Fruits and Vegetables for the Immune System: Who Benefits Most?

Updated: Aug 24, 2020

You don't need to hear from anybody you should eat your fruits and veggies. Your mom made that very clear while you were growing up.

But, how helpful are they exactly in a pandemic?

Can fruits and vegetables contribute to protecting you from COVID-19 or, perhaps, from more dangerous viruses lurking around the corner?

In short, yes.

However, some people benefit much more than others.

In this article you will find why it would be wise to keep your fruit and veggie drawers well-stocked, and who should DEFINITELY build a long-term intimate relationship with these colorful little superheroes.


  1. Is Losing Weight a Bad Thing?

  2. The Devil (of Age) Is in the Details

  3. Indispensable

  4. Pregnancy and the Bizarre Effect of Vegetables

  5. The 4 Best Kinds of Fruits and Vegetables

  6. The Effortless Creation of a Successful Habit

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This article is a part of the upcoming book:

Immunity Hi, Virus Bye-Bye: Proven Strategies to Optimize Your Immune Health During Pandemic Times.

It will be one of the most extensive works on natural immune optimization on the market today.

It contains:

  • The best dietary strategies that improve our immune health;

  • The best lifestyle strategies that improve our immune health;

  • How to successfully implement new changes;

  • How to successfully create desirable habits;

  • Empowering and motivational messages.

The good news?

You have a chance to get this book for FREE.

–Not only that–

You can get another book for free RIGHT NOW: COVID-19 Home Remedies and Prevention: Myths & Truths.

This book explores the accuracy of the most common beliefs surrounding COVID-19 home remedies and prevention worldwide.

Get the FREE book here.

If you download COVID-19 Home Remedies and Prevention, you will automatically receive a notice when Immunity Hi, Virus Bye-Bye is up for release.

The most important information from the upcoming book, Immunity Hi, Virus Bye-Bye, is displayed here in the article below.

Regardless, some parts lack in-depth explanations because they would detract from the topic at hand and create an immensely long article. They are, however, all covered in the book. 

To give you a heads up, they are marked here with an asterisk(*).

1. Is Losing Weight a Bad Thing?

People who try to lose weight get sick the most. That was the surprising outcome from a questionnaire published in the Australian Women’s Weekly magazine in 1978. (1)

The questionnaire sought details about the individuals in the household who were most and least prone to respiratory infections. They received information from 8470 individuals.

The people who were trying to lose weight got sick the most; almost 3 times (2.94) a year. This sounds contradictory, because a healthy weight corresponds with a better immune system after all.*

The problem lies most likely in the way they tried to lose weight. We know at least some of them were on low-carbohydrate diets.

Why is that relevant?

A low-carb diet could potentially be low in vegetables, although it isn’t completely certain because this data is missing. What is for certain though, is that low carb diets are generally low in fruit.

Thankfully, from the people who completed the questionnaire there were also people who consumed a high-fruit-and-vegetable diet so we can compare the two groups.

The first connection between immune health and diet shows here:

The people who consumed the most fruit and vegetables got sick significantly less; almost 2 times (1.95) a year.

What about the people consuming a more average diet?

They fell somewhere in the middle getting sick 2.53 times a year on average.

These statistics are quite outdated some would argue.

How does it compare to more recent science?

Before comparing the results to more recent science, there is one more interesting statistic from the questionnaire that stands out.

This statistic is relevant to what is happening during the COVID-19 pandemic.

What did they find?

The older one got the higher the risk was for contracting a respiratory infection.

2. The Devil (of Age) Is in the Details

This data is exactly in line with what we know today and have known for quite a while:

Elderly people are more vulnerable and susceptible to virus infections.

This becomes clear from the mortality rate caused by the influenza virus every year.

The elderly form our most vulnerable population.

Not surprisingly, therefore, that the mortality rate among COVID-19 infected people who are older is higher as well. As a matter of fact, the older one gets the higher the risk.

People older than 60 are at a higher risk of dying from a COVID-19 infection, but this risk increases even further if one passes the age of 80. (2, 3)

We should not form the conclusion that the elderly are condemned to die from COVID-19 or any other infectious disease.

What would be a correct assumption, however, is:

The older we get the more we should take care of our health and immune system.

It’s very encouraging that there are a multitude of ways to optimize our immune system from different angles.*

There is a strong connection between immune health and exercise or physical activity, regardless of age.

Elderly people who have a higher intake of fruits and vegetables benefit just as much as the rest of the population. One way this shows is in the improved response to vaccines. (4)

A study among people that were 65-85 years old showed that eating more vegetables and fruit had a substantial effect on their micronutrient status.

