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A Diet a Day

by Vincent Guy

“I was out in the garden planting out some carrots for the night fighters.”

This line from ‘Beyond the Fringe’, the satirical show of 1960, makes fun of the idea that carrots might be useful for improving your night vision. So I went on to think the whole carrot/eye connection was nonsense. But no, the vitamin A they generate really does promote eye health; just not specifically night vision. A total absence of Vitamin A still causes widescale blindness (even death) in some parts of the world. Whence the night vision angle? From WW2 indeed, as the line suggested. Put about by the British Ministry of Propaganda, it was meant to suggest to the Germans why the British were knocking so many Nazi planes from the night sky, and conceal the real reason, which was the invention of radar.

Why do people go on diets? For health or to lose weight, or a bit of both. There are plenty to choose from: a quick glance at Audible Books website offers no fewer than 14 different ways of listening yourself to a resonant regime.

I write all this not as an expert, but as a layman struggling to get correctly informed. The first health diet I came across was during the hippy era: macrobiotics, somehow linked to the wisdom of the East; eating rice, the chewy brown version, not the fluffy white stuff, was the road to nutritional Nirvana. Then along came the Atkins diet (cut the carbs, binge on fats and protein) meant to reduce weight, but the death of the eponymous Atkins from cardiac arrest at a mere 73, damped down the fashion. A variant of Atkins lives on in the Keto Diet (cut carbohydrates to near zero). Before him was Hay (don’t mix acidic with alkaline foods). Hay the man made it to 74, but in 1940 not such bad going. Scientific evidence for these various approaches is, to coin a phrase, rather thin. There’s some truth in the book title Dieting Makes You Fat (Geoffrey Cannon, 1983). If diets do work, it’s at least in part by making people more aware of their food intake, rather than just shovelling it down. You might rather go back to the Victorian Prime Minister Gladstone who believed in chewing every mouthful at least 32 times, once for each tooth. He made it to the age of 91.

Fast-growing in the 2020s is veganism (zero meat and dairy), built on concern over our impact on animals, the wider ecosystem, and our own health. A strict vegan approach will undersupply Vitamin B12 (add yeast flakes, shiitake mushrooms or tofu). For the calcium that conventional eating gets from dairy products, include plenty of beans, seeds and nuts.

Another topic getting attention recently is the danger of UPF, Ultra Processed Foods (Ultra-Processed People, van Tulleken, 2023). This is basically anything that hasn’t been prepared and cooked in your own kitchen. UPFs range from pizzas, biscuits and supermarket bread to fizzy drinks, ice cream and cornflakes. And by the way, whisky, gin, rum and vodka are also on the list.

All these things involve factories breaking ingredients down into near-molecular levels, then reconstituting them with added flavourings, emulsifiers, colourants, texture enhancers, sweeteners, and synthetic vitamins. At least sixteen artificial sweeteners are in common use, with names like Advantame, Sucralose, Sorbitol. Are they safe? Do they have long term negative effects on health or obesity? The evidence is at best mixed. In UPFs all the actual nutritive content has been scourged away and a host of near-toxins added in. Levels of sugar, saturated fat and salt remain high. No longer really food at all.

The microbiome is a 21st century field of study and discovery, the word itself only defined in 1988. This is the mass of micro-organisms we carry around with us. Your body is made up of many trillions of cells, all guided by your DNA. But a similar number – fungi, viruses, bacteria – live on you and inside you; on your skin, your hair, even your eyelashes, but their main residence is in your innards, concentrated in the gut. The broad profile is established as you are born, modified by what you have eaten in the years since. To cull those little passengers within is not good; they are the heart of your immune system. Antibiotics, which fit very well with the germ theory of disease (i.e., if there’s a germ around, kill it), unfortunately also devastate the microbiome. We now realise it’s important to rebuild it after taking antibiotics (e.g. with live yogurt, onions, fibres). Buccal bugs (in your mouth) remain on the blacklist; but will the time come when halitosis gets a reprieve?

