Archive for the ‘medically-oriented background info’ Category

What sweetener do you use: Part 5; Fructose effects

Saturday, January 28th, 2012

A good place to start researching

I basically knew what happens when we ingest glucose, (eating it or drinking it depending on whether it's in solid or liquid form, e.g frosting versus sweetened tea) : it goes through the liver and heads off to muscle and other body parts where insulin activity is responsible for energy use. But I wanted to compare its effects to those of fructose. First I found an old article (1986 vintage) in the American Journal of Physiology (AJP), hardly a bedside reading item for me these days, but one I used to proofread for as a research fellow. That, once I translated it into English that I could understand, changed my mind a bit.

Glucose does lead to an increase in insulin levels and an increase in carbohydrate breakdown, while lipid (fat) breakdown slows down. The net result is a considerable bump in energy use. 'So far, so good,' I thought. But a comparable amount of fructose resulted in a much smaller increase of insulin, yet considerably more carb breakdown and even less fat breakdown. So even more energy was used. That I hadn't expected, but this study was a one-time experiment with seventeen healthy folk followed for a few hours.

So my next question, and I thought this one was far more important, was what happen longterm?

Let's look at animal research first. A group from Princeton published an article online in a journal called Pharmacology, Biochemistry and Behavior in February 2010. Tha basic conclusion from these scientists contradicted what I had read elsewhere, but made sense. They concluded all sweetener calories are not equal-- after feeding rats standard foods and adding either table sugar-sweetened water or HFCS-sweetened water. Even if the HFCS water was less sweet overall, the rats gained more weight. Long-term feeding experiments showed rats fed HFCS developed many of the signs of the "metabolic syndrome." weight gain, fat deposition in the belly and abnormal blood levels of trigclycerides.

So fructose was being metabolized to form fat, while glucose was being used as it normally is. That brought their thoughts back to why fructose in HFCS is different from that in table sugar. According to this research group, HFCS contains free, unbound fructose while that found in table sugar is always tied to a glucose molecule. Their concept is that table sugar fructose has to go through an additional chemical process, freeing it from glucose, before it can be used by the body.

So why should we care what makes rats fatter?

But here's our real target

I found a long article in The Journal of Clinical Investigation (JCI), the other research magazine my boss (and I) reviewed potential articles for in 1970 to 1972. Here people who who overweight or obese to begin with were fed either glucose- or fructose-containing liquids for ten weeks.

And the results were similar. Those getting fructose had more belly fat develop. I think translates to more chance of heart disease  and other long term complications.

The evidence is gradually adding up; I think HFCS is something to be avoided. Let's feed our kids and ourselves more fruits and vegetables and less processed foods.

What sweeteners do you use? Part 4: HFCS and mercury

Tuesday, January 24th, 2012

A safer place for mercury

In my last post I mentioned that fructose metabolism appears to be more complex than I learned in medical school. Of course that was in 1962-1966 and a lot has changed in medical knowledge in the forty-five plus years since then. We all know that fructose, in the form of high-fructose corn syrup (HFCS) is added to many processed foods and sweetened drinks; the question being debated is, "Is that bad for us?"

I've been reading a variety of articles from the medical literature and some popular websites on the subject and not all scientists, physicians and dietitians agree on the answer. I previously mentioned a Mayo Clinic online article that stresses the need to cut our added-sugar intake, both table sugar and HFCS, and mentions that research on HFCS isn't yet at the point to implicate it as worse for you than other added sweeteners.

There's also an article by Jennifer Goldstein from Prevention magazine that I found on the msnbc website. I'm not sure of her science background (she's now the Beauty Director for the magazine). Nonetheless, her article is reasonably well-balanced, if you read between the lines. The over-all conclusion is that anti-HFCS evidence is slim. She quotes an NYC-based nutritionist as saying the calories in HFCS and table sugar, gram for gram, are equal, but mentions several reports that have shown HFCS samples may contain mercury... in small amounts.

But you don't want it here, or in your food

Mercury is a neurotoxin, a substance which can damage the brain, especially the developing brain of a fetus or infant. Even "small amounts" are considered dangerous for babies in the womb. We have all heard of its presence in fish, but mercury in HFCS was new to me. I'm about three years behind, it appears. I found a Washington Post article from January, 2009 which mentioned two studies examining this issue.

