January 19, 2005
Old Beagles Learn Better If Given Fruits, Vegetables, Vitamins, Exercise

Dogs are like humans in yet another way. Elderly dogs demonstrate better cognitive performance if given higher antioxidant diets and more stimulating environments.

During the two-year longitudinal study, William Milgram, Ph.D., of the University of Toronto, Elizabeth Head, Ph.D., and Carl Cotman, Ph.D., of the University of California, Irvine and their colleagues found older beagles performed better on cognitive tests and were more likely to learn new tasks when they were fed a diet fortified with plenty of fruits, vegetables and vitamins, were exercised at least twice weekly, and were given the opportunity to play with other dogs and a variety of stimulating toys. The study is reported in the January 2005 Neurobiology of Aging.

Citrus pulp mixed in with dog food? I wonder if they had problems getting the dogs to eat it.

For the study, the researchers divided 48 older beagles (ages 7 to 11) into four groups. One group was fed a regular diet and received standard care; a second group received standard care but was fed an antioxidant fortified diet, consisting of standard dog food supplemented with tomatoes, carrot granules, citrus pulp, spinach flakes, the equivalent of 800 IUs of vitamin E, 20 milligrams per kilogram of vitamin C, and two mitochondrial co-factors--lipoic acid and carnitine; the third was fed a regular diet, but their environment was enriched (regular exercise, socialization with other dogs, and access to novel toys); the fourth group received a combination of the antioxidant diet as well as environmental enrichment. In addition, a set of 17 young dogs (ages 1 to 3) were divided into two groups, one fed a regular diet and the other fed the antioxidant fortified diet.

I am skeptical that the vitamin E was a big benefit. Too much of a single antioxidant can actually dampen down metabolism by quenching too many free radicals. Not all free radicals are purely detrimental. The body uses free radical molecules for intracellular and intercellular signalling. Dampen down those signals too much and the net result can be harmful. I'd like to see this experiment repeated with more fruits and vegetables and no vitamins. I bet well chosen fruits and vegetables such as blueberry, spinach, kale, and perhaps even some nuts could provide as antioxidant punch as this study's mixture that included vitamins.

The fruits and vegetables added to the antioxidant fortified diet was the equivalent of increasing intake from 3 servings to 5 or 6 servings daily. Previous research suggests that antioxidants might reduce free radical damage to neurons in the brain, which scientists believe is involved in age-associated learning and memory problems. Mitochondrial co-factors may help neurons function more efficiently, slash free radical production and lead to improvements in brain function. Other studies suggest that stimulating environments improve learning ability, induce beneficial changes in cellular structure, may help the brain grow new neurons, and increase the resistance of neurons to injury.

I've had Australian Shepherds turn up their noses at me when I offered them various fruits - and this in spite of their begging when they saw me eating out of a human food bowl. But perhaps mixed in with much tastier foods (like some blood poured out of a red meat package) dogs could be persuaded to eat their fruits. Though getting them to eat tomato sauce is not hard when it is mixed with pasta and some oil. the right

The combination of better environment and better diet had the most powerful effect.

Overall, older dogs in the combined intervention group did the best on these learning tasks, outperforming dogs in the control group (standard diet, standard care) as well as those that received either the antioxidant diet or environmental enrichment. However, older beagles that received at least one of these interventions also did better than the control group. For instance, all 12 of the older beagles in the combined intervention group were able to solve the reversal learning problem. In comparison, 8 of the 12 dogs that ate the antioxidant diet without environmental enrichment and 8 of the 10 that received environmental enrichment without the antioxidant diet solved the problem. Only two of the eight older dogs in the control group were able to do this task. Dietary intervention in the younger canines had no effect.

Similar dietary changes for older humans would probably provide a similar cognitive benefit.

Also see my previous posts "Concord Grape Juice Improves Memory Of Aged Rats" and "Choline May Restore Middle Aged Memory Formation".

Share |      Randall Parker, 2005 January 19 02:47 AM  Brain Enhancement

Anonymous Coward said at January 19, 2005 6:08 AM:

"Citrus pulp mixed in with dog food? I wonder if they had problems getting the dogs to eat it."

