Food; or 'what you should know' - Brain Labs

Our understanding of how diet affects health is limited to 150 key nutritional components that are tracked and catalogued by Food Standards Australia and other national databases. Although this knowledge has been transformative for health sciences, helping unveil the role of calories, sugar, fat, vitamins and other nutritional factors in the emergence of common diseases, these nutritional components represent only a small fraction of the more than 26,000 distinct, definable biochemicals present in our food—many of which have documented effects on health but remain unquantified in any systematic fashion across different individual foods. Using new advances such as machine learning, a high-resolution library of these biochemicals could enable the systematic study of the full biochemical spectrum of our diets, opening new avenues for understanding the composition of what we eat, and how it affects health and disease.

The maxim of Jean Anthelme Brillat-Savarin, “Dites-moi ce que vous mangez et je vais vous dire ce que vous êtes”—‘you are what you eat’—remains as pertinent today, in the era of modern medicine, as it did in 1826. Indeed, the exceptional role of diet in health is well documented by decades of research in nutritional epidemiology, unveiling the role of nutrients and other dietary factors in cardiovascular disease, obesity, type 2 diabetes mellitus (T2DM), and other common diseases. Yet, the bulk of our current understanding of the way food affects health is anchored in the 150 nutritional components that Food Standards Australia (FSANZ) and other national databases track, and these nutritional components represent only a subset of the total pool of definable biochemicals in the food supply

The dark side of nutrition

Consider garlic, a key ingredient of the Mediterranean diet: the FSANZ quantifies 67 nutritional components in raw garlic, indicating that this bulbous plant is particularly rich in manganese, vitamin B6, and selenium. However, a clove of garlic contains more than 2,306 distinct chemical components from allicin, an organosulfur compound responsible for the distinct aroma of the freshly crushed herb, to luteolin, a flavone with reported protective effects in cardiovascular disease which are listed in FooDB, a database representing the most comprehensive effort to integrate food composition data from specialised databases and experimental data. As of August 2019, FooDB records the presence of 26,625 distinct biochemicals in food, a number that is expected to increase in the near future. This exceptional chemical diversity could be viewed as the ‘dark matter’ of nutrition, as most of these chemicals remain largely invisible to both epidemiological studies, as well as to the public at large.

Where does this remarkable chemical diversity come from? Living organisms require a large number of biochemicals to grow and survive in their limited environments, well beyond the nutritional components that we humans need in our diet. From an evolutionary perspective, plants are characterised by particularly rich chemical composition, mainly because they are unable to outrun their predators; their defense is occasionally mechanical (for example, through the development of spikes) but is predominantly chemical, exercised through smell, taste, and appearance. These chemical defenses require an extensive secondary metabolism that produces a wide range of flavonoids, terpenoids, and alkaloids. Polyphenols—a highly studied group of chemicals believed to be responsible for the health effects of tea and other plants—are the product of that secondary metabolism. The number of secondary metabolites is estimated to exceed 49,000 compounds, indicating that the 26,000 chemicals currently assigned to food represent an incomplete assessment of the true complexity of the ingredients we consume. Multiple environmental factors, from light to soil moisture, fertility, and salinity, can influence the biosynthesis and accumulation of such secondary metabolites. Humans and other animals who can hunt for the necessary food sources do not have the ability to synthesise many molecules our metabolism requires, like ascorbic acid or alpha-linolenic acid, necessitating a source for these essential nutrients.

Overall, an analysis of FSANZ and FooDB data confirms that plants as a group have the highest chemical diversity, with approximately 2,000 chemicals detected in most examples. Yet, 85% of these chemicals remain unquantified, meaning that while their presence has been detected or inferred, their concentration in specific food ingredients remains unknown. With garlic, for example, FooDB reports the chemical concentration for just 146 chemical components; the remaining 2,160 chemicals listed in FooDB are not quantified. We, therefore, raised the question as to whether the scientific literature contains valuable information on food composition beyond that currently compiled by food databases. Indeed, experimental and analytical projects focused on specific foods and food-borne chemicals are published on a daily basis, and only a small fraction of them inform databases.

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Robbie V

 

Rob VDM

Author Rob VDM

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