At that time, in spite of industry denials, nearly half of HFCS samples tested contained mercury as did almost a third of processed food and beverage products. The researchers writing on this  enormously significant problem noted that HFCS had been made using chemicals produced in industrial plants clinging to an outmoded, 19th century method

A now-retired FDA scientist, Renee Dufault, headed a study in 2009 showing low levels of mercury in all the processed foods she and colleagues tested (and none in organic foods) and then had their results verified by two independent labs. She then says the FDA's head of their Food Additives section told her to quit her HFCS studies. She quit the FDA instead and published her results. A physician-headed team at the Institute for Agriculture and Trade Policy, a non-profit watchdog, repeated her studies using commercial beverages and foods. Their twenty-plus-page paper is worth reading.

By the middle of December, 2010, the HFCS industry had gotten the message. But until all HFCS made in the United States is mercury-free I'm going to avoid it.

What sweeteners do you use: Part 3. Fructose & HFCS

Friday, January 20th, 2012

It's time to dissect out the science behind sugars

I knew that sugars are found naturally in milk, fruits, vegetables and honey. MedlinePlus, from the NIH's National Library of Medicine has a brief discussion of those natural sugars. I also knew that glucose was absorbed in the small intestine and leads to the pancreas putting out insulin. It's eventually converted to energy, though some may be stored in another form in the liver and muscles until needed.

But before I get to the artificial sweeteners, I needed to read more about fructose, the other half of table sugar.  My first source, a Mayo Clinic article, didn't make it to be much of a villain, but then I started to put the whole picture together. To start with, table sugar is half glucose and half fructose. The two "simple sugars," called monosaccharides by chemists, have the same chemical formula with six carbon atoms, twelve hydrogens and six oxygens, but the way those are arranged is quite different. They each supply four Kilocalories per gram or fifteen per teaspoonful (That's technically correct, but most of us just use the term "calories.").

If you taste table sugar and call it a "one" in terms of how sweet it is, glucose is about three-fourths as sweet and fructose is nearly one and three-fourths as sweet.  Both are considerably sweeter than lactose, the kind of sugar found in milk. Fructose is also easier to dissolve in water and hangs on to water better; that's apparently how it can lengthen the shelf life of baked goods.

That's not why I think high-fructose corn syrup (HFCS) became ever-present in sodas, other sweetened beverages and processed goods. In a blog post I wrote many  months ago, I mentioned that after WWII our government wanted to find a way to use two kinds of war-time chemicals; they eventually became pesticides and fertilizers. Corn turned out to be an extremely efficient plant in turning sunlight to stored energy, so it was subsidized. Eventually that led to "monoculture, huge farms raising nothing but corn.

What's the motive: health or profit?

Like any other industry, the corn producers needed to make a profit and have their stock prices increase. That resulted in HFCS being produced and added to lots and lots of food and beverage items.

So what? A 2208 article in Science Daily gave me a clue. The way our bodies handle fructose is considerably more complex than that of glucose. The two simple sugars are separated from each other in the small bowel and glucose quickly passes through the liver on its way to all the other spots in the body where it can become energy. Fructose, according to scientists, makes the liver work harder and there's some data pointing toward its triggering the production of fat.

And we don't just get straight fructose in our diets: HFCS, according to the USDA, is about one fourth water and the rest dissolved sugars. HFCS42  (with 42% fructose) is added to many products, especially processed foods. HFCS55 (with 55% fructose) is added to soft drinks. It's roughly comparable in sweetness to table sugar; the issue is why do you need to ingest any more sugar?

There's been more research in this area and I'll cover that in my next post.

 

 

 

What Sweeteners Do You Use? Part 2

Monday, January 16th, 2012

Sugarcane grows in the tropics

In my last post I said I'd dig more fully into the background and safety record of the artificial sweeteners. Then I got diverted; one question was what kind of sugars were there before the artificial sort? I ended up at a website called Lab Cat which, in a brief verbal and visual format, described the sugars we commonly might ingest. Table sugar usually comes from either sugarcane or beets; it's a combination of two other sugars, glucose and fructose, the former found, typically in grapes and corn; the latter in honey, fruits and vegetables.

When a physician measures your blood sugar level; he or she is checking for glucose. The WebMD site has a nice discussion of blood sugar, mainly focused on those who have too much of it, namely diabetics. Another brief discussion, this one by a Harvard Medical School professor, can be found in an abcNEWS piece online. Normal fasting blood sugar levels are in the 70 to 99 milligrams per deciliter (mg/dl) range.  A deciliter is one-tenth of a liter, a little over three and a third ounces or six and two-thirds tablespoons. A liter is 1.05 quarts and a liter of water has 33.81 ounces of water. Even after eating, a non-diabetic person doesn't usually  have a blood sugar level over 135 to 140 mg/dl.

