Fact or Fiction? Nutrition and Immunity

Angela Charlton R.D.-N.'s picture
By Angela Charlton... on December 3, 2020

With flu season starting while COVID-19 cases continue to rise, it's natural to be looking for ways to keep your immune system strong this winter. 

Much of the advice going around focuses on food and nutrition—and since winter is comfort-food season, too, it's certainly important to stay mindful of of what we're eating.    

But, we also need to take some of the suggestions we see or hear with a grain of salt. This is especially true of some "preventive" or "immune-boosting" products that unscrupulous marketers may try to push.
Let’s take a look at some claims about food and immunity and then separate fact from fiction together—so we can support our health the smart and safe way this season!
I Can “Boost” My Immune System by Eating Certain Foods 
This is fiction.
Good nutrition does play a role in supporting a healthy immune system as part of a healthy lifestyle.

But there is no one food or combination of foods, or any particular vitamin, mineral or other nutrient, that can “boost” your immune system.
In fact, we don’t necessarily want to “boost” the immune system in the sense of making it stronger or more powerful than normal. An overreactive immune response can be dangerous!
Instead, the goal should be to support the immune system by providing the body with what it needs for optimal overall health.

MyPlate illustration showing a plate half-filled with vegetables, one-quarter filled with meat and one-quarter filled with grains, with a glass of milk on the side.
This is what a healthy plate looks like!

A Balanced Diet Best Supports My Immune System
A balanced diet provides a variety of nutrients that help support all the body’s systems, including the immune system.
So what does a balanced diet look like?
MyPlate is one tool you can use to help with visualizing a healthy diet.
When you look at your plate before you eat, you should see half of it filled with fruits and veggies, one-quarter of it filled with grains and one-quarter of it filled with protein. Now that’s a well-balanced meal!
Whenever possible, fill your plate with:

  • Whole grains
  •  Lean proteins
  • Anti-inflammatory fats
  • Cultured dairy or dairy alternatives (think yogurt and kefir)

Evidence shows that these foods benefit your overall health. 
All Foods Can Fit in a Balanced Diet
Of course, sugary and processed foods should be kept to a minimum. You don’t want to fill up on these at the expense of healthier whole foods.
In high quantities these foods can contribute to chronic inflammation and stress, neither of which are helpful to your immune system.
But, there is room for the occasional treat in a balanced diet.
I Need To Take Supplements to Support My Immune System 
The best (and most inexpensive!) way to get the nutrients you need is by eating a well-balanced diet.

Fresh peppers are rinsed in a colander.
Washing fresh produce before eating or cooking it is an important part of food hygiene.

If you are concerned that you may not be getting enough of a certain vitamin or mineral in your diet, ask your health care provider whether taking supplements could be beneficial.
If you do need to take vitamins or supplements, look for products with a certification seal from an organization such as consumerlab.com, U.S. Pharmacopeia or NSF International on the packaging. This verifies that the product contains what the label says it does, and that it is free of contaminants. 
Be especially careful with herbal supplements. These can sometimes be contaminated with chemicals like pesticides, and some do not contain what the package claims.

Mega Doses of Vitamins Can Keep Me From Getting Sick
Taking more than the recommended dose of any vitamin can cause side effects and can even be dangerous.
It’s true that vitamin C, vitamin D and zinc are important to immune function.
Still, you should always take vitamins and supplements as instructed, and ask your health care provider if you have any questions about the appropriate dosage for you. 
Probiotics Defend Against Viruses  
This one is both fact and fiction.
It’s true that probiotics contribute to a healthy intestinal environment—which in turn may contribute to immune health.

A few studies have linked probiotics to a reduced risk of respiratory infections. But much more evidence is needed overall, and no studies have tested whether probiotics could reduce the risk of getting COVID-19 in particular.
The bottom line: It definitely won’t hurt to add probiotic-rich foods to your daily diet—these foods are usually healthy in general! Just don’t think of them as a “magic pill” for avoiding illnesses.
Some good probiotic-rich foods to try include:

  • Cultured dairy like yogurt and kefir
  • Pickled vegetables like sauerkraut and kimchi
  • Fermented beans like tempeh and miso
  • Fresh sourdough bread

Food Hygiene Helps Keep Me Healthy
Food hygiene means:

  • Washing your hands before you eat or prepare meals (and after returning from the grocery store)
  • Disinfecting grocery carts with a sanitizing wipe before use 
  • Washing fresh produce after buying
  • Keeping the surfaces you eat, cook and prepare food on clean

These steps can help reduce the risks of catching a respiratory illness like the flu or COVID-19 and food-borne illnesses like E. Coli, norovirus or others.
Sleep, Exercise and Stress-Management Are Just as Important as What I Eat
Good nutrition is an important piece of the immune-supportive puzzle—but without the other pieces, it can’t do as much good!
Along with your healthy balanced diet, aim for:

  • A good night’s sleep—that means seven to nine hours for adults, nine hours for kids
  • Physical activity—whether going for a walk or bike ride or following a YouTube workout in your living room
  • A manageable level of stress (yoga, breathing exercises and meditation can help)

It is known that high levels of stress can compromise the body’s ability to fight all infections. 
Sleep and exercise can help combat stress—as can some mood-boosting healthy eating habits!
We are all paying some extra attention to ways we can stay healthy lately. While food isn’t a cure-all, it is very much a powerful tool!
Angela Charlton, R.D.N., leads our Community Health and Outreach nutrition team and is a regular contributor to Carilion Living. 

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