The potential to accurately and rapidly measure hundreds of individual molecular species provides novel opportunities for food and nutrition sciences. By enabling the molecular fingerprinting of food components and their metabolites, metabolomics is helping scientists to investigate the intricate relationship between food and human health. Here, we look at the various applications, strategies, and tools related to metabolomics.
Food not only provides us with energy, but also modulates our health and well-being. Yet it remains largely unclear which components in food — and through which mechanism of action — can reduce the risk of disease or improve health. As we enter a new era of technology, the potential to accurately and rapidly measure hundreds of individual molecular species provides novel opportunities for food science and nutrition (1–4). For food and nutrition researchers, metabolomics, the screening of small-molecule metabolites, enables the molecular fingerprinting of food components. Of no less consequence, metabolomics also confers the ability to evaluate the effect of ingested food, by providing an analytic "snapshot" of metabolism.
Food MetabolomeBecause of metabolomics, considerably more chemical detail emerges from the analysis of foods and beverages. In certain foods, thousands of chemical entities are now detected, identified, or both. Knowledge of food metabolomes (collections of natural and nonnatural components in a particular food or food group) could provide critical information for studying complex interactions between nutrition and health. The characterization of food metabolomes also affects food producers, who optimize organoleptic properties (aromas and flavors) and increase the abundance of healthy compounds in their products.
Natural Food Components
Until recently, food analyses were limited to estimating nutritional values within the content of six broad categories: carbohydrates, fats, proteins, water, vitamins, and minerals. Metabolomics is transforming modern nutrition research by revealing the thousands of nonnutrient food components that, although not life-sustaining, could affect human well-being and health. For example, we know that phytochemicals such as lycopene (in tomatoes), isoflavones (in soy), and flavanoids (in fruits) are responsible not only for the organoleptic properties of the plants in which they are found but also for their salutary effect on human health.
Nonnatural Food Components
Besides natural products, metabolomics is used to screen foods and beverages for a plethora of environmental chemicals like pesticides, contaminants derived from drugs and consumer products, or even pathogens and toxins (5–10). Thus, metabolomics is helping to solve some of the new challenges that the modern food industry faces such as the discovery of biomarkers that detect the safety, quality, and traceability of food products. Furthermore, metabolomics is providing novel insights into the effects of food additives, preservatives, and transgenic modifications on human health and the environment.
Food Processing and Storage
Metabolomics is leading scientists to discover and characterize the chemical modifications in food caused by its storage and processing, which could dramatically alter molecular content and health properties. Indeed, food preparation methods (frying versus baking and steaming versus boiling) could significantly affect the molecular composition of food products, as could preservation processes like freezing, drying, smoking, and refrigerating.
The characterization of food metabolomes is leading to the discovery of food-specific biomarkers, which are indicators of diet exposure and food consumption. Already, metabolomic screenings have revealed urinary markers associated with an individual's dietary intake. These markers include 1-methylhistidine, for meat-rich diets; trimethylamine, for fish-rich diets; and phenylacetylglutamine, for vegetable-rich diets. Similar quantitative screening of metabolites could facilitate the monitoring of food consumption in epidemiological or dietary intervention studies.
Food and Human Health
Epidemiologic studies suggest dietary patterns could significantly lower the risk of certain diseases including cardiovascular disease, Alzheimer's disease, and cancer. Currently, diets enriched in natural antioxidant, vitamins, and phytochemicals are perceived as healthy in western countries, where diets generally include those compounds in the form of nutritional supplements. Yet knowledge of the mechanism by which dietary compounds and diet regimens actually affect human health is limited. Investigating the effects of dietary compounds on human health could help in formulating optimal nutritional recommendations.
Dietary Fats and Lipidomics
Lipids represent the bulk of fats found in food. Along with proteins and carbohydrates, they constitute the three major classes of nutrients. Typical examples of dietary lipids are cholesterol, triglycerides, saturated fatty acids, and trans-fat. Ingestion of lipids has been linked to various pathological conditions including obesity, metabolic syndrome, and cardiovascular diseases. However, not all lipids are associated with increased disease risk. Indeed, some other well-known dietary lipids, such as omega-3 fatty acids and vitamins A and D have been linked to improving human health, which might explain their exponential growth as nutraceuticals.
Lipidomics, the metabolomic analysis of lipids, falls under the umbrella of metabolomics. Nevertheless, the distinct solubility properties of lipids often dictate their separate analysis in metabolomic experiments. Indeed, unlike polar metabolites (for example, amino acids and nucleotides), lipids are mostly insoluble in water. Thus, lipids require organic solvents or distinct solid-phase extraction (SPE) procedures for their extraction from biological samples.