To put it more simply: their vitamin and mineral status improved. (4)

Why is that a good thing?

Our vitamin and mineral status is clearly associated with our immune health.*

The elderly are not the only vulnerable group...

3. Pregnancy and the Bizarre Effect of Vegetables

Pregnant women are also a vulnerable group that would benefit more from having a good immune system.

In a study involving over 1000 pregnant women, vegetables unexpectedly appeared unprotective. There was however a more shocking part:

Vegetables seemed to be harmful instead and increase the risk of contracting a respiratory infection.

This is highly peculiar because the health benefits that are associated with vegetable intake are well established.

The scientists thought they found the explanation...

They stated the vegetable intake could have still been too low, because pregnant women have increased nutrient requirements.

Hence, the results might not be accurate.

The scientists also mentioned that the women had to recall what they consumed long after they gave birth. It’s harder to recall something that happened a while ago. This is called ‘recall bias’.

What about fruit intake?

Fruit is usually easier to recall because 1 piece of fruit generally equates to 1 serving, whereas vegetable serving sizes are harder to estimate.

Surprisingly, also fruit didn’t show benefits in the protection against respiratory infections. On the other hand, there was no increased risk either, which is peculiar because fruit—like vegetables—is associated with health benefits.

In other words, vegetables and fruit may strangely enough not offer protection for pregnant women against virus infections. At least, not individually...

Although there may have been some recall bias, when the scientists looked at the combination of both vegetable AND fruit intake, the results were suddenly very different.

Over the course of 3-5 months the risk of contracting a virus infection was significantly reduced, namely by 27-38%. (5)

How can we explain these contrasting results?

One reason could be the food synergy concept; many phytochemicals, or nutrients, can have synergistic effects.*

Another reason could be that the total amount of servings of fruits and vegetables simply needs to be higher to confer any benefits, because of pregnant women's increased requirements.

As a matter of fact:

The women with the highest total amount of fruit and vegetable intake were most protected.

They consumed on average 8,5 servings of fruits and vegetables daily.

Coincidentally, more than 8 servings a day offers also significantly more protection against cardiovascular disease, the number 1 cause of death worldwide. (6)

Furthermore, the improvement in immune function is a wonderful addition in the middle of a pandemic.

Are only pregnant women and elderly at a higher risk?

No, there are other groups at a higher risk as well.

In a recent study, scientists analyzed the progression of COVID-19 in over a thousand patients.

4. Indispensable

What was the conclusion?

Those of us who have underlying health conditions, including hypertension, diabetes, cardiovascular disease, chronic respiratory disease, and cancer are at an increased risk for complications and death after having contracted a COVID-19 infection. (3)

Is an increased fruit and vegetable intake also protective for them?

If we want to learn the effect of fruits and vegetables on immune function in these vulnerable groups, it is important to look at people with various health conditions.

Fruits and vegetables are also associated with improved immune responses in these groups, but the results are much more intriguing...

A big meta-analysis, consisting of almost a 100 individual studies, showed increased consumption of fruits and vegetables not only improved the immune cell (white blood cell) profile,* it also lowered inflammation in a very important part of the body...

After a virus settles within the airways, an inflammatory reaction follows and makes us feel sick. More fruit and vegetables had beneficial effects on this airway inflammation. (6)

If we compare inflammation to an open wound, fruits and vegetables are like a soothing balm that alleviates the painful and burning sensations that arise as a result of the wound.

This is excellent news—in the midst of pandemic—for three reasons:

  1. An improved immune cell profile is more able to prevent a virus infection from occurring.

  2. An improved immune cell profile can deal with a virus infection (incl. COVID-19) more efficiently if the virus manages to sneak past our defenses.

  3. Reduced inflammation can reduce the severity of our symptoms.

5. The 4 Best Kinds of Fruits and Vegetables

Despite fruits and vegetables being salubrious and healthy, we should not eat an apple every day.

At least, not solely an apple.

To eat the same fruit every day without any variation is not a good strategy, because we limit our exposure to only a small variety of nutrients. Varying our fruits and vegetables instead is generally a good idea, since this way we get exposed to a wider variety of nutrients.

For example, if you do eat an apple everyday, make sure you vary with other types of fruit.

How many fruits and vegetables do we need to gain benefits in respect to immune function?

The servings consumed in the studies varied quite a lot, ranging from 5 to almost 9 servings daily. Since 5 servings daily is the minimum recommended amount in most countries, we should aim for, at least, 5 servings daily, but more is likely better. (7)

Especially if we want to protect ourselves against our number 1 killer: Heart disease.


Not all vegetables and fruits are created equal. It seems that specific fruits and vegetables may have more protective properties. (7)

In particular:

  • Cruciferous vegetables such as broccoli, cauliflower, kale and radish.

