Viruses, Fungi and Bacteria want to live inside our body, feed off our food supplies and reproduce. They have been and remain the greatest threat to human health.
Our immune system stops them from entering and kills them if they get in therefore by understanding your immune system, you can help to reduce your risk of disease or illness.
Our immune system is constantly being rebuilt and good nutrition plays a vital role in providing the building blocks. If you run low on some of the vital raw materials, you may become more susceptible to infection. So lets take a look at overall immunity, including foods.
The first part of our immune system is physical barriers
Our skin covers us from invasion so take care to tend to cuts and open sores. Our sweat glands produce sebum that form a protective layer over our skin. We have hairs or cilia lining our entrances (nose, throat, ears) and mucous membranes in the throat that trap them. I often wonder why people shave all their bodily hair as it has a role to play in immunity. The cells of the lining secrete mucous to trap the invaders.
Then you will notice that we sneeze and cough to get rid of the invader and we need to be well educated on the need to protect people around us from what we expel. We urinate and defecate to eliminate bugs out of our body, for example a food poisoning event can lead to vomiting, sweating and diarrhea. Hand hygiene is important to stop the bug spreading. Update 2020: of course, some viruses evade capture such as Covid-19.
The second part is our Gut Bacteria and Immune Cell clusters
Our stomach acid is particularly important to kills bugs. However some bacteria can survive it, such as Helicobacter Pylori. If the invader gets past the stomach, it then meets our healthy gut bacteria. Trillions of them line our small and large bowel keeping an eye on traffic. They ‘chat’ to clusters of immune cells called Peyer’s Patches, that look similar to lymph nodes, located in our intestines who send on communications to other immune cells.
The third part is our army of White Blood Cells
White Blood Cells (WBC’s) live in our lymphatic system, patrolling our tissue and fluids, always on the alert for invaders. They have a short life (few hours to a few days).When you are well, they are low in numbers. Take a look at your last set of blood test results and you will see a low count. A high count of WBC’s is a red flag to a GP. Tobacco smoking raises WBC’s and I have seen this on some of my client records.
New WBC’s are continuously being made using the nutrients you eat and store. When a virus, bacteria or fungi invades the body, our immune system is activated. We need to be able to make WBC’s fast, given their short life. That is why nutrition is important to immunity so eat well and maintain good stores of nutrients.
Antibiotics are lifesaving medications but beware of taking too many as you will develop resistance to them. Always follow an antibiotic with a probiotic and a high-fibre diet rich in prebiotic foods.
Food and Immunity
Following is a detailed description of what you need, why and where to find it in food.
Protein is the essential building block for all new cells. Interferon, Complement and Transferrin are 3 protein molecules used in the fight against invaders. Therefore we need a protein-rich diet more than ever when under attack. An easy figure to remember is to eat protein to support your weight. So if your ideal weight is 70kg, eat 70 grams of protein. Note – your ideal weight not your overweight or underweight number. Use a Food APP is check.
Healthy proteins: Lean meat, eggs, venison, free-range poultry, white fish, oily fish, shellfish, whey protein, lentils, beans, nuts, seeds, brown/wild/basmati rice. Avoid processed meats (low quality sausages, burgers, pies).
2. Vitamin A
We mentioned earlier the role of mucous-producing interior skin lining cells trapping viruses and bacteria.. Vitamin A is needed for the structure and integrity of these cells. Vitamin A increases lymphocyte (white blood cells) numbers and enhances resistance to infection.
Vitamin A food sources: (it is a fat-soluble vitamin so stores well) Liver, whole-fat or fortified milk, yogurt, butter and oil of fish. The best Pro-vitamin A are dark green leafy vegetables(spinach, chard, spring greens, kale) and yellow and orange vegetables and fruits – peach, apricots, parsley, sweet potatoes, yam, carrots, sweet potato. squash, broccoli, spinach, cantaloupe melon.
3. Vitamin E
The main role of vitamin E is to protect the fat in our cell structures and to mop up harmful substances. It protects organs such as the thymus where white blood cells are made and protects the army of white blood cells as they patrol the body.
Best food sources of Vitamin E: (again a fat-soluble vitamin, storing well)The oils from seeds and nuts, particularly wheat germ oil, safflower and sunflower oil, whole nuts and seeds, green leafy vegetables, avocado, asparagus, tomatoes, broccoli
NOTE: avoid cooking at high temperatures with nut and seed oils as the fat is damaged and large amounts of Vitamin E are needed to mop up the damage. Cook high heat with butter or coconut fat and use olive oil for moderate heat cooking.
4. Vitamin C
Vitamin C also has a protective role. It is best taken in small quantities across the day (250mg x 4) so as to keep the blood vessels topped up, because like other water-soluble vitamins, you pee it out after it has traveled through your system doing its protective job. Vit C travels in our blood, semen, plasma and all bodily fluids protecting tissue and mopping up harmful substances.