Diabetics may have considerably higher blood sugar levels, enough so their urine contains sugar. Up to levels of 180-200 mg/dl your kidneys can reabsorb sugar; above those levels a urine dipstick test will be positive (briefly immersing a plastic strip into the urine; the chemicals on the strip will cause a color change if glucose is present in the urine).

If your blood sugar is low, below the low 70 mg/dl level, either from missing meals or overdosing with insulin or oral drugs used for diabetes (there are a host of other causes), you usually will feel shaky, hungry and perhaps have other symptoms. Most of us who are otherwise healthy  are unlikely to have our blood sugar level fall to really low levels, but those can be extremely dangerous.

If you get an IV with sugar, it's really glucose under its pseudonym, dextrose. A common IV solution is D5W; that means the composition of the fluid is 5% dextrose (glucose) dissolved in water. another is D5NS, meaning the sugar is dissolved in a salt solution. That is usually given to patients who are dehydrated and need volume; the sugar, in the form of dextrose, is added to make the sterile intravenous fluid "isotonic," An isotonic solution has the same salt concentration as the normal cells of the body and the blood.(using only salt enough to approximately match what your normal blood level of sodium should be and not adding the dextrose would result in a fluid too dilute for safety).

Fructose can be added to foods, drinks, or, eventually, your waistline

When I read what I had written thus far I realized I wasn't sure anymore what exactly happens to the fructose part of table sugar, or for that matter the high-fructose corn syrup added to so many processed foods. That turns out to be more complicated than I remembered so I'll save that discussion for my next post.

 

 

 

What sweetener do you use? Part 1

Wednesday, January 11th, 2012

real sugar has some calories

I have a confession to make. On the rare occasions when I do use a sweetener, I actually use sugar or occasionally honey.

Now that doesn't happen very often; I don't have all that much of a "sweet tooth" and usually add a few Crasins to my unsweetened cereal in the morning and drink a non-coffee called Cafix (now that's a clever name; I suppose it's implying "Caffeine Fix") with a small amount of vanilla soy milk, but no sugar.

On Wednesday, January 4th of this year, The Wall Street Journal had a big spread in their "Personal Journal" section with an eye-catching title, Bracing for the Fake Sugar Rush." In the article four artificial sweeteners, Truvia, Splenda, Equal and Sweet"n Low' were compared to sugar. Prices were listed, tastes and aftertastes were compared, the sweetening agents were mentioned and the calories noted (0 for the articial sweeteners and 15 calories per teaspoon for the good old fashioned stuff).

Then I started thinking. I knew that adding 3,500 calories to my food intake theoretically would result in a weight gain of a pound. Since I enjoy math I wanted to figure out how much sugar that is. That translates into 233 and 1/3 teaspoons full or 1.167 kilograms of sugar (about two and a half pounds). So I'd have to eat two and a half pounds of sugar to, in theory, gain a pound of weight?

These three don't; but do they have any risks?

I went back to the article I just mentioned: my real reason for not using artificial sweeteners is two-fold. The WSJ admittedly "unscientific taste test" confirmed one of those; all four of the fake sugars had strange aftertastes according to their samplers: one was "Tab-like," one was compared to soap water, another termed metallic and the fourth said to leave a taste "like a copper pipe."

The other is safety; consumers often hear much later of concerns about new chemicals, whether they be sweeteners or medications. The managing director of a "brand-consulting firm" says one worry is "Did they test it on enough rats over a long enough period of time?"

Well, I've done basic lab research with rodents (three and a half years in medical school) and I'd really like to be able to say those experiments directly apply to humans, but I can't be sure that's a true statement. I did later work with dogs and when my boss (an associate professor at UCLA) was getting ready to present some of our results at an international conference, he came up with a great idea.

"Peter," he said, "when I show the slides with our data, someone in the back of the room is going to get up and ask if humans react the same way. So let's replicate our experiment in at least a few people."

Guess who was the first of those "people?" I was poked and prodded and infused with the same materials as our dogs.

In our case the data was essentially the same and when that inevitable heckler at the back of the room said his piece, my boss replied, "Let's have the first large slide."

