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Fact: Rats consume approximately 5 g per 100 g of body weight in food per day.  In general, the rat will consume food to meet its energy requirements.  Temperature, age, and activity influence their energy requirements.

Fact: Higher Vitamin A concentrations are needed under conditions of stress (e.g. surgical recovery).

Fact: Male rats rare more susceptible than female rats to develop EFA (essential fatty acid) deficiency signs. 

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Spinach and apples and the brain

In the first study, co-authored by USF's M. Claire Cartford, PhD, older rats fed a diet rich in spinach for six weeks showed a reversal in the normal loss of learning that occurs with age. The rats that ate rat chow containing 2 percent freeze-dried spinach learned to associate the sound of a bell tone with a subsequent puff of air faster than those fed regular rat chow, the study found.

The test measured how quickly the rats learned to blink, after hearing the tone, in anticipation of the oncoming puff of air — a conditioned response shown to slow with age in rodents and humans.

Spinach is rich in antioxidants, which scientists say can counteract free radicals generated in the body during normal metabolism and exposure to environmental insults such as pollution, ultraviolet light and radiation. An excess of free radicals can damage cellular lipids, protein and DNA. Studies suggest that a lifelong accumulation of free radicals can slow mental processes in old age and may be a factor in Alzheimer's and Parkinson's diseases, Dr. Bickford said.

The second study, co-authored by Carmelina Gemma, PhD, of USF and James A. Haley VA Hospital, found that the benefit of a diet high in fruits and vegetables depends on the levels of antioxidant nutrients in the fruits and vegetables. Furthermore, the researchers suggest, the protective effect of antioxidants may be linked to their ability to reverse age-related accumulations of potentially harmful inflammatory substances in the brain.

The USF researchers compared three groups of older rats. One group ate a diet supplemented by spirulina, a blue-green algae high in antioxidant activity. The second group was fed a daily ration of apple, a food moderate in antioxidant activity, with their rat chow. The third group ate a cucumber-enriched diet, low in antioxidant activity.

Aged rats fed either spirulina-or apple-enriched diets for two weeks demonstrated improved neuron function, a suppression of inflammatory substances in the brain, and a decrease in malondialdehyde (MDA), a marker for oxidative damage. In fact, spirulina reversed the impairment in adrenergic neural function normally associated with aging. There was no improvement in rats fed a diet supplemented with cucumber.

"Not all foods are created equal," Dr. Bickford said. "Cucumbers taste good and have lots of fiber. But unlike spirulina and apples, they are not rich in phytochemicals that have antioxidant or anti-inflammatory effects in the brain."

The research has hopeful implications for the prevention of neurodegenerative disorders in an increasingly aging population, but still must be tested in humans, Dr. Bickford said.

Until then, the USF neuroscientist recommends that daily diets include a variety of richly colored fruits and vegetables — the most colorful ones tend to pack the greatest antioxidant punch. She favors spinach salads for lunch and routinely snacks on blueberries and strawberries.

"Studies like these are lending scientific credibility to what nutritionists, and our mothers, have been telling us for years," Dr. Bickford said. "Eat your fruits and vegetables. They're good for you!"

Researchers at the University of Colorado Health Sciences Center and Denver Veterans Affairs Medical Center contributed to the study on diets enriched with spirulina, apples and cucumbers.

M. Claire Cartford¹, Carmelina Gemma², and Paula C. Bickford³; ¹ Center for Aging and Brain Repair, Department of Neurosurgery, University of South Florida College of Medicine, Tampa, Florida 33612, and ² James A. Haley Veterans Medical Center, Tampa, Florida 33612

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Can Blueberries Combat Aging?

WASHINGTON--A recent Tufts University study published in the Sept. issue of The Journal of Neuroscience found that elderly rats fed the human equivalent of half a cup of blueberries, daily, had improved coordination, short-term memory and balance.

The rats were 19 months old--the human equivalent would be 65 to 70 years old. In rats, the loss of motor skills becomes apparent around 12 months. By 19 months, rats begin to lose the ability to balance, or to stay balanced. The average rat could stay balanced on a narrow rod for 13 seconds at the age of 12 months; at 19 months, that drops to 5 seconds. Nineteen-month old rats that consumed the blueberry extract could stay balanced for an average of 11 seconds.
Blueberries contain antioxidants, which, scientists believe, protect the body against oxidative stress and free radicals and help the body combat the aging process. Free radicals are responsible for destroying cell membranes and DNA, which weaken cells and result in cell deaths. The presence of too much oxidative stress or too many free radicals directly relates to weak bodies and the acceleration of the aging process. Strawberries and spinach also rated high on the antioxidant scale. The study's authors reported that spinach and strawberry extracts produced some improvements in memory, but only blueberry extract had any positive effect on balance and coordination.

Previous Tufts studies demonstrated that antioxidant supplementation in young rats slowed free radical damage, but this current study was the first to demonstrate a direct link between antioxidants and the reversal of age-related decline, according to the scientists. Further clinical trials to investigate the significance for humans must be undertaken, but scientists speculated that the antioxidants worked by improving the integrity of the cell membranes, making it easier for important nutrients and chemicals to pass through.

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Veggies May Improve Bone Density

LONDON--A research conducted at the University of Bern in Switzerland reports that onions and other vegetables may help reduce osteoporosis, or brittle bone disease. Large amounts of dried onions and other vegetables were fed to lab rats and helped increase their bone density. One gram of dried onion fed to male rats everyday for four weeks increased bone density by 3.1 percent, compared to rats not on the diet. It was also helpful in female rats. Scientists also administered a mixture of 500 mg each of onion and Italian parsley and a combination of lettuce, tomato, cucumber, arugala, onion, garlic, wild garlic, common parsley, Italian parsley and dill. It was found to significantly inhibit bone re-absorption. Researchers Roman Muhlbauer and Feng Li are not exactly sure of the substance within the vegetables that promotes this increase in density, but are hoping to isolate it and eventually have a purified extract and then a pill.

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In Rats, Raspberries Protect Against Throat Cancer (Cancer Research 2001;61:6112-6119)

Black raspberries may contain compounds that prevent cancer and keep precancerous growths from becoming malignant, preliminary study findings suggest.

According to the report in a recent issue of Cancer Research, rats injected with a cancer-causing compound were less likely to develop cancer of the esophagus when black raspberries comprised 5% to 10% of their daily diet. The findings add to a growing body of evidence linking berries with lower cancer risk.

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For more information on Rattie Express or any of our animals, please email me (Tara) at rattie.express@comcast.net.