How To Boost Your Immune System Through Your Diet
There is no magic here, eating well has always played an important role in supporting our body’s immune system. Nutrition can easily take the back seat, however when it comes to preventing illness, it plays a pivotal role. If you haven’t paid attention to your diet in a while, now is a good time to review and make a start on some changes that will keep your body healthy now and into the future.
When we get sick, the bugs and bacteria damage our bodies cells which is followed up with an immune response to fight and clear away the illness from the body. One of the key pathways of this process is the inflammatory pathway. Establishing and maintaining a healthy diet is one key modifiable factor that can improve immune function, reduce inflammation and boost overall health.
Generally speaking, a healthy balance diet includes a good balance of macronutrients (carbohydrates, fats and protein) and a variety of foods which contribute to micronutrient intake (vitamins, minerals and antioxidants). When convenience options are taken off the tables, all it takes is a quick Google search to find easy and nutritious meals you can cook in bulk ahead of time.
And when we are looking to really zoom in on immune function, below are some of the key nutrients which can help boost your immune function.
1. Vitamin D
Vitamin D is a unique ‘vitamin’ as it actually acts more like a hormone. Our body can produce it in the skin from contact with light, and only gets small amounts from the diet. It plays a role in many important functions in the body, most notable in bone health and immune function. Getting enough vitamin D daily is important for maintain bone health and a healthy immune system.
Foods rich in vitamin D: Oily fish, eggs, mushrooms and fortified foods
Daily intake: Males and females 5 ug/day
10-15 minutes of morning or late afternoon light on the forearms, chest and face is adequate to maintain vitamin D levels in most people (avoid long periods of direct sun in the middle of the day and use sun protection).
2. Vitamin E
Vitamin E is a fat-soluble vitamin and acts as an antioxidant for the body and is involved in immune function. Antioxidants help protect cells from damage caused by exposure to environmental toxins. Vitamin E supplementation may assist with reducing viral
Foods that contain vitamin E: Nuts, seeds, olive oil, green leafy vegetables, wheat germ, broccoli.
Daily Intake: Males: 15mg, females: 15mg
Zinc is a mineral that is involved with a wide variety of functions in the human body including maintaining the health of immune system cells.
Daily Intake: 14mg males, 8mg females
Foods rich in Zinc: Meats shellfish, eggs, dairy, nuts, seeds whole grains
4. Fish oil and Omega 3 Fatty Acids
Essential fatty acids are important for healthy cells and cannot be produced in the body, so need to be consumed regularly in the diet. Omega 3 fatty acids are a type of essential poly-unsaturated fatty acid, which have anti-inflammatory properties. These fats are involved with inhibiting the production of pro-inflammatory molecules in the body. While Omega 3’s can be consumed in both plant and animal sources, marine sources of these fats are the most powerful in reducing inflammation- plant sources, while health promoting, need to be converted via other pathways in order to be used by the body, making them less potent.
Foods rich in essential fatty acids: Oily fish and seafood.
Plant based omega 3 sources: Chia seeds, flaxseeds, walnuts, soy
Daily Intake: 250-500 mg
5. Green Tea
Green tea contains health boosting compounds called EGCG’s (Epigallocatechin-3-Gallate) which help support the cells of the immune system and to reduce inflammation. Swapping a cup of coffee of more green tea could be an easy option to boost immune function.
6. Herbs and spices
Herbs and spices can have powerful antioxidant, anti-microbial and anti-inflammatory properties making them a great addition to the diet on a regular basis and provide flavour without adding extra calories. Use garlic, ginger, chilli, cinnamon a turmeric for a powerful boost to the immune system.
7. Gut Health
Our gut microbiome consists of the trillions of different species of bacteria that line our digestive tract and it is one of our body’s first line of attack for foreign particles that have entered the body; they also help to digest our food and produce some other health promoting nutrients such as short chain fatty acids. As such a healthy gut is imperative for a strong immune system, and a generally healthy body. A healthy gut can be characterised as one with a diverse range of bacteria in balance.