But how much safety testing has been done with humans for these sweeteners? I'll try to find out if there are any long-term data on those of us who use non-caloric alternatives to sugar and write about that next.

 

Vindication?: part 2

Sunday, January 8th, 2012

here's a high-protein diet

In my my previous post, I talked about my own dieting program, but mentioned a very recent article in the Journal of the American Medical Association, typically called JAMA. I came across a newspaper article on this research study while reading The Wall Street Journal . Now I want to analyze  the  JAMA article. Let me give you a quick overview and then I'll tell you what bothers me about the implications.

Three groups of relatively young people (18 to 35) were fed extra calories with varying amounts  of protein while living in a special metabolic unit. They all gained weight, but those fed a low-protein diet gained less. That group increased their total body fat just like the others did, but did not gain "lean body mass" (that's anything but fat: i.e., bones, organ weight and muscles), while those on a normal protein intake and those eating more protein than usual gained not just fat, but also muscle mass. So calories count more than composition of a diet, but extra calories with too little protein leads to weight gain that's all fat (90% of those surplus calories formed fat; 10% went into the energy necessary to do so).

Okay, that's the classic comic version. Let me dissect the study and its conclusions a bit more.

This was a relatively short-term study of what happens when people overeat.  The extra calories the subjects ate were in the form of fat. It was also a small study with only twenty-five subjects who were healthy non-smokers, weren't allowed alcohol or caffeine and had stable weights to begin with. They varied from quite lean to overweight, but none of them were obese. It was a "single-blind" study, that usually translates to meaning a study in which either the investigator or the participant, but not both of them, is unaware of the nature of the treatment the participant is receiving; in this case only the kitchen staff knew who was in which diet group.

The research was exceedingly well done with careful methods, an inpatient ward for the study subjects, a preliminary period where diets were adjusted to keep their weight constant, and lots of state-of-the art measurements of how much fat and how much muscle each person had before and after the eight-week diet.

So far, so good: eating too much makes you gain weight; lots of that weight is fat. Eating more protein tends to add muscle (I can't see that their bones got heavier or the basic weight of their organs, though they likely accumulated some fat).

all vegetarian food

All that makes sense to me; now how does that apply to dieting? I think it likely does, but that's not what this study was designed to show. The question that remains is what should I eat if I want to lose weight? I just found an article in The Telegraph (a London paper I never read otherwise). The title was "Vegetarian low protein diet could be key to long life."

Unfortunately, the study was done in fruit flies. The lead author said "...similar results have been found in mice." Thus far a variety of studies in animals imply we can live longer by eating less. I'll accept that, but for now, until there are large-group human studies, I'm sticking to reasonable amounts of protein and less overall calories.

 

 

Vindication? Part 1

Thursday, January 5th, 2012

One way to get lots of protein

Since the late 1990s when I invented a diet, or perhaps I should say an eating pattern, I've relied on one principal concept: Eat Less; Do More. I came upon this simple idea after listening to a group of medical professionals who were discussing which diet they should go on while they were simultaneously consuming huge portions at our hospital cafeteria.

One of them, I recalled, had tried a high-carb, low-protein diet the past year; losing nearly twenty pounds, then regained it all and more in a few months. Now she was going to attempt  to lose twenty-five pounds with a different approach, this one with an emphasis on protein. I had seen weight-loss plans come and go and didn't believe any of them were the answer, at least not for everyone. I remember coming home and saying to my wife, "Lynn, I've invented a new diet"

I explained it was simply, "Never finish anything; No snacks between (meals); Nothing after eight." I added, "Get lots of exercise."

I lost the seven pounds I had gained on a two-week vacation and didn't need my strategy again until early in 2009. Then I weighed 177 one morning, up three pounds from my normal weight since 1991. I attributed that to eating out four times in the prior week. But when I tried on a pair of good suit slacks, I realized the weight hadn't changed much, but the distribution sure had.

I went back to my eating plan, lost five pounds easily, then coasted a while before resuming the diet. Lynn bought me a digital scale and I weighed myself daily. I also started going to our gym six days a week. Eventually I shed thirty pounds and five inches off my waistline. At 147 pounds I was twenty-five under my usual high school weight. This morning, nearly two years later, I weighed 148.

I allow myself a three-pound zone of weight fluctuation, thinking that would account for fluid shifts and the occasional big splurge. Whenever I exceed 150 pounds I go back on my plan.

