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reading matters 12: food mysteries

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New Scientist 3292 July 25 2020

Jacinta: So this cover story reminds me of something I read or heard a few years back  – that if you were to list the chemical ingredients of a hen’s egg, you’d never come to the end, or something like that. 

Canto: Well you’re on the right track, the cover story is titled ‘the dark matter in your diet’, but instead of a hen’s egg it starts with garlic. Both of these commonly consumed edibles, like just about everything else we eat, contain ‘nutritional dark matter’ that scientists have only recently started to focus on, surprisingly considering that we are, to a fair degree, what we eat. 

Jacinta: Yes, so we all know that food components or nutrients are usually divided into fats, carbohydrates and proteins, though these three can be subdivided to a near-infinite degree, but there are also vitamins, minerals and other biochemical elements in various quantities, and with variously vital effects. Currently the US Dept of Agriculture (USDA) has a database of 188 nutritional components of food, under which some info is provided on many thousands of chemical elements. 

Canto: So garlic, the USDA reckons, is found in 58,055 foodstuffs, including, uhh, garlic. Raw garlic itself is described as containing 67 nutrients, both macro and micro, some of which can only be found in very minute quantities. And yet many components, such as allin, which helps to give garlic its particular odour and flavour, aren’t listed on the database. 

Jacinta: Allin is converted into allicin, through the enzyme allinase, when you crush or chop garlic. That’s when that lovely/notorious stink hits you. 

Canto: Right, and this is apparently a major problem across the whole database. They added a few dozen flavonoids – plant compounds that can lower the prevalence of cardiovascular disease – in 2003, but recent researchers have been frustrated by the many gaps, and are building their own more comprehensive database, based on their own chemical analyses. It’s called FooDB, which now lists almost 400 times the number of nutritional compounds as the USDA database. 2306 for garlic, for example, compared to the USDA’s 67. But there’s a lot of work still to be done, even on garlic. Only a tiny fraction of those compounds have been quantified – we don’t know the exact concentrations. And this is a problem for the whole of FooDB, with about 85% of compounds unquantified.

Jacinta: Sounds like we need an equivalent of the old human genome project – but for every single edible product? Nice, a few hundred lifetimes’ work, if you can get the funding. 

Canto: Well, it suggests that we’ve massively overlooked the complexity of our food – and not only the foods themselves, but their interaction with the microbes and enzymes in our body. But here’s the thing – brace yourself – some nutritionists disagree!

Jacinta: OMG! Scientists are disagreeing?

Canto: The counter-argument is that ‘dark matter’ in nutritional terms is a beat-up. That, though much research is still needed in nutritional epidemiology, in relation to particular conditions and so forth, we know what the essential nutrients are, so the ‘dark matter’, which tends to exist in ultra-minute quantities, would make little difference. But the researcher who coined the term ‘nutritional dark matter’, Albert-Laszlo Barabasi, begs to differ – of course. He points out, for example, that vitamin E, or its absence, can have adverse effects at minuscule quantities, and it may be that all the flip-flopping advice we’re given about nutrition may have much to do with the gaps in our knowledge. Taking garlic again, it was found that of the 67 compounds listed for it on the USDA database, 37 had health effects one way or another, but of the 2306 on FooDB, some 574 had what they called ‘potential’ health effects. In any case, it seems to me that a more complete knowledge of what’s in our food can’t be a bad thing, and will very likely be of benefit in the long run. 

Jacinta: That makes sense, but isn’t everything even more complicated, when you think of how all these nutrients interact with our individual microbiota, and the enzymes that break down our food more or less efficiently, depending on how numerous and healthy they are, which no doubt varies between individuals? 

Canto: Yes, Barabasi and others working on all this ‘dark matter’ are well aware of these complex interactions, but they reckon that doesn’t detract from the need to know much more about this particular component of the food-nutrient-digestion-health cycle. And Barabasi does in fact compare the current state of knowledge with the days before the human genome project, when much DNA was considered ‘junk’. It’s just not a good idea to assume that such a large proportion of nutrients are barely worth knowing about. Let’s return to garlic again. It features quite a lot in the Mediterranean diet, which seems protective against cardiovascular disease. Steak, on the other hand, can be problematic. Our gut bacteria breaks down red meat, in the process producing a compound, trimethylamine, which our liver converts into trimethylamine-N-oxide (TMAO). High levels of TMAO in the bloodstream are linked to heart and vascular problems. But allicin, from garlic, which we’ve mentioned before, and which wasn’t on the USDA database, is known to inhibit the production of trimethylamine, so a diet containing red meat – not too much mind you – can be rendered a wee bit safer, and tastier, with a nice garlic dressing. 

Jacinta: And allicin appears to be an anti-carcinogen too. And luteolin, another component of garlic not on the standard database, is also reported to protect against cardiovascular disease. We love garlic! But what about processed foods. Surely there are all sorts of ways of processing, that’s to say transforming, foods and their component nutrients that won’t show up on the list of ingredients. And how do we know if those ingredient lists are accurate in the first place?

