Food: from fuel for survival to social and personal identity
It is difficult to find a dimension of everyday life that holds at once more federative and dissentious power than food. Beyond the purely physiological dimension of keeping the body’s metabolism alive and in working order, food is endowed with a huge symbolic power that often overrides any purely nutritional effect. Omitting certain foods while privileging others may gain you respect and social inclusion or it may guarantee you the status of a pariah.
Whether vegan or low-carb, fat-friendly or -stigmatising, whether you skip breakfast or never miss a snack, whether pork or beef is the enemy, whether you crave crisps or are a cookie fiend says at least as much about you and your cultural identity as about the status of your health. As the French writer and food philosopher, Jean Anthelme Brillat-Savarin put it in the early 19th century: “Tell me what you eat, and I will tell you what you are”.
Indeed, we have come a long way from early humankind when the ingestion of food and its frequency was probably more a matter of happenstance and instinct than the product of true personal choice. Before modern nutritional science started investigating the biochemical effects of certain foods and diets on the human metabolism, it was local availability, geographical provenance, ethnic belonging, socio-economic status and religion rather than personal preference that guided and regulated the selection and intake of food. Of course, empirical observation of the effects of certain foods on health or constitution also played an important role in the dietary recommendations of e.g., traditional Chinese or Ayurvedic medicine.
But even today, after decades of research in food and diet, culminating in Western public health recommendations such as the famous food pyramid, it is virtually impossible to define the one best diet for everyone. In fact, human, as opposed to animal, physiology seems characterised by a surprising plasticity and even resilience. People can adapt to and even thrive on the most contrarian regimens: from the high-fat, high-protein mostly animal-based diet of the Inuit to the vegetarian fare found in vast swathes of South and Southeast Asia. Of course, it still seems reasonable to assume that tolerance to certain foods, not to mention their respective bioavailability or health-inducing properties, has a strong evolutionary hence socio-geographical component. And this has long been an object of intense (paleo)anthropological research, with many studies focusing on the analysis of various ancient and contemporary hunter-gatherer diets, the introduction of grinding, roasting, cooking and fermenting as well as the transition to agriculturally based food cultures.
This transition has highlighted very tangible effects on various physiological parameters such as height, weight, bone density, dental health, etc. To some extent, this has led to the recent popularisation and fetishization of so-called “paleo” diets – often crude simplifications of complex local food traditions evolved over centuries. But it has also provided plausible explanations for the prevalence of certain diseases in some ethnic groups, an occurrence that becomes particularly obvious when these populations migrate and rapidly change diets. It may also account for specific food (in)tolerances such as the (in)ability to digest lactose, which varies strongly with exposure to pastoral culture and may explain significant regional differences.
Globalisation: from colonisation to industrialisation
There is, however, a relative scientific consensus on the fact that colonisation and – even more so – industrialisation with their far-reaching consequences on food production, distribution and consumption are probably the most disruptive factors in human nutrition globally. The move away from local and seasonal cultivation and distribution to globally controlled networks continues to have a significant impact on human diet and health – from ensuring the availability in Europe of strawberries in December and oranges in June or of exotic delicacies such as coffee, ginger or tomatoes, not to mention refrigerated transport or novel processing and preservation methods, such as the hydrogenation of fats.
This gradual transformation and its public health impacts – long-experienced in early industrialised regions such as Europe and North America but increasingly perceived in emerging economies – is seen as one of the major causes for the epidemic rise of civilisation diseases such as obesity, cancer, cardiovascular disease or diabetes, not to mention a host of auto-immune conditions. Potential culprits include diets rich in tablesalt, refined sugars and grains, artificial sweeteners, processed fats as well as all manner of additives used to influence appearance, texture, smell, taste or shelf-life. The rise of industrial agriculture has also shed light on the indirect impact on health of nutritionally depleted soils, chemical fertilisers and pesticides, not to mention GMO-based cultivation. Similar effects can be observed with factory farming, featuring a move away from grass feeding towards mainly grain and bean fodder as well as the use of antibiotics and growth hormones in animal husbandry. Of course, the latter aspects remain the object of embittered debate featuring the diverging interests of consumers, local governments, global lobbies and international organisations based, among other factors, on the seemingly unresolvable tension between the necessity of feeding an ever-increasing world population whilst aiming for ecological sustainability.
