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ETYMOLOGY

Scientific Words: Their Structure and Meaning

INTRODUCTION

A ZOOLOGIST has described Human as: 'metazoan, triphoblastic, chordate, vertebrate, pentadactyle, mammalian, eutherian, primate'.

A chemist has written that: 'in the formation of mono-substitution products of benzoic acid the halogen takes up the meta-position with respect to the carboxyl'.

From a technical dictionary we read that a carbuncle is: 'a circumscribed staphylococcal infection of the subcutaneous tissues'.

Such passages as these are probably unintelligible to the non scientist and might even puzzle a scientist if he specialised in a totally different field. They are, however, sensible statements of certain scientific facts. Their difficulty lies in the concepts which are involved - concepts with which the reader may not be familiar - and also in the technical terms which are used

Why do scientists use such unfamiliar, and apparently difficult, words? Why do they need a special vocabulary of their own?

What is the nature of the specialised words of science? What are their origins? Are they just fanciful inventions or have they been sensibly and logically constructed?

Are these words necessarily unintelligible to all but the scientific expert or can an ordinary educated person, who knows a little science, make some sense of them and gain at least a general idea of their meanings?

The Purpose and Nature of Scientific Words

The development of an appropriate vocabulary is essential to the development of any subject. Words are the elements of language; language is the vehicle of ideas. By silent language thoughts are developed in the mind, and by written or spoken language thoughts are communicated to others.

It is obvious that a scientist must have names by which to identify and refer to the various chemical substances, minerals, plants, animals, structural units, instruments, etc., with which he deals. He/she must have suitable adjectives for describing these things and suitable verbs for defining their behaviour.

He also needs suitable names by which to identify the various abstractions with which he deals - processes, states, qualities, relationships, and so on. Thus, after Faraday had investigated the passage of electric currents through different solutions and noted the resulting liberation of chemical substances, the term electrolysis was invented. This one word was a kind of shorthand symbol for the process; it 'pinned down' the process and conveniently embraced its many aspects. From then on it was possible to think about the process and to talk about it to others. Similarly, the single term symbiosis conveniently summarises a biological state.

Many scientific words are of this kind. Without the name (or technical term) a concept remains vague and ill-defined; the scientist is hindered in his mental processes, in his recording of what he thinks and does, and in his communication with others.

The meanings of many ordinary words of our language are not single and precise. Although the original, basic meanings may be clear, the words have acquired a range of meanings over the years. Thus the familiar word fair has somewhat different meanings when used to describe the weather, a person's hair, an action or decision, or a boy's performance at school. Hence a scientist avoids the ordinary words of the language; he prefers his own words. These words can then be rigorously defined and given the necessary precision of meaning.

The use of words which are 'set apart' from everyday life also enables the scientist to avoid evoking irrelevant and distorting associations. Some ordinary words convey more than their literal meanings; they evoke further images, emotions and reactions on the part of the hearer or reader. (Thus red, basically a word denoting a certain colour, may conjure up thoughts and feelings relating to danger, to blood, or to a particular political outlook.) The specialised words of science, if used in their proper contexts, are largely free from distorting associations. It is interesting to note that when a scientific term, originally well-defined, becomes a word of ordinary speech, it usually suffers a widening of meaning and acquires a number of associations. Thus criticism (as well as sulphuric acid) may be vitriolic, a man may be electrified into action, and people may claim to be allergic to all sorts of things and conditions. The word atomic, whose meaning is quite clear to the scientist, may conjure up in the public mind a picture of widespread destruction or of unlimited power.

In addition to precision of meaning and freedom from associations, most scientific words have a third quality: by their form and structure they reveal something of their meanings. Many scientific words are logically built up from simpler word-elements (usually of Greek or Latin origin) and the general meaning of the whole can be inferred from an understanding of the parts. Some terms, in fact, are self-explanatory if the Latin and Greek roots are known; they have only to be 'translated' for their meanings to become apparent.