I knew a couple of beagles over the years, and they weren't fussy eaters. Beagles seem to be one of the breeds that will happily eat most kinds of food and as much of it as you pile in front of them. That might be why they were chosen for the experiment.

Invisible Scientist said at January 19, 2005 9:54 AM:

One great book about all the mind enhancing foods and food supplements, is
"Mind Boosters" by Dr. Ray Sahelian. But one must be careful with the fish oil tablets
mentioned in the book, because fish oil might be contaminated with mercury and other toxic
materials, despite molecular distillation to purify the oil that contains memory enhancing
Omega acids.

However, it is written in some articles that antioxidants, such as Vitamin E, actually
weaken the immune system of older people, thereby shortening their life expectancy to some

Dick Thompson said at January 19, 2005 1:12 PM:

I am 71 and active and still cognitively alert. Until recently I had been taking 800 units of E. Then I read the recent longitudinal study where people who took 400 Units of E died sooner than those who took none, and those who took 800 Units died sooner than those who took 400. Damned if you do and damned if you don't. I dumped my E; better to be alive and dumb, than dead.

Invisible Scientist said at January 20, 2005 4:56 AM:

I have also read that article about Vitamin E, but instead of stopping taking Vitamin E
altogether, I still take some, but less frequently. For instance, the multivitamin and multimineral
tablets have very small amounts of all the required minimum amounts for all vitamins, including
Vitamin E, much less than the 400 IU of E.

I strongly recommend reading the book of Dr Ray Sahelian: "Mind Boosters". Taking small
amounts of all the ingredients in the book, such as alpha-lipoic acid, carnitine, and many
other anti-oxidants will all help memory and mental functioning. The key is to take small
amounts of many of these.

I am also allergic to artificial sweeteners like aspartame found in various products such as
chewing gum ( this makes me stupid! ) Also monosodium glutamate almost certainly seems to make
me stupid and it is causing headaches. It is a VERY good idea to avoid these artificial
flavorings and also preservatives. They seem to cause cumulative damage, which starts to
become more significant after one gets older than 40.

Ellen K said at January 20, 2005 10:28 PM:

My dog liked all kinds of fruits and vegetables. She particularly liked apples and carrots. The only ones she would not eat were cucumber and bananas.

Richard said at January 25, 2005 6:07 AM:

According to Ray Kurzweil, the guy who is going to help me live forever, just taking vitamin E in the form of alpha-tocopherol is what the study is saying brings about the possibility of premature death. He recommends that people do not take just alpha tocopherol, but take a vitamin E blend that includes all the tocopherols including gamma tocopherol. To read his take on this go to: http://fantastic-voyage.net/ReaderQandA.htm and scroll down.

Randall Parker said at January 25, 2005 11:31 AM:


Free radicals are used for inter-cellular and intra-cellular signalling. Pour on too much of an antioxidant and you can quench those radicals and prevent needed signalling. Denman Harman, who originally proposed the free radical theory of aging in the mid 1950s, argued years ago in an interview I read of him that you can take too much antioxidants and prevent needed chemical reactions from occurring in your body.

I do not see how switching to blends of tocopherols sidesteps that problem.

The irony here is that after decades of researchers searching for benefits from taking antioxidant vitamins the one vitamin that looks like it could provide us the most benefit is vitamin D and its mechanisms of benefit are probably unrelated to quenching of free radicals.

Richard said at January 25, 2005 6:07 PM:


Let me be honest. I enjoy your blog no end, but I really understand none of the science. As a market gardener, I hope I get enough vitamin D, but will continue to have my two glasses of vin rouge with dinner just in case. I am going to keep off the vitamin E as that appears to be the concensus here.


Samantha said at December 21, 2006 3:33 PM:

My puppy beagle who is only about 5-6 months old will eat anything and i mean anything!!!! My dad was eating a apple one day and Herbie (my dog) was practically on top of my dad trying to get to it. So my dad gave him some of the apple, well it ended up being the rest of the apple. And now were trying carrots. He seems to like it. Its also good because of the iron and he can play with it as well. He is just funny

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