Food for Life

Highlights

• Many of our problems around the science of food come down to over-simplifying the properties of foods and our responses to them. I want to restore the complexity and the wonder to our food.

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• Current estimates suggest there are as many bacterial cells as there are human cells in our bodies (actually it’s slightly more bacteria at a ratio of 1:1.3), which really means we are half human, half bug.

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• The current research focus is on at least 40 trillion bacteria in our guts, but our microbial garden is teeming with other forms of life. Viruses also play a role in our digestion and health and outnumber bacteria by five to one, but we cannot yet measure them accurately. These viruses eat bacteria and are crucial in controlling their numbers when they get out of control and may also be helpful to us. We are also full of natural fungi, of which the best known subtype is yeasts. As well as yeasts used in beer- and bread-making, we also have plenty of candida living happily inside us.

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• Polyphenols are essentially plant chemicals created to protect against environmental attacks such as harsh weather or specific predators. Foods vary massively in the quantities of polyphenols they contain – with a tenfold difference between different coloured vegetables of the same type, which can also vary if processed or super-heated. In general, plants have more polyphenols if they have grown in a stressful rather than a cushy environment.

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• The latest evidence shows that our microbes actually help inform us about what foods we should be eating, even causing us to crave certain foods. Our microbes literally send chemical messages to our brain to encourage us to eat what they need for their survival. Having lots of unhealthy microbes in your gut, therefore, can lead to a vicious cycle whereby you crave foods that help these less friendly bacteria, which in turn drive you to become less healthy.

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• After five years collecting over 11,000 samples from citizen scientists around the world, the American/British Gut Project team produced its first findings. What turned out to be more important for gut health than whether you were a paleo follower, a fruitarian, a vegetarian or even a vegan, was the number of different plant species you ate each week.13 Thirty different plants per week appeared to be optimal.

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• By fermented I mean foods that use live microbes in their production, what used to be called ‘cold-cooking’, but are also present in the final product.

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• We also now realise that every time our cells replicate, they produce some DNA mutations and that these mutations accumulate to produce microscopic tumour cells throughout our body. Luckily, our immune defences identify these mutant cells as ‘alien’ and destroy them. But when cancer-seeking immune cells are weakened by disease, poor diet or some immuno-suppressant drugs, these micro-tumours go unchecked and can become life-threatening.

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• All human cells contain mini batteries of bacterial origin called ‘mitochondria’ that generate energy for us to function and convert oxygen. A by-product of this chemical change leaves a few molecules, ‘free oxygen radicals’, floating around, like flying sparks in a metalworks. Too many free radicals can cause inflammation, damage and stress to other cells, so they are usually removed rapidly, with the help of the immune system, which loses efficiency as we age.

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• Thanks to their reproductive system and the need to interact with and protect a foreign foetus, pre-menopausal females typically have a more resilient immune system than males. When matched for age and weight, females have higher numbers of circulating B cells, which most of the time provides an advantage against infections, but it also leads to a much greater risk of autoimmune diseases than for males.

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• We have an illogical approach to the concept of risk, which is partly due to the influence of the media and the dearth of hard facts. We routinely overestimate the risks of overdue sell-by dates, raw meat, sulphites, gluten and lactose, or of getting food poisoning by reheating leftovers or eating unpasteurised cheeses or salami. We are probably underestimating risks of consuming pesticides or herbicides, infected chickens and eggs, antibiotic-fed animals, snacking, or the long-term effects of artificial sweeteners and other chemicals in ultra-processed foods. We tend to massively overestimate the benefits of vitamins, and underestimate potential risks of anything labelled a ‘health supplement’.

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• Knowledge of seasonality can help us bypass the labels and enjoy a varied and nutritious diet.

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• I experienced this myself in my own experiments using a continuous glucose monitor when trying different porridges and saw a range of steadily reducing blood sugar spikes from instant oats, rolled oats and steel-cut oats, which all have different cell wall structures but similar fibre count. These studies raise major doubts about how fibre is currently measured as this fails to account for the cell structure and how it is digested. It also questions the effectiveness of artificial fibre supplements increasingly being added to food to allow claims of healthiness on the label. New ingredients and food processing techniques could deliver more of the benefits of fibre-rich foods, while some methods are providing false reassurance of healthiness because much of the fibre’s activity may be lost when cell walls become damaged during food processing and in normal digestion. For the same reason, nor should we assume that smoothies are healthy.

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• (Ripe bananas are big ethylene factories and can speed up the ripening of other fruits if kept nearby.)