Best food sources of Vitamin C: ( a water-soluble vitamin, not storing, needs daily dosage) Fresh Fruits & Vegetables – Red chilli pepper, Bell peppers, Papaya, Guava, Parsley, Watercress, Cauliflower, Orange juice, Kiwi, strawberries, Broccoli, Brussel Sprouts, Potato, Tomato, Berries, Kale
The B Vitamins all work together (B1, B2, B3, B5, B6, B12 & folic acid) and are essential for the conversion of food into energy. B6 is a co-enzyme in over 50 processes in the body and one symptom of B6 deficiency is low White Blood Cell count (lymphocyte) and decreased antibody production suggesting it is an essential nutrient for immunity. Maintaining energy levels to fight an infection makes all the entire B family essential.
Best food sources of Vitamin B6: (it is a water-soluble vitamin, needing daily topping up) /> Sunflower Seeds, Soya Bean, Lentils, all types of beans, Wholegrains (brown/wild/basmati rice, oats, Wheat, Barley, Rye), banana, avocado, walnuts, hazlenuts, chestnuts, turnip, spinach, raisins, prunes, brussel sprouts, peppers, potato
6. B12 & Folic Acid
Both of these are required for DNA and RNA – the making of new White Blood cells.
Best food sources of Vitamin B12: liver, lean meat, milk, cheese, eggs, fortified soya products, fortified cereals. There is no reliable plant source of B12 – some sedweeds are edible but it is not clear if B12 is absorbed by the human intestine.
Best food sources of Folic Acid: Leafy green vegetables lightly cooked, Wheat germ kidney beans, spinach, broccoli. A small amount found in a wide variety of fruits, vegetables, wholegrains.
7. Zinc, Copper, Manganese
These 3 nutrients are needed to make an antioxidant Enzyme called Superoxide Dimutase which protects the white blood cells from an increased level of free radicals as a result of the attack on the immune system. We all heard about the cytokine storm during Covid-19.
A deficiency of zinc and copper in humans increases a person’s susceptible to infections and leads to a low count in white blood cells.Supplementation of manganese has been shown to enhance natural killer cell and macrophage activity
Best food sources of Zinc: Liver,Oysters, Meats, Beans, Nuts, Wholegrains, Pumpkin & Sunflower Seeds
Best food sources of Manganese: Tea, Pineapple, Pecans, Almonds, Peanuts, Beans, Brown rice, Spinach
Best food sources of Copper: Shellfish – oysters, mussels, Nuts, Beans, Lentils, Wholegrains, Avocado, Artichoke, Radishes, Mushrooms, Organ meats, Yeast, Dark bitter chocolate.
Selenium is required for an antioxidant enzyme called Glutathione Peroxidase (GPx) which protects white blood cells. It has been shown in selenium-deficient humans that some white blood cell numbers are low and that the killing aspect of others is defective. Selenium deficiency may allow viruses to mutate into more dangerous pathogens.
Best food sources of Selenium: Offal, Meat, Fish, Brazil nuts, Eggs, Wholegrains and currently vegetables are being promoted as being grown on selenium-enriched soils – mushrooms and brussel sprouts
9. Iron There is a third protective antioxidant enzyme called Catalase and this enzyme requires iron. We need adequate iron for red blood cell production which carry oxygen, an essential nutrient for life. However certain microbes thrive on iron and our immune system produces or activates proteins (transferrins) that removes ‘free’ and ‘excess’ iron during an infection to prevent this happening.
Best food sources of iron: Offal, Meat, Wholegrains, Spinach (cooked), Fish, Eggs, Beans, vegetables
11. Vitamin D
Vitamin D is a hormone interacting with most cells in the body at a genetic level. It is unique because it can be made in the skin from exposure to sunlight. Vitamin D receptors are present in immune cells, thereby affecting the proliferation (growth) of some white blood cells and the production of antimicrobial proteins.
Best sources of Vitamin D : 20 minutes Summer strength sunlight per day on a patch of naked white skin (5 to 6 times that amount of time needed for dark skin) salmon, mackerel, sardines, anchovy and herring. I recommend supplementing Vit D from Oct-May in Ireland due to lack of sun. Supplements are available in health stores and pharmacies @ 1000iu, 3000iu and higher.
Stress & Immunity
We have stress hormones that rise as we start to feel anxious, scared, overwhelmed. The function of the stress hormones, cortisol and adrenaline, is to protect us so it dampens down our immune cells, stopping them from attacking and allowing us to flee from danger. However long-term chronic stress leaves us vulnerable to invaders such as viruses and to old viruses such as Shingles that lie dormant in our spine since we had chicken pox as kids. Have a look at 2 other articles on my site about stress – Part 1 and 2.
Stress burns through nutrients. Alot of people do not recognise or acknowledge that they are stressed. Stressors can be 4 types:
Emotional (death, divorce, financial upset )
Physical (low-calorie dieting, accident, lack of sleep, working too hard, too cold/too hot temperature);
Psychological (depression, bullying)
Chemical (pollutants, radiation, too many chemicals on skin, hair, food etc).
Joan Moloney is a nutritional therapist, specialising in Weight-Loss and motivating people to make healthier choices. Get in touch if you need help.
Recognise stress, acknowledge it and learn to manage it with meditation, talk therapy and exercise. This will certainly protect your immunity.
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