As you might have noticed, there’s been a wave of nutrition-related articles being released in the past week. First to help people stock up with food, now on choosing immune boosting foods.
Spoiler alert: there are no specific foods, supplements or natural health products that will prevent infection with COVID-19. Proper handwashing, social distancing and other recommendations made by public health agencies remain the best ways to help slow the spread.
Having said that, there are ways that adults can support their immune systems. As our bodies age, our immune system naturally declines for a variety of reasons. By paying some attention to getting enough of specific nutrients, you can support your body in it’s work now, and for future health.
A bit about the immune system as we age
As our bodies get older, our immune system’s abilities decrease. As early as the age of 50, the immune system’s functions begin to deteriorate.
This is for multiple reasons, including a lifetime of oxidative stress. As well, our defences begin to lower: skin and mucous membranes are less able to defend against germs and immune cells are less effective meaning a longer period of inflammation in the body.
Older adults become more susceptible to infections like urinary tract infections, upper and lower respiratory tract infections, pressure sores and foodborne illnesses. During periods of illness, people with lowered immune systems have longer recovery times compared to younger adults, in part because of increased inflammation.
While everyone is paying extra attention to having more immune boosting foods, I’d like to highlight that these are foods that we should consider having more of, for so many reasons.
Especially because it often comes back to reducing inflammation in our bodies … which is linked to conditions like heart disease, diabetes risk, arthritis and cancers to name a few.
Nutrition-related factors and immunity
Nutrition deficiencies in older adults that may be linked to the immune system.
With age comes a higher risk of nutrient deficiencies. Specifically vitamins A, B12, C, D, E, folate, iron and zinc which are thought to play an important role in the ability of an aging immune system.
Keep reading to learn more about what foods have these nutrients as well as how you can easily get more of them in your eating pattern.
Immune boosting foods
To be clear, there are NO specific foods to eat or supplements to take that will prevent COVID-19.
There are a number of points I want to highlight:
- Undernutrition can affect the immune system – being deficient in vitamins or minerals or being malnourished can weaken your immune system.
- Having more of a specific vitamin or mineral won’t boost your immunity. It can support your immunity if your body currently doesn’t have enough.
- Being able to eat enough calories and protein may be the bigger problem for some older adults.
- Infection can increase the body’s need for some vitamins and minerals.
- Supplementation may be helpful for people with deficiencies, however professional advice is recommended. For example, chronic high intakes of zinc may actually suppress the immune system.
- Current labeling laws do not support the claim that any food or ingredient will boost your immune system.
- Many people can easily meet the recommended needs for most of these nutrients with their usual way of eating.
- There are multiple other factors in reducing risk of and decreasing effect of infections.
Food sources of immune-supporting nutrients
As you’ll can see below, having a generally well-rounded eating pattern, with variety, is a sure bet to supporting your immune system … and all of your body’s systems.
foods of animal origin: egg yolks, butter, milk (if fortified), beef liver, fish liver oils, carrots, sweet potatoes, broccoli, spinach, apricots
animal protein, spinach, bananas, beans, peanut butter, many vegetables
animal products, fortified foods such as cereals and grain products
citrus fruits, strawberries, cantaloupe, tomatoes, peppers, potatoes, broccoli
fortified options are the most common food sources including milk, margarine, cereals, naturally found in egg yolks, fatty fish, fish oil
Most Canadians are recommended to supplement with vitamin D. However, if you have kidney disease, please consult with your healthcare team.
foods of plant origin: vegetable oils, seeds, nuts, whole grains, dark green leafy veggies, sweet potatoes
green leafy veggies, orange juice, fortified grain products, liver
nuts, dried fruit, organ meats, dried beans, whole grain cereal
animal proteins (especially darker meats), grains, fortified cereals, dried fruit
green leafy veggies, fruits, grains, nuts, milk, meat, eggs, shellfish
mushrooms, Brazil nuts, sunflower seeds, pork, eggs, baked beans
meat, seafood, whole grains, legumes
Zinc may be a concern if you’ve had a poor eating pattern over a long period of time or if you’ve had excessive gastrointestinal losses.
How to eat more of the foods that support your immune system
Rather than tell you exactly what you need to eat to help support your immune system, take a moment to think about these questions:
- Are there any foods in the above lists that you usually don’t eat?