Canto: Well, baby steps I suppose. Cooking, of course, has vital transformative effects upon many foods. And I recall that when you whisk an egg it becomes ‘denatured’ – how transformative does that sound! The more you think about the interaction of foods, with all their barely recognised components, with transformative processes occurring both outside and within our bodies, the more it makes your head spin, and the more you realise that dietary science has a long long way to go. 

garlic cultivars from the Phillippines

Written by stewart henderson

September 30, 2020 at 7:33 pm

thoughts on smoking, cancer and government

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a simple and provenly effective solution

Recently I was talking about unhealthy habits to my students – I teach academic English to NESB students – and smoking came up. A student from Saudi Arabia piped up: ‘smoking isn’t unhealthy’.
Now, considering that this same student, a married man aged around thirty, had previously told me that, in ancient times, humans lived to be over 900 years old – ‘it says so in the Bible’ – I wasn’t entirely surprised, and didn’t waste too much time in arguing the point. Actually, I think now he probably mentioned the Bible to show or suggest that Moslems and Judeo-Christians might agree on some things!

Of course, this student was a smoker. Many of my male students are. These students are predominantly Chinese, Vietnamese and Arabic speakers, that’s to say from countries whose governments have acted less forcefully in dealing with smoking than has the Australian government. I myself smoked. albeit lightly, until the age of 24 (a long time ago). Now, having been diagnosed with bronchiectasis, I’m extremely intolerant of cigarette smoke, not to say smokers.

I’m currently ploughing though Siddhartha Mukherjee’s classic Emperor of All Maladies, and have just finished the section on smoking and cancer, and the battle with tobacco companies in libertarianism’s heartland, the USA. 

Cigarette smoke contains a number of carcinogens – but what is a carcinogen? It’s basically a product or agent that has a reasonable likelihood of causing cancer, which doesn’t of course mean that it will cause cancer in every instance. You can play Russian roulette with the 60 or more well-established carcinogens in cigarette smoke, and risk-taking young men in particular will continue to do so, but it’s a massive risk, and the dangers increase with age and length and frequency of use. Lung cancer is the most regularly cited outcome, but as the US surgeon-general’s 2010 report shows in vast detail, cancers of the larynx, oral cavity, pharynx, oesophagus, pancreas, bladder, kidney, cervix, stomach and liver can all be induced by this inhaled chemical cocktail. And cancer isn’t the only issue. There is the problem of nicotine addiction, as well as cardiovascular and pulmonary disease, and fertility and foetal developmental effects. 

With all this evidence, why do people still smoke, and why don’t governments step in? Drugs with far less devastating effects are illegal, so what gives?

Of course the role governments should play in determining or influencing public health has always been debated, as has the efficacy of banning particular substances and practices. The situation isn’t helped by the facts on the ground, an ad hoc regime in which relatively harmless substances such as marihuana are banned almost worldwide, while proven carcinogens like tobacco, costing millions in treatment, are merely ‘discouraged’ to varying degrees. Similarly, in some countries you have ‘cults’ like falun gong being treated as highly dangerous and criminal while more mainstream ‘cults’ such as christianity, no less or more nonsensical, being given a free ride. None of which promotes faith in government decision-making regarding our physical or psychological health.
Even so, I believe governments should play a role. We pay taxes to government so that it can organise our particular state more effectively for all of its citizens – and that means subsidising education, health and general welfare, to reduce inequalities of opportunity and outcome. Democratic government and an open society helps to reduce government ineptitude, ignorance and corruption. The science and technology sector in particular – a proudly elitist institution – should play a more significant role in government decision-making. But a real weakness of capitalist democracy is that political leaders are too often swayed by business leaders, and the money and influence they bring to the table, than by knowledge leaders. This obeisance paid to business success, with insufficient regard paid to scientific evidence, is possibly the greatest failing of modern political society.

Written by stewart henderson

January 5, 2020 at 10:47 am

a brief history of radical mastectomy

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Dr William Halsted

Siddhartha Mukherjee is an oncologist, an academic and an astonishingly gifted writer and story-teller, in the Indian tradition of seemingly effortless, self-effacing wordsmiths. I read, and learned heaps from, his 2016 book The Gene a while back, and now I’m being educated by his first book The Emperor of all Maladies, a history of cancer. 

The book twists together different threads of cancer treatment in the modern era, most notably various forms of chemotherapy, and surgery. I’m focusing solely on surgery here, as it pertains to breast cancer, because it highlights the relation between experts (very predominantly male) and sufferers (exclusively female).

The term mastectomy is a bit of a mystery, at least to me. The suffix –ectomy is clear enough, meaning ‘cutting out’, or surgical removal, and ‘lumpectomy’ is a slightly dismissive term for the surgical removal of lumps (from the days when full-blown excision was king) . Maybe mastectomy refers to the removal of a mass of tissue, though why it wouldn’t be called massectomy or masectomy, and why it refers only to the breast, I don’t know. It has nothing to do with mast cells.

