Update: October 24, 2007

BETTER FOOD and ADDICTION

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

We’ve got a wide variety of scientific news for you today.  We’ll start with a couple of stories about foodstuffs that are near and dear to the hearts of most islanders.

The first story is about manioc (Manihot esculenta).  This never really became a staple on Guam and in the Marianas and it’s a good thing too.  Manioc (which goes by an astounding number of names like cassava, tapioca and yucca) is probably the least nutritious of the starchy foods and has caused widespread problems in places where it replaced more traditional and nutritious starches like taro.  Not only is starch virtually manioc’s only claim for nutrition, the starch manioc contains is amylose, which is remarkably hard to digest.  Manioc is easier to grow than other starches but worse for your health.

Manioc roots at a roadside stand.

In a new study, plant scientists have identified a variety of cassava with less than 3 percent amylose, compared to 18-24 percent of the hard-to-digest material in traditional manioc.  The natural mutation the manioc plant drastically reduces the amylose content in root starch and may also make the mutated manioc better suited for the production of bioethanol.

Although manioc grows here in the Marianas (the plant looks remarkably like marijuana), it certainly isn’t the starch of choice in these islands.  That honor belongs to rice and though we no longer grow our own rice here in any quantities, this Asian food staple has its own ecological problems. 

Rice (Oryza sativa) is a notorious water guzzler when compared to other crops.  It typically uses up to three times more water than other food crops such as maize or wheat and consumes around 30 percent of the fresh water used for crops worldwide.

Now, an international team of scientists has produced a new type of rice that grows better and uses water more efficiently than other rice crops.  They have isolated a gene known as HARDY that improves key features of this important grain crop.  The research shows that the HARDY gene contributes to more efficient water use in rice, a primary source of food for more than half of the world's population.

HARDY rice shows a significant increase in biomass under both drought and non-drought conditions.  The researchers found that the biomass of HARDY rice increased by around 50 percent under conditions of water deprivation (drought) compared to the unmodified version of the same type of rice.
Since we live in the part of the world where rice is the primary source of food, this is excellent news.  I’d personally rather drink the water than give it to the rice!!

SEEING IN COLOR
Several months ago, I talked about color vision in this column.  Or more specifically night vision.  I said that human eyes contain the cells that let us see both in black and white (rods) and color (cones).  Since most animals are nocturnal or diurnal, they tend to have one set or the other and humans and other apes are unusual in having both sets.  This is usually explained by the fact that we evolved from nocturnal ancestors into (mostly) day living creatures.  This hypothesis is borne out by the fact that our cone cells cluster in the center of our retinas while the rods have been pushed to the periphery.

There is a lot of research interest in the evolution of color vision, and a group of scientists turned to a kind of lemur called the aye-aye to help them puzzle out some of the answers.  Lemurs split from other primate groups including humans, apes, and monkeys more than sixty million years ago, and are thought to be in some ways representative of the early primates that lived at that time.  George Perry, one of the researchers said, "We chose the aye-aye specifically because it is fully nocturnal, and so, it raises an obvious and straightforward question: If you are an animal that lives at night, do you need color vision?"

In a simple case of 'use it or lose it,' the prevailing theory suggests that since nocturnal primates don’t use color vision to see, the genes they have for color vision would accumulate mutations and degrade over evolutionary time. From a practical standpoint, studying color vision in the aye-aye proved to be a daunting endeavor.  Since the aye-aye is an endangered species, obtaining DNA samples in the wild was not possible. The group turned to a few rare international research institutions and colleagues that have aye-ayes to obtain DNA samples for their study. What they discovered astounded them.  The genes for color vision were not only not degrading, in the gene that codes for the ability to see the color green, there wasn’t a single mutation.  In their next research phase, the scientists plan to collaborate with others to perform behavioral studies to see if aye-ayes respond to colors.

The aye-aye the world's largest nocturnal primate and certainly one of the most unusual. (Credit: Duke University)

The study has not only proved important to understanding color vision evolution, but also has shown the value of examining the dazzling diversity of life, especially in endangered species.  Perry said, "We not only need to focus on organisms that are related to us and are common, but also organisms that are uncommon and endangered, for there may be behaviors and physical features that, once they are lost, we may never understand." 

Amen, brother, amen.

