Scientists Are Studying How to Help Dogs Have Longer Lives, in a Bid to Further Our Own
Feeding dogs only once a day is showing health benefits in a large study, scientists report.
The sad eyes. The wagging tail. The frustrated whine. The excited bark. Dogs know how to get their owners to fork over the food more often.
The extra calories dogs get from feeding patterns now used by many Americans may not be good for them from a health and longevity viewpoint. In research from a large study called the Dog Aging Project, canines fed once a day had better scores on cognition tests and lower odds of developing diseases of organs throughout the body: intestinal tract, mouth and teeth, bones and joints, kidneys and bladder, and liver and pancreas.
Fewer than 1 in 10 dog owners fed their furry friends once daily, while nearly three fourths provided two daily meals.
“Most veterinarians have been led to believe that feeding dogs twice a day is optimal, but this is a relatively new idea that has developed over the past few decades with little supportive evidence from a health standpoint,” said Matt Kaeberlein, PhD, Co-Director of the Dog Aging Project, a professor of pathology and Director of the Healthy Aging and Longevity Research Institute at the University of Washington. Kaeberlein studies basic mechanisms of aging to find ways of extending the healthspan, the number of years of life lived free of disease. It’s not enough to extend the lifespan unless declines in biological function and risks of age-related diseases are also studied, he believes, hence the healthspan.
The Dog Aging Project is studying tens of thousands of dogs living with their owners in the real world, not a biology laboratory. The feeding study is the first of several reports now coming from the project based on owners’ annual reports of demographics, physical activity, environment, dog behavior, diet, medications and supplements, and health status. It has been posted on bioRxiv as it goes through peer review.
“All available evidence suggests that most biological mechanisms of aging in dogs will be conserved in humans. It just happens much faster in dogs.”
“The Dog Aging Project is one of the most exciting in the longevity space,” said David A. Sinclair, professor in the Department of Genetics and co-director of the Paul F. Glenn Center for Biology of Aging Research at Harvard Medical School. “Not only is it important to help our companions live longer and healthier, but because they are like people and share the same environment and many of the lifestyles as their owners, they are the perfect model for human longevity interventions.”
The epigenetic clock — and specifically changes in gene expression resulting from methylation of cytosine and guanine in the DNA — provides the critical connection between aging in dogs and people. “All available evidence suggests that most biological mechanisms of aging in dogs will be conserved in humans,” Kaeberlein said. “It just happens much faster in dogs.” These methylation changes, called the “methylomes,” have been associated with rates of aging in dogs, humans, and also mice.
In a 2020 study young dogs matched with young adults and aged dogs matched with older adults showed the greatest similarities in methylomes. In the Cell Systems report, Tina Wang of the University of California, San Diego, and colleagues wrote that the methylome “can be used to quantitatively translate the age-related physiology experienced by one organism (i.e., a model species like dog) to the age at which physiology in a second organism is most similar (i.e., a second model or humans).” This allows rates of aging in one species to be mapped onto aging in another species, providing “a compelling tool in the quest to understand aging and identify interventions for maximizing healthy lifespan.”
In the Dog Aging Project study, 8% of 24,238 owners fed their dogs once daily, the same as the percentage of owners serving three daily meals. Twice-daily feedings were most common (73%), and just over 1 in 10 owners (11%) “free fed” their dogs by just filling up the bowl whenever it was empty — most likely Rover’s favorite option.
“The notion of breakfast, lunch, and dinner for people in the United States is not based on large studies that compared three meals a day to two meals a day, or to four, “ said Kate E. Creevy, chief veterinary officer with the Dog Aging Project and associate professor at Texas A&M University. “It’s more about what we are accustomed to. Similarly, there are not large population studies comparing outcomes of dogs fed once, twice, or three times a day.”
“We do not recommend that people change their dogs’ diets based on this report,” Creevy emphasized. “It’s important to understand the difference between research that finds associations versus research that finds cause and effect.”
To establish cause and effect, the Dog Aging Project will follow their cohort over many years. Then, Creevy said, “We will be able to determine whether the associations we have found with feeding frequency are causes, or effects, or neither.”
While not yet actionable, the feeding findings fit with biology across a variety of animals, Kaeberlein said, including indicators that better health translates into longer healthspans. He said that caloric restriction and perhaps time-restricted eating or intermittent fasting — all ways that some human diets are structured — can have a positive impact on the biology of aging by allowing the gastrointestinal tract to have time each day to rest and repair itself, just as sleep benefits the brain through rest.
Timing of meals is also related to the concept of ketogenesis, Kaeberlein explained. Without access to glucose, animals switch over to a ketogenic state in which back-up systems produce energy through metabolic pathways that generate ketones. Mice go into this state very quickly, after a few hours or an overnight fast, while people shift to ketogenesis more slowly, from a few hours to up to 36 hours for people on typical Western diets, Kaeberlein said.
Dogs are different. They take at least two days to shift to ketogenesis, suggesting they have evolved to need fewer meals that are spaced out rather than the multiple daily meals plus snacks that people prefer.