Then I read a Wall Street Journal article titled "New Ways Calories Can Add Up to Weight Gain: Study Challenges Idea That Varying Amounts Of Fat, Protein and Carbohydrates Are Key to Weight Loss." It quoted the Journal of the American Medical Association, AKA: JAMA. I went online and found the JAMA article and an accompanying editorial.

I read both pieces in detail, even finding a wild typo, "...their diets were returned to baseline energy levels and diet compositions (15% from protein, 35% from fat and 60% from carbohydrate)." I called the AMA and suggested they correct the numbers since they added to 110%.

Is a high-carb, low-protein diet safer?

But the basic premise of the study's data intrigued me. It's something I've believed for years, calories count, as opposed to what form those calories come in. But there's one extra facet: low-protein diets can be dangerous.

I'll analyze that in detail in my next post.

 

 

Meth Madness: Part 2

Sunday, January 1st, 2012

Users of both genders and all ages abuse this drug

I want to be perfectly clear: methamphetamine use is a terrible plague in our society.  Although overall numbers are down over the past decade, we're still talking about a million plus people in the United States, many of whom are young and heterosexual. But, of course, that's not the only population group with members who abuse the drug; The CDC factsheet on its risk for HIV/AIDS stresses it can contribute to sexual risk behaviors, regardless of the sexual orientation of the user. I spoke recently to a long-term friend who is gay.  I asked him about its use in the gay community and he replied, "Everyone I ever knew about who used meth is dead."

There's a brain chemical called dopamine that affects how we experience pleasurable activities. Lab experiments show this highly addictive and illegal drug can lead to considerably greater dopamine being released than either eating or having sex.

A user experiences a high, a "rush" much more intense than from any normal activity. But there's a problem; it doesn't last more than eight to 24 hours. And it's not as intense in succeeding uses. So that leads to a pattern of addiction, the need for not only repeated  drug use, but more and more of the substance.

Chronic, repeated meth exposure, whether by oral ingestion, 'snorting", smoking or injection, clearly leads to damage in the brain, the teeth and the skin.

An online review by the  National Institute on Drug Abuse, part of the National Institutes of Health, says imaging studies (e.g., MRIs) done on meth addicts show alterations in parts of the brain involved in motor skills, verbal learning, emotion and memory.

I went back to the PBS special, "How Meth Destroys the Body" and was stuck by the graphic photos of "meth mouth." A common sign of abuse of this drug is severe tooth decay. The cause is uncertain, but meth does lead to shrinkage of a user's blood vessels and the mouth requires an adequate blood supply to stay healthy. The addicts often binge on high-sugar foods and drinks; their mouths lack sufficient saliva to maintain optimal healthy oral tissue and, on a high, meth users often grind their teeth and, of course, forget to brush or floss.

Between the tooth decay, the increased physical activity frequently experienced and the failure to eat adequately, meth users lose weight and look older.

the model of meth's structure looks benign; it's not, though!

They also lose interest in any activities other than those related to obtaining and snorting or injecting the drug. Men may become impotent; women may lose their interest in sex.

So why don't we require simply prescriptions for the cold and allergy pills that contain psudoephedrine, the chemical I mentioned in my last post that is used in the production of methamphetamine? I read an article in the 20 December 2011 edition of the Annals of Internal Medicine which told of the widespread abuse of controlled substances in the United States. It wasn't describing illegal drugs, just ones that normally do require a doctor's prescription. Many of these can now be purchased on the Internet.

That series of photos of meth users mouths and "before" and "after" photos of addicts may be one place to start.

 

 

 

 

 

Meth Madness: Part 1

Wednesday, December 28th, 2011

Some people just pop pills

Recently our local paper, the Fort Collins Coloradoan, published a USA Today article titled "Missouri grapples with meth." I read about the nearly 7,000 law-enforcement seizures of laboratories and methamphetamine-related material in 2011 (through late November), saw that Colorado wasn't in the top ten states involved (at least in methamphetamine lab seizures) and wondered why Missouri, with 1,744 confiscations, was clearly the hot spot for this drug

A contentious issue is whether state law requires a  doctor's prescriptions for over-the-counter medications containing pseudoephedrine, a chemical also used for meth production. That's not true in Missouri where, at present the rules vary from county to county. Oregon and Mississippi have already passed such laws with impressive declines in meth seizures as a result. Fifteen other states have proposed similar legislation.

