may aid search for anti-aging drugs,” the news seems to focus on looking for a way to develop anti-aging drugs rather than foods based gene suppression. A team of University of Michigan scientists has found that suppressing a newly discovered gene lengthens the lifespan of roundworms.
The leap that science hopes to provide is to find out how this applies to humans, since there are some similar genes between roundworms and humans. The research focuses on caloric restriction. Similarly, at UC Davis, the research also focuses on not only caloric restriction, but the type of nutrition that’s helpful in maintaining health.
Scientists who study aging have long known that significantly restricting food intake makes animals live longer. But the goal is to find less drastic ways to achieve the same effect in humans someday. The U-M results offer promising early evidence that scientists may succeed at finding targets for drugs that someday could allow people to live longer, healthier lives.
In a study in the August issue of Aging Cell, “Genes encoding longevity: from model organisms to humans,” U-M scientists found that a gene, drr-2, is an important component in a key cellular pathway, the TOR nutrient-sensing pathway, where many scientists are looking for potential drug targets. The U-M scientists then found that when they caused the drr-2 gene to be under- or over-expressed, they could lengthen or shorten lifespan in C. elegans, a worm widely used in research. Manipulating the drr-2 gene’s action produced the same effects as reducing or increasing caloric intake.
“We showed that in C. elegans, drr-2 is one of the essential genes for the TOR pathway to modulate lifespan,” says Ao-Lin Allen Hsu, Ph.D., the study’s senior author and a scientist at the U-M Geriatrics Center. He also is an assistant professor in internal medicine and molecular and integrative physiology at U-M. The study also found that drr-2 appears analogous to a human gene, eIF4H, that controls similar cell functions.
The idea is to find paths for developing future anti-aging drugs
To find possible avenues for future anti-aging drugs, many scientists around the world are focusing on signaling pathways in cells that sense nutrients. The one Hsu examined, the target of rapamycin pathway or TOR pathway, is so named because its activity can be influenced by the drug rapamycin. Recent results from a large federal study being conducted at U-M and elsewhere have shown that in mice, rapamycin is effective at mimicking the anti-aging effects of dietary restriction.
Why aren’t more scientists looking for anti-aging foods rather than drugs? Is it because you have to follow the money, and there’s less money in anti-aging foods? Who would be interested in anti-aging foods other than consumers, farmers, and natural or organic grocery and produce food stores?
Research in the last 25 years has shown that animals, including mammals, live longer and have lower levels of certain measures of age-related decline when scientists have restricted their food intake. No one has been able to show yet that the same effect happens in humans, though some studies are under way. There are groups in Sacramento where people follow restricted calorie diets, raw food diets, vegetarian diets, and vegan diets, low-carb diets, and various types of diets. You’ll find many of these groups online.
Nationally, you can look for information and see whether there’s a local chapter of the Calorie Restriction Society in your local area. See the website, Help the Calorie Restriction Society Raise Research Funding.
Active members of the Calorie Restriction Society have had a positive influence on the degree and direction of calorie restriction (CR) research in humans for a number of years now, helping scientists who have demonstrated that fewer calories mean less age-related disease and quite probably more healthy life, according to the Calorie Restriction Society.
As is true of many of the best patient advocate and pro-research advocacy groups, the Calorie Restriction Society has close ties with the scientific community; members have stepped up to the plate to help human studies happen more rapidly. You can find links to a number of more recent results at the websites, The Longevity Meme, and also including these sites: Calorie Restriction and the Heart and The Evidence For Calorie Restriction.
Now the society is stepping up again, this time to raise funding for further CR research. This initiative will build upon existing relationships with talented, well known scientists to correlate gene expression and cell signaling indicators in human calorie restriction practitioners to clinical markers of health and aging.
In essence, this work will continue to raise the bar in proving beyond a doubt that CR in humans is very beneficial to healthy longevity. You can find more information about the researchers in a PDF format release at the society website.
If you’re interested in the new calorie restriction study mentioned on the Calorie Restriction Society’s website, a key aspect of the new study will be to build on the calorie restriction study reported by Dr. Fontana in 2004. The idea with research is to find out whether long-term calorie restriction with adequate nutrition results in the same metabolic, hormonal, and gene expression changes in humans that scientists have seen with caloric restriction in rodents.
According to the August 18, 2010 press release on the University of Michigan, Ann Arbor research, “Genes encoding longevity: from model organisms to humans,” when calories or certain nutrients are restricted, scientists detect less oxidative damage in animal cells and a slower decline in DNA repair, a decline that normally occurs with age. It’s thought that limiting oxidative damage and slowing the decline in DNA repair could help postpone or avoid many age-related diseases.
But scientists know relatively little about why reducing food intake causes these effects. In the last 10 years, they have made progress in identifying genes and associated proteins that are suppressed when diet is restricted. By learning more about the cell processes involved, they may be able to discover targets for future drugs that could delay aging without the need to restrict food intake.
Drugs tailored to block specific genes or proteins involved in nutrient-sensing pathways would have much more appeal than reducing what one eats. To achieve anti-aging benefits, it’s thought that people would have to restrict food intake by 30 to 40 percent, a grim prospect. In addition, drugs might be designed to avoid other disadvantages of this level of dietary restriction, which include reduced fertility.
Why study caloric restriction in the roundworm? Its genes are found in other animals
C. elegans is a tiny roundworm, a nematode whose two-week lifespan is a great advantage for scientists studying aging. The 1-millimeter-long transparent worms have other advantages, too. C. elegans exhibits many age-associated changes observed in higher organisms.
“Many genes identified in C. elegans to control the speed of aging turned out to be evolutionarily conserved, meaning that you can find them in other animals, too. And many are very similar to those found in humans,” Hsu says in the news release.
Hsu and his team created different mutant strains of roundworms, some with drr-2 genes silenced and others in which the gene was over-expressed. They wanted to learn whether inactivating drr-2 is essential for TOR to influence longevity, and found that it was. Other newly discovered genes may affect TOR signaling as well. But Hsu’s team has found a promising lead for anti-aging drugs of the future: They were able to show that silencing drr-2’s action alone was sufficient to make worms live longer than wild-type C. elegans used as controls.
“It is known that reduction of TOR signaling in response to a change in the environment or genetic manipulation triggers a cascade of cellular signals that alter cell growth, metabolism, and protein synthesis, and decrease the pace of aging,” says Hsu. “Our recent studies have shown that drr-2 might play a pivotal role in the TOR signaling network to control protein synthesis as well as longevity.”
The news release also mentioned additional U-M authors: Tsui-Ting Ching, Alisha B. Paal, Avni Mehta, and Linda Zhong, all of the Division of Geriatric Medicine, U-M Department of Internal Medicine Funding: Ellison Medical Foundation and the National Institutes of Health. Citation: DOI: 10.1111/j.1474-9726.2010.00.