STC® / Food Chemistry

LESSON 15

LabelTest ResultsNutrient

Record Sheet 15-A

Carbohydrates

Fats

Proteins

Comparing Test Results and Food Labels Table

Comparing Test Results and Food Labels

Food:

List the food’s ingredients:

Name:

Date:

STC® / Food Chemistry138 / Examining Labels: Making the Connection

LESSON 15

Think back to the days of tall sailing ships.Did you know one of the greatest dangers asailor faced was getting sick from a diseasecalled scurvy? It’s true. Of course, warshipsand pirates were dangerous too. Even so,scurvy was one of a sailor’s worst enemies. Itcould make a sailor’s gums bleed, give himlarge black sores on his body, and make himextremely weak. Many men died from scurvy.

Lind decided to collect more informationabout scurvy. He learned that Frenchexplorers in North America had oncerecovered from scurvy by drinking a broth ofpine needles given to them by IroquoisIndians. He also heard about some Dutchsailors traveling on a boat full of citrus fruit.The Dutchmen came down with scurvy butquickly recovered after eating some of theircargo. Lind decided to conduct some diet-related tests.

A Surprising CureThe doctor selected twelve sailors sick with

scurvy and supplemented their diets. Everyday, two were given apple cider; two weregiven spoonfuls of vinegar; two were givengarlic and mustard herbs; two were given saltwater; two were given sulfuric acid andalcohol with ginger and cinnamon; and twowere given oranges and lemons.

The two sailors who ate the citrus fruitrecovered quickly. They were even healthyenough to return to work within a few days.Lind decided he was onto something. Hesuggested that the British Navy begin givingits sailors a daily dose of lemon juice.

But the British Navy was not convinced thatLind’s experiment proved anything. After all,how could fruit juice prevent a serious diseaselike scurvy? Naval officials just chalked up thesailors’ recovery to coincidence and didnothing about Lind’s suggestions.

Several years later, during Pacific voyages inthe 1770s, the famous British explorerJames Cook decided to put Lind’s theory tothe test. During a long voyage, he stockedenough lemon juice to give each crewmember a daily ration. It worked. Only onecrew member developed scurvy duringCook’s exploration.

Reading Selections: Vitamins

Vitamin C: Scurvy No More

In the mid 1700s, a Scottish doctor namedJames Lind became interested in scurvywhen he sailed with a British warship calledthe Salisbury. After three months ofpatrolling the southern coast of England,several crew members died of scurvy. Allwere sailors. None were officers.

Lind suspected that the cause of scurvy wasrelated to food or to the crowded, dark,damp conditions on the ship. Lind observedthat the officers ate meat, dried vegetables,and fruits. The crew ate salted meat, driedbiscuits, butter, and small amounts of driedbeans. He also observed that sailors sleptunder extremely crowded conditions in thelower decks of the ship.

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LESSON 15

But the Navy refused to change its policies.It was another twenty years before most ofthe ships carried limes or lime juice, whichall sailors were required to consume. Andthat is how British sailors came to be knownas “Limeys.”

What Causes Scurvy?So, citrus fruits cured the disease. But

what caused it? The mystery remainedunsolved until Casimir Funk, a Polishscientist, began to unravel it in the early1900s. He was researching a disease calledberiberi when he discovered that somesubstances within fruits, vegetables, and milkare essential to human health. He namedthose substances “vitamins.”

Then, around 1925, a Hungarian scientistnamed Albert Szent-Gyorgyi isolated acertain type of acid in citrus fruit, and in1932, a scientist named Charles G. King(along with students at the University ofPittsburgh) analyzed this acid. After runningsome tests, King and his students realizedthat the acid was the elusive substance thatprevents scurvy. They called the substanceascorbic acid.

We call it vitamin C.

STC® / Food Chemistry140 / Examining Labels: Making the Connection

LESSON 15

For many centuries, people have toldstories about how certain foods can heal thesick. Some stories have turned out to be “talltales.” Others are grounded in fact. One ofthe more interesting of these tales led to thediscovery of vitamin A.

Then, in 1912 or so, scientists around theworld doing food-related experiments foundand isolated this useful stuff and named itvitamin A. People who wanted to maintaingood eyesight started taking a spoonful ofcod liver oil each day to get their vitamin A.

Three Blind Rats?Several years later, some scientists

were experimenting with laboratoryrats that had vitamin A deficiencies.When the rats ate spinach, theirvitamin A deficiencies disappeared.Scientists were puzzled by theseresults, because they knew thatspinach does not contain vitamin A.After doing more experiments, theydiscovered that a substance calledcarotene was involved. Carotene is asubstance that we read and hear a lotabout these days.