As this relates to longevity, Kaeberlein said that a couple of studies show that mice who are fed a ketogenic diet have longer lifespans (years of life regardless of health). “For us, the next step is to analyze the composition of the dogs’ diets or the relationship of multiple daily feedings with obesity,” he said. “Maybe not being obese is related to better health.”
To learn more, the Dog Aging Project needs dogs — lots of dogs! Kaeberlein wants at least 100,000 dogs, including small dogs, large dogs, dogs of all ages. Puppies are needed for the researchers to follow across their lifespan. The project has an excellent website where owners can volunteer to participate.
Nutritional strategies are often not built around sound scientific principles, Kaeberlein said. In human nutrition, people have tried all kinds of diets over the years, including some that were completely wrong. Kaeberlein and his colleagues in the Dog Aging Project want to change that, at least for people’s canine companions, and hopefully, as a result, give dogs added years of healthy life and provide clues for human nutrition.
After that, maybe they can do something about those sad eyes and the frustrated whine.
A woman receives a mammogram, which can detect the presence of tumors in a patient's breast.
When a patient is diagnosed with early-stage breast cancer, having surgery to remove the tumor is considered the standard of care. But what happens when a patient can’t have surgery?
Whether it’s due to high blood pressure, advanced age, heart issues, or other reasons, some breast cancer patients don’t qualify for a lumpectomy—one of the most common treatment options for early-stage breast cancer. A lumpectomy surgically removes the tumor while keeping the patient’s breast intact, while a mastectomy removes the entire breast and nearby lymph nodes.
Fortunately, a new technique called cryoablation is now available for breast cancer patients who either aren’t candidates for surgery or don’t feel comfortable undergoing a surgical procedure. With cryoablation, doctors use an ultrasound or CT scan to locate any tumors inside the patient’s breast. They then insert small, needle-like probes into the patient's breast which create an “ice ball” that surrounds the tumor and kills the cancer cells.
Cryoablation has been used for decades to treat cancers of the kidneys and liver—but only in the past few years have doctors been able to use the procedure to treat breast cancer patients. And while clinical trials have shown that cryoablation works for tumors smaller than 1.5 centimeters, a recent clinical trial at Memorial Sloan Kettering Cancer Center in New York has shown that it can work for larger tumors, too.
In this study, doctors performed cryoablation on patients whose tumors were, on average, 2.5 centimeters. The cryoablation procedure lasted for about 30 minutes, and patients were able to go home on the same day following treatment. Doctors then followed up with the patients after 16 months. In the follow-up, doctors found the recurrence rate for tumors after using cryoablation was only 10 percent.
For patients who don’t qualify for surgery, radiation and hormonal therapy is typically used to treat tumors. However, said Yolanda Brice, M.D., an interventional radiologist at Memorial Sloan Kettering Cancer Center, “when treated with only radiation and hormonal therapy, the tumors will eventually return.” Cryotherapy, Brice said, could be a more effective way to treat cancer for patients who can’t have surgery.
“The fact that we only saw a 10 percent recurrence rate in our study is incredibly promising,” she said.
Urinary tract infections account for more than 8 million trips to the doctor each year.
Few things are more painful than a urinary tract infection (UTI). Common in men and women, these infections account for more than 8 million trips to the doctor each year and can cause an array of uncomfortable symptoms, from a burning feeling during urination to fever, vomiting, and chills. For an unlucky few, UTIs can be chronic—meaning that, despite treatment, they just keep coming back.
But new research, presented at the European Association of Urology (EAU) Congress in Paris this week, brings some hope to people who suffer from UTIs.
Clinicians from the Royal Berkshire Hospital presented the results of a long-term, nine-year clinical trial where 89 men and women who suffered from recurrent UTIs were given an oral vaccine called MV140, designed to prevent the infections. Every day for three months, the participants were given two sprays of the vaccine (flavored to taste like pineapple) and then followed over the course of nine years. Clinicians analyzed medical records and asked the study participants about symptoms to check whether any experienced UTIs or had any adverse reactions from taking the vaccine.
The results showed that across nine years, 48 of the participants (about 54%) remained completely infection-free. On average, the study participants remained infection free for 54.7 months—four and a half years.
“While we need to be pragmatic, this vaccine is a potential breakthrough in preventing UTIs and could offer a safe and effective alternative to conventional treatments,” said Gernot Bonita, Professor of Urology at the Alta Bro Medical Centre for Urology in Switzerland, who is also the EAU Chairman of Guidelines on Urological Infections.
The news comes as a relief not only for people who suffer chronic UTIs, but also to doctors who have seen an uptick in antibiotic-resistant UTIs in the past several years. Because UTIs usually require antibiotics, patients run the risk of developing a resistance to the antibiotics, making infections more difficult to treat. A preventative vaccine could mean less infections, less antibiotics, and less drug resistance overall.
“Many of our participants told us that having the vaccine restored their quality of life,” said Dr. Bob Yang, Consultant Urologist at the Royal Berkshire NHS Foundation Trust, who helped lead the research. “While we’re yet to look at the effect of this vaccine in different patient groups, this follow-up data suggests it could be a game-changer for UTI prevention if it’s offered widely, reducing the need for antibiotic treatments.”