  • Dark-green leafy vegetables such as kale, bok choy, mustard greens and arugula.

  • Citrus fruit such as orange, mandarin, pomelo, grapefruit, lemon and lime.

  • Dark-colored berries such as these 4 immunity-boosting fruits: blackberries, blueberries, raspberries and açai berries.

This does not mean that other fruits and vegetables are not worth it.

On the contrary!

Including a variety of fruits and vegetables is always a splendid idea. Nonetheless, it is definitely beneficial to include the fruits and vegetables just mentioned on a regular basis.

Cruciferous vegetables, for example, which happen to include various green leafy vegetables, have a special effect on our immune system, hence their nickname, "immunity vegetables."

Most of us don’t consume even the recommended amount of fruits and vegetables. For this reason it would be realistic to make small incremental steps to slowly increase our consumption to at least 5 servings daily.*

This is exactly what Josephine accomplished (see below).

6. The Effortless Creation of a Successful Habit

Josephine is a single-mother of two. She has two daughters, a 10-year-old and a 12-year-old. Josephine does the bookkeeping for a well-known law firm. Finding the time to eat a healthy diet hasn’t been a big priority for her, since it’s challenging enough to juggle between her day job at the firm and taking care of her kids.

For the sake of her children, she tries to her best to make somewhat wholesome meals, but when they’re not around she simply doesn’t bother, because she feels exhausted.

Although Josephine isn’t worried about COVID-19 perse, she is worried about possibly having to get checked out and having to be quarantined. As a result, she wouldn’t be able to be there for her kids.

This has given her the motivation to start taking better care of herself. Plus, She’s kind of tired of being tired all the time, anyway.

Josephine’s main problem is that she had followed some diets in the past, but they all failed. Josephine found the longer she was on a diet, the more difficult it became to stick to it. Eventually, she would give up and return to her old lifestyle.

She read somewhere in Women’s Health magazine, it is easier to start small and go more slowly in order to make lasting changes. She decided to try it out.

Josephine decided to start eating two small pieces of fruit a day. She rarely ate fruit, but she felt this would be a realistic change.

A friend told her that eating some fruit before a meal will make you eat fewer total calories of that particular meal.

Therefore, to benefit most, she would eat the fruit right before her lunch, since this was her most unhealthy meal – it often consisted of pastry.

Josephine told her kids about her plan, and they made sure she wouldn’t leave home without taking two pieces of fruit.

The next two weeks were surprisingly easy, with the exception of the weekends where she needed a little reminder of her kids.

Because Josephine felt comfortable enough, she aimed for two regular or large-sized pieces of fruit.

She noticed that by eating the fruit before a meal, she indeed consumed less food during that meal.

Four weeks in, Josephine was excited to see she lost two pounds. It didn’t seem like much, but considering everything had been so effortless, this was amazing news.

Up until this point, besides the addition of fruit, she still hadn’t modified her meal, but that was about to change.

The success she had so far, motivated her to revitalize her lunch. She set a new goal for herself: From now on, she would have a meal salad for lunch on Mondays, Wednesdays and Fridays. 

Josephine reminded herself it’s good to go slowly and, by doing so, increase her chances of success. That’s why she left the other days unchanged.

She chose a salad, so she could also increase her vegetable intake.

Just two months after Josephine started, she lost two more pounds and felt more energized.

She felt she still had a long way to go, but these these small successful implementations motivated Josephine to continue building small healthy habits, one at a time. 

Bottom line

There is a clear link between fruits and vegetables and the immune system.

Higher vegetable and fruit consumption is associated with better protection against virus infections via better immune health. That means, fruit and veggies are of tremendous added value in pandemic times.

People at higher risk benefit especially:

  • People older than 60

  • People with underlying conditions or chronic diseases

  • Pregnant women

The majority of people don’t consume enough servings of fruits and vegetables, so there is a lot of room for optimizing our immune system.

The minimal recommended amount in many countries is a minimal intake of 5 servings or about 800g per day for general health. We don’t know the optimal intake for our immune system, but it makes sense to strive for at least 5 servings per day.

To prevent chronic disease like coronary heart disease, we should consume at least 8 servings per day. (8) It may be advisable to aim higher, especially if there are underlying conditions present. However, the most important thing is to implement change.

A slight change is better than no change. Set a realistic goal for yourself and go from there.

Although all kinds of fruits and vegetables are great choices, don’t limit yourself to only a few varieties.

Finally, regularly include green leafy vegetables, cruciferous vegetables, citrus fruits and berries, since they may have more protective properties and they are high in antioxidants, which benefits our little protectors, the immune cells.*

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