Carotene is found in leafy greenvegetables (like spinach) and yellowishvegetables (like squash and carrots). Carotenedoes not start out as vitamin A, but ourbodies convert it into vitamin A when we eatthose vegetables. Substances like carotenethat we can convert into vitamins are called“provitamins.”

Some nutritionists think that in some wayscarotene is the most efficient

Vitamin A: A Fishy Tale

The story starts like this: Long ago,fishermen passed on to their sons anddaughters the helpful hint that eating the liverof a fresh fish could cure “night blindness.”Night blindness is a condition that keepspeople from seeing well in dim light (late inthe evening, for example, when the sky isnearly dark). Most people can still see at leasta little then. But someone with nightblindness can’t see at all.

Night blindness was a commonproblem for fishermen who had been outin the bright sunlight all day long. Thefishermen didn’t eat much—maybe justsome dried bread, cheese, water, and abit of dried fish. But for some reason,eating a fish liver seemed to solve theirsight problem, or so they claimed.

At the time, most scientists thoughtthis idea sounded “fishy” and didn’t takeit seriously. Then a pair of doctorsdiscovered a substance in eggs andbutter that does, in fact, help to repairsunlight-damaged eyes. Later, scientistsdiscovered the same substance in thefatty parts of liver.

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LESSON 15

way for our bodies to get vitamin A. That’sbecause our bodies don’t convert caroteneinto vitamin A until we actually need it, so wedon’t end up with too much.

The next time someone tells you to eat yourspinach or carrots, think about the fishermen

of long ago (or the rats—you choose!). Youdon’t have to eat fish liver, but you can eat theright kind of vegetables. Best of all, if you eatvegetables to get your vitamin A, your bodywill make just the right amount.

STC® / Food Chemistry142 / Examining Labels: Making the Connection

LESSON 15

Around 1880, a new disease called beriberiwas taking its toll on Japanese sailors.Victims felt very weak, suffered frominsomnia, and lost their appetite. Sometimes,their hands and feet became partiallyparalyzed. Some ships lost a third of theirsailors to the disease.

A doctor in the Japanese Navy started tostudy beriberi. His findings were puzzling.Besides the sailors, rich people in cities (notpoor people living in villages) were morelikely to get the disease. Also, beriberioccurred most often in countries like Japan,where people ate a lot of rice. British sailors,for example, almost never got the disease.

received the best white rice available, not thecheap brown rice eaten by the villagers. Butnaval officials also acknowledged that theberiberi had to stop and agreed to allow theexperiment.

The doctor noted what happened in 1882when a Japanese navy ship named the Riojoheaded for Hawaii via New Zealand and SouthAmerica. The Riojo carried the usual sailorfoods—rice and small amounts of vegetablesand fish. Within ten months, 169 of the menhad contracted beriberi, and 25 had died. Thedoctor kept careful records of these events.

A year later, the Tsukua set sail for thesame places as the Riojo. But on this journey,

the ship carried some other foods aswell—oatmeal, canned milk, and extracanned vegetables. Most of the sailorsagreed to try the new foods. But 14 ofthem refused, clinging to their old dietsof rice, soups, and small amounts ofvegetables and fish. At the end of thejourney, those 14 sailors were the onlyones who came down with beriberi.

The emperor of Japan was soimpressed that he made the doctor abaron. Even more important, he orderedJapanese naval ships to stock moremeat, fish, and vegetables and to give atleast a pint of milk to each sailor everyday. In 1884, the number of beribericases among Japanese naval sailorsdropped by nearly half. By 1887,instances of beriberi in the JapaneseNavy had disappeared.

An Accidental DiscoverySome scientists still had trouble

believing that beriberi was related to diet.They thought the disease was caused by avirus or bacteria. But in the early 1900s,American forces fighting in the Philippinesstumbled onto a new clue. They took over aFilipino prison, where they found theprisoners eating old, moldy brown rice.

Vitamin B-1: The Right Rice

The doctor suspected that diet played a bigrole in the beriberi problem. How could hetest his hypothesis? He decided he would feedJapanese sailors new foods and observe whathappened. At first, the Japanese naval officialswere insulted; they felt the sailors ate wellenough. As they pointed out, the sailors even

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LESSON 15

suggested that the prisoners go back to eatingbrown rice. Within three months, the numberof beriberi cases had dropped to four.