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• Much of our misconceptions about canned fruit stem from the loss of vitamin C by heating. But while vitamin C is indeed usually reduced by a third, many fruit polyphenols are often increased, even after many months in the can. Fruit and veg preserved in tins are better for us than we might think.

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• This is still inferior to eating the whole fruit, as mechanically chopping the fibre into small pieces alters its structure, breaks up the cell walls and exposes more sugar for faster absorption. I found that eating the same weight of blueberries mixed in a blender gave me a higher blood sugar thirty minutes later than when eating them whole.

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• Counter-intuitively the faster you defrost small fruit, the less damage to the nutrients and vitamins. Use a microwave if you have one:

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• For many vegetables including brassicas, freezing is less good for preserving nutrients, though frozen spinach is a useful and notable exception. Frozen broccoli and green beans also compare well with their fresh counterparts, though we should ideally consume our carrots fresh – essential minerals and vitamins are well preserved in frozen vegetables, aside from β-carotene (the polyphenol that gives carrots their colour).

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• Where would we be if, in 1909, we had rejected Fritz Haber’s novel idea to convert nitrogen from the atmosphere into ammonia for use as a soil fertiliser? This single invention alone is estimated to have increased global food production by up to 40 per cent.

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• I have also learned that buying parboiled rice is much better nutritionally and metabolically than I thought.

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• The sneaky fungus lurked in the soil, waiting to kill bananas decades later. Only the Cavendish variety was resistant to this fungus and could be grown anywhere. Now banana forecasters are predicting the same fate for the Cavendish. The flexible fusarium fungus has now mutated to infect the Cavendish in Asia and is slowly making its way towards Central America. It’s just a matter of time and we have no plan B – so enjoy your bananas while you can.

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• Better still, studies suggest that we can extract 20–50 per cent more polyphenols if we mix a squeeze of lime and its vitamin C with our beans, which many cultures have been doing for centuries.

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• Miso powder is thus essentially a soybean probiotic that the Japanese drink daily; it makes a healthy soup or dressing, and as long as you add hot, not boiling water, enough microbes will survive to nourish Japanese guts. Daily consumption of this probiotic food may be a reason for their longevity, rather than fish or sake.

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• But soluble fibres don’t all have the same effect.

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• Now nearly half of the rice globally is parboiled. Usually pre-cooked and processed foods lack nutrients or add unhealthy chemicals, but rice is the exception: the Huzenlaub method actually retains nutrients from the bran husk, so that unlike polished white rice, it has around 80 per cent of the nutrients of brown rice.

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• A certain fungus called ergot also likes damp rye (and barley), and before fungicides often contaminated the crop, producing chemicals that caused a whole range of unusual symptoms, such as madness and gangrene. The strange outbreaks of convulsions and hallucinations may have caused quite a few people to have been burned for witchcraft as in seventeenth-century Salem. The fungus is also the basis for the hallucinogen LSD.

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• By the Middle Ages an impurity in sea salt was found that improved meat even more. This was called saltpetre (a collective term for sodium and potassium nitrate mixtures), which was transformed by friendly bacteria into the active chemical sodium nitrite. The nitrite forms nitric oxide that binds to the iron in meat and so prevents the breakdown of fats (and the rancid smells). Combining with ripening staphylococcal bacteria on the meat surface, the newly formed nitric oxide keeps the muscle pigments a vibrant red or pink colour rather than an unappealing grey. So the combination of salt and nitrites has been used naturally for centuries in artisan meats; well before anyone worried about the potential risks of nitrosamines that are also produced when nitrites mix with other proteins (see page 38).

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• Less than seventy years ago no one would have believed we might one day run out of fish. It was still common to see shoals of Atlantic fish miles wide and hundreds of metres deep, each producing thousands of eggs each that would ensure an everlasting supply. Yet since 1970, population growth has been outstripping fish production.

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• Aquaculture is under pressure to be more sustainable. In 2015 it took 1.3kg of wild fish to feed 1kg of farmed fish like salmon: a continuous 30 per cent net loss of fish. Activists claim the ratio is in reality more like 2.5kg to 1kg and point out that the 460,000 tonnes of fish food used in Scottish farms is equivalent to the whole UK population intake of fish in a year.

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• Recently, progress has been made and the good news is that in 2023 many farms are now getting their ratios below 1 and even to 0.3, making most farmed fish more sustainable than eating chicken.

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• Freshly caught fish can also smell grassy or of herbs as they share similar unsaturated fats to plants.