Paradoxically, the industrialisation and globalisation of food as well as its correlate i.e., increasing nutritional illiteracy or the erosion of traditional food wisdom, have fuelled the opportunity to redefine a lowest common denominator for a more healthful diet – from a scientific as well as a more popular perspective. “Eat food. Not too much. Mostly plants.” was American food writer Michael Pollan’s first attempt to create a universal rule for healthy eating. What may sound like a truism – i.e. “eat food” – has become anything but self-evident from his North American perspective, given the dizzying array of highly-processed pseudo-foods designed by the corporate food industry. “Not too much” references the prevalence of obesity and other weight-related conditions in westernised countries while “mostly plants” hints at the issue of sustainability, given the environmental impact of industrially driven meat- and dairy-intensive diets. In his following opus “Food Rules”, Pollan attempted to further distil simple nutritional guidelines for the average consumer such as “Don’t eat anything your great grandmother wouldn’t recognize as food” or “Eat only foods that will eventually rot” – pointing to the need for a return to a largely pre-industrial diet that emphasises locally grown, chemical-free food.
Modern nutritional science: a history of friends, foes and blind spots
This admittedly still very broad framework nevertheless begs the fascinating question of whether there are specifically health-inducing diets, foods and supplements that could benefit a majority of people. Modern nutritional science is relatively young since it can be dated back to 1926 -with the first isolation of a vitamin, thiamine, otherwise known as vitamin B1. The progressive isolation of other vitamins points to the driving force behind this research i.e., the desire to remedy illnesses caused by micronutrient deficiencies such as scurvy or rickets. This then spawned the production of fortified foods, (multi-)vitamin supplements and the determination of RDA or so-called recommended daily amounts – all developments that are still hugely influential in our contemporary dietary management.
In westernised countries, the following decades brought a shift away from a focus on caloric malnutrition linked to war and interwar deprivations. The post-war glut or Fresswelle (bingeing wave) as it was called in Germany, was then seen as catalysing an epidemic of civilisation diseases -most prominently obesity, cardiovascular complaints and type-2 diabetes. This warranted a specific focus on the role of (refined) sugar and (saturated) fat in westernised countries – as opposed to a continuing emphasis on calorie increase, micronutrient deficiencies and protein supplementation in emerging economies. At the time, saturated fat won over refined sugar as the nutrient to be demonised for its role in cardiovascular disease. This contentious consensus was to have a lasting impact on westernised diets reaching a peak in the 1980s with the emergence of low-fat (and sugar-free) or “light” products. Even into the 1990s, the prevalent nutritional recommendations focused on an excess versus deficiency model: limiting calories, saturated fat and sugar while increasing dietary fibre, vitamins and minerals.
This rather myopic take on the potentially pathogenic effects of single food groups and the consequent obscuring of the complexity of nutritional interactions could only be corrected through the rising popularity of evidence-based medicine. The design of large-scale and long-term nutritional studies focusing on specific cohorts enabled a much broader investigative focus: beyond the effects of single (micro-)nutrients, regional dietary patterns could be taken into account and compared for various health effects, and increasingly so on a genetic level. This, for instance, enabled the singling out of some regional diets as particularly health-supportive or -inducing such as the traditional Mediterranean diet with its emphasis on fresh plant-based foods, fish and olive oil, while further highlighting noxious patterns related to westernised malnutrition and its reliance on heavily processed foods. According to researchers Mozaffarian, Rosenberg and Uauy in their article on the history of modern nutritional science: “Building on the evidence for multifaceted effects of different foods, processing methods, and diet patterns, new priorities for research are emerging in nutrition science. These include optimal dietary composition to reduce weight gain and obesity; interactions between prebiotics and probiotics, fermented foods, and gut microbiota; effects of specific fatty acids, flavonoids, and other bioactives; personalised nutrition, especially for non-genetic lifestyle, sociocultural, and microbiome factors; and the powerful influences of place and social status on nutritional and disease disparities.”
Nutrigenomics, ageing and the future of the human diet
In recent years, the science of nutritional genetics or nutrigenomics has emerged. Based on the increasingly complex mapping of the human genome, the increased availability and cost-effectiveness of molecular testing and the tremendously enabling effect of artificial intelligence with its capacity to process and compare large data collections, its stated aim is to provide increasingly personalised or group-specific nutritional insights to enhance health. While extremely promising, the new science raises a number of regulatory and ethical issues and it still needs to take into account and overcome several levels of complexity such as the interaction between e.g., genes, nutrients, ethnicity, environment and disease.
These most recent developments have fascinating implications for the anti-ageing field since the health-enhancing or -diminishing properties of food almost automatically impact the evolution of senescence. Enrolling both the macro-insights generated by large-scale studies on dietary patterns and more targeted genetic or epigenetic findings on the effect of specific micronutrients may enable individuals to tailor truly personal diets in order to lead long and healthy lives – perhaps prompting Brillat-Savarin to posthumously declare: “Tell me what you eat, and I will tell you how old you are”.
“Dis-moi ce que tu manges, je te dirai ce que tu es” aphorism no 4 from the foreword to : Brillat-Savarin, Jean Anthelme, Physiologie du Goût, Paris : Sautelet, 1825
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