Then I found a series of articles that brought this issue squarely home to my state. In April 2011  the Denver Post published  two articles about proposed Colorado legislation that, if passed by the state Senate, would have made a number of pseudoephedrine-containing medications, used to treat the symptoms of colds and allergies, available only by prescription; eventually the potential new law went down to defeat by a 7 to 2 vote.

Yet the Colorado Meth Project, part of a much larger, multi-state prevention program whose focus is reducing the usage of this drug, said my home state ranked 7th in the U.S. in total number of "past-year meth users" aged 12 and up in a national survey on drug use during the 2006 to 2009 time frame. Did the "12 and up" catch your attention? This campaign, named the world's 3rd most effective charitable endeavour by a national magazine, was started in 2005 and works in three arenas: public service messages, public policy and community outreach.

It's been given credit for marked reduction of methamphetamine use in a number of states. As part of an ongoing CDC surveillance system, monitoring six types of health-risk behaviors that contribute to the leading causes of death and disability among youth and adults, the 2010 Youth Risk Behavior Survey saw a highly significant decline of teen meth use: 52% in Idaho, 63% in Montana and 65% in Arizona.

But we're not just speaking about teens. In late November of 2011, a 68-year-old former Colorado county sheriff was arrested; he allegedly was trading meth for gay sex. If proven guilty, he clearly wasn't alone in his drug-related activities.

Others inject their drug of choice

So returning to the question of why is this particular illegal substance so important? It's a highly addictive stimulant responsible for risky sexual behavior and extreme violence. The Centers for Disease Control and Prevention (CDC), published an extensive  2007 review on methamphetamine use and the risk for HIV/Aids. After discussing research indicating that meth-using gay men may increase their risk factors, they mentioned that heterosexual adults and adolescents who use meth may also engage in sexual practices that markedly increase their possibility of developing STDs including HIV.

That's by no means all that methamphetamine does to its users, but I'll write more concerning the chemistry and effects of the drug in my next post.

 

 

 

 

 

It goes far beyond football, boxing and hockey

Wednesday, December 7th, 2011

The brain is vulnerable to trauma

I feel like I've opened the proverbial can of worms, finding, in this case, a topic that keeps expanding. I started with reading an article in The New York Times about the death of a professional hockey player, but I quickly delved into the medical literature.

I've spent much of the day reading article after article on traumatic brain injury  (TBI), which can be mild or severe, and another entity called chronic traumatic encephalopathy or CTE, one that's frequently been in the news over the last two years. Let's start with TBI. I'll be writing about teens and younger kids. I'll deal with CTE in another post focused on adults.

A Center for Disease Control and Prevention (CDC)  report in the most recent edition of the Journal of the American Medical Association reviewed nonfatal TBI related to either sports or recreational activities in kids age 19  or younger. The numbers involved were staggering, nearly 175,000 per year being seen in Emergency Departments (EDs).

A large majority of those sports and recreation-related TBI ED visits were by boys and the annual total of those ED trips increased markedly during that nine-year time frame. They were injured biking, playing football, soccer, basketball or while engaging in miscellaneous playground activities. They went to the ED in smaller numbers for injuries suffered in many other activities, including horseback riding, ice skating, ATV riding, tobogganing and even golfing (here the injuries included those related to golf carts). Surprisingly, skateboarding accounted for only a fourth of the ED visits for biking and football accidents and TBI was less frequently seen.

A helmet is a good start

As my wife and I drive around town, we often see college students riding their bikes at night while helmet-less and light-less. I fear for their brains.

There's another, less well-accepted entity, so-called "Second Impact Syndrome." I read an article about this in a February 2009 article by two authors on the faculty of the University of California, Irvine School of Medicine. In this scenario athletes who've had a TBI then have a second brain injury when they go back to playing their sport far too quickly. The initial injury may have been relatively mild; the recurrent trauma may kill them in a matter of minutes.

Another review of this  syndrome said 94 catastrophic head injuries had been reported in American high school and college football players in a 13-year time frame, 92 in high schoolers.  Seven of ten had a prior concussion in the same football season; over a third played with continuing symptoms.

This speaks to the crucial question of when an athlete (or a bike or horseback rider) who has suffered TBI should return to their sport/activity. Last night I called a younger friend who had been bucked off his spooked mare and suffered a concussion eight days ago. He was still having headaches and agreed with me that it was far too soon to get back on his horse.

A new CDC program called Heads Up offers TBI guidelines for coaches, parents and physicians.