The radical mastectomy – the concept refers to ‘root’ as in rooting out, rather than quasi-political radicalism – is most associated with an American physician, William Halsted, though radical surgery in the treatment of cancer was far from unknown when Halsted began practising in the 1870s. Cancer at the time was recognised as the growth and spread of malignant tissue, at mysteriously varying rates, and the surgical removal of that tissue seemed the obvious response. Nineteenth century developments in anaesthesia helped to make the procedure more bearable for all, but operations in the US were often ad hoc and unsanitary. In the late 1870s Halsted made a trip to Europe, which radically changed his outlook and practice. He encountered and absorbed the ideas of various pioneers in surgery and anatomy, including Joseph Lister, Theodor Billroth, Richard von Volkmann and Hans Chiari, then returned to the US, and in the 1880s he quickly established a reputation for boldness and skill as a surgeon. Having become familiar with cocaine, which he recommended as an anaesthetic, he soon became addicted to the drug, which gave him seemingly boundless energy. He tried using morphine to kick the habit, and then found himself in a struggle with both drugs, but this barely damped his work-rate.

Hasted had become particularly interested in Volkmann’s surgical work on breast cancer, and noted that, though the surgeries became more extensive, the cancers returned. An English surgeon, Charles Moore, was experiencing the same problem. Moore’s painstaking analysis of the operations and the following relapses showed that malignant cells had begun to proliferate around the edges of previous surgeries. It seemed clear to him that the surgeries just weren’t extensive enough, and by limiting the surgery to the clearly evident cancerous tissue, and not widening the margins to ensure that the malignant region was properly cleaned out, surgeons were exercising ‘mistaken kindness’. Of course, the problem with this argument was that more radical surgery could itself be life-threatening as well as permanently disfiguring and debilitating. What was also not known at the time was the detailed mechanism of cancer’s metastatic spread throughout the body via the blood and lymph systems. However, this was a time when medical expertise tended to go unquestioned. Halsted and his surgical followers were considered heroes, and the delayed return of the cancers tended not to be dwelt on. The surgeons certainly did buy time for their patients, but often at great cost. Volkmann, for example, had taken breast surgery further by removing not just the breast but the muscle beneath it, the pectoralis minor, to try to ensure the complete removal of the cancer. Impressed, Halsted took things to the next level, cutting through the more vital pectoralis major, essentially killing off movement of the shoulder and arm. Radical mastectomy had now truly arrived, and was to become even more radical, with the collarbone and the group of lymph nodes beneath it becoming the next target, and it didn’t stop there, as cancer kept recurring. As Mukherjee describes it:

A macabre marathon was in progress. Halsted and his disciples would rather evacuate the entire contents of the body than be faced with cancer recurrences. In Europe, one surgeon evacuated three ribs and other parts of the rib cage and amputated a shoulder and a collarbone from a woman with breast cancer.

Siddhartha Mukherjee, The Emperor of all Maladies, p65

There were, of course, no female surgeons at this time, and precious few female doctors, and the male-female power imbalance was coupled with that of the expert and his suffering if not panicking victim to create a kind of juggernaut of largely unnecessary suffering. It took years to reverse this radicalising trend. Nowadays, radical mastectomies are very rarely performed, but with so many giants in the field – who often controlled the nature of clinical trials related to cancer – having earned their reputations through their surgical expertise, change was slow in coming, in spite of a gradual increase in often heroic dissenting voices. For example, Rachel Carson, the author of Silent Spring, refused to undergo a radical mastectomy, which would in any case have offered only brief respite as the cancer had already spread to her bones. Changing attitudes to experts and their secret and superior knowledge was of course a feature of the sixties and seventies, when the turning point really occurred. Developments in the field of course played their part. The knock-out blow for the procedure is largely associated, according to Mukherjee, with another surgeon, not unlike Halsted in energy and drive.

Bernard Fisher had been analysing the data of Halsted’s critics, notably Geoffrey Keynes in England and George Crile in the US, and became increasingly convinced, for a number of reasons, that radical mastectomy was a wrong-headed approach. In 1967, Fisher became the chair of a national consortium in the US, the National Surgical Adjuvant Breast and Bowel Project (NSABP), and began an uphill battle to run large-scale trials to test the efficacy of different treatments of breast cancer. Patients were reluctant to engage, and most surgeons were hostile. The process took years, but results were finally made public in 1981. Here’s Mukherjee’s summary.

The rates of breast cancer recurrence, relapse, death and distant caner metastasis were statistically identical among all three groups [i.e treated with radical mastectomy, with simple mastectomy, or with surgery followed by radiation]. The group treated with the radical mastectomy had paid heavily in morbidity, but accrued no benefits in survival, recurrence or mortality.

Siddhartha Mukherjee, The Emperor of all Maladies, p201
Dr Bernard Fisher

So. Richard Feynman once famously/notoriously said ‘science is the belief in the ignorance of experts. When someone says science teaches us such and such, s/he’s using the word incorrectly – science doesn’t teach us, experience teaches us.’ I agree. Science isn’t a person, let alone an expert person. Science is, to me, an open-ended set of methods based on experience. Experience creates new methods out of which new experiences are created, and we move on, trying to right the wrongs and to minimise the damage, while always maintaining our skepticism.


The Emperor of all Maladies: a biography of cancer, by Siddhartha Mukherjee, 2011

Written by stewart henderson

December 22, 2019 at 3:01 pm