Micronutrients: The Key to Good Health

We eat food for survival, to get enough energy to work and maintain good health. This is possible through a variety of chemical substances in food, such as nutrients, non-nutritional compounds and also certain helpful microorganisms. These food constituents assist in producing energy from food and play specific roles in normal body functioning, growth and development. We spend energy in carrying out internal body functions such as digestion, and in doing physical activities. The concept of energy balance to maintain desirable body weight is explained in this chapter. Amongst nutrients, carbohydrates, proteins, and fats are macronutrients, that we require in large amounts. Raw and cooked foods rich in macronutrients are described with examples. Types of carbohydrates, proteins, composition of dietary fats and oils, essential fatty acids and cholesterol levels in foods are also illustrated. Food also contains micronutrients –vitamins and minerals, that the body needs in small amounts. Micronutrients are essential for many body functions. We need to obtain both the macro and micronutrients daily from the diet in desired quantities, known as Recommended Dietary Allowance (RDA). The interrelationship of macro and micronutrients in metabolic functions is elucidated in this chapter. Similarly, the fundamental knowledge about basic food groups and nutritive values of foods, the bioavailability of macronutrients and their role in biological functions are explained. A brief outline of the potential role of protein, fat and carbohydrate intake in obesity, metabolic disorders and health is also provided.

Micronutrients are increasingly recognised for their multiple roles in a variety of body functions. For example, micronutrients are necessary for cellular growth, energy production, formation of antibodies, blood clotting, and immunity. This chapter illustrates the nature and structure of 16 vitamins and 14 minerals, their specific roles in a variety of body functions, their daily dietary requirements across age-sex groups and rich food sources. As a part of our daily diet, we seldom think about nutritional aspects, especially in the case of micronutrient contents of foods. Good dietary sources of micronutrients are exemplified with tables providing percent contents of each micronutrient in plant and animal foods. It is known that vitamins are sensitive to heat and light, and may get destroyed while cooking food. The chapter explains how vitamins and minerals are lost during cooking and food processing methods and how to reduce these micronutrient losses. Once the food is ingested, absorbability of micronutrients is essential for their involvement in body functions. Factors affecting or enhancing micronutrient absorption and interactions of vitamins and minerals, nutrients and other dietary factors are described in tabular form so as to quickly understand the compatibility of foods in the diet.

Dietary diversification and modification include changes in habitual diet with micronutrient-dense foods and choosing proper food preparation methods for increasing micronutrient bioavailability. Natural plant foods provide us with nutrients as well as non-nutrients such as phytochemicals, which together contribute to multiple health benefits. This chapter illustrates different methods to develop nutritious food products at household or community levels, specific for various age groups like infants, toddlers, adolescents, and adults. To devise micronutrient-rich food products, raw foods with high nutrient contents from different food groups are listed in the tables for ready reference. Practical tips for combining various foods to enhance micronutrient quality of the food product are provided. Furthermore, proper methods of preparation of recipes to minimise nutrient loss are recommended. Good practices in pre-cooking and cooking methods that can retain nutritional quality and digestibility of foods are explained. Many authentic recipes are presented with scientific information about their laboratory-estimated nutrient contents. The extent of difference in micronutrient contents of healthy recipes vs commonly consumed snacks is highlighted. This chapter also provides useful tips to enable the development of recipes of one’s choice, that will contain the essential nutrients. Lastly, dietary guidelines are described explaining the desired quantity of foods from different food groups in daily diet so as to have complete nourishment that may not be met from fortified foods. 

Micronutrients perform a key role in almost all vital body functions like those related to vision, immunity, bone formation, brain function and many others that help in proper growth and maintaining good health. Deficiency of any one or more of the micronutrients can have a negative impact on the overall health. The causes of micronutrient deficiencies and their signs and symptoms are explained in this chapter in a precise manner. Plant and animal food sources with high micronutrient contents with ready-to-eat food supplements per serving size are illustrated for each micronutrient. These can serve as a guideline for preventive measures and diet therapy. Micronutrients are increasingly used as an adjunct therapy in managing various health problems. Effective therapeutic uses of vitamins and minerals are exemplified for a ready reference. Overdose of synthetic supplements of micronutrients and certain environmental conditions may result in toxic effects. To address this, the upper limit for micronutrient intakes and toxic effects of excess micronutrient intakes are also described. The relevance of the yogic concept of ‘sattvic’ diet in modern nutrition and the potential of yoga for micronutrient absorption is also highlighted. The approach of yoga towards healthy diet and the relation between diet and psychological health is explained based on experimental data. The importance of specific micronutrients in health at different stages of life, from pregnancy to old age, is elucidated and remedial measures are suggested. Lastly, evidence for micronutrient supplements as an adjunct therapy for COVID-19 is briefly described. 

Many plants and herbs have been known for healing a variety of health disorders since the ancient practice of medicine. Recent advances in laboratory methods have now identified the chemical compounds in plants (phytochemicals) that are responsible for the health-promoting effects. There are thousands of phytochemicals known so far which have no nutritional value but can help in many biological processes in the human body. The phytochemicals mainly include flavonoids, carotenoids, phenolic acids and lignans. They play a role in many body functions and are equally important as micronutrients in maintenance of health and wellbeing. The synergistic actions of phytochemicals and micronutrients as antioxidative and anti-inflammatory agents may contribute towards disease prevention and betterment of health. Food sources of phytochemicals, their role in various metabolic functions, and health effects are described in this chapter. Gut microbiome, which comprises of intestinal microbial population, performs important functions like digestion of food, regulation of immune system and shares an interactive relationship with dietary nutrients and non-nutrients. Phytochemicals that can influence the gut microbiome have recently been studied as adjuvants for the treatment of obesity, diabetes, cardiovascular disease and inflammatory diseases. The effect of different phytochemicals on gut microbiota and their beneficial health effects are elucidated. New developments related to potential of probiotics as prophylaxis or their therapeutic use in treating the COVID-19 infection is briefly mentioned.