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• Plankton is the water equivalent of grass and converts sunshine into energy (and omega-3 oils).

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• For years, the type of fat oil produced naturally both by fish and animals eating grass has been cherished, and omega-3 supplements are taken by about 10 per cent of Americans and about one in five Britons, being their commonest supplement. It is widely recommended to prevent heart problems or cancer for people who find it hard to eat their two portions of fish per week. But data is strangely not as good as people think: the latest studies and massive clinical trials did not show any strong benefits.

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• The closer the fish are to the source of the original nutrients in plankton, the healthier they are for us, so it is probably better to eat small fish that eat plankton directly rather than eating the fish that feed off them naturally or via artificial feed.

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• Tuna is a particular problem because of the demand and high prices at the top-end. US surveys reported over 70 per cent of sushi tuna was fake, and the use of ‘white tuna’ is common in restaurants. The problem is that white tuna doesn’t actually exist, and is usually escolar, a cheap fish nicknamed ‘ex-lax’ for its effects on the gut, that are so bad it is banned in Japan and Italy.

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• I have swapped my tuna mayo sandwiches for an equally satisfying and nutritionally superior chickpea rye sourdough version. Smash some tinned chickpeas with the back of a fork adding lemon juice, caraway seeds, spring onions, garlic salt and mayo. Add some torn nori sheets for extra flavour. Sliced celery adds some extra crunch.

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• Sushi was originally used as a way of preserving fish by wrapping it in salt and rice, allowing microbes to ferment and protect it from going rancid, and has slowly evolved to the global business we see today.

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• Finland has the highest rates of dementia in the world and they eat a lot of fish compared to most countries, but they also have long dark winters and a very high rate of depression and suicide.

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• When considering the latest evidence, long-term regular consumption of cow’s milk does not seem a great idea for most people, and again moderation may be the key.

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• We stupidly believed we could just process the milk industrially to remove the fatty layer, and this would leave all the healthy stuff behind. The fat-soluble vitamins and nutrients get eliminated when you remove the saturated fat content, including vitamins A, D, E and K as well as healthy fatty acids like omega-3 which grass-fed cows will have high levels of.

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• Drinking cow’s milk does not improve bone health or vitamin D status and likely increases weight.

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• The clever chemists that had managed to make liquid vegetable oil solid via hydrogenation had also created a novel chemical bond linking the fat molecules that our body couldn’t deal with, called trans fats, which are so harmful to our health they are now completely illegal in some countries.

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• The small company Doux Matok in Israel uses mechanical tricks to halve the sugar content of its version of hazelnut chocolate spread without affecting the perception of sweetness. This secretive process involves getting sugar molecules to interact more than usual with your saliva to fool your brain into thinking it is sweeter than it really is

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• Molasses has little nutritional value, and in many countries it is used as a temporary, inexpensive, but smelly tarmac for covering dusty roads.

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• It is hard to reconcile the general consensus that high-sugar fruits and berries are healthy, and honey may have some benefits, while refined sugar with virtually the same principle ingredients is considered deadly. This is another example of our muddled reductionist view of nutrition.

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• it takes twelve worker bees their entire lifetime to produce just one teaspoon of honey.

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• The amount of honey consumed (much of it in the US) far exceeds the number of hives capable of producing it. There are, for example, over three times more sales of New Zealand Manuka honey than is physically possible based on the number of hives,

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• Since the ‘honeygate’ scandal of 2013, honey launderers have become smarter and, after milk and olive oil, honey is the third most faked food in the world.

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• Cashews also have high levels of starches, allowing them to be used to thicken sauces and soups.

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• Some countries sell almonds with their skins covered in paprika, an excellent combined source of polyphenols.

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• Roman legionaries were paid with bags of salt, thus the word soldier (saldare) and salary in English, and cash in modern Italian (soldi).

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• The trigeminal nerves of the face and tongue are responsible for a dual role of detecting burning as well as cool sensations. The capsaicin in chilli affects these nerves by releasing a chemical called substance P, which is picked up by a pain receptor, first irritating then numbing the nerve.

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• To gauge the quality of your EVOO, sniff it or slurp it around your palate with plenty of air like wine. As well as grassy or even smoky aromas, you should detect some peppery, fresh and fruity notes from the polyphenols: if good quality, it sometimes makes you cough.

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• The French still look down disdainfully on English sauces, with Voltaire supposedly writing, ‘In England, there are forty-two different religions and only two sauces,’

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