Our immune system is like an “army” that protects us from environmental toxins and infectious agents, including bacteria, viruses and parasites. The soldiers are the different immune cells, each with a highly specified function. Assisting these soldiers are chemical mediators and receptor cells that act as messengers to inform the immune system when to attack.
The first line of defence involves the cells that make up the epithelial layer of the gut. They have a gatekeeper function and are tightly packed together to form a barrier, preventing invaders from entering the gut. The M cells (macrophages) patrol for potential pathogens and engulf foreign cells.
They also recruit other immune cells such as the T cells into action. The two major types of immune cells are the B cells and T cells. The B cells produce antibodies, which are proteins designed to recognise the pathogens. The T cells are proteins that destroy the pathogens, once they are tagged with the antibodies.
The key nutrients that promote and support the mediators, receptors and immune cells are: protein; vitamins C, A, E, D and B6; essential fatty acids; and the minerals selenium and zinc. As most of the immune cells are in our gut, an adequate intake of dietary fibre is essential for the billions of bacteria to produce the substances that keep our gut healthy and the immune system strong and robust.
Nutrient-dense foods we need to consume
Foods that provide essential nutrients are:
- Fresh vegetables
- Fresh fruit
- Legumes such as beans, lentils, soya beans and chickpeas
- Wholegrains such as brown rice, corn, barley, rolled oats, quinoa, seed bread and sweet potatoes
- Healthy plant-based fats such as seeds, nuts and vegetable oils
How do we ensure that we get enough nutrients?
1. Structure your meal
Structure your eating pattern into three nutritious meals a day. Enjoy healthy snacks, should you feel hungry between meals. This will ensure that your blood glucose levels stay within acceptable limits.
2. Include balance in your meals
Nutritious meals should include most of the major food groups. These are proteins; whole grains; fruit and/ or vegetables; and healthy fats. (See the menu below.)
3. Plan and shop wisely during lockdown
We don't always have enough healthy foods in our fridges and pantry to put together healthy meals. We therefore need to plan what we're going to eat and draw up a shopping list accordingly. If you decide on some of the meals listed below, it will help you compile a healthy shopping list.
4. Limit the consumption of nutrient-poor foods
Foods devoid of nutrients and fibre, and high in salt, sugar and trans fats should only be enjoyed occasionally as a treat. This includes: white bread; white rice; pasta; peeled and mashed potatoes; oven baked chips; refined breakfast cereals; hot cross buns; white wraps; scones; croissants; pies; pastries; white salty crackers; potato crisps; white rusks; cakes; and biscuits.
Researchers have found that consuming too much sugar (sweets, chocolates, desserts and ice cream) can inhibit the uptake of essential nutrients by your body's immune cells.
5. Don’t forget healthy lifestyle habits
Research has demonstrated that moderate exercise; limiting alcoholic drinks; getting an adequate amount of sleep (approximately seven hours); and drinking enough water are essential practices to keep your immune system strong.
And also bear in mind that a healthy diet will help you to maintain a positive state of mind throughout this difficult period.