Thus a quadrilateral is clearly a four-sided figure, entomology is the study of insects, gastrectomy is the cutting out of the stomach (or part of it). In the case of a large number of words the full or precise meaning may not be directly disclosed but the general meaning is apparent and the word is seen to 'make sense'. Thus cyanosis indicates a state (possibly a morbid state) of blueness; it is a sensible word to use to denote the blue condition of the skin which results from insufficient oxygen in the blood. A xerophyte (literally "a dry plant") is one which is adapted for living in very dry conditions; a hydrophyte is one which lives on the surface of, or submerged in, water. A polymer consists of "many parts"; the term is an appropriate one for a giant molecule which is built up from a large number of simple units.

Scientific language, to be efficient, must be universally intelligible. The classical languages, Latin and Greek, are so fundamental to the civilised world that words constructed from elements of these languages are readily understood the world over. (Even if scientists know little of the classical languages, they can easily learn to 'translate' the scientific terms which they may meet.) Most scientific terms are effectively international.

Sources of Scientific Words

Scientific words in English may conveniently be divided, from the standpoint of their origins, into three groups:

1. those taken from the ordinary English vocabulary;
2. those taken virtually unchanged from another language;
3. those which have been invented.

The third group is by far the largest.

The scientist has occasionally taken ordinary English words and endowed them with specialised meanings. Energy, work, power, salt, base, fruit are examples of such words. They are unsatisfactory as scientific terms because they lack the essential qualities which we have described. Although the scientist may give them precise meanings, they are liable to be interpreted more loosely (or even differently) by the non-scientist.

The English language contains a number of words which have been taken from another language with little or no change of spelling. Amongst them are morgue, souvenir, trek, marmalade and agenda. Practically all the scientific words of this kind have been taken from Latin or Greek. As examples of Latin words we may note axis, fulcrum, larva, radius, locus, nimbus, cortex. Many parts of the human body, e.g. cerebrum, pelvis, cornea, have Latin names. There are fewer unaltered Greek words - thorax, stigma, iris, helix are examples - but it should be noted that many terms adopted in Latin form, e.g. trachea, bronchus, phylum, were themselves based on Greek. Many of the Greek or Latin terms have retained their original meanings but in some cases the meanings have been restricted and rendered more precise.

The largest group of scientific words are those which have been invented. The advance of science during the last few centuries has been so rapid and so extensive that no language has been capable of providing, ready-made, all the words which were required. Further, the classical languages do not contain words appropriate to modern discoveries, inventions and concepts. (There is no Latin word, for example, for photography!) Hence the scientist has had to invent new words for his own purposes.

It is very rare for a scientist to make up a word 'out of his head'; the term ester for a compound formed by the interaction of an alcohol and an organic acid was perhaps such an invention. A small but interesting group of terms comprises those based on proper names. In the naming of the chemical elements recourse has been made to the names of places (as in polonium, ytterbium), of gods and goddesses (as in thorium, vanadium), of planets and asteroids (as in uranium, cerium), and of scientists themselves (as in curium, gadolinium). Scientists' names have also been used to provide the names of units (e.g. watt, volt, gauss, joule) and hence the names of measuring instruments (e.g. voltmeter). Among the other terms based on the names of scientists are daltonism, nicotine, bakelite and mendelism. A number of plants, e.g. fuchsia, dahlia are named after botanists.

In his task of inventing new terms, however, the scientist has usually turned to the classical languages for his raw material. He has taken 'bits and pieces' - roots, prefixes, suffixes - from these languages and joined them together to form the terms he needed. Thus, when he needed a general name for animals such as snails and slugs which apparently walk on their stomachs, he took the Greek roots gast(e)ro- (stomach) and -pod (foot) and formed the new word gastropod. When he wanted a word to describe a speed greater than that of sound he took the Latin prefix super- (above, beyond) and the Latin root son- (sound) and coined the adjective supersonic. Thousands of scientific words have been built up from classical word-elements in this way.

