Why you can’t boost immune function (but good nutrition helps optimize)

Wondering how to boost immune system function?  We get asked this question all the time.

While optimizing your immune system all year long is a good strategy for your overall health and wellbeing, this becomes extra important in the fall and winter months with cold and flu season.   You may be wondering if there are immune system booster strategies in general for your health or what you can eat to reduce the risk of colds and flus.  You also might be wondering what foods you should eat if you are stuck at home from work or school sick to help aid in a speedy recovery.

Read on to learn answers to these questions and more.

Can nutrition boost the immune system?

The simple answer is healthy food choices can’t “boost” the immune system above normal functioning and a boost to our immune system isn’t always a good thing.

Your immune system is a complicated system that is still being actively researched as many things remain a mystery.  There is much to be learned about how all the interconnected immune system cells and organs such as bone marrow, spleen, thymus and the lymphatic system work together to help or harm our health.

 Nutrition is linked to immunity and infections and if you have a poor diet and are not eating well you are at a greater risk of infections, colds and flus. Infections can also lead to nutrition concerns or worsen your intake of essential nutrients, vitamins and minerals.  When you are ill and experience vomiting, diarrhea and a poor appetite it is no surprise it can be hard to eat well.

It’s also important to note that it isn’t always better to have a more active immune system as too much of a good thing isn’t ideal. Having a hyperactive immune response such as in the case of an allergic reaction to ordinary nontoxic substances isn’t ideal. An active and changing immune system is also connected to disease such as diabetes, lupus and rheumatoid arthritis.

Which foods help support a healthy immune system during cold and flu season?

No one food, meal, or supplement will significantly support your immune function for the long term. You require a continual supply of healthy food since the immune system is constantly under attack by cold and flu bugs.

Emphasize an overall balanced diet and pay special attention to the following ideas:

Fluids

Essential to prevent dehydration and moisten the lining of the respiratory tract. When dehydrated, tiny cracks form in nasal membranes making viruses more easily able to pass into the body. Drink hot fluids, such as tea and soup, when sick to help with nasal congestion and a sore throat. Adult females require approximately 3 litres of fluid per day, and male adults require about 4 litres of fluid per day (from drinking water, water in beverages, and water that is part of food).

Protein

While the vast majority of North Americans get enough protein, failing to consume enough protein rich foods hinders immune system function. Protein found in foods such as meat, poultry, seafood, legumes, nuts, seeds, tofu, eggs, and dairy foods are the building blocks for antibodies to fight infection and help regulate body processes. Consume a good source of protein at each main meal. To find out more information about protein read our previous blog post here: How Much Protein Do I Need Per Day?

Fruits & Veggies

Fruits and veggies are loaded with vitamins (such as vitamin A and C) and phytonutrients (health promoting properties found in plants), many of which act as antioxidants. Antioxidants work like a police force that is constantly searching for trouble and attempt to raid what looks suspicious. Eating enough antioxidant rich foods means the body has a better chance of fighting colds and flu bugs. Variety is the spice of life when it comes to fruits and vegetables since they all offer a different nutrient and antioxidant profile.

Vitamin D

Failing to get enough Vitamin D in your diet through food and supplements can impair your immune function. It’s difficult to get enough Vitamin D from, and because we live so far north of the equator (making enough sun exposure difficult, another way the body produces Vitamin D), it’s recommended that we all take a supplement. Most adults can supplement 1000-2000 IU of Vitamin D3 daily, but make sure you chat with your healthcare team to make sure you’re taking the right dose for you. 

Probiotics & Fermented Foods

The gut is one of the biggest players in immune function. Some yogurts, kefir and other fermented foods support the “good” probiotic bacteria that live in the gut to fight foreign substances and prevent the growth of harmful bacteria. Since not all probiotics have specific benefit for fighting colds, work with your Registered Dietitian on which yogurts and supplements offer benefit. Note that just because there is some evidence that probiotics may reduce the duration of a cold it does not mean they will be effective for coronavirus or influenza. In time hopefully we will have more research on probiotic supplements for these purposes, until then enjoy your probiotics from food.

Limit Alcohol

A large amount of research suggests drinking alcohol suppresses immune function. There may be a small protective benefit from antioxidant rich wine over other alcohol containing beverages. If you choose to drink, do so moderately and avoid alcohol altogether during times you are already run down.

Supplements

Avoid getting biased information from a supplement store, or so-called “expert” that sells supplements from their office, which imparts a conflict of interest. Instead, work with a Registered Dietitian, the nutrition experts, for credible advice about other popular supplements such as multivitamins, vitamin A, vitamin C, zinc, herbs and dietary supplements. Learn more about common supplements for the immune system.

If you are home sick from school or work what healthy eating advice is best to help with a speedy recovery?  

If you are at home sick from school or work and experiencing cold and flu symptoms and a loss of appetite here are some general eating strategies that can help:

Stay hydrated.

Drink water, sparkling water, tea and broth based soups.  Also consider extra watery based foods such as watermelon, smoothies, juice and sports drinks to ensure your body has adequate fluid.

Eat often.

Since your appetite may be low and you may not want to eat much at one time it is best to increase the frequency of your meals and snacks to every few hours. For a list of healthy snack ideas grab our list of 51 Healthy Snack Attacks here.

Choose healthy comfort foods.

Often when we are sick it is best to go with easy to digest, bland foods. If you can’t think of something appealing to eat do your best to start with carbohydrate rich foods such as toast, bagels, English muffins, plain rice, bananas, applesauce, muffins, apples, pears, canned fruit, crackers, oatmeal cookies, pretzels, popcorn, rice pudding, bread pudding, mac n’cheese, chicken noodle soup or plain pasta with butter, salt and pepper.  If possible add in a bit of protein as this would be ideal.  Protein is found in foods such as yogurt, Greek yogurt, cottage cheese, milk, eggs, meat, poultry, fish, dessert tofu, savory firm cubed tofu, legumes, hummus, nuts, seeds and nut butter.

Ask for help!

If friends or family members offer assistance take advantage of this and ask them for a homemade meal or snack option that you think would be appealing. Also take advantage of online grocery delivery and a family or friend that offers shopping support for you.

Where can I get more information?

Hopefully, the above information helped you better understand the role of nutrition for immune function and help you understand why the common question of how to boost immune system function is actually complicated.  Do you have another nutrition question for me?  Leave a comment down below.

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