We are what we eat, or so the saying goes, and the emerging science of nutrigenomics (nutrition + genome), puts this adage to the test. Nutrigenomics is the study of how the foods we and our pets eat “speak” to our cells to regulate gene expression, which in turn plays a role in determining if we’re healthy or plagued by illness. In this article, adapted from Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health, by W. Jean Dodds, DVM, and Diana Laverdure, MS, the authors consider the ways that applying related discoveries in nutrigenomics can help our dogs gain or retain quality of life as they move into their senior years.
Which ingredients are proven to ramp up cognitive activity in aging dogs? Researchers at the University of California, Irvine, fed their dogs vitamins E and C (antioxidants) along with a mixture of fruits and vegetables to reduce free radical damage. They also included alpha-lipoic acid and L-carnitine (mitochondrial cofactors), which improve the function of aged mitochondria—specialized parts of cells that produce most of a cell’s energy—in their diets. The result? According to the study report, the diet resulted in a significant improvement in the ability of aged (but not young) animals to acquire progressively more difficult learning tasks (Cotman et al. 2002).
Other important nutrients also show the ability to improve cognitive function in senior dogs. Among the most studied: milk thistle, phosphatidylserine (a phospholipid), SAMe (s-adenosylmethionine), medium-chain triglycerides (MCTs) found in coconut oil, and DHA and EPA omega-3 fatty acids (Milgram et al. 2002, Landsberg et al. 2011, Bensimoun 2013).
Many functional nutritional ingredients don’t just benefit one part of the body; they promote health across a wide range of systems. This, of course, makes sense because the body is not made up of isolated parts (as many Western medical specialists would like us to believe); it contains an intricately related set of systems that all perform a complex, wonderfully intertwined dance. Coconut oil, omega-3 fatty acids and many of the other functional ingredients target the body holistically, producing a wide range of benefits from head to toe—or, in the case of dogs, from nose to tail.
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Coconut oil possesses many therapeutic qualities, but perhaps the most amazing is its scientifically proven ability to improve brain function in older dogs and people. As the body’s supercomputer, the brain requires a lot of energy, most of which is satisfied when the body breaks down glucose from food. However, as we age, we metabolize glucose less efficiently, leaving a gap in the brain’s energy requirement.
When this occurs, alternative sources of fuel become important to fill this gap and provide much-needed energy to the brain. This is where medium-chain triglycerides (MCTs), such as those contained in coconut oil, can help save the day. Unlike regular fats (which the body metabolizes slowly), MCTs break down and absorb rapidly into the bloodstream, providing a quick source of non-carbohydrate energy.
Further, they readily cross the blood-brain barrier, supplying up to 20 percent of a normal brain’s energy requirement; are important for ketone production, which serves as an additional source of “brain food”; and help the body use omega-3 fatty acids more efficiently and increase omega-3 concentrations in the brain—a good reason to give your dog both omega-3s and coconut oil (Aldrich 2009, Laflamme 2012, Wolf 2009).
One study showed that when 24 Beagles who were between the ages of 7.5 and 11.6 years old at the start of the trial were fed a diet supplemented with 5.5 percent MCT, their cognitive ability improved significantly. The dogs showed improvement in learning-related tasks after only about two weeks of consuming the supplemented diet, and within one month, their learning ability improved significantly. The study’s authors concluded that supplementation with MCTs can improve age-related cognitive decline by providing an alternative source of brain energy (Pan et al. 2010).
In addition to its brain-boosting qualities, coconut oil is purported to provide a host of other benefits. It contains antiviral, antimicrobial and antifungal properties; helps with weight loss (MCTs increase metabolism, so they send signals of satiety and cannot be stored as fat), improves digestion and absorption of fat-soluble vitamins, benefits the skin and coat, and provides a rapid form of non-carbohydrate energy (Aldrich 2009, Wolf 2009).