HANG UP QUICK!
Although none of us want to be hospitalized, it does happen, and researchers in the Netherlands have come up with one more little hazard you might encounter at GMH besides superbugs and the notorious hospital food.  Making that important cell phone call from your hospital bed could kill you.

Dutch researchers examined the effects of cell phone signals on critical care equipment like ventilators and pacemakers.  Almost 50 incidents were recorded and 75% of them were significant or hazardous.  Hazardous incidents varied from a total switch off and restart of mechanical ventilators (Said into cell phone: Why is Granny choking and waving her arms?); complete stops without alarms in syringe pumps; to incorrect pulsing by an external pacemaker.

While first generation mobile phones are used mainly for voice transmission, second and third generation phones enable Internet access, sending and receiving data.  Unfortunately they entered the market with little testing regarding their safe use in the medical environment.

The researchers recommend that cell phones should come absolutely no closer than three feet to hospital beds and equipment.  They also discovered that electromagnetic interference from second and third generation mobile phones occurred at distances of over ten feet.

So think twice before you make that cell phone call from your hospital room or anybody else’s hospital room.  Better to be safe than dead!!

DON’T MAKE ME COME IN THERE!
Have your kids been bad lately?  Are they bouncing off the walls?  Have you decided that if you could just plug them into the wall, you could thumb your nose at GPA?

Well, a new study by researchers in England has shown evidence of increased levels of hyperactivity (read “bouncing off the walls”) in young children that consumed some artificial food colors and the preservative sodium benzoate.

The possibility of food colors and preservatives affecting children's behavior has long been an unresolved question for parents.  This significant new research provides a clear demonstration that changes in behavior can be detected in three-year-old and eight-year-old children after they eat these food additives.

The children's families were asked to put them on a diet free from the additives used in the study.  Over a six-week period the children were then given a drink each day which either contained one of two mixtures of food colors and benzoate preservative, or just fruit juice - with all the drinks looking and tasting identical.

Hyperactivity is defined as a behavior indicated by increased movement, impulsivity and inattention (Did I not say “bouncing off the walls?).  The results of the study show that children given the drinks containing the food coloring and sodium benzoate had behavior that was significantly more hyperactive.

The research team used a combination of reports on the children's behavior from teachers and parents, together with recordings of the children's behavior in the classroom made by an observer, and, for the older children, a computer-based test of attention.  None of the participants - teachers, parents, the observer, or the children - knew which drink each child was taking at any one time.

So . . . maybe if you’re tired of screaming “Stop hitting your sister!” and “Sit STILL!!” you just might want to read the label of that pack of cookies, or that can of Coke or that bag of chips.  What you find may change your eating habits and your children’s behavior!!

CURBING ADDICTIONS
University of Minnesota researchers have discovered that a common amino acid, available as a health food supplement, may help curb pathological gamblers' addiction.  In a recent eight-week trial, 27 people were given increasing doses of an amino acid, which has an impact on the chemical glutamate -- often associated with reward in the brain.  At the end of the trial, 60 percent of the participants reported fewer urges to gamble.

"It looks very promising," said Jon Grant, J.D., M.D., a University of Minnesota associate professor of psychiatry and principal investigator of the study. "We were able to reduce people's urges to gamble."
Because subjects knew they were taking a supplement during the first phase of the study and since there was a relatively small number of subjects in the double-blind portion, a larger study is warranted to confirm the validity of these findings.

So . . . who knew that what you eat can make you gamble??

TO CHOCOLATE?
And in our final item, researchers have discovered that although most of us SAY we’re addicted to chocolate (and I am numbered among the ranks), we really aren’t.

Evidence and logic find little support for the ‘chocoholic’ hypothesis.  Substances present in chocolate which have been singled out as potentially addictive include serotonin, tryptophan, phenylethylamine, tyramine and cannabinoids.  However, most of these compounds exist in higher concentrations in other foods with less appeal than chocolate.

A further observation is that the most widely preferred chocolate is milk chocolate and chocolate-covered confectionery.  These contain a lower amount of cocoa solids, and therefore a lower concentration of potentially psychoactive compounds, than 'dark' chocolate, which is not so widely craved.

It is therefore far more plausible to suggest that a liking for chocolate, and its effects on mood, are due mainly to its principal constituents, sugar and fat, and their related sensory and nutritional effects.
I still have the cravings though!!