The bacteria in our gut feed off the indigestible carbohydrates (AKA fibres) that we consume from our fruits, vegetables, wholegrains, legumes, nuts and seeds, and a diet rich in a variety of fibre sources helps to support the diversity of bacteria in our gut.
Probiotics from fermented foods, which contain live strains of bacteria (such a yoghurt and sauerkraut) and supplemental probiotics can also have a positive impact on gut health, particularly when gut balance is known to be out after taking antibiotics or after bouts of food poisoning. They can do this by helping to rebuild the barrier of bacteria in the gut after infection and help to reduce gut permeability. There are thousands of different strains of bacteria, all of which can play different roles in modulating gut health. As such, it is important to note that treatment with probiotics may require specific strains of bacteria, so if looking to supplement it is important to seek out advice from a health professional.
There is a lot of information emerging on factors which impact our gut health; however it is still a developing area of research. You can get started on boosting your gut health now with some simple and actionable steps to improve and maintain your gut health:
- Consume a variety of plants, aiming for 30 different plants each week. This provides a variety of fibres for the bacteria of the gut to feed from, which helps promote the maintenance of a diverse gut microbiome. This allows ensures a mix of soluble fibre (which softens stools) and insoluble fibres (which helps move stools through the bowels) are consumed, which in combination, promotes healthy bowels generally.
- Consume a range of colours, the colours from fruit and vegetables not only help boost our immune cells, but they are also important for the bacteria in our gut.
- Consume fermented foods which contain probiotics that can help boost the population of beneficial bacteria in the gut. There are some conditions where supplementation with probiotics may also be useful, however check in with your doctor or dietitian before supplementing to make sure you are taking the right product.
- Stay hydrated. Adequate water intake helps to keep the lining of the gut healthy and helps keep your bowels moving properly.
- Reduce alcohol intake. Consumption of alcohol can promote inflammation in the gut and alter the balance of gut bacteria. Reducing alcohol, or not consuming it all, will help keep promote a healthy gut.
8. Boost your micronutrients by maximising the colour in your diet
Micronutrients are essential nutrients that keep our body healthy, but unlike macronutrients, they don’t provide us with energy. Micronutrients are vital for hundreds of different chemical reactions and function in our body. We only need to consume small amounts of these, but we need to ensure that we have regular doses. Micronutrients include vitamins and minerals, and we can also include antioxidants in this group.
Vitamins are used for important reactions such as energy production, immune function, tissue production, nerve function, blood clotting and growth. There are 13 vitamins, some of which are fat soluble (Vitamins D, E, A and K) and the rest are water soluble (vitamin C and the B vitamins).
Minerals are important for functions such as bone and teeth formation, fluid balance, nerve and muscle function and several chemical reactions in the body. There are 14 main essential minerals the main minerals are Calcium, Iodine, Iron, Magnesium, Potassium, Sodium and Zinc and others which are essential but required in much smaller doses are Selenium, Fluoride, Manganese, Molybdenum, Phosphorus, Chromium, and Copper.
11. Daily Intake Recommendations
There are known minimum requirements for each micronutrient; some are required in larger quantities and some in smaller quantities, but this does not make one more important that the other. Without adequate intakes of each of the essential vitamins and minerals the body will not function properly, and eventually it can lead to deficiencies and disease. Therefore, we need to consume a variety of fresh micronutrient rich foods each day in order to be healthy over the long term. There are daily recommendations for each nutrient set by National Health and Medical Research Council in Australia, based on a very large body of research for each micronutrient. A Recommended Daily Intake (RDI’s) for a nutrient refers to the amount required each day in order to prevent 97.5% of the population from deficiency- pretty much everyone. These amounts will vary from person to person according to age, sex physiological state (e.g. pregnancy) and in some cases, activity levels. There is a handy online calculator by the NHMRC which will calculate your RDI’s available at www.eatforhealth.gov.au.