The Formation of Scientific Words from Classical Word-elements

Despite the enormous size of the modern vocabulary of science, the basic elements from which the words have been constructed are comparatively few. (The greater part of the vocabulary of medicine and anatomy - perhaps 30,000 words - has been constructed by the use of only about 150 standard word-elements and the names of the parts of the body.) Many elements appear in a range of words distributed among a number of different sciences. Thus the element pter- (Gk. pteron, wing) appears in the names of many sub-classes of insects (e.g. Diptera, Lepidoptera), of certain types of aircraft (e.g. helicopter) of a group of chemical substances (e.g. methopterin) and in the name of a mesozoic flying reptile (Pterodactyl).

As will be seen from the Glossary, the word-elements are generally used in forms which are specially adapted to word-building. Thus the Greek noun nephros (kidney) is used in the combining-form nephro- (or nephr- before a vowel). Let us take this root and look at the range of words which have been built up from it. We may suffer from nephropathy (disease of the kidney), nephralgia (pain in the kidney), nephritis (inflammation of the kidney) or nephroptosis (a dropping of the kidney). We may undergo the surgical operations of nephrotomy (a cutting of the kidney), nephrectomy (a cutting out), nephrorrhaphy (a sewing up) or nephropexy (a fixing in place). Yet more terms will be found in a 'medical dictionary. We might like to invent a few more terms ourselves. The kidney can suffer the processes of nephrothermolysis (being cooked) and nephrophagy (being eaten)! The root has also been used in forming the names of excretory structures in certain lower animals. In an Earthworm, for example, each normal segment contains a pair of excretory organs which have been called the nephridia (literally, the little kidneys).

Prefixes which indicate degree, position or number are of particular value in word-building. Thus we may suffer from hyperpiesis (high blood pressure) or from hypopiesis (low blood pressure), the two terms being formed by the addition of contrasting prefixes to the same root. Similarly, the ectoplasm is the thin protoplasm near the outside of a cell and the endoplasm is the denser protoplasm well within the cell. The Apoda have no legs, the Decapoda have ten, and the Myriapoda have many. Radio valves may be classified as diodes (two electrodes), triodes (three electrodes) . . . pentodes (five electrodes) . . . octodes (eight electrodes), and so on.

Sometimes both Greek and Latin elements are combined in the same word. Television is a well-known example; the prefix tele(from afar) is Greek and the root vis- (seeing) is Latin. (The 'all-Greek' word teleorama would have been more satisfying to the purists but it is unlikely to be adopted.) The formation of 'hybrid' words of this kind may be considered objectionable if 'pure' alternatives are readily available and equally convenient. Thus the term odoriphore* is a needless hybrid; the 'all-Greek' term osmophore would serve just as well. There appears to be no justification for the invention of the hybrid word pluviometer (rain gauge) when two all-Greek terms, hyetometer and ombrometer, are available. And chemists still seem not to have made up their minds whether to use Latin or Greek prefixes of number before the Latin root -valent.

Undoubtedly some hybrids have been formed because of thoughtlessness or ignorance, but many have been formed because certain prefixes and suffixes have become well known and have been found to be convenient. Thus the familiar Greek root -meter (measurer) has been added to all sorts of stems, e.g. to a Latin stem in audiometer and to an English stem in weatherometer. (Note the insertion of the o before -meter; in all-Greek terms an o ' normally arises as the ending of the stem.) The Greek element -logy (often regarded as -ology) is now freely added to stems of ' various kinds and origins; the three common medical elements -itis (inflammation), -oma (growth, tumour) and -osis (morbid state) are not infrequently added to Latin stems (e.g. as in gingivitis, fibroma, ' and silicosis). Certain prefixes of classical origin, e.g. re-, pre-, micro-, sub-, tele-, are still 'living' and are freely used in combination with words of any origin, e.g. in re-oxidise, pre-Cambrian, microfilm, substandard and telecommunication.

The Analysis and Interpretation of Scientific Words

Not many people are in the position of needing to invent new scientific words. A scientist may need to do so occasionally, particularly if he is researching in a new field. Sometimes a manufacturer invents a pseudo-scientific name (often a verbal monstrosity) for his products, apparently to make them seem more attractive. The layman is never called upon to invent scientific words.

