Along with a healthy diet the following factors have a positive impact on our immune system.

1. Adequate sleeping, 2. Avoiding alcoholic beverages, 3. Avoiding cigarettes or any other intoxicants, 4. Exercising Regularly, 5. Maintaining a healthy body weight, 6. Drinking an abundant amount of water and 7. Avoiding mental stress or minimizing mental stress.

The first six factors could be maintained by anybody with the will power. Number 7 largely depends on the environment in which we belong, especially in the countries like Bangladesh. All said and done, food habit remains one of the most important criteria to boost our immune system.​

Ensuring appropriate micronutrients in our daily diet is a must to generate strong immunity against any foreign body inside ourselves. Especially vitamin A, B, C, D, E, and minerals (Zn, Se and Fe) have been considered as immune boosting or enhancing micronutrients. Unfortunately, most of us believe that the food supplements and multivitamin tablets are only one way to ensure micronutrients in our body. The actual scenario is completely the opposite. These micronutrients absorb properly and effectively if we intake these directly with the food item containing respective micronutrients. Because each and every biomolecule needs to be well prepared before taking part in any biochemical reactions inside our cells which could be ensured from natural sources. This implies that the sources of these micronutrients could be easily collected and incorporated in our daily diet chart.

Vitamin A: There are two different forms of vitamin A, one preformed Vitamin A (Retinol) and another one is Provitamin A or Carotenoids. The former one usually comes from animal sources (fish, meat, chicken and milk) while the latter from coloured vegetables or fruits. If we include guavas, cantaloupe, carrots, sweet potatoes, spinach, pumpkin, lettuce and most green leafy vegetables in our daily diets, we can get enough Vitamin A to boost our immunity.

Vitamin B: There are eight different types of Vitamin B available of which Vitamin B6 (Pyridoxine) and Vitamin B9 (folate or folic acid) have the influence on enhancing the immune system. Beans, lentils, mustard, seeds (especially pumpkin seeds), chicken, eggs, liver, citrus fruits, peanuts, onions, bananas, raisins and green vegetables could be the standard sources of Vitamin B6 and B9.

Vitamin C: Vitamin C or ascorbic acid is the most available vitamin in food, at least in Bangladesh. If our diet contains citrus fruits, amla, guava, grapes, broccoli, cauliflower, peas, spinach, vine spinach, potato, tomatoes, etc, then we can get enough Vitamin C necessary for a healthy immune system.

Vitamin D: The best source of Vitamin D, Calciferol, is sunbathing at least for 30 minutes (the best timing is 10 am to 3 pm). The UV rays from sunlight trigger the conversion process of cholesterol to Vitamin D in our skin cells. Along with immunity boosting, this vitamin also helps our body to absorb calcium. The potential sources of these vitamins are milk, salmon, cod liver oil, sea food, mushrooms, eggs, meats, bananas, apples, brown rice, brown wheat flour.

Vitamin E: Vitamin E is a lipid-soluble phenolic cellular antioxidant compound and found as tocopherol in our blood. In addition to immune boosting it also acts as a very good antioxidant to reduce the reactive oxygen species (ROS), responsible for various diseases including cancer, in our body. Amla, sunflower oil, almonds, peanuts, kiwifruit, hazelnuts, lettuce, spinach, broccoli, mango, ripe tomatoes, etc, are sources of Vitamin E in our diet.

Food or vaccines cannot save us from COVID-19 if we do not follow the guidelines of WHO and local public health departments or IEDCR. The people on the streets seem to be inviting COVID-19 by avoiding the rules of wearing masks and maintaining social distance

Iron: Iron is one of the most important minerals for any living organism containing blood red. It is the central component of the red blood cell which is indispensable for carrying oxygen for cellular respiration. In addition it is one of the important components for boosting the immune system. Dietary iron has two main forms: heme and nonheme. Plants , for example esculent root, esculent leaves, broccoli, potato, cabbage etc, and iron-fortified foods contain nonheme iron only, whereas meat, seafood, and poultry contain both heme and nonheme iron.

Zinc: Zinc plays the crucial role in the process of generation of new immune cells, therefore it is an important mineral in any pandemic situation brought upon by any virus or bacteria. Chicken, yogurt, crabs, beans, mushroom, cabbage, etc. are sources of Zinc.

Selenium: To protect us from any kind of infection Selenium is nutritionally essential for humans and the constituent of more than two dozen selenoproteins that play critical roles in reproduction, thyroid hormone metabolism, DNA synthesis, and protection from oxidative damage and infection. It could be ensured from sea food, meat, liver, cheese, lentils, beans, spinach and carrots.

Most countries do not produce vegetables during winter whereas vegetables are the most abundant during the winter in Bangladesh. Public health specialists predicted a second wave of COVID-19 this winter. The availability of the winter vegetables and diets rich with these elements could play a vital role to build herd immunity among the people of Bangladesh. Unfortunately, the prices of the vegetables are almost one and a half times higher than the previous year. Reducing the price or making those food items cheaply available for the low income groups could help us to fight COVID-19. However, bringing your daily needs with the plan to ensure at least one item in each diet could help our family ensure a healthy diet during this pandemic. We may take eggs, milk, spinach, esculent roots and leaves, cauliflowers, potato, amla, carrots, peanuts, lentils and if possible meat and fish to ensure a healthy diet. Such a diet will ensure a recommended amount of vitamins A, B, C, D, E, Fe, Zn and Se to generate a healthy immune system in our body to protect us from COVID-19.

However, food or vaccines cannot save us from COVID-19 if we do not follow the guidelines of WHO and local public health departments or IEDCR. The people on the streets seem to be inviting COVID-19 by avoiding the rules of wearing masks and maintaining social distance. We need to keep in mind that COVID-19 costs 1.5 million lives within 365 days! Therefore, we must change our lifestyle in a planned way to ensure a balanced diet, careful movements and balanced life to save ourselves.

Sheikh Mahatabuddin is an associate professor at the department of NFE, DIU, Dhaka and can be contacted at [email protected]

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