The coconut oil you select should be unrefined (virgin) and expeller- or cold pressed. Processed, heat-treated foods lose their natural life-giving nutritional force. If possible, choose organic brands to avoid potential contamination from pesticides.
Coconut oil does not need to be stored in the refrigerator, but since it is light sensitive (like all oils), it’s best to keep it in a dark cupboard. Dark glass containers are excellent storage choices, as they protect the oil from light while also ensuring that no bisphenol-As (BPAs) leach into the product.
There are many ways to incorporate coconut oil into your dog’s diet. Try mixing a tablespoon into some goat- or sheep’s-milk yogurt, or adding a dollop on top of some fresh organic blueberries. You can even scoop it straight from the container and let him lick the spoon. Dogs love the taste!
Studies show that coconut oil fed as 10 percent or less of your dog’s diet poses no digestive or other health issues (Aldrich 2009).
The omega-3 fatty acids DHA and EPA fight obesity, decrease inflammation, combat arthritis and cancer, and promote overall health, so it should come as no surprise that DHA and EPA also benefit brain health—especially since the brain is made up of as much as 60 percent fat (Mercola 2012).
About 20 percent of the brain’s cerebral cortex (the outermost layered structure of neural tissue) is made up of DHA, which also provides structural support to neurons (the cells that make up the central nervous system). Studies in people show that supplementation with DHA is beneficial in supporting cognitive health in aging brains, and that inadequate levels can cause neurons to become stiff, hindering proper neurotransmission both within and between cells (Mercola 2012, Yurko-Mauro 2010).
A study of 48 Beagle puppies showed that dietary fortification of fish oil rich in DHA following weaning resulted in improved cognitive learning, memory, psychomotor, immunologic and retinal functions during the developmental stage. The high-DHA food also contained higher concentrations of the antioxidant vitamin E, taurine, choline and l-carnitine, which may also have played a positive role on the puppies’ development (Zicker et al. 2012).
EPA, along with DHA, can also benefit mood. As anyone who has cared for an elderly relative or friend knows, depression is a common side effect of age-related cognitive decline. EPA from marine sources such as fish oil can decrease cytokines associated with depression (Mercola 2012).
Silibinin extracted from the seeds of the milk thistle plant shows tremendous promise as a therapeutic agent to treat cancer, but its benefits don’t stop there. It also prevents impairment of both short-term memory and recognition memory in mice injected with a highly toxic peptide fragment called Aβ25–35, which exerts neurotoxic properties. Silibinin works as an antioxidant, protecting the hippocampus (the part of the brain associated with memory) against oxidative damage caused by this powerful neurotoxin (Lu et al. 2009).
Phosphatidylserine is a phospholipid, a class of lipids (fats) that makes up a major part of cell membranes. Synthetic phosphatidylserine was once derived from cows’ brains, but due to concerns about mad cow disease, it is now manufactured primarily from soy lecithin.
Until November 2004, the FDA held the position that phosphatidylserine showed no benefit in people with cognitive dysfunction, citing a lack of credible scientific evidence. However, on November 24, 2004, they changed their position. In a document titled “Letter Updating the Phosphatidylserine and Cognitive Function and Dementia Qualified Health Claim,” the FDA acknowledged studies demonstrating the beneficial effects of phosphatidylserine for individuals at risk of dementia and cognitive dysfunction, and admitted that there is “credible evidence” for its use.
Senilife, manufactured by Ceva Animal Health, combines phosphatidylserine with ginkgo biloba, vitamin E, pyridoxine (vitamin B6) and grape-skin extract. According to the company’s studies, Senilife improves several signs of canine cognitive dysfunction (CCD), decreasing sleeping problems, apathy and disorientation, and increasing playful behavior and response to commands. According to Ceva, dogs began showing improvement within seven days of taking Senilife (Straus 2012).
DNA methylation is an important epigenetic signaling tool for normal gene expression. SAMe (s-adenosylmethionine) is the brain’s major methyl donor and is responsible for forming a variety of compounds, including proteins, nuerotransmitters, phospholipids, glutathione, myelin, coenzyme Q-10, carnitine and creatine (Brogan 2013, Messonnier n.d.).