All kinds of people, however, may find themselves needing to interpret the meanings of scientific words. The scientist may meet new terms invented by other scientists; he may meet words which are unfamiliar to him because they are in specialised fields outside his own. The student frequently meets words which are strange to him but which he must learn and understand in order to progress in his studies. And, in these modern times, the layman meets scientific words in his newspapers, in advertisements, and through television.

Words which are pure Latin or pure Greek, and which cannot be broken down into simpler parts, do not readily disclose their meanings; one either knows the meanings or one does not. Thus one cannot infer the meaning of tibia, thallus, or soma merely from the spelling. It has been shown, however, that the majority of scientific words have been constructed from simpler word- elements and thus, from an understanding of the parts, one may deduce the meaning (or at least the general sense) of the whole. This is, indeed, one of the virtues of scientific words.

As has already been pointed out, the meanings of a large number of scientific words are directly revealed by simple translation. Conchology is obviously the study of shells, a lignicolous fungus is clearly one which lives on wood, and what else can hypodermic mean than under (or below) the skin? Antiseptic, microphyllous, anemometer, centripetal, pentadactyl, hyperglycaemia are among the thousands of scientific words whose meanings may be readily deduced by simple analysis. It is possible that by simple translation one might occasionally miss some subtle shade of meaning or of application but one would nevertheless gain a useful idea of what the words denote.

There are thousands of other words, of course, whose full meanings cannot be determined by simple deduction. Thus pericardium clearly means "round the heart", but we cannot deduce exactly what it is; an electrometer is apparently an instrument for measuring electricity but we cannot tell what property of electricity it measures. The word isotope tells us no more than that 'it' is in the same place as something else. The translation of the names given to plants and animals is often of no help in identification; we cannot recognise Myosotis by translating the name as "mouse ear" nor do we know what Oligochaeta are even if we deduce that they have "few bristles".

The word photometer readily breaks down into the elements photo- (light) and -meter (a measurer); it is evidently the name of an instrument for measuring some quality (e.g. intensity) of light. The word geomorphology breaks down into the elements geo (Earth), morpho- (form, shape) and -logy (which may be interpreted as 'the study of'); geomorphology is thus the study of the shape of the Earth (actually of the origin and nature of its surface shape and features). The term gastromyotomy breaks down into its elements gastro- (stomach), myo- (muscle) and -tomy (cutting); we deduce that gastromyotomy is the surgical cutting of the muscles of the stomach. Similarly, we deduce that and that arteriosclerosis is a hardening of the arteries. We understand why lines on a map passing through places which have the same temperature are called isotherms (iso-, equal, therm-, heat) and so deduce the meanings of isobar and similar terms. Having learned that the element cyto- indicates a cell, we can make sense of such terms as cyto'logy, cyto'genesis and cyto'lysis.

Let us take one example to illustrate how a long chemical name may be interpreted. What can be made of the name polytetrafluoroethylene? As is often useful when analysing chemical names, we work from right to left. We start with ethylene, the name of a well-known hydrocarbon (hydrogen-carbon compound) with the chemical formula C₂H₄. Tetra-fluoro- indicates that four fluorine atoms are taking the place of four (in this case all) hydrogen atoms in the molecule. So we reach a compound which may be represented by the formula C₂F₄. The prefix poly- in chemical names indicates that a giant molecule, as in a 'plastic', has been built up by the joining together of a large number of simple units.

Polytetrafluoroethylene is, in fact, a 'plastic' substance built up from C₂F₄ units, known commercially as P.T.F.E. or Teflon.

We live in a scientific age; an understanding of science is at least as necessary to the make-up of an educated person as a knowledge of the arts. More and more people need to understand the words of science. This does not mean that traditional courses of Latin and Greek should therefore form a part of everyone's education but it indicates the desirability of teaching the more important roots which enter into the formation of English, and especially scientific, words.