- Are you trying to eliminate certain food group because of a diet you’re following or because of a religious / cultural belief?
- If so, what other foods in your eating pattern can give you the vitamins and minerals your body needs?
Putting it in action
With some basic meal-planning strategies, you can fill your days with foods that will nourish your body and in turn support your immune system.
Aside from swapping regular potatoes to sweet potatoes as your starch, for example, many of the foods listed above can be used in more interesting ways. For example:
- homemade granola
- homemade hot cereal mix
- sweet potato pancakes
- trail mix
- roasted chickpeas
- fruit and yogurt popsicles
Many people I talk to say they love beans and think that this is one way to boost their nutrition. But they just don’t know how to cook them, other than in chilli! Here are a couple of my favourite websites for recipes:
This is yet another reason I’ve created the Complete Guide to Meal-Planning. Eating to support your overall health is hard if you don’t have a plan! Download it for free.
FAQs about immune boosting foods
What about garlic?
Available results from research are mixed and inconclusive about whether or not garlic supplementation can prevent or treat a common cold or flu.
It seems that in general, any effect on garlic’s ability to reduce the chance of getting or the severity / duration of the common cold is modest at best.
I take extra vitamin C – will that help?
In general, most trials have used a minimum dose of 200mg/d of vitamin C. Supplementation was used as this is an amount that is unlikely to be available from food sources alone.
Tobacco users might also consider supplementing with vitamin C on a regular basis as tobacco can increase your vitamin C needs.
For people with kidney stone or kidney functioning concerns, it’s best to talk with your healthcare team as vitamin C supplements can increase the risk of oxalate stones.
For the common cold
Research is showing that regularly taking vitamin C supplements might lower the severity and duration of the common cold slightly in the general public, but not lower your chance of getting a cold.
For people who took 200mg or more/day vitamin C before having symptoms, this was the case. However, those who started taking high doses of vitamin C after symptoms appeared did not have shorter or less severe colds compared to those taking a placebo.
Routine vitamin C supplementation may reduce the chance of getting pneumonia as well as the severity for those who did get pneumonia. A wide range of doses were trialled with 200mg/day showing a possible reduction in severity.
But I should avoid sugar though, right?
With only a couple of studies available, there is not enough evidence to suggest that sugar directly affects the immune system.
Having said that, one question to ask yourself is if you are choosing foods or beverages that are high in simple sugars instead of items that are power-packed with nutrients known to support your body’s functions?
What about probiotics?
This is a huge area of interest when it comes to many parts of our health.
At this time, there is little high quality evidence to support a recommendation for probiotics for protection against infection or for reducing the effect.
In addition, because older adults are more likely to be immunosuppressed, probiotic use should be discussed with the healthcare team.
Other factors of immunity
Physical activity cannot be overlooked as an important part of maintaining the immune system with age. Compared to older adults who are sedentary, those those participate regularly in moderate-intensity exercise are less likely to have infections.
Too little sleep and too much stress impact the immune system, especially over the long run.
Having blood sugars that are higher than your target can also increase risks of a variety of infections. Luckily, the many of foods listed above can help with keeping blood sugars in check as well as reducing inflammation.
Food safety is so often over-looked. Especially in this time where people have (possibly) over-stocked cupboards. And especially for older adults. We hate the idea of wasting food, however if our immune system is busy dealing with spoiled food, it can’t also be defending us against other possible infections.
Take-aways about immune boosting foods
First and foremost, continue to question who it is that you’re getting your nutrition-related information from. Misinformation is wide, especially when it comes to claims about immunity and supplements.
Secondly, eating a well balanced diet full of a variety of foods can easily support your immune system, as well as all of your body’s systems. While there may not be any specific immune boosting foods, there are a number of nutrition-related strategies that can help your immune system out and get you through an illness if you do become infected.
Lastly, our immune systems are complex! Food alone cannot prevent you from becoming ill or getting infections. Many other factors, in addition to proper hand hygiene practices, also play a part.
If this is something you have questions about, I’m here to help. Just send me a message about what you find challenging with this.
Angela Hubbard is a Registered Dietitian (RD) and Certified Diabetes Educator (CDE) with 10 years experience working in the field of nutrition. Her work focuses on helping people take back control of their health & weight … before it feels like their health controls their life. In her off time she loves swapping recipes, creating and exploring Northern BC life with her young family.