So, why had the Japanese sailors, thewealthy people, and the well-treatedprisoners been victims of beriberi? Thesegroups ate mostly processed white rice withthe husks of the rice kernels removed.Clearly, there was something in those husksthat prevented beriberi. And, apparently, thesame substance existed in the food eaten bythe Japanese sailors on the Tsukua whoagreed not to eat rice. But what could thismystery substance be?

In 1906, a team of scientists discovered thatwhen rice husks were soaked in water, thewater could cure beriberi. In 1912, CasimirFunk, a Polish chemist, finally isolated thesubstance that had dissolved into the water.We now call it thiamine, or vitamin B-1.

Today, we add vitamins to white rice toreplace those lost during processing. Andplain old brown rice—once considered“peasant” food—is starting to make acomeback. As we now know, it is anexcellent, natural source of vitamin B-1.

Hoping to improve the poor prisoners’conditions, the Americans started servingpolished white rice. Within three months, thenumber of cases of beriberi in the prison hadjumped from 2 to 1,087. The Americans thenlaunched a campaign to sanitize the prison, butthat made no difference—the number of casescontinued to climb. Finally, a European doctor

STC® / Food Chemistry144 / Examining Labels: Making the Connection

LESSON 15

Next time you eat a peanut butter sandwichand wash it down with a big glass of milk,think about this: both the milk and thepeanut butter have first been exposed toultraviolet light. It may sound like a strangething to think about, but there is a reason.When ultraviolet light shines on milk andcertain oils (likepeanut oil),cholesterol is madeinto vitamin D. Andvitamin D helpsstrengthen bones.

Scientists didn’talways know aboutthe value of vitaminD. In fact, it wasdiscovered byaccident. A doctornamed Alfred Hesswas looking for a curefor rickets (achildren’s bonedisease) when hestumbled upon thefact that when youexpose certain foodsto ultraviolet light,they undergo anunusual reaction. Sowhile seeking the cause of rickets, Hess alsodiscovered its cure—vitamin D.

In the late 1800s, rickets posed a seriousthreat to children living in cities. The diseasecaused defective bone growth. And it usuallyresulted in curved bones and large joints thatcaused its young victims to walk bowlegged. Achild with rickets usually had weak teeth, too.

To find out what caused this horribledisease, Hess fed rats a special diet, free offats and oils. He and other scientists hadalready found that this diet caused the rats todevelop rickets. But in one case, a group ofrats didn’t get rickets. Why? These rats hadreceived the same food as the others. Sowhat was different about this group?

The doctor studied everything he couldabout the rat groups, comparing the waysthey ate, slept, and lived. The rats’ habitswere all the same, except for one seeminglyminor detail. The group of healthy rats waskept near an ultraviolet light. Could this bethe key to the mystery?

To find out,the doctor setup a newexperiment. Heformed two newgroups of youngrats and fedeach group thesame food. Butbefore feedingGroup One, heexposed its foodto ultravioletlight. Hess’sresults werestartling: GroupOne did notdevelop rickets.The key topreventing thisdisease was inthe light.

Big City WoesUltraviolet light also helped explain why

rickets was such a problem in theindustrialized cities of America and Europe.After the Industrial Revolution, people nolonger worked for long hours in sunny fields.Instead, they spent their days laboring indark factories. More people also moved intocities, which became crowded.

And children were often raised in crampedurban conditions and sent off to work at ayoung age. All of this, combined with long,dark, winter months, greatly decreased theamount of light present in people’s lives. Andit greatly increased the number of childrenwith rickets.

Vitamin D: Shedding Light on Rickets

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LESSON 15

contagious, like measles or chicken pox.Others thought it could be cured by a dose ofcod liver oil. Then Hess “shed some light” onthe subject. But he still wasn’t sure whyultraviolet light made such a difference.

The question of “why” was answered in the1920s. Scientists found a way to isolate thenew substance that is created (in food and inour bodies) when ultraviolet light shines onthe cholesterol in fats and oils. Eventually,this substance was named vitamin D.

But what does vitamin D have to do withbones? Well, it turns out that vitamin D playsa role in the way our bodies absorbcalcium—a key part of bones. Withoutvitamin D, our bones can’t be strong. Isn’t itlucky for us that Hess made the connectionbetween ultraviolet light and rickets? Now wecan make sure we eat foods with plenty ofvitamin D.

Until Hess’s experiments, people haddebated for years about the true cause ofrickets. Some folks thought it was

STC® / Food Chemistry

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STC® / Food Chemistry

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