(from Scientific words: Their structure and meaning, by W. E. Flood, Oldbourne, 1960)

ACTIVITY. 

Say the meaning of these words:

cardiopathology,

epicenter,

myoma,

osteopathy,

hydrofobic molecule,

hydrophillic substance,

seismograph,

hepatitis,

traumatology,

osteolysis,

osteoarthritis,

eukaryotic cell,

neurology,

rhinitis,

gastroenteritis,

antiseptic,

anemometer,

pentadactyl,

hyperglycaemia,

geomorphology,

pericardium,

isotope,

isotherm,

cytology,

arteriosclerosis.

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Final del formulario

Principio del formulario

Final del formulario

What’s in a name? Etymology of Scientific words.

http://technophilicmag.com/2014/02/26/scientific-words-etymology/
Everyone and everything we know has a history. A wooden table was originally part of a tree, a colorful butterfly used to be a revolting caterpillar, and the entire cosmos was perhaps once a single, concentrated point with a bright future.
Words too have their linguistic histories. Several of the names assigned to various mathematical quantities, scientific principles and phenomena were created from verbs and adjectives that date back to the days when Greek and Latin were the languages of learning in the Western world. Many of these scientific words have a historical or mythological aspect to them.
Examining the etymology of such words may or may not enhance our knowledge of that object or phenomena, but the nature of their origin directs us to the mindset, limitations, and challenges of that era. We discover new stories behind the old, accustomed names, just like the charm we find in revisiting familiar places with new eyes after spending some time from them.

Here are a few examples of such words:

13. Electric

The word electric was first used in English in the 1600s. This name was derived from the Greek word for amber (electrum), a substance that was known to attract bits of paper when rubbed with wool.

12. Composite

Derives from a Latin verb (componere), which means, “to assemble together”. The prefix com- means “together”. Ponere means “to place”; it is also the root for the word ‘position’.

11. Gravity

The persistent pull we experience is from Latin (gravis) “heavy”; the same root gave us the adjective ‘grave’, to describe any emotionally heavy moments and moods.

10. Vulcanization

 

A chemical process that is used to create durable materials by transforming polymers. This is typically carried out by the addition of sulphur.
In Roman mythology, Vulcan is the god of fire. It is also the origin for volcano, the ‘burning mountain’.

9. Photolithography

A chemical process used in microfabrication to transfer patterns from a mask to a sample. Its name derives from a word (lithos) for stone. Lithography, therefore, means writing with stone, and photolithography refers to writing with light or photons.

8. Gadget

Gadget was originally a slang word in the nautical realm; sailors used it for any mechanical object that they did not have or could not remember the name of. The etymology of this word is not settled but many believe it derives from a French word for a firing mechanism (gâchette).

7. Division

The least favored mathematical operation amongst beThe least favored mathematical operation amongst beginners in elementary arithmetic, originated from a Latin verb (dividere), which means, “to share”.

6. Algebra

A broad field of mathematics, originated from an Arabic word (al jabr) that means “reunion (jabara in Arabic) of broken parts”; the same root also gave us ‘algorithm’.
Interestingly, the ‘restoration’ quality of algebra was used in the 15th and 16th centuries in a literal sense for describing “the treatment of fracture”.

5. Vector

In the field of linear algebra, an alphabet is crowned with an arrowhead to denote a quantity that has a magnitude and a direction; it is called a vector. This name is derived from a Latin word (vehere) for ‘to carry or convey’. In addition to describing such driven alphabets, this Latin word is also the root of ‘vehicle’.

4. Calculus

A Latin word that originally meant a small pebble because it was used for calculations. Calx means limestone, hence calculus has also been used in dentistry to refer to deposits on the teeth and in medicine to denote kidney stones (calculus in the kidneys), a painful experience for some, just like calculus in its mathematical sense, which includes the concepts of integration and differentiation.