12. A healthy diet is more than just calories and macros
You can see, while knowing around how many calories and macronutrients you should consume each day is important, these two pieces of information do not give us any indication of how healthy a diet is. You can stay within your calorie ‘budget’ and hit your protein, carbohydrate and fat requirements, however if you do this by consuming foods that are highly processed and lack adequate amounts of the micronutrients, it is highly likely that over a period of time, your energy levels, body and health will suffer.
A really easy way of assessing if your meal is providing you with a decent dose of nutrients is by looking at how many colours are on your plate. The colour of fruits and vegetables are one of the key reasons they are good for us. These colours are pigments from vital phytochemicals (natural and healthy plant chemicals).
13. Blue and purple fruits and vegetables
Are rich in a flavonoid called anthocyanin. Foods like red grapes, berries, wild black rice, egg plant, and plums are rich in anthocyanins, which are thought to have antioxidant and antimicrobial properties (they help mop up damage to your cells and fight off unwanted microbes in your body).
14. Red fruit and vegetables
Are coloured by a carotenoid called lycopene. Lycopene intake is associated with reduced risk of certain cancers, heart disease and diabetes. Foods such as tomatoes, red grapefruits, watermelon and papaya are rich in lycopene.
15. Orange and yellow fruits and vegetables
Are coloured by another carotenoid called beta-carotene. Beta-carotene acts as an antioxidant which converts in the body to vitamin A- an essential vitamin. Foods such as carrots, sweet potatoes, pumpkin, rockmelon, red and yellow capsicums and apricots.
16. Green vegetables
Contain a range of nutrients including folate, iron, vitamin C, vitamin K and glucosinolates (sulphur rich compounds that are really good for you). Green vegetables such as broccoli, kale, cabbage, spinach, dark green lettuce varieties, boy choy, herbs and rocket are all rich in these beneficial nutrients.
17. White vegetables and fruit
Although not technically colourful, also provide many beneficial nutrients. These foods can be rich in fibre, potassium vitamins and minerals and should definitely make a regular appearance on your plate. White foods include cauliflower, garlic, white onions, mushrooms, potatoes and bananas.
Given that 95% of Australians are not consuming enough fruits and vegetables, it is a good opportunity to review your intake and make a plan to increase how much you have each day. Here are some general guidelines to help you fill your day with more colour.
- Aim to have three different colours on your plate at lunch and dinner.
- Put vegetables on your plate first and aim to fill half you plate.
- Aim to build up to having 400-500g of vegetables per day. If you have not eaten this volume previously, make sure you build up rather than going straight to the upper volume.
- Aim to have 1-2 pieces of fruit per day.
- Aim for 30 different plants each week to help enhance the diversity of your gut bacteria
18. Easy to store kitchen staples to build a healthy diet
- Carbohydrates which are rich in fibre and that are unrefined such as brown rice, quinoa, oats, wholegrain cereals, wholegrain flours, wholegrain breads, fruits, vegetables and legumes.
- Protein which are lean such as chicken breast, steak, tinned tuna and frozen salmon, eggs (whites) and whey protein
- Healthy fats including olive oil, nuts, seeds, nut and seed butters, flaxseed oil, egg (yolk)
- Frozen vegetables
- Frozen fruit
- Herbs and spices to flavour and to add extra nutrition such as garlic, mustard, basil
- Other essential cooking items such as stock, tinned tomatoes, tomato paste, soy sauce, honey
- UHT milks, coconut mik
19. Nutritious, quick and easy cooking ideas:
- Slow cooked meats wit root vegetables
- Bolognaise (with lean mince or with lentils)
- Vegetable soups
- Roasted vegetables
- Minced meat with spice mixes
- Zucchini loaf
- Overnight oats
- Wholemeal muffins
- Pre-made smoothie bags (keep in the freezer)
- Muesli slice
- Protein balls
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