In modern times, the COVID-19 pandemic is the most severe public health challenge. India has pulled out all the stops in keeping its people safe. Yet, every citizen needs to play her/his part by adhering to the official directives in ensuring the overall well-being of the nation.
In dealing with this infectious epidemic, considerable discussions have revolved around the human defence mechanisms and the role of vitamins in boosting the same.
Deficiencies and Diseases
Undoubtedly, nutritional deficiency can impair immune functions – which are meant to protect against disease or potentially-damaging foreign bodies. Accordingly, maintaining a healthy immune system is critical at all times – more so during the COVID-19 outbreak.
Multiple factors weaken immunity, particularly poor diet and malnutrition, stress, lack of sleep, excess alcohol consumption, smoking and similar bad habits. Nonetheless, vitamins can play a key role in optimising immune functions by boosting the body’s defence mechanism and resistance to infection.
Vitamins are essential dietary constituents, which the body requires to function normally. Our bodies do not produce most vitamins, except vitamin D, which are required in small amounts to maintain good health. Therefore, these must be obtained via the food we eat. Together, vitamins and minerals are termed micronutrients because their requirement is minuscule unlike those of carbohydrates, proteins and fats, which are referred to as macronutrients.
Known to influence the immune system, vitamins A, C, D and E have received specific attention in recent years as these boost immune functions. Vitamin A plays a central role in vision, skin, genes, growth and immunity. This vitamin is found as carotenoid – a pre-vitamin in many foods such as green leafy vegetables, spinach, broccoli, carrots, pumpkins, melons, mangoes. Carotenoids are converted into active vitamin A in the body. Vitamin A’s active form is found in liver, egg yolk, butter, whole milk and cheese.
Its deficiency is a major problem in populations subsisting on cereals with limited intake of green leafy vegetables and fruits. Vitamin A deficiency is widespread in India. Its supplementation in preschool children decreases mortality and morbidity from some forms of diarrhoea, measles and malaria by improving immunity.
Dietary Intake and Immunity
Another key one is vitamin D, synthesized by the body with the help of sunlight while some foods are natural sources. These include oily fish, egg yolk, veal and mushrooms. Its deficiency is universal. Even in countries such as India with ample sunshine, it remains deficient. Epidemiological studies show vitamin D deficiency is present in most parts of India and across age, gender and socio-economic groups. The best-known function is in calcium absorption and bone health while its role in supporting immunity is complex. Nonetheless, it improves innate and adaptive immunity while enhancing the pathogen-fighting ability of white blood cells.
Next comes vitamin C, which plays multiple roles – synthesizing collagen, absorbing iron, scavenging free radicals and defending against infections and inflammation. Fruits (especially citrus), cabbage-type and green leafy vegetables, lettuce, tomatoes, potatoes, and liver comprise rich sources. Its deficiency can cause scurvy with symptoms such as bleeding gums, bruised skin, fatigue, appetite and weight loss as well as lower resistance to infections. A potent antioxidant, it contributes to immune defence by supporting various cellular functions of both the innate and adaptive immune system.
Then there is vitamin E – naturally available as a group of eight fat-soluble compounds. The liver converts these into alpha-tocopherol – the chemical nomenclature for vitamin E. Nuts, seeds, and vegetable oils are among the best sources of alpha-tocopherol. Green leafy vegetables are also rich in vitamin E. It is a potent antioxidant and can modulate immune functions. Although its deficiency is rare, supplementation significantly enhances immune functions, especially in the elderly.
Collectively called micronutrient deficiencies, vitamin and mineral deficiencies are widespread across India. The National Nutrition Monitoring Bureau (NNMB) monitors the population’s dietary intake. A series of surveys by NNMB highlight the poor dietary diversity in our population. More than 75% of children and women receive less than 50% of their daily dietary requirement of vitamin A. The recent Comprehensive National Nutrition Survey revealed that barely 6.4% of Indian children below two years received a minimum acceptable dietary intake.
The ideal way to augment vitamin and mineral intake is by diversifying the diet, which is a sustainable, long-term approach. But to quickly boost a person’s micronutrient status in the short term, it is best to rely on fortified foods (including home fortification) as well as vitamin and mineral supplements, under the guidance of a doctor or dietician.
The writer is Senior Advisor, Nutrition – Tata Trusts