3. Trigonometry

A branch of mathematics that describes the relationship between the angles and sides of triangles. Its name originated from a Greek word (trigonon); triangle, the star of this territory of mathematics, is also derived from the same root. Tri- refers to “three”. The word gonia means “angle or corner” and is related to “knee” probably because of the angular form of bent knees. The word metron means “a measure” and is also the root of meter.
Goniometer, then, not surprisingly is an instrument that is used to measure angles.

2. Equation

Originates from a Latin word for equal (aequare). It is a word that immediately suggests a balance in an expression describing a chemical reaction or a mathematical principle. It is therefore interesting to note that it was first used in English in the context of astrology in the late 14th century by people who believed that the everyday lives of insignificant creatures in a small planet are fascinating enough for the entire cosmos to take an interest. We have come a long way since then, and now, equations are reputable (and, sometimes daunting) expressions.

1. Revolutionary

As a final reflection on the origins of names relevant to the sciences and mathematics, let us consider the word revolution. Presently, we use the word “revolutionary” to imply something that is drastically new or different, typically in a positive light. It might then be surprising to find that the origins of this word lie in astronomy and astrology. It derives from a Latin word (revolvere), which means “to revolve”. Copernicus used it to describe the motion of the planets around the sun, a theory not readily accepted at the beginning (making his treatise “revolutionary” in the modern sense of the word too).
 Next, the word made its way into the language of astrologers who claimed to be able to predict the deterministic future, particularly those of generals and princes. They used “revolution” for any dramatic and unexpected episodes in the affairs of humans, in direct contrast to the initial application of the word in the field of astronomy, which suggested consistency and order in the movement of the planets.
The names we have seen, and many others that we have not considered here, are mostly remnants of words from the antiquated languages of learning. These names are then verbal time machines, sending us back a few centuries, sometimes showing us the links between two seemingly detached words, and forming a multidisciplinary bridge between history, linguistics, and science.
What’s in a name then? There is namon (Proto-Germanic), namo (Old High German), nomen (Latin), onoma (Greek), naam (Dutch), noma, nama (Old English), nama (Sanskrit), nam (Persian), namo (Old Saxon), and perhaps many others; regardless, it is still a name by any other name.

 

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http://knpb.pbslearningmedia.org/resource/f661a5a7-3d95-4579-9b6f-cdaa3894b324/the-truth-about-exercise-calories-and-fat-deposits/

Are any foods save to eat anymore?

Is bacon really as bad for you as cigarettes? Will coffee give you a heart attack? Do wheat-eaters suffer “brain fog”? BBC Future examines the foods, the fears – and the facts.
 
By David Robson
30 October 2015

Food was once seen as a source of sustenance and pleasure. Today, the dinner table can instead begin to feel like a minefield. Is the bacon on your plate culinary asbestos, and will the wheat in your toast give you “grain brain”? Even the bubbles of gas in your fizzy drinks have been considered a hazard.
Worse still, the advice changes continually.  As TV-cook Nigella Lawson recently put it: “You can guarantee that what people think will be good for you this year, they won’t next year.”

Many of our favourite foods are not the ticking time bomb we have been led to believe

This may be somewhat inevitable: evidence-based health advice should be constantly updated as new studies explore the nuances of what we eat and the effects the meals have on our bodies. But when the media (and ill-informed health gurus) exaggerate the results of a study without providing the context, it can lead to unnecessary fears that may, ironically, push you towards less healthy choices.
We’ve tried to cut through the confusion by weighing up all the available evidence to date. You may be pleased to learn that many of your favourite foods are not the ticking time bomb you have been led to believe.

The WHO warns against bacon, but how worried should you be? (Wendy/Flickr/CC BY-ND 2.0)

The food: Bacon

The fear: Processed meats are as dangerous as cigarettes.