Advice in the media, and even direct from doctors, flips around all the time…

Coffee? Don’t touch it if you want to keep your heart ticking. - No, that little stimulus is good after all.

Eggs? OMG! The cholesterol! Avoid! – Latest: eggs are excellent, plenty of protein, little fat, plus lutein and zeaxanthin (you can Google those two yourself).

Milk? When I was a kid, it was top of the pops, delivered to our door by a friendly milkman, pecked at by the local robins, helping us all grow tall and strong-boned. At school we got free milk (to which we kids sneakily added chocolate powder, sugar and heat from the school radiators - yummee!). Mrs Thatcher, as Education Minister, scrapped school milk to save taxpayer money. Schoolkids’ reaction hit the headlines: “Thatcher! Thatcher! Milk Snatcher!”. Then suddenly milk was out, the source of high cholesterol inside and ballooning bellies outside. Today? Well, it depends who you ask.

As part of an overall health check, I recently had a colonoscopy (photos taken inside my insides. The specialist advised me to stop eating nuts: “Tend to get trapped in the crevices, leading to inflammation”. For the next 3 days I went nutless, until I did some due diligence on the internet. According to widescale research reported by the US National Institutes of Health (NIH), “nuts harm your guts” is total nonsense. Care is needed if you suffer from peanut allergy, but then peanuts aren’t really nuts. Deeper digging in the data reveals that going nuts on nuts brings a slightly enhanced risk of liver cancer, which my colonoscopist didn’t mention.

Let’s look into vitamin D, an essential item which the body cannot create; lack of it brings rickets and bowlegs to the young, osteoporosis to the elderly. As it’s absent from most food, you must get out more, sit in the sun. But watch out, too much sun will bring your sunbathing days to an early cancerous close. So best to take a daily supplement. Hold on, mushrooms contain Vitamin D and the shrooms themselves can be put out to sunbathe and build up even more of that delightful D. More time with the googled data reveals two varieties of the magic compound: D2 and D3. Whatever happened to D1? Bear with me while we go into yet more detail. The correct dosage can be measured in at least two ways: IU/day (give me 400–800, please) or micrograms (that’ll be 10–20, thanks). And the heathy level in your blood stream? Tricky. The NIH propose 50 nmol/L or, if you prefer, 20 ng/mLnanograms per milliliter. Sadly, half the US population scores well below this which perhaps explains all those bow-legged cowboys (just don’t blame the horses). Within the EU you’ll get by on 30 nmol. In the UK it’s somewhere between the two (at least since Brexit). With me so far? Be careful you don’t overdo it. Over-D will lead to excessive calcium in your blood (hypercalcemia), which can cause nausea, vomiting, weakness, frequent urination, and stones in your kidneys. Not much to worry about there, then.

My approach in practice? Diversify. I don’t observe or measure myself closely: I don’t do selfies, I haven’t weighed myself in years, don’t have a step monitor and have never counted a calorie. Not to say I don’t get obsessive. For example, my regular recipe for morning porridge includes at least 18 ingredients*, described in normal language, without considering the microscopic level or chemical structures.

With the Neolithic revolution, farming boosted population survival but reduced dietary diversity. More of us survived but in poorer condition. This paradox is even greater today: people are living longer, populations are bursting, but narrowed food range means obesity, diabetes and other long-term debilities are increasing.

We all live in a degree of ignorance; even the experts have only limited knowledge; scientific conclusions shift over time. So eat a highly diversified diet. On the one hand, you’re picking up at least a trace of that microbe or mineral, fungus or fibre that will do you some good. On the other, you’re not pumping yourself full of that harmful stuff which will only be found to be so ten years from now.

*My porridge ingredients: oats (large and small flakes), buckwheat, millet, rye, barley, oat bran, wheat bran, kefir, yoghurt, raisins, 5 kinds of nuts [almond, brazil, cashew, pistachio, hazel], mixed seeds, and on top a swirl of honey or molasses, plus a handful of blueberries, chopped in half if time allows.


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