SAMe also improves neuron membrane fluidity and increases levels of serotonin and dopamine metabolites (Messonnier n.d.). In several human studies, reduced SAMe concentrations were detected in the brains of patients with Alzheimer’s disease, indicating that a methyl-group deficiency in the central nervous system may play a part in causing the disease (Bottiglieri 2002). Supplementation with SAMe has also been shown to effectively reduce the symptoms of depression in people—and might even be as beneficial as some prescription antidepressants.
Novifit, a SAMe supplement manufactured by Virbac Animal Health, has undergone testing in senior dogs with signs of CCD. Novifit showed favorable results beginning after just one month of testing on client-owned dogs, including a 44 percent reduction in problem behaviors, including a reduction in house soiling, after both four and eight weeks (compared to 24 percent in the placebo group); marked improvement in activity and playfulness; significant increase in awareness; and decreased sleep problems, disorientation and confusion. A separate study on laboratory dogs supplemented with Novifit showed improvement in cognitive processes, including attention and problem solving (Straus 2012).
Denosyl, manufactured by Nutramax Laboratories, is another SAMe product marketed to support liver and brain health.
SAMe works in conjunction with the methyl donors folate and vitamin B12, so supplementing with a B-complex vitamin is also advised. People with bipolar disorder, migraine headaches, Parkinson’s disease and active bleeding, as well as those on prescription antidepressants, should not take SAMe. While the contraindications in dogs are not known, similar precautions should be followed. We advise starting with a very low dose and monitoring your dog for adverse effects, which in people have been noted to include anxiety, restlessness, insomnia and mania (Messonnier n.d.).
Antioxidants also benefit the cognitive health of senior dogs. Anthocyanins, the phytochemical compounds that give berries their pigment, are a rich source of antioxidants. Anthocyanins can protect against—and even reverse—declines in cognitive function due to age-related oxidative stress (Joseph 1999, Lila 2004, Mercola 2012).
Anthocyanins are credited with enhancing memory, helping prevent age-related declines in neural function, and modulating cognitive and motor function (Lila 2004).
And here’s a reason to consider removing gluten from your senior dog’s diet: gluten sensitivity in people has been linked with impairment of brain function, including learning disabilities, attention-deficit-hyperactivity disorder (ADHD) and memory problems. Gluten sensitivity may even manifest exclusively as a neurological disease, without any gastrointestinal (GI) symptoms.
The link between gluten sensitivity and impairment of brain function makes perfect sense, according to David Perlmutter, MD, FACN, ABIHM, a board-certified neurologist and fellow of the American College of Nutrition as well as the author of Grain Brain: The Surprising Truth about Wheat, Carbs, and Sugar—Your Brain’s Silent Killers.
Perlmutter points out that the body’s antibody response to gliadin, a protein in gluten, results in elevated levels of inflammatory cytokines that are present in Alzheimer’s disease and other neurological conditions, such as Parkinson’s, multiple sclerosis and autism. The last thing your aging dog needs is a cascade of brain-related inflammation. For this and many other reasons, we advise removing gluten from your dog’s diet.
We’d also like to point out an important non-nutritional aspect of canine cognitive health: mental stimulation. Just as with humans, dogs “use it or lose it” when it comes to their cognitive ability. And, while your canine companion can’t pick up the latest New York Times crossword puzzle, he can engage in a variety of mentally challenging “dog brain games.”
Don’t for a second believe the old adage, “you can’t teach an old dog new tricks.” It’s not true! Old dogs are wonderful students, and most love to learn. There are lots of great books and articles with fun tricks you can teach your dog, which will not only help keep his brain young, but will also add a new dimension to your relationship and deepen the bond the two of you share.
Adapted from Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health (Dogwise Publishing). © 2015 by W. Jean Dodds, DVM; Diana R. Laverdure, MS. Used with permission.