The facts: While the World Health Organisation has announced overwhelming evidence that bacon (and other kinds of processed meat) can contribute to colorectal cancer, the real dangers are not quite as worrying as the subsequent headlines would have us believe.
As Cancer Research UK points out in an astute blog, colorectal cancer is itself relatively rare. If you eat barely any meat, there is a 5.6% risk of developing the disease over your lifetime; even if you pig out on bacon and ham every day, it only rises to about 6.6%. In other words, for every 100 people who stop eating bacon, only one will have avoided cancer. To put that in perspective, consider the figures for tobacco: for every 100 smokers who give up, 10-15 lives may be saved. The two are hardly comparable.
Even so, you may want to reconsider a 20-rashers-a-day habit. The UK government advises that an average of 70g a day is still healthy – about three rashers, or two sausages.
In a nutshell? The odd English breakfast may not do you as much good as a bowl of granola – but nor is it gastronomic asbestos.

Should you avoid a daily cup? (Guwash999/Flickr/CC BY 2.0)

The food: Coffee
The fear: Our caffeine addiction will drive us to a heart attack.

The facts: There is very little evidence that a cup of Joe will send you to an early grave; in fact, the opposite may be true. In 2012, the New England Journal of Medicine reported on the health of 400,000 Americans over the course of 13 years. The scientists found that people who drank between three and six cups a day were around 10% less likely to die during the 13-year period, with lower rates of heart disease, stroke, diabetes and infections. Considering a string of studies examining the health of more than a million individuals, a review in 2014 painted a similar picture: people who drank four cups a day were around 16% less likely to die at any one time.
Note that these were only observational studies. Although they tried to account for other factors, there’s no way of knowing if the coffee itself was protecting the heart, or if there’s some other, hidden, explanation. Perhaps healthier people are just more likely to be drawn to coffee. But as “addictions” go, it’s pretty harmless.
In a nutshell? It’s probably not the elixir of life that some claim, but based on this evidence, you can at least savour that morning espresso with impunity.

We've been eating wheat for 10,000 years (Glory Foods/Flickr/CC BY 2.0)

 The food: Wheat
The fear:  So-called “grain brain” could contribute to Alzheimer’s disease.
The facts: First things first: a very small number of people – around 1% of the population – do have a genuine gluten allergy known as celiac disease, that can damage their intestines and lead to malnutrition. Others may not suffer from celiac disease, but they may instead be “sensitive” to wheat; although they don’t suffer symptoms if they only eat a small amount, they may experience some discomfort if they eat too much bread.
Explanations for this “non-celiac gluten sensitivity” are controversial: rather than the gluten in wheat specifically, it may instead be caused by a range of sugars and proteins that are also found in many other foods, including fruit and onions. If so, simply cutting wheat would not relieve the symptoms.
Then there are the people going gluten-free even without experiencing definite symptoms at all, because wheat itself is seen as being toxic. As Peter Green at Columbia University commented recently: “People who promote an anti-grain or anti-gluten agenda sometimes cite our work in celiac disease, drawing far-ranging conclusions that extend well beyond evidence-based medicine.”  One popular claim, for instance, is that wheat-based foods trigger inflammation throughout the body, which could contribute to “brain fog” and increase the risk of serious conditions like Alzheimer’s. But while diets heavy in carbohydrates and sugars may, over time, lead to neural damage, whole wheat is still better than other energy sources, such as potatoes, since it releases its sugars more slowly.
In a nutshell? Humans have been eating wheat for at least 10,000 years – and unless you have been tested for an allergy, there seems little reason to stop until we have far more evidence.

Cheese is bad for your heart, right? Not so fast (jeffreyw/Flickr/CC BY 2.0)

The food: Butter, cheese and full-fat milk
The fear: Dairy products will clog up your arteries and contribute to heart disease.
The facts: For decades, the message has been simple: “saturated” fats from cheese, butter, and full-fat milk will raise the cholesterol in your blood and put you in danger of a heart attack. For this reason, many health organisations had encouraged us to lubricate our diets with margarine and vegetable oils, replacing the saturated fats with “poly-unsaturates” typically found in the (famously healthy) Mediterranean diet.
Yet over the last few years, we’ve seen a stream and then a torrent of deeply puzzling findings that contradict the accepted wisdom. Taking all the evidence into account, one major review in the Annals of Internal Medicine recently concluded that “high levels of saturated fat intake had no effect on coronary disease”. Again, these were only observational studies, but one team decided to put it to a test with a carefully planned intervention, feeding their participants 27%-fat Gouda cheese every day for eight weeks. At the end of the trial, they had lower cholesterol than controls asked to stomach a zero-fat alternative.
The oddest finding? Despite the fact that full-fat milk and butter are packed with calories, people eating full-fat dairy were no more likely to be obese than those drinking semi-skimmed milk; 12 separate studies have in fact found them to be leaner. It’s possible that the fat itself could help regulate the metabolism, meaning that you burn off energy more efficiently; or it could be that full-fat dairy keeps our hunger locked away for longer, making us less likely to fill up with unhealthy snacks later on.
In a nutshell? We still don’t understand why, but “full-fat” may be the new “skinny”.

Pasteurisation of milk has many benefits (Intrinsic-Image/Flickr/CC BY-NC-ND 2.0)

 The food: Pasteurised milk
The fear: Pasteurisation could contribute to eczema, asthma and other immune disorders.
The facts:  It’s not just full-fat milk that has come under fire. A common assumption is that the more “natural” a food is, the healthier it must be, and this has led some to shun pasteurised milk. Proponents claim that pasteurisation damages many of the useful nutrients in milk, including proteins that may protect us from allergies. The process of pasteurisation, they believe, also kills “friendly” microbes in the milk that could add to the microbiome in our gut, aiding digestion, strengthening the immune system and even protecting against cancer.
Many doctors, however, believe this is premature. The mild heating involved in pasteurisation should leave almost all the nutrients intact, and it seems unlikely that the friendly bacteria in raw milk will bring many benefits: its colonies would need to be thousands of times bigger for enough of the bacteria to survive digestion and make their way to the intestine. And although there is some tentative evidence that people who drank raw milk as children tend to have fewer allergies, it’s hard to be sure this was caused by the milk itself, and not just the fact that many of these children mostly grew up on farms. Living among so many animals, their body may have been trained to deal with allergens at a young age, making them less likely to suffer as adults. What’s more, drinking raw milk could be potentially dangerous: we pasteurise the drink for good reason, to kill microbes that could cause serious disease, like tuberculosis, Salmonella and E coli.
In a nutshell? Before you risk a nasty infection, you might want to wait for the evidence to match the extravagant claims.

How many eggs is too many? (Tom Fassbender/Flickr/CC BY-ND 2.0)

The food: Eggs
The fear: A heart-attack in a shell.
The facts: Like full-fat milk, eggs were once thought to cake our arteries in cholesterol and increase the risk of heart disease. There may be some truth in these claims, but provided you are otherwise healthy, eating up to seven eggs a week seems to come with no ill-consequences.
In a nutshell? Besides the risk of flatulence and constipation, eggs are a safe and valuable source of protein.

Many fear the health effects of sweeteners in diet drinks (Ze’ev Barkan/Flickr/CC BY 2.0)

 The food: “Diet” soft drinks
The fear: Artificial sweeteners can contribute to cancer risk.
The facts: We already know that too much sugar leads to obesity, diabetes and heart disease – but what about the artificial sweeteners we add to “diet” drinks to try to lessen the impact? One common fear is that they promote the growth of tumours. But as Claudia Hammond recently explained on BBC Future, the risks may have been exaggerated; a vast study conducted by the US National Cancer Institute found no increase in the risk of brain cancer, leukaemia or lymphoma in people consuming aspartame, the most common sweeteners, and the same seems to be true for other sugar alternatives. There is, however, a chance that they might contribute to glucose intolerance, and type 2 diabetes – though it has yet to be proven. (Incidentally, Hammond has also punctured the idea that the bubbles in soft drinks are themselves a hazard, debunking claims that it could harm your stomach and weaken your bones.)
In a nutshell? Artificial sweeteners may be the lesser of two evils – they may carry some risks, but are still healthier than the full-sugar alternatives.
David Robson is BBC Future’s feature writer. He is @d_a_robson on Twitter